bruh vsync griefs my laptop

.gitignore

@@ -1 +1,2 @@
 /target
+perf.data*

Cargo.toml

@@ -1,13 +1,38 @@
 [package]
-name = "gui"
-version = "0.1.0"
-edition = "2021"
+name = "iris"
+default-run = "test"
+version.workspace = true
+edition.workspace = true
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-pollster = "0.4.0"
-winit = "0.30.11"
-wgpu = "26.0.1"
-bytemuck = "1.23.1"
+iris-core = { workspace = true }
+iris-macro = { workspace = true }
+cosmic-text = { workspace = true }
+unicode-segmentation = { workspace = true }
+winit = { workspace = true }
+arboard = { workspace = true, features = ["wayland-data-control"] }
+pollster = { workspace = true }
+wgpu = { workspace = true }
+image = { workspace = true }
 
+[workspace]
+members = ["core", "macro"]
+
+[workspace.package]
+version = "0.1.0"
+edition = "2024"
+
+[workspace.dependencies]
+pollster = "0.4.0"
+winit = "0.30.12"
+wgpu = "27.0.1"
+bytemuck = "1.23.1"
+image = "0.25.6"
+cosmic-text = "0.15.0"
+unicode-segmentation = "1.12.0"
+fxhash = "0.2.1"
+arboard = "3.6.1"
+iris-core = { path = "core" }
+iris-macro = { path = "macro" }

TODO

@@ -0,0 +1,40 @@
+images
+    settings (sampler)
+
+text
+    figure out ways to speed up / what costs the most
+    resizing (per frame) is really slow (assuming painter isn't griefing)
+    j is weird / fix x offset
+
+masks r just made to bare minimum work
+
+scaling
+    could be just a simple scaling factor that multiplies abs
+    and need to ensure text uses raw abs and not scaled abs
+    naming? (pt, px)
+    want to keep (drawn) regions using px? or should I add another field to UiScalar/Vec
+    field could be best solution so redrawing stuff isn't needed & you can specify both as user
+
+WidgetRef<W> or smth instead of Id
+    enum that's either an Id or an actual concrete instance of W
+    painter takes them in instead of (or in addition to) id
+    then type wrapper widgets to contain them
+    allows for compile time optimization if a widget wrapper's inner is known at compile time
+        and the id of inner is not needed anywhere
+    maybe introduce InnerWidget trait to allow for editors to expose & modify inner type
+    maybe could also store a parent widget and keep using InnerWidget trait? unsure if possible
+
+really weird limitation:
+    I don't think you can currently remove an element from a parent and put it in a child of the same parent
+    because it removes the unused children after the entire parent redraw
+    but the child gets drawn during that, so it will think the child is still active !!!
+    or something like that idk, maybe I need a special enum for parent that includes a undecided state where it may or may not get redrawn by the parent
+    or just do ref counting and ensure all drawn things == 1 afterwards (seems like best way)
+    ok so I'm removing the limit for now
+
+don't forget I'm streaming
+
+tags
+vecs for each widget type?
+
+POTENTIAL BUG: closures that store IDs will not decrement the id!!! need to not increment id if moved into closure somehow??? wait no, need to decrement ID every time an event fn is added...... only if the id is used in it..??

core/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "iris-core"
+version.workspace = true
+edition.workspace = true
+
+[dependencies]
+winit = { workspace = true }
+wgpu = { workspace = true }
+bytemuck ={ workspace = true }
+image = { workspace = true }
+cosmic-text = { workspace = true }
+fxhash = { workspace = true }

core/src/attr.rs

@@ -0,0 +1,25 @@
+use crate::{HasUi, StateLike, WidgetIdFn, WidgetLike, WidgetRef};
+
+pub trait WidgetAttr<State, W: ?Sized> {
+    type Input;
+    fn run(state: &mut State, id: WidgetRef<W>, input: Self::Input);
+}
+
+pub trait Attrable<State, W: ?Sized, Tag> {
+    fn attr<A: WidgetAttr<State, W>>(self, input: A::Input) -> impl WidgetIdFn<State, W>;
+}
+
+impl<State: HasUi + StateLike<State>, WL: WidgetLike<State, Tag>, Tag>
+    Attrable<State, WL::Widget, Tag> for WL
+{
+    fn attr<A: WidgetAttr<State, WL::Widget>>(
+        self,
+        input: A::Input,
+    ) -> impl WidgetIdFn<State, WL::Widget> {
+        |state| {
+            let id = self.add(state);
+            A::run(state, id, input);
+            id
+        }
+    }
+}

core/src/event/ctx.rs

@@ -0,0 +1,116 @@
+use crate::{HasEvents, HasState, HasUi, StateLike, Ui, Widget, WidgetRef};
+use std::ops::{Deref, DerefMut};
+
+pub struct EventCtx<'a, State, Data> {
+    pub state: &'a mut State,
+    pub data: &'a mut Data,
+}
+
+pub struct EventIdCtx<'a, State, Data, W: ?Sized> {
+    pub widget: WidgetRef<W>,
+    pub state: &'a mut State,
+    pub data: &'a mut Data,
+}
+
+impl<State: HasUi, Data, W: ?Sized> Deref for EventIdCtx<'_, State, Data, W> {
+    type Target = State;
+
+    fn deref(&self) -> &Self::Target {
+        self.state
+    }
+}
+
+impl<State: HasUi, Data, W: ?Sized> DerefMut for EventIdCtx<'_, State, Data, W> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        self.state
+    }
+}
+
+impl<State: HasUi, Data, W: Widget> EventIdCtx<'_, State, Data, W> {
+    pub fn widget(&mut self) -> &mut W {
+        &mut self.state.get_mut()[self.widget]
+    }
+}
+
+impl<State: HasUi, Data, W: Widget> HasUi for EventIdCtx<'_, State, Data, W> {
+    fn get(&self) -> &Ui {
+        self.state.ui()
+    }
+
+    fn get_mut(&mut self) -> &mut Ui {
+        self.state.ui_mut()
+    }
+}
+
+impl<State: HasUi, Data, W: Widget> HasState for EventIdCtx<'_, State, Data, W> {
+    type State = State;
+}
+
+impl<State: HasEvents<State = State>, Data, W: Widget> HasEvents
+    for EventIdCtx<'_, State, Data, W>
+{
+    fn get(&self) -> &super::EventManager<Self::State> {
+        self.state.events()
+    }
+
+    fn get_mut(&mut self) -> &mut super::EventManager<Self::State> {
+        self.state.events_mut()
+    }
+}
+
+impl<State, Data, W: Widget> StateLike<State> for EventIdCtx<'_, State, Data, W> {
+    fn as_state(&mut self) -> &mut State {
+        self.state
+    }
+}
+
+// fn test() {
+//     use crate::*;
+//     struct ClientRsc;
+//     impl<State, Data> HasUi for EventCtx<'_, State, Data> {
+//         fn get(&self) -> &Ui {
+//             todo!()
+//         }
+//
+//         fn get_mut(&mut self) -> &mut Ui {
+//             todo!()
+//         }
+//     }
+//     fn on(_: impl for<'a> EventFn<ClientRsc, &'a mut i32>) {}
+//
+//     pub trait WidgetLike<State: HasUi, Tag>: Sized {
+//         type Widget: Widget + ?Sized + std::marker::Unsize<dyn Widget>;
+//
+//         fn add(self, state: &mut State) -> WidgetHandle<Self::Widget>;
+//
+//         fn with_id<W2>(
+//             self,
+//             f: impl FnOnce(&mut State, WidgetHandle<Self::Widget>) -> WidgetHandle<W2>,
+//         ) -> impl WidgetIdFn<State, W2> {
+//             move |state| {
+//                 let id = self.add(state);
+//                 f(state, id)
+//             }
+//         }
+//
+//         fn set_root(self, state: &mut State) {
+//             state.get_mut().root = Some(self.add(state));
+//         }
+//
+//         fn handles(self, state: &mut State) -> WidgetHandles<Self::Widget> {
+//             self.add(state).handles()
+//         }
+//     }
+//
+//     pub struct WidgetTag;
+//     impl<State: HasUi, W: Widget> WidgetLike<State, WidgetTag> for W {
+//         type Widget = W;
+//         fn add(self, state: &mut State) -> WidgetHandle<W> {
+//             state.get_mut().add_widget(self)
+//         }
+//     }
+//
+//     on(move |ctx| {
+//         ().add(ctx);
+//     });
+// }

core/src/event/manager.rs

@@ -0,0 +1,145 @@
+use crate::{
+    ActiveData, Event, EventCtx, EventFn, EventIdCtx, EventLike, IdLike, LayerId, Widget,
+    WidgetData, WidgetEventFn, WidgetId, WidgetRef,
+    util::{HashMap, TypeMap},
+};
+use std::{any::TypeId, rc::Rc};
+
+pub struct EventManager<State> {
+    types: TypeMap<dyn EventManagerLike<State>>,
+}
+
+impl<State> Default for EventManager<State> {
+    fn default() -> Self {
+        Self {
+            types: Default::default(),
+        }
+    }
+}
+
+impl<State: 'static> EventManager<State> {
+    pub fn get_type<E: EventLike>(&mut self) -> &mut TypeEventManager<State, E::Event> {
+        self.types.type_or_default()
+    }
+
+    pub fn register<W: Widget + ?Sized, E: EventLike>(
+        &mut self,
+        id: WidgetRef<W>,
+        event: E,
+        f: impl for<'a> WidgetEventFn<State, <E::Event as Event>::Data<'a>, W>,
+    ) {
+        self.get_type::<E>().register(id, event, f);
+    }
+
+    pub fn type_key<E: EventLike>() -> TypeId {
+        TypeId::of::<TypeEventManager<State, E::Event>>()
+    }
+}
+
+pub trait EventsLike {
+    fn remove(&mut self, id: WidgetId);
+    fn draw(&mut self, data: &WidgetData, active: &ActiveData);
+    fn undraw(&mut self, data: &WidgetData, active: &ActiveData);
+}
+
+impl<State: 'static> EventsLike for EventManager<State> {
+    fn remove(&mut self, id: WidgetId) {
+        for m in self.types.values_mut() {
+            m.remove(id);
+        }
+    }
+
+    fn draw(&mut self, data: &WidgetData, active: &ActiveData) {
+        for t in &data.event_mgrs {
+            self.types.get_mut(t).unwrap().draw(active);
+        }
+    }
+
+    fn undraw(&mut self, data: &WidgetData, active: &ActiveData) {
+        for t in &data.event_mgrs {
+            self.types.get_mut(t).unwrap().undraw(active);
+        }
+    }
+}
+
+pub trait EventManagerLike<State> {
+    fn remove(&mut self, id: WidgetId);
+    fn draw(&mut self, data: &ActiveData);
+    fn undraw(&mut self, data: &ActiveData);
+}
+
+type EventData<State, E> = (E, Rc<dyn for<'a> EventFn<State, <E as Event>::Data<'a>>>);
+pub struct TypeEventManager<State, E: Event> {
+    // TODO: reduce visiblity!!
+    pub active: HashMap<LayerId, HashMap<WidgetId, E::State>>,
+    map: HashMap<WidgetId, Vec<EventData<State, E>>>,
+}
+
+impl<State, E: Event> EventManagerLike<State> for TypeEventManager<State, E> {
+    fn remove(&mut self, id: WidgetId) {
+        self.map.remove(&id);
+        for layer in self.active.values_mut() {
+            layer.remove(&id);
+        }
+    }
+    fn draw(&mut self, data: &ActiveData) {
+        self.active
+            .entry(data.layer)
+            .or_default()
+            .entry(data.id)
+            .or_default();
+    }
+    fn undraw(&mut self, data: &ActiveData) {
+        if let Some(layer) = self.active.get_mut(&data.layer) {
+            layer.remove(&data.id);
+        }
+    }
+}
+
+impl<State, E: Event> Default for TypeEventManager<State, E> {
+    fn default() -> Self {
+        Self {
+            active: Default::default(),
+            map: Default::default(),
+        }
+    }
+}
+
+impl<State: 'static, E: Event> TypeEventManager<State, E> {
+    fn register<W: Widget + ?Sized>(
+        &mut self,
+        widget: WidgetRef<W>,
+        event: impl EventLike<Event = E>,
+        f: impl for<'a> WidgetEventFn<State, E::Data<'a>, W>,
+    ) {
+        let event = event.into_event();
+        self.map.entry(widget.id()).or_default().push((
+            event,
+            Rc::new(move |ctx| {
+                let mut test = EventIdCtx {
+                    widget,
+                    state: ctx.state,
+                    data: ctx.data,
+                };
+                f(&mut test);
+            }),
+        ));
+    }
+
+    pub fn run_fn<'a>(
+        &mut self,
+        id: impl IdLike,
+    ) -> impl for<'b> FnOnce(EventCtx<'_, State, E::Data<'b>>) + 'a {
+        let fs = self.map.get(&id.id()).cloned().unwrap_or_default();
+        move |ctx| {
+            for (e, f) in fs {
+                if e.should_run(ctx.data) {
+                    f(&mut EventCtx {
+                        state: ctx.state,
+                        data: ctx.data,
+                    })
+                }
+            }
+        }
+    }
+}

core/src/event/mod.rs

@@ -0,0 +1,41 @@
+mod ctx;
+mod manager;
+mod rsc;
+
+pub use ctx::*;
+pub use manager::*;
+pub use rsc::*;
+
+pub trait Event: Sized + 'static + Clone {
+    type Data<'a> = ();
+    type State: Default = ();
+    #[allow(unused_variables)]
+    fn should_run(&self, data: &mut Self::Data<'_>) -> bool {
+        true
+    }
+}
+
+pub trait EventLike {
+    type Event: Event;
+    fn into_event(self) -> Self::Event;
+}
+
+impl<E: Event> EventLike for E {
+    type Event = Self;
+
+    fn into_event(self) -> Self::Event {
+        self
+    }
+}
+
+pub trait EventFn<State, Data>: Fn(&mut EventCtx<State, Data>) + 'static {}
+impl<State, F: Fn(&mut EventCtx<State, Data>) + 'static, Data> EventFn<State, Data> for F {}
+
+pub trait WidgetEventFn<State, Data, W: ?Sized>:
+    Fn(&mut EventIdCtx<State, Data, W>) + 'static
+{
+}
+impl<State, F: Fn(&mut EventIdCtx<State, Data, W>) + 'static, Data, W: ?Sized>
+    WidgetEventFn<State, Data, W> for F
+{
+}

core/src/event/rsc.rs

@@ -0,0 +1,47 @@
+use crate::{
+    Event, EventCtx, EventLike, EventManager, HasUi, IdLike, Widget, WidgetEventFn, WidgetRef,
+};
+
+pub trait HasState {
+    type State: HasUi;
+}
+
+pub trait HasEvents: Sized + HasState + HasUi {
+    fn get(&self) -> &EventManager<Self::State>;
+    fn get_mut(&mut self) -> &mut EventManager<Self::State>;
+    fn events(&self) -> &EventManager<Self::State> {
+        HasEvents::get(self)
+    }
+    fn events_mut(&mut self) -> &mut EventManager<Self::State> {
+        HasEvents::get_mut(self)
+    }
+
+    fn register_event<W: Widget + ?Sized, E: EventLike>(
+        &mut self,
+        id: WidgetRef<W>,
+        event: E,
+        f: impl for<'a> WidgetEventFn<Self::State, <E::Event as Event>::Data<'a>, W>,
+    ) where
+        Self::State: 'static,
+    {
+        self.events_mut().register(id, event, f);
+        self.ui_mut()
+            .widgets
+            .data_mut(id)
+            .unwrap()
+            .event_mgrs
+            .insert(EventManager::<Self::State>::type_key::<E>());
+    }
+}
+
+pub trait RunEvents: HasEvents + HasState<State = Self> + 'static {
+    fn run_event<E: EventLike>(
+        &mut self,
+        id: impl IdLike,
+        data: &mut <E::Event as Event>::Data<'_>,
+    ) {
+        let f = self.events_mut().get_type::<E>().run_fn(id);
+        f(EventCtx { state: self, data })
+    }
+}
+impl<T: HasEvents + HasState<State = Self> + 'static> RunEvents for T {}

core/src/lib.rs

@@ -0,0 +1,35 @@
+#![feature(macro_metavar_expr_concat)]
+#![feature(const_ops)]
+#![feature(const_trait_impl)]
+#![feature(const_convert)]
+#![feature(map_try_insert)]
+#![feature(unboxed_closures)]
+#![feature(fn_traits)]
+#![feature(const_cmp)]
+#![feature(const_destruct)]
+#![feature(portable_simd)]
+#![feature(associated_type_defaults)]
+#![feature(unsize)]
+#![feature(coerce_unsized)]
+
+mod attr;
+mod event;
+mod num;
+mod orientation;
+mod primitive;
+mod render;
+mod ui;
+mod widget;
+
+pub mod util;
+
+pub use attr::*;
+pub use event::*;
+pub use num::*;
+pub use orientation::*;
+pub use primitive::*;
+pub use render::*;
+pub use ui::*;
+pub use widget::*;
+
+pub type UiColor = primitive::Color<u8>;

core/src/num.rs

@@ -0,0 +1,49 @@
+use crate::util::Vec2;
+use std::marker::Destruct;
+
+pub const trait UiNum {
+    fn to_f32(self) -> f32;
+}
+
+impl const UiNum for f32 {
+    fn to_f32(self) -> f32 {
+        self
+    }
+}
+
+impl const UiNum for u32 {
+    fn to_f32(self) -> f32 {
+        self as f32
+    }
+}
+
+impl const UiNum for i32 {
+    fn to_f32(self) -> f32 {
+        self as f32
+    }
+}
+
+pub const fn vec2(x: impl const UiNum, y: impl const UiNum) -> Vec2 {
+    Vec2::new(x.to_f32(), y.to_f32())
+}
+
+impl<T: const UiNum + Copy> const From<T> for Vec2 {
+    fn from(v: T) -> Self {
+        Self {
+            x: v.to_f32(),
+            y: v.to_f32(),
+        }
+    }
+}
+
+impl<T: const UiNum, U: const UiNum> const From<(T, U)> for Vec2
+where
+    (T, U): const Destruct,
+{
+    fn from((x, y): (T, U)) -> Self {
+        Self {
+            x: x.to_f32(),
+            y: y.to_f32(),
+        }
+    }
+}

core/src/orientation/align.rs

@@ -0,0 +1,200 @@
+use crate::vec2;
+
+use super::*;
+
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub struct Align {
+    pub x: Option<AxisAlign>,
+    pub y: Option<AxisAlign>,
+}
+
+impl Align {
+    pub const TOP_LEFT: RegionAlign = RegionAlign::TOP_LEFT;
+    pub const TOP_CENTER: RegionAlign = RegionAlign::TOP_CENTER;
+    pub const TOP_RIGHT: RegionAlign = RegionAlign::TOP_RIGHT;
+    pub const CENTER_LEFT: RegionAlign = RegionAlign::CENTER_LEFT;
+    pub const CENTER: RegionAlign = RegionAlign::CENTER;
+    pub const CENTER_RIGHT: RegionAlign = RegionAlign::CENTER_RIGHT;
+    pub const BOT_LEFT: RegionAlign = RegionAlign::BOT_LEFT;
+    pub const BOT_CENTER: RegionAlign = RegionAlign::BOT_CENTER;
+    pub const BOT_RIGHT: RegionAlign = RegionAlign::BOT_RIGHT;
+    pub const LEFT: CardinalAlign = CardinalAlign::LEFT;
+    pub const H_CENTER: CardinalAlign = CardinalAlign::H_CENTER;
+    pub const RIGHT: CardinalAlign = CardinalAlign::RIGHT;
+    pub const TOP: CardinalAlign = CardinalAlign::TOP;
+    pub const V_CENTER: CardinalAlign = CardinalAlign::V_CENTER;
+    pub const BOT: CardinalAlign = CardinalAlign::BOT;
+
+    pub fn tuple(&self) -> (Option<AxisAlign>, Option<AxisAlign>) {
+        (self.x, self.y)
+    }
+}
+
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub enum AxisAlign {
+    Neg,
+    Center,
+    Pos,
+}
+
+impl AxisAlign {
+    pub const fn rel(&self) -> f32 {
+        match self {
+            Self::Neg => 0.0,
+            Self::Center => 0.5,
+            Self::Pos => 1.0,
+        }
+    }
+}
+
+pub struct CardinalAlign {
+    axis: Axis,
+    align: AxisAlign,
+}
+
+impl CardinalAlign {
+    pub const LEFT: Self = Self::new(Axis::X, AxisAlign::Neg);
+    pub const H_CENTER: Self = Self::new(Axis::X, AxisAlign::Center);
+    pub const RIGHT: Self = Self::new(Axis::X, AxisAlign::Pos);
+    pub const TOP: Self = Self::new(Axis::Y, AxisAlign::Neg);
+    pub const V_CENTER: Self = Self::new(Axis::Y, AxisAlign::Center);
+    pub const BOT: Self = Self::new(Axis::Y, AxisAlign::Pos);
+
+    pub const fn new(axis: Axis, align: AxisAlign) -> Self {
+        Self { axis, align }
+    }
+}
+
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub struct RegionAlign {
+    pub x: AxisAlign,
+    pub y: AxisAlign,
+}
+
+impl RegionAlign {
+    pub const TOP_LEFT: Self = Self::new(AxisAlign::Neg, AxisAlign::Neg);
+    pub const TOP_CENTER: Self = Self::new(AxisAlign::Center, AxisAlign::Neg);
+    pub const TOP_RIGHT: Self = Self::new(AxisAlign::Pos, AxisAlign::Neg);
+    pub const CENTER_LEFT: Self = Self::new(AxisAlign::Neg, AxisAlign::Center);
+    pub const CENTER: Self = Self::new(AxisAlign::Center, AxisAlign::Center);
+    pub const CENTER_RIGHT: Self = Self::new(AxisAlign::Pos, AxisAlign::Center);
+    pub const BOT_LEFT: Self = Self::new(AxisAlign::Neg, AxisAlign::Pos);
+    pub const BOT_CENTER: Self = Self::new(AxisAlign::Center, AxisAlign::Pos);
+    pub const BOT_RIGHT: Self = Self::new(AxisAlign::Pos, AxisAlign::Pos);
+
+    pub const fn new(x: AxisAlign, y: AxisAlign) -> Self {
+        Self { x, y }
+    }
+    pub const fn rel(&self) -> Vec2 {
+        vec2(self.x.rel(), self.y.rel())
+    }
+}
+
+impl UiVec2 {
+    pub fn partial_align(&self, align: Align) -> UiRegion {
+        UiRegion {
+            x: if let Some(align) = align.x {
+                self.x.align(align)
+            } else {
+                UiSpan::FULL
+            },
+            y: if let Some(align) = align.y {
+                self.y.align(align)
+            } else {
+                UiSpan::FULL
+            },
+        }
+    }
+
+    pub fn align(&self, align: RegionAlign) -> UiRegion {
+        UiRegion {
+            x: self.x.align(align.x),
+            y: self.y.align(align.y),
+        }
+    }
+}
+
+impl Vec2 {
+    pub fn partial_align(&self, align: Align) -> UiRegion {
+        let s = UiVec2::from(*self);
+        UiRegion {
+            x: if let Some(align) = align.x {
+                s.x.align(align)
+            } else {
+                UiSpan::FULL
+            },
+            y: if let Some(align) = align.y {
+                s.y.align(align)
+            } else {
+                UiSpan::FULL
+            },
+        }
+    }
+
+    pub fn align(&self, align: RegionAlign) -> UiRegion {
+        let s = UiVec2::from(*self);
+        UiRegion {
+            x: s.x.align(align.x),
+            y: s.y.align(align.y),
+        }
+    }
+}
+
+impl UiScalar {
+    pub const fn align(&self, align: AxisAlign) -> UiSpan {
+        let rel = align.rel();
+        let mut start = UiScalar::rel(rel);
+        start.abs -= self.abs * rel;
+        start.rel -= self.rel * rel;
+        let mut end = UiScalar::rel(rel);
+        end.abs += self.abs * (1.0 - rel);
+        end.rel += self.rel * (1.0 - rel);
+        UiSpan { start, end }
+    }
+}
+
+impl From<RegionAlign> for Align {
+    fn from(region: RegionAlign) -> Self {
+        Self {
+            x: Some(region.x),
+            y: Some(region.y),
+        }
+    }
+}
+
+impl From<Align> for RegionAlign {
+    fn from(align: Align) -> Self {
+        Self {
+            x: align.x.unwrap_or(AxisAlign::Center),
+            y: align.y.unwrap_or(AxisAlign::Center),
+        }
+    }
+}
+
+impl From<CardinalAlign> for RegionAlign {
+    fn from(align: CardinalAlign) -> Self {
+        Align::from(align).into()
+    }
+}
+
+impl From<CardinalAlign> for Align {
+    fn from(cardinal: CardinalAlign) -> Self {
+        let align = Some(cardinal.align);
+        match cardinal.axis {
+            Axis::X => Self { x: align, y: None },
+            Axis::Y => Self { x: None, y: align },
+        }
+    }
+}
+
+impl const From<RegionAlign> for UiVec2 {
+    fn from(align: RegionAlign) -> Self {
+        Self::rel(align.rel())
+    }
+}
+
+impl RegionAlign {
+    pub const fn pos(self) -> UiVec2 {
+        UiVec2::from(self)
+    }
+}

core/src/orientation/axis.rs

@@ -0,0 +1,115 @@
+use super::*;
+
+#[derive(Copy, Clone, Eq, PartialEq)]
+pub enum Axis {
+    X,
+    Y,
+}
+
+impl std::ops::Not for Axis {
+    type Output = Self;
+
+    fn not(self) -> Self::Output {
+        match self {
+            Self::X => Self::Y,
+            Self::Y => Self::X,
+        }
+    }
+}
+
+#[derive(Clone, Copy, Eq, PartialEq)]
+pub struct Dir {
+    pub axis: Axis,
+    pub sign: Sign,
+}
+
+impl Dir {
+    pub const fn new(axis: Axis, dir: Sign) -> Self {
+        Self { axis, sign: dir }
+    }
+
+    pub const LEFT: Self = Self::new(Axis::X, Sign::Neg);
+    pub const RIGHT: Self = Self::new(Axis::X, Sign::Pos);
+    pub const UP: Self = Self::new(Axis::Y, Sign::Neg);
+    pub const DOWN: Self = Self::new(Axis::Y, Sign::Pos);
+}
+
+#[derive(Clone, Copy, Eq, PartialEq)]
+pub enum Sign {
+    Neg,
+    Pos,
+}
+
+impl Vec2 {
+    pub fn axis(&self, axis: Axis) -> f32 {
+        match axis {
+            Axis::X => self.x,
+            Axis::Y => self.y,
+        }
+    }
+
+    pub fn axis_mut(&mut self, axis: Axis) -> &mut f32 {
+        match axis {
+            Axis::X => &mut self.x,
+            Axis::Y => &mut self.y,
+        }
+    }
+
+    pub const fn from_axis(axis: Axis, aligned: f32, ortho: f32) -> Self {
+        Self {
+            x: match axis {
+                Axis::X => aligned,
+                Axis::Y => ortho,
+            },
+            y: match axis {
+                Axis::Y => aligned,
+                Axis::X => ortho,
+            },
+        }
+    }
+}
+
+pub const trait AxisT {
+    fn get() -> Axis;
+}
+
+pub struct XAxis;
+impl const AxisT for XAxis {
+    fn get() -> Axis {
+        Axis::X
+    }
+}
+
+pub struct YAxis;
+impl const AxisT for YAxis {
+    fn get() -> Axis {
+        Axis::Y
+    }
+}
+
+#[derive(Clone, Copy, Debug, Default)]
+pub struct BothAxis<T> {
+    pub x: T,
+    pub y: T,
+}
+
+impl<T> BothAxis<T> {
+    pub const fn axis<A: const AxisT>(&mut self) -> &mut T {
+        match A::get() {
+            Axis::X => &mut self.x,
+            Axis::Y => &mut self.y,
+        }
+    }
+    pub fn take_axis<A: const AxisT>(self) -> T {
+        match A::get() {
+            Axis::X => self.x,
+            Axis::Y => self.y,
+        }
+    }
+    pub fn axis_dyn(&mut self, axis: Axis) -> &mut T {
+        match axis {
+            Axis::X => &mut self.x,
+            Axis::Y => &mut self.y,
+        }
+    }
+}

core/src/orientation/len.rs

@@ -0,0 +1,198 @@
+use super::*;
+use crate::{UiNum, util::impl_op};
+
+#[derive(Debug, Default, Clone, Copy, PartialEq)]
+pub struct Size {
+    pub x: Len,
+    pub y: Len,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct Len {
+    pub abs: f32,
+    pub rel: f32,
+    pub rest: f32,
+}
+
+impl<N: UiNum> From<N> for Len {
+    fn from(value: N) -> Self {
+        Len::abs(value.to_f32())
+    }
+}
+
+impl<Nx: UiNum, Ny: UiNum> From<(Nx, Ny)> for Size {
+    fn from((x, y): (Nx, Ny)) -> Self {
+        Self {
+            x: x.into(),
+            y: y.into(),
+        }
+    }
+}
+
+impl From<Len> for Size {
+    fn from(value: Len) -> Self {
+        Self { x: value, y: value }
+    }
+}
+
+impl Size {
+    pub const ZERO: Self = Self {
+        x: Len::ZERO,
+        y: Len::ZERO,
+    };
+
+    pub const REST: Self = Self {
+        x: Len::REST,
+        y: Len::REST,
+    };
+
+    pub fn abs(v: Vec2) -> Self {
+        Self {
+            x: Len::abs(v.x),
+            y: Len::abs(v.y),
+        }
+    }
+
+    pub fn rel(v: Vec2) -> Self {
+        Self {
+            x: Len::rel(v.x),
+            y: Len::rel(v.y),
+        }
+    }
+
+    pub fn rest(v: Vec2) -> Self {
+        Self {
+            x: Len::rest(v.x),
+            y: Len::rest(v.y),
+        }
+    }
+
+    pub fn to_uivec2(self) -> UiVec2 {
+        UiVec2 {
+            x: self.x.apply_rest(),
+            y: self.y.apply_rest(),
+        }
+    }
+
+    pub fn from_axis(axis: Axis, aligned: Len, ortho: Len) -> Self {
+        match axis {
+            Axis::X => Self {
+                x: aligned,
+                y: ortho,
+            },
+            Axis::Y => Self {
+                x: ortho,
+                y: aligned,
+            },
+        }
+    }
+
+    pub fn axis(&self, axis: Axis) -> Len {
+        match axis {
+            Axis::X => self.x,
+            Axis::Y => self.y,
+        }
+    }
+}
+
+impl Len {
+    pub const ZERO: Self = Self {
+        abs: 0.0,
+        rel: 0.0,
+        rest: 0.0,
+    };
+
+    pub const REST: Self = Self {
+        abs: 0.0,
+        rel: 0.0,
+        rest: 1.0,
+    };
+
+    pub fn apply_rest(&self) -> UiScalar {
+        UiScalar {
+            rel: self.rel + if self.rest > 0.0 { 1.0 } else { 0.0 },
+            abs: self.abs,
+        }
+    }
+
+    pub fn abs(abs: impl UiNum) -> Self {
+        Self {
+            abs: abs.to_f32(),
+            rel: 0.0,
+            rest: 0.0,
+        }
+    }
+    pub fn rel(rel: impl UiNum) -> Self {
+        Self {
+            abs: 0.0,
+            rel: rel.to_f32(),
+            rest: 0.0,
+        }
+    }
+    pub fn rest(ratio: impl UiNum) -> Self {
+        Self {
+            abs: 0.0,
+            rel: 0.0,
+            rest: ratio.to_f32(),
+        }
+    }
+}
+
+pub mod len_fns {
+    use super::*;
+
+    pub fn abs(abs: impl UiNum) -> Len {
+        Len {
+            abs: abs.to_f32(),
+            rel: 0.0,
+            rest: 0.0,
+        }
+    }
+    pub fn rel(rel: impl UiNum) -> Len {
+        Len {
+            abs: 0.0,
+            rel: rel.to_f32(),
+            rest: 0.0,
+        }
+    }
+    pub fn rest(ratio: impl UiNum) -> Len {
+        Len {
+            abs: 0.0,
+            rel: 0.0,
+            rest: ratio.to_f32(),
+        }
+    }
+}
+
+impl_op!(Len Add add; abs rel rest);
+impl_op!(Len Sub sub; abs rel rest);
+
+impl_op!(Size Add add; x y);
+impl_op!(Size Sub sub; x y);
+
+impl Default for Len {
+    fn default() -> Self {
+        Self::rest(1.0)
+    }
+}
+
+impl std::fmt::Display for Size {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "({}, {})", self.x, self.y)
+    }
+}
+
+impl std::fmt::Display for Len {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        if self.abs != 0.0 {
+            write!(f, "{} abs;", self.abs)?;
+        }
+        if self.rel != 0.0 {
+            write!(f, "{} rel;", self.rel)?;
+        }
+        if self.rest != 0.0 {
+            write!(f, "{} rest;", self.rest)?;
+        }
+        Ok(())
+    }
+}

core/src/orientation/mod.rs

@@ -0,0 +1,11 @@
+mod align;
+mod axis;
+mod len;
+mod pos;
+
+use crate::util::Vec2;
+
+pub use align::*;
+pub use axis::*;
+pub use len::*;
+pub use pos::*;

core/src/orientation/pos.rs

@@ -0,0 +1,464 @@
+use std::{fmt::Display, hash::Hash, marker::Destruct};
+
+use super::*;
+use crate::{
+    UiNum,
+    util::{LerpUtil, impl_op},
+};
+
+#[repr(C)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, bytemuck::Pod, bytemuck::Zeroable, Default)]
+pub struct UiVec2 {
+    pub x: UiScalar,
+    pub y: UiScalar,
+}
+
+impl UiVec2 {
+    pub const ZERO: Self = Self {
+        x: UiScalar::ZERO,
+        y: UiScalar::ZERO,
+    };
+
+    pub const fn new(x: UiScalar, y: UiScalar) -> Self {
+        Self { x, y }
+    }
+
+    pub const fn abs(abs: impl const Into<Vec2>) -> Self {
+        let abs = abs.into();
+        Self {
+            x: UiScalar::abs(abs.x),
+            y: UiScalar::abs(abs.y),
+        }
+    }
+
+    pub const fn rel(rel: impl const Into<Vec2>) -> Self {
+        let rel = rel.into();
+        Self {
+            x: UiScalar::rel(rel.x),
+            y: UiScalar::rel(rel.y),
+        }
+    }
+
+    pub const fn shift(&mut self, offset: impl const Into<UiVec2>) {
+        let offset = offset.into();
+        *self += offset;
+    }
+
+    pub const fn offset(mut self, offset: impl const Into<UiVec2>) -> Self {
+        self.shift(offset);
+        self
+    }
+
+    pub const fn within(&self, region: &UiRegion) -> UiVec2 {
+        UiVec2 {
+            x: self.x.within(&region.x),
+            y: self.y.within(&region.y),
+        }
+    }
+
+    pub const fn outside(&self, region: &UiRegion) -> UiVec2 {
+        UiVec2 {
+            x: self.x.outside(&region.x),
+            y: self.y.outside(&region.y),
+        }
+    }
+
+    pub fn axis_mut(&mut self, axis: Axis) -> &mut UiScalar {
+        match axis {
+            Axis::X => &mut self.x,
+            Axis::Y => &mut self.y,
+        }
+    }
+
+    pub fn axis(&self, axis: Axis) -> UiScalar {
+        match axis {
+            Axis::X => self.x,
+            Axis::Y => self.y,
+        }
+    }
+
+    pub fn to_abs(&self, rel: Vec2) -> Vec2 {
+        Vec2 {
+            x: self.x.to_abs(rel.x),
+            y: self.y.to_abs(rel.y),
+        }
+    }
+
+    pub const FULL_SIZE: Self = Self::rel(Vec2::ONE);
+
+    pub const fn from_axis(axis: Axis, aligned: UiScalar, ortho: UiScalar) -> Self {
+        match axis {
+            Axis::X => Self {
+                x: aligned,
+                y: ortho,
+            },
+            Axis::Y => Self {
+                x: ortho,
+                y: aligned,
+            },
+        }
+    }
+
+    pub fn get_abs(&self) -> Vec2 {
+        (self.x.abs, self.y.abs).into()
+    }
+
+    pub fn get_rel(&self) -> Vec2 {
+        (self.x.rel, self.y.rel).into()
+    }
+
+    pub fn abs_mut(&mut self) -> Vec2View<'_> {
+        Vec2View {
+            x: &mut self.x.abs,
+            y: &mut self.y.abs,
+        }
+    }
+}
+
+impl Display for UiVec2 {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "rel{};abs{}", self.get_rel(), self.get_abs())
+    }
+}
+
+impl_op!(UiVec2 Add add; x y);
+impl_op!(UiVec2 Sub sub; x y);
+
+impl const From<Vec2> for UiVec2 {
+    fn from(abs: Vec2) -> Self {
+        Self::abs(abs)
+    }
+}
+
+impl<T: const UiNum, U: const UiNum> const From<(T, U)> for UiVec2
+where
+    (T, U): const Destruct,
+{
+    fn from(abs: (T, U)) -> Self {
+        Self::abs(abs)
+    }
+}
+
+#[repr(C)]
+#[derive(Debug, Copy, Clone, PartialEq, bytemuck::Pod, Default, bytemuck::Zeroable)]
+pub struct UiScalar {
+    pub rel: f32,
+    pub abs: f32,
+}
+
+impl Eq for UiScalar {}
+impl Hash for UiScalar {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        state.write_u32(self.rel.to_bits());
+        state.write_u32(self.abs.to_bits());
+    }
+}
+
+impl_op!(UiScalar Add add; rel abs);
+impl_op!(UiScalar Sub sub; rel abs);
+
+impl UiScalar {
+    pub const ZERO: Self = Self { rel: 0.0, abs: 0.0 };
+    pub const FULL: Self = Self { rel: 1.0, abs: 0.0 };
+
+    pub const fn new(rel: f32, abs: f32) -> Self {
+        Self { rel, abs }
+    }
+
+    pub const fn rel(rel: f32) -> Self {
+        Self { rel, abs: 0.0 }
+    }
+
+    pub const fn abs(abs: f32) -> Self {
+        Self { rel: 0.0, abs }
+    }
+
+    pub const fn rel_min() -> Self {
+        Self::new(0.0, 0.0)
+    }
+
+    pub const fn rel_max() -> Self {
+        Self::new(1.0, 0.0)
+    }
+
+    pub const fn max(&self, other: Self) -> Self {
+        Self {
+            rel: self.rel.max(other.rel),
+            abs: self.abs.max(other.abs),
+        }
+    }
+
+    pub const fn min(&self, other: Self) -> Self {
+        Self {
+            rel: self.rel.min(other.rel),
+            abs: self.abs.min(other.abs),
+        }
+    }
+
+    pub const fn offset(mut self, amt: f32) -> Self {
+        self.abs += amt;
+        self
+    }
+
+    pub const fn within(&self, span: &UiSpan) -> Self {
+        let anchor = self.rel.lerp(span.start.rel, span.end.rel);
+        let offset = self.abs + self.rel.lerp(span.start.abs, span.end.abs);
+        Self {
+            rel: anchor,
+            abs: offset,
+        }
+    }
+
+    pub const fn outside(&self, span: &UiSpan) -> Self {
+        let rel = self.rel.lerp_inv(span.start.rel, span.end.rel);
+        let abs = self.abs - rel.lerp(span.start.abs, span.end.abs);
+        Self { rel, abs }
+    }
+
+    pub fn within_len(&self, len: UiScalar) -> Self {
+        self.within(&UiSpan {
+            start: UiScalar::ZERO,
+            end: len,
+        })
+    }
+
+    pub fn select_len(&self, len: UiScalar) -> Self {
+        len.within_len(*self)
+    }
+
+    pub const fn flip(&mut self) {
+        self.rel = 1.0 - self.rel;
+        self.abs = -self.abs;
+    }
+
+    pub const fn to(&self, end: Self) -> UiSpan {
+        UiSpan { start: *self, end }
+    }
+
+    pub const fn to_abs(&self, rel: f32) -> f32 {
+        self.rel * rel + self.abs
+    }
+}
+
+#[repr(C)]
+#[derive(Debug, Copy, Clone, PartialEq, bytemuck::Pod, bytemuck::Zeroable)]
+pub struct UiSpan {
+    pub start: UiScalar,
+    pub end: UiScalar,
+}
+
+impl UiSpan {
+    pub const FULL: Self = Self {
+        start: UiScalar::ZERO,
+        end: UiScalar::FULL,
+    };
+
+    pub const fn rel(rel: f32) -> Self {
+        Self {
+            start: UiScalar::rel(rel),
+            end: UiScalar::rel(rel),
+        }
+    }
+
+    pub const fn new(start: UiScalar, end: UiScalar) -> Self {
+        Self { start, end }
+    }
+
+    pub const fn flip(&mut self) {
+        self.start.flip();
+        self.end.flip();
+        std::mem::swap(&mut self.start.rel, &mut self.end.rel);
+        std::mem::swap(&mut self.start.abs, &mut self.end.abs);
+    }
+
+    pub const fn shift(&mut self, offset: UiScalar) {
+        self.start += offset;
+        self.end += offset;
+    }
+
+    pub const fn within(&self, parent: &Self) -> Self {
+        Self {
+            start: self.start.within(parent),
+            end: self.end.within(parent),
+        }
+    }
+
+    pub const fn outside(&self, parent: &Self) -> Self {
+        Self {
+            start: self.start.outside(parent),
+            end: self.end.outside(parent),
+        }
+    }
+
+    pub const fn len(&self) -> UiScalar {
+        self.end - self.start
+    }
+}
+
+#[repr(C)]
+#[derive(Debug, Copy, Clone, PartialEq, bytemuck::Pod, bytemuck::Zeroable)]
+pub struct UiRegion {
+    pub x: UiSpan,
+    pub y: UiSpan,
+}
+
+impl UiRegion {
+    pub const FULL: Self = Self {
+        x: UiSpan::FULL,
+        y: UiSpan::FULL,
+    };
+
+    pub const fn new(x: UiSpan, y: UiSpan) -> Self {
+        Self { x, y }
+    }
+
+    pub const fn rel(rel: Vec2) -> Self {
+        Self {
+            x: UiSpan::rel(rel.x),
+            y: UiSpan::rel(rel.y),
+        }
+    }
+    pub const fn within(&self, parent: &Self) -> Self {
+        Self {
+            x: self.x.within(&parent.x),
+            y: self.y.within(&parent.y),
+        }
+    }
+    pub const fn outside(&self, parent: &Self) -> Self {
+        Self {
+            x: self.x.outside(&parent.x),
+            y: self.y.outside(&parent.y),
+        }
+    }
+
+    pub const fn axis(&mut self, axis: Axis) -> &UiSpan {
+        match axis {
+            Axis::X => &self.x,
+            Axis::Y => &self.y,
+        }
+    }
+
+    pub const fn axis_mut(&mut self, axis: Axis) -> &mut UiSpan {
+        match axis {
+            Axis::X => &mut self.x,
+            Axis::Y => &mut self.y,
+        }
+    }
+
+    pub const fn flip(&mut self, axis: Axis) {
+        match axis {
+            Axis::X => self.x.flip(),
+            Axis::Y => self.y.flip(),
+        }
+    }
+
+    pub fn shift(&mut self, offset: impl Into<UiVec2>) {
+        let offset = offset.into();
+        self.x.shift(offset.x);
+        self.y.shift(offset.y);
+    }
+
+    pub fn offset(mut self, offset: impl Into<UiVec2>) -> Self {
+        self.shift(offset);
+        self
+    }
+
+    pub fn to_px(&self, size: Vec2) -> PixelRegion {
+        PixelRegion {
+            top_left: self.top_left().get_rel() * size + self.top_left().get_abs(),
+            bot_right: self.bot_right().get_rel() * size + self.bot_right().get_abs(),
+        }
+    }
+
+    pub const fn center(&self) -> UiVec2 {
+        Align::CENTER.pos().within(self)
+    }
+
+    pub const fn size(&self) -> UiVec2 {
+        UiVec2 {
+            x: self.x.len(),
+            y: self.y.len(),
+        }
+    }
+
+    pub const fn top_left(&self) -> UiVec2 {
+        UiVec2 {
+            x: self.x.start,
+            y: self.y.start,
+        }
+    }
+
+    pub const fn bot_right(&self) -> UiVec2 {
+        UiVec2 {
+            x: self.x.end,
+            y: self.y.end,
+        }
+    }
+
+    pub const fn from_axis(axis: Axis, aligned: UiSpan, ortho: UiSpan) -> Self {
+        Self {
+            x: match axis {
+                Axis::X => aligned,
+                Axis::Y => ortho,
+            },
+            y: match axis {
+                Axis::X => ortho,
+                Axis::Y => aligned,
+            },
+        }
+    }
+}
+
+impl Display for UiRegion {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "{} -> {} (size: {})",
+            self.top_left(),
+            self.bot_right(),
+            self.size()
+        )
+    }
+}
+
+#[derive(Debug)]
+pub struct PixelRegion {
+    pub top_left: Vec2,
+    pub bot_right: Vec2,
+}
+
+impl PixelRegion {
+    pub fn contains(&self, pos: Vec2) -> bool {
+        pos.x >= self.top_left.x
+            && pos.x <= self.bot_right.x
+            && pos.y >= self.top_left.y
+            && pos.y <= self.bot_right.y
+    }
+
+    pub fn size(&self) -> Vec2 {
+        self.bot_right - self.top_left
+    }
+}
+
+impl Display for PixelRegion {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{} -> {}", self.top_left, self.bot_right)
+    }
+}
+
+pub struct Vec2View<'a> {
+    pub x: &'a mut f32,
+    pub y: &'a mut f32,
+}
+
+impl Vec2View<'_> {
+    pub fn set(&mut self, other: Vec2) {
+        *self.x = other.x;
+        *self.y = other.y;
+    }
+
+    pub fn add(&mut self, other: Vec2) {
+        *self.x += other.x;
+        *self.y += other.y;
+    }
+}

core/src/primitive/color.rs

@@ -0,0 +1,163 @@
+use std::marker::Destruct;
+
+/// stored in linear for sane manipulation
+#[repr(C)]
+#[derive(Clone, Copy, Hash, PartialEq, Eq, bytemuck::Zeroable, Debug)]
+pub struct Color<T> {
+    pub r: T,
+    pub g: T,
+    pub b: T,
+    pub a: T,
+}
+
+impl<T: ColorNum> Color<T> {
+    pub const BLACK: Self = Self::rgb(T::MIN, T::MIN, T::MIN);
+    pub const WHITE: Self = Self::rgb(T::MAX, T::MAX, T::MAX);
+    pub const GRAY: Self = Self::rgb(T::MID, T::MID, T::MID);
+
+    pub const RED: Self = Self::rgb(T::MAX, T::MIN, T::MIN);
+    pub const ORANGE: Self = Self::rgb(T::MAX, T::MID, T::MIN);
+    pub const YELLOW: Self = Self::rgb(T::MAX, T::MAX, T::MIN);
+    pub const LIME: Self = Self::rgb(T::MID, T::MAX, T::MIN);
+    pub const GREEN: Self = Self::rgb(T::MIN, T::MAX, T::MIN);
+    pub const TURQUOISE: Self = Self::rgb(T::MIN, T::MAX, T::MID);
+    pub const CYAN: Self = Self::rgb(T::MIN, T::MAX, T::MAX);
+    pub const SKY: Self = Self::rgb(T::MIN, T::MID, T::MAX);
+    pub const BLUE: Self = Self::rgb(T::MIN, T::MIN, T::MAX);
+    pub const PURPLE: Self = Self::rgb(T::MID, T::MIN, T::MAX);
+    pub const MAGENTA: Self = Self::rgb(T::MAX, T::MIN, T::MAX);
+
+    pub const NONE: Self = Self::new(T::MIN, T::MIN, T::MIN, T::MIN);
+
+    pub const fn new(r: T, g: T, b: T, a: T) -> Self {
+        Self { r, g, b, a }
+    }
+    pub const fn rgb(r: T, g: T, b: T) -> Self {
+        Self { r, g, b, a: T::MAX }
+    }
+    pub fn alpha(mut self, a: T) -> Self {
+        self.a = a;
+        self
+    }
+
+    pub fn as_arr(self) -> [T; 4] {
+        [self.r, self.g, self.b, self.a]
+    }
+}
+
+pub const trait F32Conversion {
+    fn to(self) -> f32;
+    fn from(x: f32) -> Self;
+}
+
+pub trait ColorNum {
+    const MIN: Self;
+    const MID: Self;
+    const MAX: Self;
+}
+
+macro_rules! map_rgb {
+    ($x:ident,$self:ident, $e:tt) => {
+        #[allow(unused_braces)]
+        Self {
+            r: {
+                let $x = $self.r;
+                $e
+            },
+            g: {
+                let $x = $self.g;
+                $e
+            },
+            b: {
+                let $x = $self.b;
+                $e
+            },
+            a: $self.a,
+        }
+    };
+}
+
+impl<T: ColorNum + const F32Conversion> Color<T>
+where
+    Self: const Destruct,
+{
+    pub const fn mul_rgb(self, amt: impl const F32Conversion) -> Self {
+        let amt = amt.to();
+        map_rgb!(x, self, { T::from(x.to() * amt) })
+    }
+
+    pub const fn add_rgb(self, amt: impl const F32Conversion) -> Self {
+        let amt = amt.to();
+        map_rgb!(x, self, { T::from(x.to() + amt) })
+    }
+
+    pub const fn darker(self, amt: f32) -> Self {
+        self.mul_rgb(1.0 - amt)
+    }
+
+    pub const fn brighter(self, amt: f32) -> Self {
+        map_rgb!(x, self, {
+            let x = x.to();
+            T::from(x + (1.0 - x) * amt)
+        })
+    }
+
+    pub fn map_rgb(self, f: impl Fn(T) -> T) -> Self {
+        Self {
+            r: f(self.r),
+            g: f(self.g),
+            b: f(self.b),
+            a: self.a,
+        }
+    }
+
+    pub fn srgb(r: T, g: T, b: T) -> Self {
+        Self {
+            r: s_to_l(r),
+            g: s_to_l(g),
+            b: s_to_l(b),
+            a: T::MAX,
+        }
+    }
+}
+
+fn s_to_l<T: F32Conversion>(x: T) -> T {
+    let x = x.to();
+    T::from(if x <= 0.0405 {
+        x / 12.92
+    } else {
+        ((x + 0.055) / 1.055).powf(2.4)
+    })
+}
+
+impl ColorNum for u8 {
+    const MIN: Self = u8::MIN;
+    const MID: Self = u8::MAX / 2;
+    const MAX: Self = u8::MAX;
+}
+
+impl ColorNum for f32 {
+    const MIN: Self = 0.0;
+    const MID: Self = 0.5;
+    const MAX: Self = 1.0;
+}
+
+unsafe impl bytemuck::Pod for Color<u8> {}
+
+impl const F32Conversion for f32 {
+    fn to(self) -> f32 {
+        self
+    }
+    fn from(x: f32) -> Self {
+        x
+    }
+}
+
+impl const F32Conversion for u8 {
+    fn to(self) -> f32 {
+        self as f32 / 255.0
+    }
+    fn from(x: f32) -> Self {
+        (x * 255.0).clamp(0.0, 255.0) as Self
+    }
+}

core/src/primitive/layer.rs

@@ -0,0 +1,275 @@
+use std::ops::{Index, IndexMut};
+
+use crate::{
+    render::{MaskIdx, Primitive, PrimitiveHandle, PrimitiveInst, Primitives},
+    util::to_mut,
+};
+
+pub type LayerId = usize;
+
+struct LayerNode<T> {
+    next: Ptr,
+    prev: Ptr,
+    child: Option<Child>,
+    depth: usize,
+    data: T,
+}
+
+#[derive(Clone, Copy, Debug)]
+enum Ptr {
+    /// continue on same level
+    Next(usize),
+    /// go back to parent
+    Parent(usize),
+    /// end
+    None,
+}
+
+/// TODO: currently this does not ever free layers
+/// is that realistically desired?
+pub struct Layers<T> {
+    vec: Vec<LayerNode<T>>,
+    /// index of last layer at top level (start at first = 0)
+    last: usize,
+}
+
+#[derive(Clone, Copy)]
+struct Child {
+    head: usize,
+    tail: usize,
+}
+
+pub type PrimitiveLayers = Layers<Primitives>;
+
+impl<T: Default> Layers<T> {
+    pub fn new() -> Layers<T> {
+        Self {
+            vec: vec![LayerNode::head()],
+            last: 0,
+        }
+    }
+
+    pub fn clear(&mut self) {
+        self.vec.clear();
+        self.vec.push(LayerNode::head());
+    }
+
+    fn push(&mut self, node: LayerNode<T>) -> LayerId {
+        let i = self.vec.len();
+        self.vec.push(node);
+        i
+    }
+
+    pub fn next(&mut self, i: LayerId) -> LayerId {
+        if let Ptr::Next(i) = self.vec[i].next {
+            return i;
+        }
+        let i_new = self.push(LayerNode::new(
+            T::default(),
+            self.vec[i].next,
+            Ptr::Next(i),
+            self.vec[i].depth,
+        ));
+        self.vec[i].next = Ptr::Next(i_new);
+        self.vec[i_new].prev = Ptr::Next(i);
+        match self.vec[i_new].next {
+            Ptr::Next(i) => self.vec[i].prev = Ptr::Next(i_new),
+            Ptr::Parent(i) => self.vec[i].child.as_mut().unwrap().tail = i_new,
+            Ptr::None => self.last = i_new,
+        }
+        i_new
+    }
+
+    pub fn child(&mut self, i: LayerId) -> LayerId {
+        if let Some(c) = self.vec[i].child {
+            return c.head;
+        }
+        let i_child = self.push(LayerNode::new(
+            T::default(),
+            Ptr::Parent(i),
+            Ptr::Parent(i),
+            self.vec[i].depth + 1,
+        ));
+        self.vec[i].child = Some(Child {
+            head: i_child,
+            tail: i_child,
+        });
+        i_child
+    }
+
+    pub fn iter_mut(&mut self) -> LayerIteratorMut<'_, T> {
+        LayerIteratorMut::new(&mut self.vec, self.last)
+    }
+
+    pub fn iter_orderless_mut(&mut self) -> impl Iterator<Item = (usize, &mut T)> {
+        self.vec.iter_mut().map(|n| &mut n.data).enumerate()
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = (LayerId, &T)> {
+        self.indices().map(|i| (i, &self.vec[i].data))
+    }
+
+    pub fn iter_depth(&self) -> impl Iterator<Item = ((LayerId, usize), &T)> {
+        self.indices()
+            .map(|i| ((i, self.vec[i].depth), &self.vec[i].data))
+    }
+
+    pub fn indices(&self) -> LayerIndexIterator<'_, T> {
+        LayerIndexIterator::new(&self.vec, self.last)
+    }
+}
+
+impl PrimitiveLayers {
+    pub fn write<P: Primitive>(
+        &mut self,
+        layer: LayerId,
+        info: PrimitiveInst<P>,
+    ) -> PrimitiveHandle {
+        self[layer].write(layer, info)
+    }
+
+    pub fn free(&mut self, h: &PrimitiveHandle) -> MaskIdx {
+        self[h.layer].free(h)
+    }
+}
+
+impl<T: Default> Default for Layers<T> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl<T> Index<LayerId> for Layers<T> {
+    type Output = T;
+
+    fn index(&self, index: LayerId) -> &Self::Output {
+        &self.vec[index].data
+    }
+}
+
+impl<T> IndexMut<LayerId> for Layers<T> {
+    fn index_mut(&mut self, index: LayerId) -> &mut Self::Output {
+        &mut self.vec[index].data
+    }
+}
+
+impl<T: Default> LayerNode<T> {
+    pub fn new(data: T, next: Ptr, prev: Ptr, depth: usize) -> Self {
+        Self {
+            next,
+            prev,
+            child: None,
+            data,
+            depth,
+        }
+    }
+
+    pub fn head() -> Self {
+        Self::new(T::default(), Ptr::None, Ptr::None, 0)
+    }
+}
+
+pub struct LayerIteratorMut<'a, T> {
+    inner: LayerIndexIterator<'a, T>,
+}
+
+impl<'a, T> Iterator for LayerIteratorMut<'a, T> {
+    type Item = (usize, &'a mut T);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let i = self.inner.next()?;
+        // SAFETY: requires index iterator to work properly
+        let layer = unsafe { to_mut(&self.inner.vec[i].data) };
+        Some((i, layer))
+    }
+}
+
+impl<'a, T> DoubleEndedIterator for LayerIteratorMut<'a, T> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        let i = self.inner.next_back()?;
+        // SAFETY: requires index iterator to work properly
+        let layer = unsafe { to_mut(&self.inner.vec[i].data) };
+        Some((i, layer))
+    }
+}
+
+impl<'a, T> LayerIteratorMut<'a, T> {
+    fn new(vec: &'a mut Vec<LayerNode<T>>, last: usize) -> Self {
+        Self {
+            inner: LayerIndexIterator::new(vec, last),
+        }
+    }
+}
+
+pub struct LayerIndexIterator<'a, T> {
+    next: Option<usize>,
+    next_back: Option<usize>,
+    vec: &'a Vec<LayerNode<T>>,
+}
+
+impl<'a, T> Iterator for LayerIndexIterator<'a, T> {
+    type Item = usize;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let ret_i = self.next?;
+        let node = &self.vec[ret_i];
+        self.next = if let Some(c) = node.child {
+            Some(c.head)
+        } else if let Ptr::Next(i) = node.next {
+            Some(i)
+        } else if let Ptr::Parent(i) = node.next {
+            let mut node = &self.vec[i];
+            while let Ptr::Parent(i) = node.next {
+                node = &self.vec[i];
+            }
+            if let Ptr::Next(i) = node.next {
+                Some(i)
+            } else {
+                None
+            }
+        } else {
+            None
+        };
+        if self.next_back.unwrap() == ret_i {
+            self.next = None;
+            self.next_back = None;
+        }
+        Some(ret_i)
+    }
+}
+
+impl<'a, T> DoubleEndedIterator for LayerIndexIterator<'a, T> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        let ret_i = self.next_back?;
+        let node = &self.vec[ret_i];
+        self.next_back = if let Ptr::Next(mut i) = node.prev {
+            while let Some(c) = self.vec[i].child {
+                i = c.tail
+            }
+            Some(i)
+        } else if let Ptr::Parent(i) = node.prev {
+            Some(i)
+        } else {
+            None
+        };
+        if self.next.unwrap() == ret_i {
+            self.next = None;
+            self.next_back = None;
+        }
+        Some(ret_i)
+    }
+}
+
+impl<'a, T> LayerIndexIterator<'a, T> {
+    fn new(vec: &'a Vec<LayerNode<T>>, last: usize) -> Self {
+        let mut last = last;
+        while let Some(c) = vec[last].child {
+            last = c.tail;
+        }
+        Self {
+            next: Some(0),
+            next_back: Some(last),
+            vec,
+        }
+    }
+}

core/src/primitive/mod.rs

@@ -0,0 +1,9 @@
+mod color;
+mod layer;
+mod text;
+mod texture;
+
+pub use color::*;
+pub use layer::*;
+pub use text::*;
+pub use texture::*;

core/src/primitive/text.rs

@@ -0,0 +1,187 @@
+use crate::{Align, RegionAlign, TextureHandle, Textures, UiColor, util::Vec2};
+use cosmic_text::{
+    Attrs, AttrsList, Buffer, CacheKey, Color, Family, FontSystem, Metrics, Placement, SwashCache,
+    SwashContent,
+};
+use image::{GenericImageView, RgbaImage};
+use std::simd::{Simd, num::SimdUint};
+
+/// TODO: properly wrap this
+pub mod text_lib {
+    pub use cosmic_text::*;
+}
+
+pub struct TextData {
+    pub font_system: FontSystem,
+    pub swash_cache: SwashCache,
+    glyph_cache: Vec<(Placement, CacheKey, Color)>,
+}
+
+impl Default for TextData {
+    fn default() -> Self {
+        Self {
+            font_system: FontSystem::new(),
+            swash_cache: SwashCache::new(),
+            glyph_cache: Default::default(),
+        }
+    }
+}
+
+#[derive(Clone, Copy)]
+pub struct TextAttrs {
+    pub color: UiColor,
+    pub font_size: f32,
+    pub line_height: f32,
+    pub family: Family<'static>,
+    pub wrap: bool,
+    /// inner alignment of text region (within where it's drawn)
+    pub align: RegionAlign,
+}
+
+impl TextAttrs {
+    pub fn apply(&self, font_system: &mut FontSystem, buf: &mut Buffer, width: Option<f32>) {
+        buf.set_metrics_and_size(
+            font_system,
+            Metrics::new(self.font_size, self.line_height),
+            width,
+            None,
+        );
+        let attrs = Attrs::new().family(self.family);
+        let list = AttrsList::new(&attrs);
+        for line in &mut buf.lines {
+            line.set_attrs_list(list.clone());
+        }
+    }
+}
+
+pub type TextBuffer = Buffer;
+
+impl Default for TextAttrs {
+    fn default() -> Self {
+        let size = 16.0;
+        Self {
+            color: UiColor::WHITE,
+            font_size: size,
+            line_height: size * LINE_HEIGHT_MULT,
+            family: Family::SansSerif,
+            wrap: false,
+            align: Align::CENTER_LEFT,
+        }
+    }
+}
+
+pub const LINE_HEIGHT_MULT: f32 = 1.1;
+
+impl TextData {
+    pub fn draw(
+        &mut self,
+        buffer: &mut TextBuffer,
+        attrs: &TextAttrs,
+        textures: &mut Textures,
+    ) -> RenderedText {
+        // TODO: either this or the layout stuff (or both) is super slow,
+        // should probably do texture packing and things if possible.
+        // very visible if you add just a couple of wrapping texts and resize window
+        // should also be timed to figure out exactly what points need to be sped up
+        // let mut pixels = HashMap::<_, [u8; 4]>::default();
+        let mut min_x = 0;
+        let mut min_y = 0;
+        let mut max_x = 0;
+        let mut max_y = 0;
+        let text_color = {
+            let c = attrs.color;
+            cosmic_text::Color::rgba(c.r, c.g, c.b, c.a)
+        };
+        let mut max_width = 0.0f32;
+        let mut height = 0.0;
+
+        for run in buffer.layout_runs() {
+            for glyph in run.glyphs.iter() {
+                let physical_glyph = glyph.physical((0., 0.), 1.0);
+
+                let glyph_color = match glyph.color_opt {
+                    Some(some) => some,
+                    None => text_color,
+                };
+
+                if let Some(img) = self
+                    .swash_cache
+                    .get_image(&mut self.font_system, physical_glyph.cache_key)
+                {
+                    let mut pos = img.placement;
+                    pos.left += physical_glyph.x;
+                    pos.top = physical_glyph.y + run.line_y as i32 - pos.top;
+                    min_x = min_x.min(pos.left);
+                    min_y = min_y.min(pos.top);
+                    max_x = max_x.max(pos.left + pos.width as i32);
+                    max_y = max_y.max(pos.top + pos.height as i32);
+                    self.glyph_cache
+                        .push((pos, physical_glyph.cache_key, glyph_color));
+                }
+            }
+            max_width = max_width.max(run.line_w);
+            height += run.line_height;
+        }
+        let img_width = (max_x - min_x + 1) as u32;
+        let img_height = (max_y - min_y + 1) as u32;
+        let mut image = RgbaImage::new(img_width, img_height);
+
+        for (pos, key, color) in self.glyph_cache.drain(..) {
+            let img = self
+                .swash_cache
+                .get_image(&mut self.font_system, key)
+                .as_ref()
+                .unwrap();
+            let mut merge = |i, color: [u8; 4]| {
+                let i = i as i32;
+                let x = (i % pos.width as i32 + pos.left - min_x) as u32;
+                let y = (i / pos.width as i32 + pos.top - min_y) as u32;
+                let pixel = &mut image[(x, y)].0;
+                // TODO: no clue if proper alpha blending should be done
+                *pixel = Simd::from(color).saturating_add(Simd::from(*pixel)).into();
+            };
+
+            match img.content {
+                SwashContent::Mask => {
+                    for (i, a) in img.data.iter().enumerate() {
+                        let mut color = color.as_rgba();
+                        color[3] = ((color[3] as u32 * *a as u32) / u8::MAX as u32) as u8;
+                        merge(i, color);
+                    }
+                }
+                SwashContent::SubpixelMask => todo!("subpixel mask text rendering"),
+                SwashContent::Color => {
+                    let (colors, _) = img.data.as_chunks::<4>();
+                    for (i, color) in colors.iter().enumerate() {
+                        merge(i, *color);
+                    }
+                }
+            }
+        }
+
+        let max_dim = 8192;
+        if image.width() > max_dim || image.height() > max_dim {
+            let width = image.width().min(max_dim);
+            let height = image.height().min(max_dim);
+            eprintln!(
+                "WARNING: image of size {:?} cropped to {:?} (texture too big)",
+                image.dimensions(),
+                (width, height)
+            );
+            image = image.view(0, 0, width, height).to_image();
+        }
+
+        RenderedText {
+            handle: textures.add(image),
+            top_left_offset: Vec2::new(min_x as f32, min_y as f32),
+            size: Vec2::new(max_width, height),
+        }
+    }
+}
+
+#[derive(Clone)]
+pub struct RenderedText {
+    pub handle: TextureHandle,
+    pub top_left_offset: Vec2,
+    pub size: Vec2,
+}

core/src/primitive/texture.rs

@@ -0,0 +1,136 @@
+use crate::{
+    render::TexturePrimitive,
+    util::{RefCounter, Vec2},
+};
+use image::{DynamicImage, GenericImageView};
+use std::{
+    ops::Index,
+    sync::mpsc::{Receiver, Sender, channel},
+};
+
+#[derive(Debug, Clone)]
+pub struct TextureHandle {
+    inner: TexturePrimitive,
+    size: Vec2,
+    counter: RefCounter,
+    send: Sender<u32>,
+}
+
+/// a texture manager for a ui
+/// note that this is heavily oriented towards wgpu's renderer so the primitives don't need mapped
+pub struct Textures {
+    free: Vec<u32>,
+    images: Vec<Option<DynamicImage>>,
+    updates: Vec<Update>,
+    send: Sender<u32>,
+    recv: Receiver<u32>,
+}
+
+pub enum TextureUpdate<'a> {
+    Push(&'a DynamicImage),
+    Set(u32, &'a DynamicImage),
+    Free(u32),
+    PushFree,
+    SetFree,
+}
+
+enum Update {
+    Push(u32),
+    Set(u32),
+    Free(u32),
+}
+
+impl Textures {
+    pub fn new() -> Self {
+        let (send, recv) = channel();
+        Self {
+            free: Vec::new(),
+            images: Vec::new(),
+            updates: Vec::new(),
+            send,
+            recv,
+        }
+    }
+    pub fn add(&mut self, image: impl Into<DynamicImage>) -> TextureHandle {
+        let image = image.into();
+        let size = image.dimensions().into();
+        let view_idx = self.push(image);
+        // 0 == default in renderer; TODO: actually create samplers here
+        let sampler_idx = 0;
+        TextureHandle {
+            inner: TexturePrimitive {
+                view_idx,
+                sampler_idx,
+            },
+            size,
+            counter: RefCounter::new(),
+            send: self.send.clone(),
+        }
+    }
+
+    fn push(&mut self, image: DynamicImage) -> u32 {
+        if let Some(i) = self.free.pop() {
+            self.images[i as usize] = Some(image);
+            self.updates.push(Update::Set(i));
+            i
+        } else {
+            let i = self.images.len() as u32;
+            self.images.push(Some(image));
+            self.updates.push(Update::Push(i));
+            i
+        }
+    }
+
+    pub fn free(&mut self) {
+        for idx in self.recv.try_iter() {
+            self.images[idx as usize] = None;
+            self.updates.push(Update::Free(idx));
+            self.free.push(idx);
+        }
+    }
+
+    pub fn updates(&mut self) -> impl Iterator<Item = TextureUpdate<'_>> {
+        self.updates.drain(..).map(|u| match u {
+            Update::Push(i) => self.images[i as usize]
+                .as_ref()
+                .map(TextureUpdate::Push)
+                .unwrap_or(TextureUpdate::PushFree),
+            Update::Set(i) => self.images[i as usize]
+                .as_ref()
+                .map(|img| TextureUpdate::Set(i, img))
+                .unwrap_or(TextureUpdate::SetFree),
+            Update::Free(i) => TextureUpdate::Free(i),
+        })
+    }
+}
+
+impl TextureHandle {
+    pub fn primitive(&self) -> TexturePrimitive {
+        self.inner
+    }
+    pub fn size(&self) -> Vec2 {
+        self.size
+    }
+}
+
+impl Drop for TextureHandle {
+    fn drop(&mut self) {
+        if self.counter.drop() {
+            let _ = self.send.send(self.inner.view_idx);
+        }
+    }
+}
+
+impl Index<&TextureHandle> for Textures {
+    type Output = DynamicImage;
+
+    fn index(&self, index: &TextureHandle) -> &Self::Output {
+        self.images[index.inner.view_idx as usize].as_ref().unwrap()
+    }
+}
+
+impl Default for Textures {
+    fn default() -> Self {
+        Self::new()
+    }
+}

core/src/render/data.rs

@@ -0,0 +1,50 @@
+use crate::{UiRegion, util::Id};
+use wgpu::*;
+
+#[repr(C)]
+#[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable, Default)]
+pub struct WindowUniform {
+    pub width: f32,
+    pub height: f32,
+}
+
+#[repr(C)]
+#[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
+pub struct PrimitiveInstance {
+    pub region: UiRegion,
+    pub binding: u32,
+    pub idx: u32,
+    pub mask_idx: MaskIdx,
+}
+
+impl PrimitiveInstance {
+    const ATTRIBS: [VertexAttribute; 7] = vertex_attr_array![
+        0 => Float32x2,
+        1 => Float32x2,
+        2 => Float32x2,
+        3 => Float32x2,
+        4 => Uint32,
+        5 => Uint32,
+        6 => Uint32,
+    ];
+
+    pub fn desc() -> VertexBufferLayout<'static> {
+        VertexBufferLayout {
+            array_stride: std::mem::size_of::<Self>() as BufferAddress,
+            step_mode: VertexStepMode::Instance,
+            attributes: &Self::ATTRIBS,
+        }
+    }
+}
+
+pub type MaskIdx = Id<u32>;
+
+impl MaskIdx {
+    pub const NONE: Self = Self::preset(u32::MAX);
+}
+
+#[repr(C)]
+#[derive(Debug, Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
+pub struct Mask {
+    pub region: UiRegion,
+}

core/src/render/mod.rs

@@ -0,0 +1,356 @@
+use std::num::NonZero;
+
+use crate::{
+    Ui,
+    render::{data::PrimitiveInstance, texture::GpuTextures, util::ArrBuf},
+    util::HashMap,
+};
+use data::WindowUniform;
+use wgpu::{
+    util::{BufferInitDescriptor, DeviceExt},
+    *,
+};
+use winit::dpi::PhysicalSize;
+
+mod data;
+mod primitive;
+mod texture;
+mod util;
+
+pub use data::{Mask, MaskIdx};
+pub use primitive::*;
+
+const SHAPE_SHADER: &str = include_str!("./shader.wgsl");
+
+pub struct UiRenderNode {
+    uniform_group: BindGroup,
+    primitive_layout: BindGroupLayout,
+    rsc_layout: BindGroupLayout,
+    rsc_group: BindGroup,
+
+    pipeline: RenderPipeline,
+
+    layers: HashMap<usize, RenderLayer>,
+    active: Vec<usize>,
+    window_buffer: Buffer,
+    textures: GpuTextures,
+    masks: ArrBuf<Mask>,
+}
+
+struct RenderLayer {
+    instance: ArrBuf<PrimitiveInstance>,
+    primitives: PrimitiveBuffers,
+    primitive_group: BindGroup,
+}
+
+impl UiRenderNode {
+    pub fn draw<'a>(&'a self, pass: &mut RenderPass<'a>) {
+        pass.set_pipeline(&self.pipeline);
+        pass.set_bind_group(0, &self.uniform_group, &[]);
+        pass.set_bind_group(2, &self.rsc_group, &[]);
+        for i in &self.active {
+            let layer = &self.layers[i];
+            if layer.instance.len() == 0 {
+                continue;
+            }
+            pass.set_bind_group(1, &layer.primitive_group, &[]);
+            pass.set_vertex_buffer(0, layer.instance.buffer.slice(..));
+            pass.draw(0..4, 0..layer.instance.len() as u32);
+        }
+    }
+
+    pub fn update(&mut self, device: &Device, queue: &Queue, ui: &mut Ui) {
+        self.active.clear();
+        for (i, primitives) in ui.layers.iter_mut() {
+            self.active.push(i);
+            for change in primitives.apply_free() {
+                if let Some(inst) = ui.active.get_mut(&change.id) {
+                    for h in &mut inst.primitives {
+                        if h.layer == i && h.inst_idx == change.old {
+                            h.inst_idx = change.new;
+                            break;
+                        }
+                    }
+                }
+            }
+            let rlayer = self.layers.entry(i).or_insert_with(|| {
+                let primitives = PrimitiveBuffers::new(device);
+                let primitive_group =
+                    Self::primitive_group(device, &self.primitive_layout, primitives.buffers());
+                RenderLayer {
+                    instance: ArrBuf::new(
+                        device,
+                        BufferUsages::VERTEX | BufferUsages::COPY_DST,
+                        "instance",
+                    ),
+                    primitives,
+                    primitive_group,
+                }
+            });
+            if primitives.updated {
+                rlayer
+                    .instance
+                    .update(device, queue, primitives.instances());
+                rlayer.primitives.update(device, queue, primitives.data());
+                rlayer.primitive_group = Self::primitive_group(
+                    device,
+                    &self.primitive_layout,
+                    rlayer.primitives.buffers(),
+                );
+                primitives.updated = false;
+            }
+        }
+        let mut changed = false;
+        changed |= self.textures.update(&mut ui.textures);
+        if ui.masks.changed {
+            ui.masks.changed = false;
+            self.masks.update(device, queue, &ui.masks[..]);
+            changed = true;
+        }
+        if changed {
+            self.rsc_group = Self::rsc_group(device, &self.rsc_layout, &self.textures, &self.masks);
+        }
+    }
+
+    pub fn resize(&mut self, size: &PhysicalSize<u32>, queue: &Queue) {
+        let slice = &[WindowUniform {
+            width: size.width as f32,
+            height: size.height as f32,
+        }];
+        queue.write_buffer(&self.window_buffer, 0, bytemuck::cast_slice(slice));
+    }
+
+    pub fn new(
+        device: &Device,
+        queue: &Queue,
+        config: &SurfaceConfiguration,
+        limits: UiLimits,
+    ) -> Self {
+        let shader = device.create_shader_module(ShaderModuleDescriptor {
+            label: Some("UI Shape Shader"),
+            source: ShaderSource::Wgsl(SHAPE_SHADER.into()),
+        });
+
+        let window_uniform = WindowUniform::default();
+        let window_buffer = device.create_buffer_init(&BufferInitDescriptor {
+            label: Some("window"),
+            contents: bytemuck::cast_slice(&[window_uniform]),
+            usage: BufferUsages::UNIFORM | BufferUsages::COPY_DST,
+        });
+
+        let uniform_layout = device.create_bind_group_layout(&BindGroupLayoutDescriptor {
+            entries: &[BindGroupLayoutEntry {
+                binding: 0,
+                visibility: ShaderStages::VERTEX | ShaderStages::FRAGMENT,
+                ty: BindingType::Buffer {
+                    ty: BufferBindingType::Uniform,
+                    has_dynamic_offset: false,
+                    min_binding_size: None,
+                },
+                count: None,
+            }],
+            label: Some("window"),
+        });
+
+        let uniform_group = Self::bind_group_0(device, &uniform_layout, &window_buffer);
+
+        let primitive_layout = device.create_bind_group_layout(&BindGroupLayoutDescriptor {
+            entries: &core::array::from_fn::<_, { PrimitiveBuffers::LEN }, _>(|i| {
+                BindGroupLayoutEntry {
+                    binding: i as u32,
+                    visibility: ShaderStages::FRAGMENT,
+                    ty: BindingType::Buffer {
+                        ty: BufferBindingType::Storage { read_only: true },
+                        has_dynamic_offset: false,
+                        min_binding_size: None,
+                    },
+                    count: None,
+                }
+            }),
+            label: Some("primitive"),
+        });
+
+        let tex_manager = GpuTextures::new(device, queue);
+        let masks = ArrBuf::new(
+            device,
+            BufferUsages::STORAGE | BufferUsages::COPY_DST,
+            "ui masks",
+        );
+
+        let rsc_layout = Self::rsc_layout(device, &limits);
+        let rsc_group = Self::rsc_group(device, &rsc_layout, &tex_manager, &masks);
+
+        let pipeline_layout = device.create_pipeline_layout(&PipelineLayoutDescriptor {
+            label: Some("UI Shape Pipeline Layout"),
+            bind_group_layouts: &[&uniform_layout, &primitive_layout, &rsc_layout],
+            push_constant_ranges: &[],
+        });
+        let pipeline = device.create_render_pipeline(&RenderPipelineDescriptor {
+            label: Some("UI Shape Pipeline"),
+            layout: Some(&pipeline_layout),
+            vertex: VertexState {
+                module: &shader,
+                entry_point: Some("vs_main"),
+                buffers: &[PrimitiveInstance::desc()],
+                compilation_options: Default::default(),
+            },
+            fragment: Some(FragmentState {
+                module: &shader,
+                entry_point: Some("fs_main"),
+                targets: &[Some(ColorTargetState {
+                    format: config.format,
+                    blend: Some(BlendState::ALPHA_BLENDING),
+                    write_mask: ColorWrites::ALL,
+                })],
+                compilation_options: Default::default(),
+            }),
+            primitive: PrimitiveState {
+                topology: PrimitiveTopology::TriangleStrip,
+                strip_index_format: None,
+                front_face: FrontFace::Cw,
+                cull_mode: Some(Face::Back),
+                polygon_mode: PolygonMode::Fill,
+                unclipped_depth: false,
+                conservative: false,
+            },
+            depth_stencil: None,
+            multisample: MultisampleState {
+                count: 1,
+                mask: !0,
+                alpha_to_coverage_enabled: false,
+            },
+            multiview: None,
+            cache: None,
+        });
+
+        Self {
+            uniform_group,
+            primitive_layout,
+            rsc_layout,
+            rsc_group,
+            pipeline,
+            window_buffer,
+            layers: HashMap::default(),
+            active: Vec::new(),
+            textures: tex_manager,
+            masks,
+        }
+    }
+
+    fn bind_group_0(
+        device: &Device,
+        layout: &BindGroupLayout,
+        window_buffer: &Buffer,
+    ) -> BindGroup {
+        device.create_bind_group(&BindGroupDescriptor {
+            layout,
+            entries: &[BindGroupEntry {
+                binding: 0,
+                resource: window_buffer.as_entire_binding(),
+            }],
+            label: Some("ui window"),
+        })
+    }
+
+    fn primitive_group(
+        device: &Device,
+        layout: &BindGroupLayout,
+        buffers: [(u32, &Buffer); PrimitiveBuffers::LEN],
+    ) -> BindGroup {
+        device.create_bind_group(&BindGroupDescriptor {
+            layout,
+            entries: &buffers.map(|(binding, buf)| BindGroupEntry {
+                binding,
+                resource: buf.as_entire_binding(),
+            }),
+            label: Some("ui primitives"),
+        })
+    }
+
+    fn rsc_layout(device: &Device, limits: &UiLimits) -> BindGroupLayout {
+        device.create_bind_group_layout(&BindGroupLayoutDescriptor {
+            entries: &[
+                BindGroupLayoutEntry {
+                    binding: 0,
+                    visibility: ShaderStages::FRAGMENT,
+                    ty: BindingType::Texture {
+                        sample_type: TextureSampleType::Float { filterable: false },
+                        view_dimension: TextureViewDimension::D2,
+                        multisampled: false,
+                    },
+                    count: Some(NonZero::new(limits.max_textures).unwrap()),
+                },
+                BindGroupLayoutEntry {
+                    binding: 1,
+                    visibility: ShaderStages::FRAGMENT,
+                    ty: BindingType::Sampler(SamplerBindingType::NonFiltering),
+                    count: Some(NonZero::new(limits.max_samplers).unwrap()),
+                },
+                BindGroupLayoutEntry {
+                    binding: 2,
+                    visibility: ShaderStages::FRAGMENT,
+                    ty: BindingType::Buffer {
+                        ty: BufferBindingType::Storage { read_only: true },
+                        has_dynamic_offset: false,
+                        min_binding_size: None,
+                    },
+                    count: None,
+                },
+            ],
+            label: Some("ui rsc"),
+        })
+    }
+
+    fn rsc_group(
+        device: &Device,
+        layout: &BindGroupLayout,
+        tex_manager: &GpuTextures,
+        masks: &ArrBuf<Mask>,
+    ) -> BindGroup {
+        device.create_bind_group(&BindGroupDescriptor {
+            layout,
+            entries: &[
+                BindGroupEntry {
+                    binding: 0,
+                    resource: BindingResource::TextureViewArray(&tex_manager.views()),
+                },
+                BindGroupEntry {
+                    binding: 1,
+                    resource: BindingResource::SamplerArray(&tex_manager.samplers()),
+                },
+                BindGroupEntry {
+                    binding: 2,
+                    resource: masks.buffer.as_entire_binding(),
+                },
+            ],
+            label: Some("ui rsc"),
+        })
+    }
+
+    pub fn view_count(&self) -> usize {
+        self.textures.view_count()
+    }
+}
+
+pub struct UiLimits {
+    max_textures: u32,
+    max_samplers: u32,
+}
+
+impl Default for UiLimits {
+    fn default() -> Self {
+        Self {
+            max_textures: 100000,
+            max_samplers: 1000,
+        }
+    }
+}
+
+impl UiLimits {
+    pub fn max_binding_array_elements_per_shader_stage(&self) -> u32 {
+        self.max_textures + self.max_samplers
+    }
+    pub fn max_binding_array_sampler_elements_per_shader_stage(&self) -> u32 {
+        self.max_samplers
+    }
+}

core/src/render/primitive.rs

@@ -0,0 +1,282 @@
+use std::ops::{Deref, DerefMut};
+
+use crate::{
+    Color, UiRegion, WidgetId,
+    render::{
+        ArrBuf,
+        data::{MaskIdx, PrimitiveInstance},
+    },
+};
+use bytemuck::Pod;
+use wgpu::*;
+
+pub struct Primitives {
+    instances: Vec<PrimitiveInstance>,
+    assoc: Vec<WidgetId>,
+    data: PrimitiveData,
+    free: Vec<usize>,
+    pub updated: bool,
+}
+
+impl Default for Primitives {
+    fn default() -> Self {
+        Self {
+            instances: Default::default(),
+            assoc: Default::default(),
+            data: Default::default(),
+            free: Vec::new(),
+            updated: true,
+        }
+    }
+}
+
+pub trait Primitive: Pod {
+    const BINDING: u32;
+    fn vec(data: &mut PrimitiveData) -> &mut PrimitiveVec<Self>;
+}
+
+macro_rules! primitives {
+    ($($name:ident: $ty:ty => $binding:expr,)*) => {
+        #[derive(Default)]
+        pub struct PrimitiveData {
+            $(pub(crate) $name: PrimitiveVec<$ty>,)*
+        }
+
+        pub struct PrimitiveBuffers {
+            $($name: ArrBuf<$ty>,)*
+        }
+
+        impl PrimitiveBuffers {
+            pub fn update(&mut self, device: &Device, queue: &Queue, data: &PrimitiveData) {
+                $(self.$name.update(device, queue, &data.$name);)*
+            }
+        }
+
+        impl PrimitiveBuffers {
+            pub const LEN: usize = primitives!(@count $($name)*);
+            pub fn buffers(&self) -> [(u32, &Buffer); Self::LEN] {
+                [
+                    $((<$ty>::BINDING, &self.$name.buffer),)*
+                ]
+            }
+            pub fn new(device: &Device) -> Self {
+                Self {
+                    $($name: ArrBuf::new(
+                        device,
+                        BufferUsages::STORAGE | BufferUsages::COPY_DST,
+                        stringify!($name),
+                    ),)*
+                }
+            }
+        }
+
+        impl PrimitiveData {
+            pub fn clear(&mut self) {
+                $(self.$name.clear();)*
+            }
+            pub fn free(&mut self, binding: u32, idx: usize) {
+                match binding {
+                    $(<$ty>::BINDING => self.$name.free(idx),)*
+                    _ => unreachable!()
+                }
+            }
+        }
+
+        $(
+            unsafe impl bytemuck::Pod for $ty {}
+            unsafe impl bytemuck::Zeroable for $ty {}
+            impl Primitive for $ty {
+                const BINDING: u32 = $binding;
+                fn vec(data: &mut PrimitiveData) -> &mut PrimitiveVec<Self> {
+                    &mut data.$name
+                }
+            }
+        )*
+    };
+    (@count $t1:tt $($t:tt)+) => { 1 + primitives!(@count $($t),+) };
+    (@count $t:tt) => { 1 };
+}
+
+pub struct PrimitiveInst<P> {
+    pub id: WidgetId,
+    pub primitive: P,
+    pub region: UiRegion,
+    pub mask_idx: MaskIdx,
+}
+
+impl Primitives {
+    pub fn write<P: Primitive>(
+        &mut self,
+        layer: usize,
+        PrimitiveInst {
+            id,
+            primitive,
+            region,
+            mask_idx,
+        }: PrimitiveInst<P>,
+    ) -> PrimitiveHandle {
+        self.updated = true;
+        let vec = P::vec(&mut self.data);
+        let i = vec.add(primitive);
+        let inst = PrimitiveInstance {
+            region,
+            idx: i as u32,
+            mask_idx,
+            binding: P::BINDING,
+        };
+        let inst_i = if let Some(i) = self.free.pop() {
+            self.instances[i] = inst;
+            self.assoc[i] = id;
+            i
+        } else {
+            let i = self.instances.len();
+            self.instances.push(inst);
+            self.assoc.push(id);
+            i
+        };
+        PrimitiveHandle::new::<P>(layer, inst_i, i)
+    }
+
+    /// returns (old index, new index)
+    pub fn apply_free(&mut self) -> impl Iterator<Item = PrimitiveChange> {
+        self.free.sort_by(|a, b| b.cmp(a));
+        self.free.drain(..).filter_map(|i| {
+            self.instances.swap_remove(i);
+            self.assoc.swap_remove(i);
+            if i == self.instances.len() {
+                return None;
+            }
+            let id = self.assoc[i];
+            let old = self.instances.len();
+            Some(PrimitiveChange { id, old, new: i })
+        })
+    }
+
+    pub fn free(&mut self, h: &PrimitiveHandle) -> MaskIdx {
+        self.updated = true;
+        self.data.free(h.binding, h.data_idx);
+        self.free.push(h.inst_idx);
+        self.instances[h.inst_idx].mask_idx
+    }
+
+    pub fn data(&self) -> &PrimitiveData {
+        &self.data
+    }
+
+    pub fn instances(&self) -> &Vec<PrimitiveInstance> {
+        &self.instances
+    }
+
+    pub fn region_mut(&mut self, h: &PrimitiveHandle) -> &mut UiRegion {
+        self.updated = true;
+        &mut self.instances[h.inst_idx].region
+    }
+}
+
+pub struct PrimitiveChange {
+    pub id: WidgetId,
+    pub old: usize,
+    pub new: usize,
+}
+
+#[derive(Debug)]
+pub struct PrimitiveHandle {
+    pub layer: usize,
+    pub inst_idx: usize,
+    pub data_idx: usize,
+    pub binding: u32,
+}
+
+impl PrimitiveHandle {
+    fn new<P: Primitive>(layer: usize, inst_idx: usize, data_idx: usize) -> Self {
+        Self {
+            layer,
+            inst_idx,
+            data_idx,
+            binding: P::BINDING,
+        }
+    }
+}
+
+primitives!(
+    rects: RectPrimitive => 0,
+    textures: TexturePrimitive => 1,
+);
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct RectPrimitive {
+    pub color: Color<u8>,
+    pub radius: f32,
+    pub thickness: f32,
+    pub inner_radius: f32,
+}
+
+impl RectPrimitive {
+    pub fn color(color: Color<u8>) -> Self {
+        Self {
+            color,
+            radius: 0.0,
+            thickness: 0.0,
+            inner_radius: 0.0,
+        }
+    }
+}
+
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct TexturePrimitive {
+    pub view_idx: u32,
+    pub sampler_idx: u32,
+}
+
+pub struct PrimitiveVec<T> {
+    vec: Vec<T>,
+    free: Vec<usize>,
+}
+
+impl<T> PrimitiveVec<T> {
+    pub fn new() -> Self {
+        Self {
+            vec: Vec::new(),
+            free: Vec::new(),
+        }
+    }
+    pub fn add(&mut self, t: T) -> usize {
+        if let Some(i) = self.free.pop() {
+            self.vec[i] = t;
+            i
+        } else {
+            let i = self.vec.len();
+            self.vec.push(t);
+            i
+        }
+    }
+    pub fn free(&mut self, i: usize) {
+        self.free.push(i);
+    }
+    pub fn clear(&mut self) {
+        self.free.clear();
+        self.vec.clear();
+    }
+}
+
+impl<T> Default for PrimitiveVec<T> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl<T> Deref for PrimitiveVec<T> {
+    type Target = Vec<T>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.vec
+    }
+}
+
+impl<T> DerefMut for PrimitiveVec<T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.vec
+    }
+}

core/src/render/shader.wgsl

@@ -0,0 +1,178 @@
+const RECT: u32 = 0u;
+const TEXTURE: u32 = 1u;
+
+@group(0) @binding(0)
+var<uniform> window: WindowUniform;
+@group(1) @binding(RECT)
+var<storage> rects: array<Rect>;
+@group(1) @binding(TEXTURE)
+var<storage> textures: array<TextureInfo>;
+
+struct Rect {
+    color: u32,
+    radius: f32,
+    thickness: f32,
+    inner_radius: f32,
+}
+
+struct TextureInfo {
+    view_idx: u32,
+    sampler_idx: u32,
+}
+
+struct Mask {
+    x: UiSpan,
+    y: UiSpan,
+}
+
+struct UiSpan {
+    start: UiScalar,
+    end: UiScalar,
+}
+
+struct UiScalar {
+    rel: f32,
+    abs: f32,
+}
+
+struct UiVec2 {
+    rel: vec2<f32>,
+    abs: vec2<f32>,
+}
+
+@group(2) @binding(0)
+var views: binding_array<texture_2d<f32>>;
+@group(2) @binding(1)
+var samplers: binding_array<sampler>;
+@group(2) @binding(2)
+var<storage> masks: array<Mask>;
+
+struct WindowUniform {
+    dim: vec2<f32>,
+};
+
+struct InstanceInput {
+    @location(0) x_start: vec2<f32>,
+    @location(1) x_end: vec2<f32>,
+    @location(2) y_start: vec2<f32>,
+    @location(3) y_end: vec2<f32>,
+    @location(4) binding: u32,
+    @location(5) idx: u32,
+    @location(6) mask_idx: u32,
+}
+
+struct VertexOutput {
+    @location(0) top_left: vec2<f32>,
+    @location(1) bot_right: vec2<f32>,
+    @location(2) uv: vec2<f32>,
+    @location(3) binding: u32,
+    @location(4) idx: u32,
+    @location(5) mask_idx: u32,
+    @builtin(position) clip_position: vec4<f32>,
+};
+
+struct Region {
+    pos: vec2<f32>,
+    uv: vec2<f32>,
+    top_left: vec2<f32>,
+    bot_right: vec2<f32>,
+}
+
+@vertex
+fn vs_main(
+    @builtin(vertex_index) vi: u32,
+    in: InstanceInput,
+) -> VertexOutput {
+    var out: VertexOutput;
+
+    let top_left_rel = vec2(in.x_start.x, in.y_start.x);
+    let top_left_abs = vec2(in.x_start.y, in.y_start.y);
+    let bot_right_rel = vec2(in.x_end.x, in.y_end.x);
+    let bot_right_abs = vec2(in.x_end.y, in.y_end.y);
+
+    let top_left = floor(top_left_rel * window.dim) + floor(top_left_abs);
+    let bot_right = floor(bot_right_rel * window.dim) + floor(bot_right_abs);
+    let size = bot_right - top_left;
+
+    let uv = vec2<f32>(
+        f32(vi % 2u),
+        f32(vi / 2u)
+    );
+    let pos = (top_left + uv * size) / window.dim * 2.0 - 1.0;
+    out.clip_position = vec4<f32>(pos.x, -pos.y, 0.0, 1.0);
+    out.uv = uv;
+    out.binding = in.binding;
+    out.idx = in.idx;
+    out.top_left = top_left;
+    out.bot_right = bot_right;
+    out.mask_idx = in.mask_idx;
+
+    return out;
+}
+
+@fragment
+fn fs_main(
+    in: VertexOutput
+) -> @location(0) vec4<f32> {
+    let pos = in.clip_position.xy;
+    let region = Region(pos, in.uv, in.top_left, in.bot_right);
+    let i = in.idx;
+    var color: vec4<f32>;
+    switch in.binding {
+        case RECT: {
+            color = draw_rounded_rect(region, rects[i]);
+        }
+        case TEXTURE: {
+            color = draw_texture(region, textures[i]);
+        }
+        default: {
+            color = vec4(1.0, 0.0, 1.0, 1.0);
+        }
+    }
+    if in.mask_idx != 4294967295u {
+        let mask = masks[in.mask_idx];
+        let tl = UiVec2(vec2(mask.x.start.rel, mask.y.start.rel), vec2(mask.x.start.abs, mask.y.start.abs));
+        let br = UiVec2(vec2(mask.x.end.rel, mask.y.end.rel), vec2(mask.x.end.abs, mask.y.end.abs));
+
+        let top_left = floor(tl.rel * window.dim) + floor(tl.abs);
+        let bot_right = floor(br.rel * window.dim) + floor(br.abs);
+        if pos.x < top_left.x || pos.x > bot_right.x || pos.y < top_left.y || pos.y > bot_right.y {
+            color *= 0.0;
+        }
+    }
+    return color;
+}
+
+// TODO: this seems really inefficient (per frag indexing)?
+fn draw_texture(region: Region, info: TextureInfo) -> vec4<f32> {
+    return textureSample(views[info.view_idx], samplers[info.sampler_idx], region.uv);
+}
+
+fn draw_rounded_rect(region: Region, rect: Rect) -> vec4<f32> {
+    var color = unpack4x8unorm(rect.color);
+
+    let edge = 0.5;
+
+    let size = region.bot_right - region.top_left;
+    let corner = size / 2.0;
+    let center = region.top_left + corner;
+
+    let dist = distance_from_rect(region.pos, center, corner, rect.radius);
+    color.a *= 1.0 - smoothstep(-min(edge, rect.radius), edge, dist);
+
+    if rect.thickness > 0.0 {
+        let dist2 = distance_from_rect(region.pos, center, corner - rect.thickness, rect.inner_radius);
+        color.a *= smoothstep(-min(edge, rect.inner_radius), edge, dist2);
+    }
+
+    return color;
+}
+
+fn distance_from_rect(pixel_pos: vec2<f32>, rect_center: vec2<f32>, rect_corner: vec2<f32>, radius: f32) -> f32 {
+    // vec from center to pixel
+    let p = pixel_pos - rect_center;
+    // vec from inner rect corner to pixel
+    let q = abs(p) - (rect_corner - radius);
+    return length(max(q, vec2(0.0))) - radius;
+}
+

core/src/render/texture.rs

@@ -0,0 +1,129 @@
+use image::{DynamicImage, EncodableLayout};
+use wgpu::{util::DeviceExt, *};
+
+use crate::{TextureUpdate, Textures};
+
+pub struct GpuTextures {
+    device: Device,
+    queue: Queue,
+    views: Vec<TextureView>,
+    view_count: usize,
+    samplers: Vec<Sampler>,
+    null_view: TextureView,
+    no_views: Vec<TextureView>,
+}
+
+impl GpuTextures {
+    pub fn update(&mut self, textures: &mut Textures) -> bool {
+        let mut changed = false;
+        for update in textures.updates() {
+            changed = true;
+            match update {
+                TextureUpdate::Push(image) => self.push(image),
+                TextureUpdate::Set(i, image) => self.set(i, image),
+                TextureUpdate::SetFree => self.view_count += 1,
+                TextureUpdate::Free(i) => self.free(i),
+                TextureUpdate::PushFree => self.push_free(),
+            }
+        }
+        changed
+    }
+    fn set(&mut self, i: u32, image: &DynamicImage) {
+        self.view_count += 1;
+        let view = self.create_view(image);
+        self.views[i as usize] = view;
+    }
+    fn free(&mut self, i: u32) {
+        self.view_count -= 1;
+        self.views[i as usize] = self.null_view.clone();
+    }
+    fn push(&mut self, image: &DynamicImage) {
+        self.view_count += 1;
+        let view = self.create_view(image);
+        self.views.push(view);
+    }
+    fn push_free(&mut self) {
+        self.view_count += 1;
+        self.views.push(self.null_view.clone());
+    }
+
+    fn create_view(&self, image: &DynamicImage) -> TextureView {
+        let image = image.to_rgba8();
+        let (width, height) = image.dimensions();
+        let texture = self.device.create_texture_with_data(
+            &self.queue,
+            &TextureDescriptor {
+                label: None,
+                size: Extent3d {
+                    width,
+                    height,
+                    depth_or_array_layers: 1,
+                },
+                mip_level_count: 1,
+                sample_count: 1,
+                dimension: TextureDimension::D2,
+                format: TextureFormat::Rgba8Unorm,
+                usage: TextureUsages::TEXTURE_BINDING,
+                view_formats: &[],
+            },
+            wgt::TextureDataOrder::MipMajor,
+            image.as_bytes(),
+        );
+        texture.create_view(&TextureViewDescriptor::default())
+    }
+
+    pub fn new(device: &Device, queue: &Queue) -> Self {
+        let null_view = null_texture_view(device);
+        Self {
+            device: device.clone(),
+            queue: queue.clone(),
+            views: Vec::new(),
+            samplers: vec![default_sampler(device)],
+            no_views: vec![null_view.clone()],
+            null_view,
+            view_count: 0,
+        }
+    }
+
+    pub fn views(&self) -> Vec<&TextureView> {
+        if self.views.is_empty() {
+            &self.no_views
+        } else {
+            &self.views
+        }
+        .iter()
+        .by_ref()
+        .collect()
+    }
+
+    pub fn samplers(&self) -> Vec<&Sampler> {
+        self.samplers.iter().by_ref().collect()
+    }
+
+    pub fn view_count(&self) -> usize {
+        self.view_count
+    }
+}
+
+pub fn null_texture_view(device: &Device) -> TextureView {
+    device
+        .create_texture(&TextureDescriptor {
+            label: Some("null"),
+            size: Extent3d {
+                width: 1,
+                height: 1,
+                depth_or_array_layers: 1,
+            },
+            mip_level_count: 1,
+            sample_count: 1,
+            dimension: TextureDimension::D2,
+            format: TextureFormat::Rgba8Unorm,
+            usage: TextureUsages::TEXTURE_BINDING,
+            view_formats: &[],
+        })
+        .create_view(&TextureViewDescriptor::default())
+}
+
+pub fn default_sampler(device: &Device) -> Sampler {
+    device.create_sampler(&SamplerDescriptor::default())
+}

core/src/render/util/mod.rs

@@ -32,7 +32,7 @@ impl<T: Pod> ArrBuf<T> {
     fn init_buf(device: &Device, size: usize, usage: BufferUsages, label: &'static str) -> Buffer {
         let mut size = size as u64;
         if usage.contains(BufferUsages::STORAGE) {
-            size = size.max(1);
+            size = size.max(std::mem::size_of::<T>() as u64);
         }
         device.create_buffer(&BufferDescriptor {
             label: Some(label),

core/src/ui/active.rs

@@ -0,0 +1,14 @@
+use crate::{LayerId, MaskIdx, PrimitiveHandle, TextureHandle, UiRegion, WidgetId};
+
+/// important non rendering data for retained drawing
+#[derive(Debug)]
+pub struct ActiveData {
+    pub id: WidgetId,
+    pub region: UiRegion,
+    pub parent: Option<WidgetId>,
+    pub textures: Vec<TextureHandle>,
+    pub primitives: Vec<PrimitiveHandle>,
+    pub children: Vec<WidgetId>,
+    pub mask: MaskIdx,
+    pub layer: LayerId,
+}

core/src/ui/cache.rs

@@ -0,0 +1,18 @@
+use crate::{BothAxis, Len, UiVec2, WidgetId, util::HashMap};
+
+#[derive(Default)]
+pub struct Cache {
+    pub size: BothAxis<HashMap<WidgetId, (UiVec2, Len)>>,
+}
+
+impl Cache {
+    pub fn remove(&mut self, id: WidgetId) {
+        self.size.x.remove(&id);
+        self.size.y.remove(&id);
+    }
+
+    pub fn clear(&mut self) {
+        self.size.x.clear();
+        self.size.y.clear();
+    }
+}

core/src/ui/draw_state.rs

@@ -0,0 +1,235 @@
+use crate::{
+    ActiveData, Axis, EventsLike, Painter, SizeCtx, Ui, UiRegion, UiVec2, WidgetId,
+    render::MaskIdx,
+    util::{HashSet, forget_ref},
+};
+use std::ops::{Deref, DerefMut};
+
+/// state maintained between widgets during painting
+pub struct DrawState<'a> {
+    pub(super) ui: &'a mut Ui,
+    pub(super) events: &'a mut dyn EventsLike,
+    draw_started: HashSet<WidgetId>,
+}
+
+impl<'a> DrawState<'a> {
+    pub fn new(ui: &'a mut Ui, events: &'a mut dyn EventsLike) -> Self {
+        Self {
+            ui,
+            events,
+            draw_started: Default::default(),
+        }
+    }
+
+    pub fn redraw_updates(&mut self) {
+        while let Some(&id) = self.widgets.needs_redraw.iter().next() {
+            self.redraw(id);
+        }
+        self.ui.free(self.events);
+    }
+
+    /// redraws a widget that's currently active (drawn)
+    pub fn redraw(&mut self, id: WidgetId) {
+        self.widgets.needs_redraw.remove(&id);
+        self.draw_started.remove(&id);
+        // check if parent depends on the desired size of this, if so then redraw it first
+        for axis in [Axis::X, Axis::Y] {
+            if let Some(&(outer, old)) = self.cache.size.axis_dyn(axis).get(&id)
+                && let Some(current) = self.active.get(&id)
+                && let Some(pid) = current.parent
+            {
+                self.cache.size.axis_dyn(axis).remove(&id);
+                let new = self.size_ctx(id, outer).len_axis(id, axis);
+                self.cache.size.axis_dyn(axis).insert(id, (outer, new));
+                if new != old {
+                    self.redraw(pid);
+                }
+            }
+        }
+
+        if self.draw_started.contains(&id) {
+            return;
+        }
+
+        let Some(active) = self.remove(id, false) else {
+            return;
+        };
+
+        self.draw_inner(
+            active.layer,
+            id,
+            active.region,
+            active.parent,
+            active.mask,
+            Some(active.children),
+        );
+    }
+
+    pub(super) fn size_ctx<'b>(&'b mut self, source: WidgetId, outer: UiVec2) -> SizeCtx<'b> {
+        SizeCtx {
+            source,
+            cache: &mut self.ui.cache,
+            text: &mut self.ui.text,
+            textures: &mut self.ui.textures,
+            widgets: &self.ui.widgets,
+            outer,
+            output_size: self.ui.output_size,
+            id: source,
+        }
+    }
+
+    pub fn redraw_all(&mut self) {
+        // free all resources & cache
+        for (id, active) in self.ui.active.drain() {
+            let data = self.ui.widgets.data(id).unwrap();
+            self.events.undraw(data, &active);
+        }
+        self.ui.cache.clear();
+        self.ui.free(self.events);
+        self.layers.clear();
+        self.widgets.needs_redraw.clear();
+
+        if let Some(id) = &self.ui.root {
+            self.draw_inner(0, id.id(), UiRegion::FULL, None, MaskIdx::NONE, None);
+        }
+    }
+
+    pub(super) fn draw_inner(
+        &mut self,
+        layer: usize,
+        id: WidgetId,
+        region: UiRegion,
+        parent: Option<WidgetId>,
+        mask: MaskIdx,
+        old_children: Option<Vec<WidgetId>>,
+    ) {
+        let mut old_children = old_children.unwrap_or_default();
+        if let Some(active) = self.ui.active.get_mut(&id)
+            && !self.ui.widgets.needs_redraw.contains(&id)
+        {
+            // check to see if we can skip drawing first
+            if active.region == region {
+                return;
+            } else if active.region.size() == region.size() {
+                // TODO: epsilon?
+                let from = active.region;
+                self.mov(id, from, region);
+                return;
+            }
+            // if not, then maintain resize and track old children to remove unneeded
+            let active = self.remove(id, false).unwrap();
+            old_children = active.children;
+        }
+
+        // draw widget
+        self.draw_started.insert(id);
+
+        let mut painter = Painter {
+            state: self,
+            region,
+            mask,
+            layer,
+            id,
+            textures: Vec::new(),
+            primitives: Vec::new(),
+            children: Vec::new(),
+        };
+
+        let mut widget = painter.state.widgets.get_dyn_dynamic(id);
+        widget.draw(&mut painter);
+        drop(widget);
+
+        let Painter {
+            state: _,
+            region,
+            mask,
+            textures,
+            primitives,
+            children,
+            layer,
+            id,
+        } = painter;
+
+        // add to active
+        let active = ActiveData {
+            id,
+            region,
+            parent,
+            textures,
+            primitives,
+            children,
+            mask,
+            layer,
+        };
+
+        // remove old children that weren't kept
+        for c in &old_children {
+            if !active.children.contains(c) {
+                self.remove_rec(*c);
+            }
+        }
+
+        // update modules
+        let data = self.ui.widgets.data(id).unwrap();
+        self.events.draw(data, &active);
+        self.active.insert(id, active);
+    }
+
+    fn mov(&mut self, id: WidgetId, from: UiRegion, to: UiRegion) {
+        let active = self.ui.active.get_mut(&id).unwrap();
+        for h in &active.primitives {
+            let region = self.ui.layers[h.layer].region_mut(h);
+            *region = region.outside(&from).within(&to);
+        }
+        active.region = active.region.outside(&from).within(&to);
+        // SAFETY: children cannot be recursive
+        let children = unsafe { forget_ref(&active.children) };
+        for child in children {
+            self.mov(*child, from, to);
+        }
+    }
+
+    /// NOTE: instance textures are cleared and self.textures freed
+    fn remove(&mut self, id: WidgetId, undraw: bool) -> Option<ActiveData> {
+        let mut active = self.active.remove(&id);
+        if let Some(active) = &mut active {
+            for h in &active.primitives {
+                let mask = self.layers.free(h);
+                if mask != MaskIdx::NONE {
+                    self.masks.remove(mask);
+                }
+            }
+            active.textures.clear();
+            self.textures.free();
+            if undraw {
+                let data = self.ui.widgets.data(id).unwrap();
+                self.events.undraw(data, active);
+            }
+        }
+        active
+    }
+
+    fn remove_rec(&mut self, id: WidgetId) -> Option<ActiveData> {
+        self.cache.remove(id);
+        let inst = self.remove(id, true);
+        if let Some(inst) = &inst {
+            for c in &inst.children {
+                self.remove_rec(*c);
+            }
+        }
+        inst
+    }
+}
+
+impl Deref for DrawState<'_> {
+    type Target = Ui;
+
+    fn deref(&self) -> &Self::Target {
+        self.ui
+    }
+}
+impl DerefMut for DrawState<'_> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        self.ui
+    }
+}

core/src/ui/mod.rs

@@ -0,0 +1,217 @@
+use crate::{
+    EventsLike, IdLike, Mask, PixelRegion, PrimitiveLayers, TextData, TextureHandle, Textures,
+    Widget, WidgetHandle, WidgetId, Widgets,
+    ui::draw_state::DrawState,
+    util::{HashMap, TrackedArena, Vec2},
+};
+use image::DynamicImage;
+use std::{
+    ops::{Index, IndexMut},
+    sync::mpsc::{Receiver, channel},
+};
+
+mod active;
+mod cache;
+mod draw_state;
+mod painter;
+mod size;
+mod state;
+
+pub use active::*;
+use cache::*;
+pub use painter::Painter;
+pub use size::*;
+
+pub struct Ui {
+    // TODO: edit visibilities
+    pub widgets: Widgets,
+
+    // retained painter state
+    pub active: HashMap<WidgetId, ActiveData>,
+    pub layers: PrimitiveLayers,
+    pub textures: Textures,
+    pub text: TextData,
+    output_size: Vec2,
+    pub masks: TrackedArena<Mask, u32>,
+    pub cache: Cache,
+
+    pub root: Option<WidgetHandle>,
+    old_root: Option<WidgetId>,
+    recv: Receiver<WidgetId>,
+    resized: bool,
+}
+
+pub trait HasUi: Sized {
+    fn get(&self) -> &Ui;
+    fn get_mut(&mut self) -> &mut Ui;
+    fn ui(&self) -> &Ui {
+        self.get()
+    }
+    fn ui_mut(&mut self) -> &mut Ui {
+        self.get_mut()
+    }
+}
+
+impl HasUi for Ui {
+    fn get(&self) -> &Ui {
+        self
+    }
+
+    fn get_mut(&mut self) -> &mut Ui {
+        self
+    }
+}
+
+impl Ui {
+    /// useful for debugging
+    pub fn set_label(&mut self, id: impl IdLike, label: String) {
+        self.widgets.data_mut(id.id()).unwrap().label = label;
+    }
+
+    pub fn label(&self, id: impl IdLike) -> &String {
+        &self.widgets.data(id.id()).unwrap().label
+    }
+
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn get<I: IdLike>(&self, id: &I) -> Option<&I::Widget>
+    where
+        I::Widget: Sized + Widget,
+    {
+        self.widgets.get(id)
+    }
+
+    pub fn get_mut<I: IdLike>(&mut self, id: &I) -> Option<&mut I::Widget>
+    where
+        I::Widget: Sized + Widget,
+    {
+        self.widgets.get_mut(id)
+    }
+
+    pub fn add_texture(&mut self, image: DynamicImage) -> TextureHandle {
+        self.textures.add(image)
+    }
+
+    pub fn resize(&mut self, size: impl Into<Vec2>) {
+        self.output_size = size.into();
+        self.resized = true;
+    }
+
+    pub fn update(&mut self, events: &mut dyn EventsLike) {
+        if !self.widgets.waiting.is_empty() {
+            let len = self.widgets.waiting.len();
+            let all: Vec<_> = self
+                .widgets
+                .waiting
+                .iter()
+                .map(|&w| format!("'{}' ({w:?})", self.label(w)))
+                .collect();
+            panic!(
+                "{len} widget(s) were never upgraded\n\
+                this is likely a memory leak; consider upgrading to strong if you plan on using it later\n\
+                weak widgets: {all:#?}"
+            );
+        }
+        if self.root_changed() {
+            DrawState::new(self, events).redraw_all();
+            self.old_root = self.root.as_ref().map(|r| r.id());
+        } else if self.widgets.has_updates() {
+            DrawState::new(self, events).redraw_updates();
+        }
+        if self.resized {
+            self.resized = false;
+            DrawState::new(self, events).redraw_all();
+        }
+    }
+
+    /// free any resources that don't have references anymore
+    fn free(&mut self, events: &mut dyn EventsLike) {
+        for id in self.recv.try_iter() {
+            events.remove(id);
+            self.widgets.delete(id);
+        }
+        self.textures.free();
+    }
+
+    pub fn root_changed(&self) -> bool {
+        self.root.as_ref().map(|r| r.id()) != self.old_root
+    }
+
+    pub fn needs_redraw(&self) -> bool {
+        self.root_changed() || self.widgets.has_updates()
+    }
+
+    pub fn num_widgets(&self) -> usize {
+        self.widgets.len()
+    }
+
+    pub fn active_widgets(&self) -> usize {
+        self.active.len()
+    }
+
+    pub fn debug_layers(&self) {
+        for ((idx, depth), primitives) in self.layers.iter_depth() {
+            let indent = " ".repeat(depth * 2);
+            let len = primitives.instances().len();
+            print!("{indent}{idx}: {len} primitives");
+            if len >= 1 {
+                print!(" ({})", primitives.instances()[0].binding);
+            }
+            println!();
+        }
+    }
+
+    pub fn window_region(&self, id: &impl IdLike) -> Option<PixelRegion> {
+        let region = self.active.get(&id.id())?.region;
+        Some(region.to_px(self.output_size))
+    }
+
+    pub fn debug(&self, label: &str) -> impl Iterator<Item = &ActiveData> {
+        self.active.iter().filter_map(move |(&id, inst)| {
+            let l = self.widgets.label(id);
+            if l == label { Some(inst) } else { None }
+        })
+    }
+}
+
+impl<I: IdLike> Index<I> for Ui
+where
+    I::Widget: Sized + Widget,
+{
+    type Output = I::Widget;
+
+    fn index(&self, id: I) -> &Self::Output {
+        self.get(&id).unwrap()
+    }
+}
+
+impl<I: IdLike> IndexMut<I> for Ui
+where
+    I::Widget: Sized + Widget,
+{
+    fn index_mut(&mut self, id: I) -> &mut Self::Output {
+        self.get_mut(&id).unwrap()
+    }
+}
+
+impl Default for Ui {
+    fn default() -> Self {
+        let (send, recv) = channel();
+        Self {
+            widgets: Widgets::new(send),
+            active: Default::default(),
+            layers: Default::default(),
+            masks: Default::default(),
+            text: Default::default(),
+            textures: Default::default(),
+            cache: Default::default(),
+            output_size: Vec2::ZERO,
+            root: None,
+            old_root: None,
+            recv,
+            resized: false,
+        }
+    }
+}

core/src/ui/painter.rs

@@ -0,0 +1,140 @@
+use crate::{
+    Axis, Len, RenderedText, Size, SizeCtx, TextAttrs, TextBuffer, TextData, TextureHandle,
+    UiRegion, Widget, WidgetHandle, WidgetId,
+    render::{Mask, MaskIdx, Primitive, PrimitiveHandle, PrimitiveInst},
+    ui::draw_state::DrawState,
+    util::Vec2,
+};
+
+/// makes your surfaces look pretty
+pub struct Painter<'a, 'b> {
+    pub(super) state: &'a mut DrawState<'b>,
+
+    pub(super) region: UiRegion,
+    pub(super) mask: MaskIdx,
+    pub(super) textures: Vec<TextureHandle>,
+    pub(super) primitives: Vec<PrimitiveHandle>,
+    pub(super) children: Vec<WidgetId>,
+    pub layer: usize,
+    pub(super) id: WidgetId,
+}
+
+impl<'a, 'c> Painter<'a, 'c> {
+    fn primitive_at<P: Primitive>(&mut self, primitive: P, region: UiRegion) {
+        let h = self.state.layers.write(
+            self.layer,
+            PrimitiveInst {
+                id: self.id,
+                primitive,
+                region,
+                mask_idx: self.mask,
+            },
+        );
+        if self.mask != MaskIdx::NONE {
+            // TODO: I have no clue if this works at all :joy:
+            self.state.masks.push_ref(self.mask);
+        }
+        self.primitives.push(h);
+    }
+
+    /// Writes a primitive to be rendered
+    pub fn primitive<P: Primitive>(&mut self, primitive: P) {
+        self.primitive_at(primitive, self.region)
+    }
+
+    pub fn primitive_within<P: Primitive>(&mut self, primitive: P, region: UiRegion) {
+        self.primitive_at(primitive, region.within(&self.region));
+    }
+
+    pub fn set_mask(&mut self, region: UiRegion) {
+        assert!(self.mask == MaskIdx::NONE);
+        self.mask = self.state.masks.push(Mask { region });
+    }
+
+    /// Draws a widget within this widget's region.
+    pub fn widget<W: ?Sized>(&mut self, id: &WidgetHandle<W>) {
+        self.widget_at(id, self.region);
+    }
+
+    /// Draws a widget somewhere within this one.
+    /// Useful for drawing child widgets in select areas.
+    pub fn widget_within<W: ?Sized>(&mut self, id: &WidgetHandle<W>, region: UiRegion) {
+        self.widget_at(id, region.within(&self.region));
+    }
+
+    fn widget_at<W: ?Sized>(&mut self, id: &WidgetHandle<W>, region: UiRegion) {
+        self.children.push(id.id());
+        self.state
+            .draw_inner(self.layer, id.id(), region, Some(self.id), self.mask, None);
+    }
+
+    pub fn texture_within(&mut self, handle: &TextureHandle, region: UiRegion) {
+        self.textures.push(handle.clone());
+        self.primitive_at(handle.primitive(), region.within(&self.region));
+    }
+
+    pub fn texture(&mut self, handle: &TextureHandle) {
+        self.textures.push(handle.clone());
+        self.primitive(handle.primitive());
+    }
+
+    pub fn texture_at(&mut self, handle: &TextureHandle, region: UiRegion) {
+        self.textures.push(handle.clone());
+        self.primitive_at(handle.primitive(), region);
+    }
+
+    /// returns (handle, offset from top left)
+    pub fn render_text(&mut self, buffer: &mut TextBuffer, attrs: &TextAttrs) -> RenderedText {
+        self.state
+            .ui
+            .text
+            .draw(buffer, attrs, &mut self.state.ui.textures)
+    }
+
+    pub fn region(&self) -> UiRegion {
+        self.region
+    }
+
+    pub fn size<W: ?Sized + Widget>(&mut self, id: &WidgetHandle<W>) -> Size {
+        self.size_ctx().size(id)
+    }
+
+    pub fn len_axis<W: ?Sized + Widget>(&mut self, id: &WidgetHandle<W>, axis: Axis) -> Len {
+        match axis {
+            Axis::X => self.size_ctx().width(id),
+            Axis::Y => self.size_ctx().height(id),
+        }
+    }
+
+    pub fn output_size(&self) -> Vec2 {
+        self.state.output_size
+    }
+
+    pub fn px_size(&mut self) -> Vec2 {
+        self.region.size().to_abs(self.state.output_size)
+    }
+
+    pub fn text_data(&mut self) -> &mut TextData {
+        &mut self.state.text
+    }
+
+    pub fn child_layer(&mut self) {
+        self.layer = self.state.layers.child(self.layer);
+    }
+
+    pub fn next_layer(&mut self) {
+        self.layer = self.state.layers.next(self.layer);
+    }
+
+    pub fn label(&self) -> &str {
+        &self.state.widgets.data(self.id).unwrap().label
+    }
+
+    pub fn id(&self) -> &WidgetId {
+        &self.id
+    }
+
+    pub fn size_ctx(&mut self) -> SizeCtx<'_> {
+        self.state.size_ctx(self.id, self.region.size())
+    }
+}

core/src/ui/size.rs

@@ -0,0 +1,86 @@
+use crate::{
+    Axis, AxisT, IdLike, Len, RenderedText, Size, TextAttrs, TextBuffer, TextData, Textures,
+    UiVec2, WidgetAxisFns, WidgetId, Widgets, XAxis, YAxis, ui::cache::Cache, util::Vec2,
+};
+
+pub struct SizeCtx<'a> {
+    pub text: &'a mut TextData,
+    pub textures: &'a mut Textures,
+    pub(super) source: WidgetId,
+    pub(super) widgets: &'a Widgets,
+    pub(super) cache: &'a mut Cache,
+    /// TODO: should this be pub? rn used for sized
+    pub outer: UiVec2,
+    pub(super) output_size: Vec2,
+    pub(super) id: WidgetId,
+}
+
+impl SizeCtx<'_> {
+    pub fn id(&self) -> &WidgetId {
+        &self.id
+    }
+
+    pub fn source(&self) -> &WidgetId {
+        &self.source
+    }
+
+    pub(super) fn len_inner<A: const AxisT>(&mut self, id: WidgetId) -> Len {
+        if let Some((_, len)) = self.cache.size.axis::<A>().get(&id) {
+            return *len;
+        }
+        let len = self
+            .widgets
+            .get_dyn_dynamic(id)
+            .desired_len::<A>(&mut SizeCtx {
+                text: self.text,
+                textures: self.textures,
+                source: self.source,
+                widgets: self.widgets,
+                cache: self.cache,
+                outer: self.outer,
+                output_size: self.output_size,
+                id,
+            });
+        self.cache.size.axis::<A>().insert(id, (self.outer, len));
+        len
+    }
+
+    pub fn width(&mut self, id: impl IdLike) -> Len {
+        self.len_inner::<XAxis>(id.id())
+    }
+
+    pub fn height(&mut self, id: impl IdLike) -> Len {
+        self.len_inner::<YAxis>(id.id())
+    }
+
+    pub fn len_axis(&mut self, id: impl IdLike, axis: Axis) -> Len {
+        match axis {
+            Axis::X => self.width(id),
+            Axis::Y => self.height(id),
+        }
+    }
+
+    pub fn size(&mut self, id: impl IdLike) -> Size {
+        let id = id.id();
+        Size {
+            x: self.width(id),
+            y: self.height(id),
+        }
+    }
+
+    pub fn px_size(&mut self) -> Vec2 {
+        self.outer.to_abs(self.output_size)
+    }
+
+    pub fn output_size(&mut self) -> Vec2 {
+        self.output_size
+    }
+
+    pub fn draw_text(&mut self, buffer: &mut TextBuffer, attrs: &TextAttrs) -> RenderedText {
+        self.text.draw(buffer, attrs, self.textures)
+    }
+
+    pub fn label(&self, id: WidgetId) -> &String {
+        self.widgets.label(id)
+    }
+}

core/src/ui/state.rs

@@ -0,0 +1,3 @@
+// pub struct DynState {
+//
+// }

core/src/util/arena.rs

@@ -0,0 +1,109 @@
+use std::ops::Deref;
+
+use crate::util::{Id, IdNum, IdTracker};
+
+pub struct Arena<T, I> {
+    data: Vec<T>,
+    tracker: IdTracker<I>,
+}
+
+impl<T, I: IdNum> Arena<T, I> {
+    pub fn new() -> Self {
+        Self {
+            data: Vec::new(),
+            tracker: IdTracker::default(),
+        }
+    }
+
+    pub fn push(&mut self, value: T) -> Id<I> {
+        let id = self.tracker.next();
+        let i = id.idx();
+        if i == self.data.len() {
+            self.data.push(value);
+        } else {
+            self.data[i] = value;
+        }
+        id
+    }
+
+    pub fn remove(&mut self, id: Id<I>) -> T
+    where
+        T: Copy,
+    {
+        let i = id.idx();
+        self.tracker.free(id);
+        self.data[i]
+    }
+}
+
+impl<T, I: IdNum> Default for Arena<T, I> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+pub struct TrackedArena<T, I> {
+    inner: Arena<T, I>,
+    refs: Vec<u32>,
+    pub changed: bool,
+}
+
+impl<T, I: IdNum> TrackedArena<T, I> {
+    pub fn new() -> Self {
+        Self {
+            inner: Arena::default(),
+            refs: Vec::new(),
+            changed: true,
+        }
+    }
+
+    pub fn push(&mut self, value: T) -> Id<I> {
+        self.changed = true;
+        let id = self.inner.push(value);
+        let i = id.idx();
+        if i == self.refs.len() {
+            self.refs.push(0);
+        }
+        id
+    }
+
+    pub fn push_ref(&mut self, i: Id<I>) {
+        self.refs[i.idx()] += 1;
+    }
+
+    pub fn remove(&mut self, id: Id<I>) -> T
+    where
+        T: Copy,
+    {
+        let i = id.idx();
+        self.refs[i] -= 1;
+        if self.refs[i] == 0 {
+            self.changed = true;
+            self.inner.remove(id)
+        } else {
+            self[i]
+        }
+    }
+}
+
+impl<T, I: IdNum> Default for TrackedArena<T, I> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl<T, I> Deref for TrackedArena<T, I> {
+    type Target = Vec<T>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.inner.data
+    }
+}
+
+impl<T, I> Deref for Arena<T, I> {
+    type Target = Vec<T>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.data
+    }
+}

core/src/util/borrow.rs

@@ -0,0 +1,35 @@
+use std::ops::{Deref, DerefMut};
+
+pub struct DynBorrower<'a, T: ?Sized> {
+    data: &'a mut T,
+    borrowed: &'a mut bool,
+}
+
+impl<'a, T: ?Sized> DynBorrower<'a, T> {
+    pub fn new(data: &'a mut T, borrowed: &'a mut bool) -> Self {
+        if *borrowed {
+            panic!("tried to mutably borrow the same thing twice");
+        }
+        Self { data, borrowed }
+    }
+}
+
+impl<T: ?Sized> Drop for DynBorrower<'_, T> {
+    fn drop(&mut self) {
+        *self.borrowed = false;
+    }
+}
+
+impl<T: ?Sized> Deref for DynBorrower<'_, T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        self.data
+    }
+}
+
+impl<T: ?Sized> DerefMut for DynBorrower<'_, T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        self.data
+    }
+}

core/src/util/change.rs

@@ -0,0 +1,30 @@
+use std::ops::{Deref, DerefMut};
+
+pub struct MutDetect<T> {
+    inner: T,
+    pub changed: bool,
+}
+
+impl<T> Deref for MutDetect<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        &self.inner
+    }
+}
+
+impl<T> DerefMut for MutDetect<T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        self.changed = true;
+        &mut self.inner
+    }
+}
+
+impl<T> From<T> for MutDetect<T> {
+    fn from(inner: T) -> Self {
+        MutDetect {
+            inner,
+            changed: true,
+        }
+    }
+}

core/src/util/id.rs

@@ -0,0 +1,87 @@
+#[repr(C)]
+#[derive(Eq, Hash, PartialEq, Debug, Clone, Copy, bytemuck::Zeroable)]
+pub struct Id<I = u64>(I);
+
+unsafe impl<I: Copy + bytemuck::Zeroable + 'static> bytemuck::Pod for Id<I> {}
+
+pub struct IdTracker<I = u64> {
+    free: Vec<Id<I>>,
+    cur: Id<I>,
+}
+
+impl<I: IdNum> IdTracker<I> {
+    #[allow(clippy::should_implement_trait)]
+    pub fn next(&mut self) -> Id<I> {
+        if let Some(id) = self.free.pop() {
+            return id;
+        }
+        let next = self.cur.next();
+        std::mem::replace(&mut self.cur, next)
+    }
+
+    #[allow(dead_code)]
+    pub fn free(&mut self, id: Id<I>) {
+        self.free.push(id);
+    }
+}
+
+impl<I: IdNum> Id<I> {
+    #[allow(dead_code)]
+    /// for debug purposes; should this be exposed?
+    /// generally you want to use labels with widgets
+    pub(crate) fn raw(id: I) -> Self {
+        Self(id)
+    }
+    pub fn idx(&self) -> usize {
+        self.0.idx()
+    }
+    pub fn next(&self) -> Id<I> {
+        Self(self.0.next())
+    }
+    pub const fn preset(value: I) -> Self {
+        Self(value)
+    }
+}
+
+impl<I: IdNum> Default for IdTracker<I> {
+    fn default() -> Self {
+        Self {
+            free: Vec::new(),
+            cur: Id(I::first()),
+        }
+    }
+}
+
+pub trait IdNum {
+    fn first() -> Self;
+    fn next(&self) -> Self;
+    fn idx(&self) -> usize;
+}
+
+impl IdNum for u64 {
+    fn first() -> Self {
+        0
+    }
+
+    fn next(&self) -> Self {
+        self + 1
+    }
+
+    fn idx(&self) -> usize {
+        *self as usize
+    }
+}
+
+impl IdNum for u32 {
+    fn first() -> Self {
+        0
+    }
+
+    fn next(&self) -> Self {
+        self + 1
+    }
+
+    fn idx(&self) -> usize {
+        *self as usize
+    }
+}

core/src/util/math.rs

@@ -0,0 +1,87 @@
+use std::ops::*;
+
+pub const trait LerpUtil {
+    fn lerp(self, from: Self, to: Self) -> Self;
+    fn lerp_inv(self, from: Self, to: Self) -> Self;
+}
+
+pub const trait DivOr {
+    fn div_or(self, rhs: Self, other: Self) -> Self;
+}
+
+impl const DivOr for f32 {
+    fn div_or(self, rhs: Self, other: Self) -> Self {
+        let res = self / rhs;
+        if res.is_nan() { other } else { res }
+    }
+}
+
+impl<T: const Add<Output = T> + const Sub<Output = T> + const Mul<Output = T> + const DivOr + Copy> const
+    LerpUtil for T
+{
+    /// linear interpolation
+    /// from * (1.0 - self) + to * self
+    fn lerp(self, from: Self, to: Self) -> Self {
+        from + (to - from) * self
+    }
+    /// inverse of lerp
+    fn lerp_inv(self, from: Self, to: Self) -> Self {
+        (self - from).div_or(to - from, from)
+    }
+}
+
+macro_rules! impl_op {
+    ($T:ident $op:ident $fn:ident $opa:ident $fna:ident; $($field:ident)*) => {
+        #[allow(non_snake_case)]
+        mod ${concat($T, _op_, $fn, _impl)} {
+            use super::*;
+            #[allow(unused_imports)]
+            use std::ops::*;
+            impl const $op for $T {
+                type Output = Self;
+
+                fn $fn(self, rhs: Self) -> Self::Output {
+                    Self {
+                        $($field: self.$field.$fn(rhs.$field),)*
+                    }
+                }
+            }
+            impl const $opa for $T {
+                fn $fna(&mut self, rhs: Self) {
+                    *self = self.$fn(rhs);
+                }
+            }
+            impl const $op<f32> for $T {
+                type Output = Self;
+
+                fn $fn(self, rhs: f32) -> Self::Output {
+                    Self {
+                        $($field: self.$field.$fn(rhs),)*
+                    }
+                }
+            }
+            impl const $op<$T> for f32 {
+                type Output = $T;
+
+                fn $fn(self, rhs: $T) -> Self::Output {
+                    $T {
+                        $($field: self.$fn(rhs.$field),)*
+                    }
+                }
+            }
+            impl const $opa<f32> for $T {
+                fn $fna(&mut self, rhs: f32) {
+                    *self = self.$fn(rhs);
+                }
+            }
+        }
+    };
+    ($T:ident $op:ident $fn:ident; $($field:ident)*) => {
+        impl_op!($T $op $fn ${concat($op,Assign)} ${concat($fn,_assign)}; $($field)*);
+    };
+    (impl $op:ident for $T:ident: $fn:ident $($field:ident)*) => {
+        impl_op!($T $op $fn ${concat($op,Assign)} ${concat($fn,_assign)}; $($field)*);
+    };
+}
+
+pub(crate) use impl_op;

core/src/util/mod.rs

@@ -0,0 +1,24 @@
+mod arena;
+mod borrow;
+mod change;
+mod id;
+mod math;
+mod refcount;
+mod slot;
+mod trust;
+mod typemap;
+mod vec2;
+
+pub use arena::*;
+pub use borrow::*;
+pub use change::*;
+pub use id::*;
+pub use math::*;
+pub use refcount::*;
+pub use slot::*;
+pub use trust::*;
+pub use typemap::*;
+pub use vec2::*;
+
+pub type HashMap<K, V> = fxhash::FxHashMap<K, V>;
+pub type HashSet<K> = fxhash::FxHashSet<K>;

core/src/util/refcount.rs

@@ -0,0 +1,36 @@
+use std::sync::{
+    Arc,
+    atomic::{AtomicU32, Ordering},
+};
+
+#[derive(Debug)]
+pub struct RefCounter(Arc<AtomicU32>);
+
+impl RefCounter {
+    pub fn new() -> Self {
+        Self(Arc::new(0.into()))
+    }
+    pub fn refs(&self) -> u32 {
+        self.0.load(Ordering::Acquire)
+    }
+    pub fn drop(&mut self) -> bool {
+        let refs = self.0.fetch_sub(1, Ordering::Release);
+        refs == 0
+    }
+    pub fn quiet_clone(&self) -> Self {
+        Self(self.0.clone())
+    }
+}
+
+impl Default for RefCounter {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl Clone for RefCounter {
+    fn clone(&self) -> Self {
+        self.0.fetch_add(1, Ordering::Release);
+        Self(self.0.clone())
+    }
+}

core/src/util/slot.rs

@@ -0,0 +1,69 @@
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub struct SlotId {
+    idx: u32,
+    genr: u32,
+}
+
+pub struct SlotVec<T> {
+    data: Vec<(u32, Option<T>)>,
+    free: Vec<u32>,
+}
+
+impl<T> SlotVec<T> {
+    pub fn new() -> Self {
+        Self {
+            data: Default::default(),
+            free: Default::default(),
+        }
+    }
+
+    pub fn add(&mut self, x: T) -> SlotId {
+        if let Some(idx) = self.free.pop() {
+            let (genr, data) = &mut self.data[idx as usize];
+            *data = Some(x);
+            SlotId { idx, genr: *genr }
+        } else {
+            let idx = self.data.len() as u32;
+            let genr = 0;
+            self.data.push((genr, Some(x)));
+            SlotId { idx, genr }
+        }
+    }
+
+    pub fn free(&mut self, id: SlotId) {
+        let (genr, data) = &mut self.data[id.idx as usize];
+        *genr += 1;
+        *data = None;
+        self.free.push(id.idx);
+    }
+
+    pub fn get(&self, id: SlotId) -> Option<&T> {
+        let slot = &self.data[id.idx as usize];
+        if slot.0 != id.genr {
+            return None;
+        }
+        slot.1.as_ref()
+    }
+
+    pub fn get_mut(&mut self, id: SlotId) -> Option<&mut T> {
+        let slot = &mut self.data[id.idx as usize];
+        if slot.0 != id.genr {
+            return None;
+        }
+        slot.1.as_mut()
+    }
+
+    pub fn len(&self) -> usize {
+        self.data.len() - self.free.len()
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+}
+
+impl<T> Default for SlotVec<T> {
+    fn default() -> Self {
+        Self::new()
+    }
+}

core/src/util/trust.rs

@@ -0,0 +1,17 @@
+#[allow(clippy::missing_safety_doc)]
+pub unsafe fn forget_ref<'a, T>(x: &T) -> &'a T {
+    unsafe { std::mem::transmute::<&T, &T>(x) }
+}
+
+#[allow(clippy::missing_safety_doc)]
+pub unsafe fn forget_mut<'a, T>(x: &mut T) -> &'a mut T {
+    unsafe { std::mem::transmute::<&mut T, &mut T>(x) }
+}
+
+#[allow(clippy::mut_from_ref, clippy::missing_safety_doc)]
+pub unsafe fn to_mut<T>(x: &T) -> &mut T {
+    #[allow(mutable_transmutes)]
+    unsafe {
+        std::mem::transmute::<&T, &mut T>(x)
+    }
+}

core/src/util/typemap.rs

@@ -0,0 +1,56 @@
+use crate::util::HashMap;
+use std::{
+    any::TypeId,
+    marker::Unsize,
+    ops::{Deref, DerefMut},
+};
+
+pub struct TypeMap<Trait: ?Sized> {
+    map: HashMap<TypeId, Box<Trait>>,
+}
+
+impl<Trait: ?Sized> TypeMap<Trait> {
+    pub fn set_type<T: Unsize<Trait> + 'static>(&mut self, val: T) {
+        self.map
+            .insert(TypeId::of::<T>(), Box::new(val) as Box<Trait>);
+    }
+
+    pub fn type_mut<T: Unsize<Trait> + 'static>(&mut self) -> Option<&mut T> {
+        Some(Self::convert_mut(self.map.get_mut(&TypeId::of::<T>())?))
+    }
+
+    pub fn type_or_default<T: Default + Unsize<Trait> + 'static>(&mut self) -> &mut T {
+        Self::convert_mut(
+            self.map
+                .entry(TypeId::of::<T>())
+                .or_insert(Box::new(T::default()) as Box<Trait>),
+        )
+    }
+
+    fn convert_mut<T: Unsize<Trait>>(entry: &mut Box<Trait>) -> &mut T {
+        // allegedly this is just what Any does...
+        unsafe { &mut *(entry.as_mut() as *mut Trait as *mut T) }
+    }
+}
+
+impl<T: ?Sized> Deref for TypeMap<T> {
+    type Target = HashMap<TypeId, Box<T>>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.map
+    }
+}
+
+impl<T: ?Sized> DerefMut for TypeMap<T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.map
+    }
+}
+
+impl<T: ?Sized> Default for TypeMap<T> {
+    fn default() -> Self {
+        Self {
+            map: Default::default(),
+        }
+    }
+}

core/src/util/vec2.rs

@@ -0,0 +1,99 @@
+use crate::util::{DivOr, impl_op};
+use std::{hash::Hash, ops::*};
+
+#[repr(C)]
+#[derive(Clone, Copy, PartialEq, Default, bytemuck::Pod, bytemuck::Zeroable)]
+pub struct Vec2 {
+    pub x: f32,
+    pub y: f32,
+}
+
+impl Eq for Vec2 {}
+
+impl Hash for Vec2 {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        state.write_u32(self.x.to_bits());
+        state.write_u32(self.y.to_bits());
+    }
+}
+
+impl Vec2 {
+    pub const ZERO: Self = Self::new(0.0, 0.0);
+    pub const ONE: Self = Self::new(1.0, 1.0);
+
+    pub const fn new(x: f32, y: f32) -> Self {
+        Self { x, y }
+    }
+
+    pub const fn round(self) -> Self {
+        Self {
+            x: self.x.round(),
+            y: self.y.round(),
+        }
+    }
+
+    pub const fn floor(self) -> Self {
+        Self {
+            x: self.x.floor(),
+            y: self.y.floor(),
+        }
+    }
+
+    pub const fn ceil(self) -> Self {
+        Self {
+            x: self.x.ceil(),
+            y: self.y.ceil(),
+        }
+    }
+
+    pub const fn tuple(&self) -> (f32, f32) {
+        (self.x, self.y)
+    }
+
+    pub const fn with_x(mut self, x: f32) -> Self {
+        self.x = x;
+        self
+    }
+
+    pub const fn with_y(mut self, y: f32) -> Self {
+        self.y = y;
+        self
+    }
+}
+
+// this version looks kinda cool... is it more readable? more annoying to copy and change though
+impl_op!(impl Add for Vec2: add x y);
+impl_op!(Vec2 Sub sub; x y);
+impl_op!(Vec2 Mul mul; x y);
+impl_op!(Vec2 Div div; x y);
+
+impl const DivOr for Vec2 {
+    fn div_or(self, rhs: Self, other: Self) -> Self {
+        Self {
+            x: self.x.div_or(rhs.x, other.x),
+            y: self.y.div_or(rhs.y, other.y),
+        }
+    }
+}
+
+impl Neg for Vec2 {
+    type Output = Self;
+
+    fn neg(mut self) -> Self::Output {
+        self.x = -self.x;
+        self.y = -self.y;
+        self
+    }
+}
+
+impl std::fmt::Debug for Vec2 {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "({}, {})", self.x, self.y)
+    }
+}
+
+impl std::fmt::Display for Vec2 {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "({}, {})", self.x, self.y)
+    }
+}

core/src/widget/data.rs

@@ -0,0 +1,26 @@
+use std::any::TypeId;
+
+use crate::{Widget, util::HashSet};
+
+pub struct WidgetData {
+    pub widget: Box<dyn Widget>,
+    pub label: String,
+    pub event_mgrs: HashSet<TypeId>,
+    /// dynamic borrow checking
+    pub borrowed: bool,
+}
+
+impl WidgetData {
+    pub fn new<W: Widget>(widget: W) -> Self {
+        let mut label = std::any::type_name::<W>().to_string();
+        if let (Some(first), Some(last)) = (label.find(":"), label.rfind(":")) {
+            label = label.split_at(first).0.to_string() + "::" + label.split_at(last + 1).1;
+        }
+        Self {
+            widget: Box::new(widget),
+            label,
+            borrowed: false,
+            event_mgrs: Default::default(),
+        }
+    }
+}

core/src/widget/handle.rs

@@ -0,0 +1,171 @@
+use std::{marker::Unsize, ops::CoerceUnsized, sync::mpsc::Sender};
+
+use crate::{
+    HasUi, Widget,
+    util::{RefCounter, SlotId},
+};
+
+pub type WidgetId = SlotId;
+
+/// An identifier for a widget that can index a UI or event ctx to get it.
+/// This is a strong handle that does not impl Clone, and when it is dropped,
+/// a signal is sent to the owning UI to clean up the resources.
+///
+/// TODO: ergonomic clones when they get put in rust-analyzer & don't cause ICEs?
+pub struct WidgetHandle<W: ?Sized = dyn Widget> {
+    pub(super) id: WidgetId,
+    counter: RefCounter,
+    send: Sender<WidgetId>,
+    ty: *const W,
+}
+
+/// A weak handle to a widget.
+/// Will not keep it alive, but can still be used for indexing like WidgetHandle.
+pub struct WidgetRef<W: ?Sized = dyn Widget> {
+    pub(super) id: WidgetId,
+    #[allow(unused)]
+    ty: *const W,
+}
+
+pub struct WidgetHandles<W: ?Sized = dyn Widget> {
+    pub h: WidgetHandle<W>,
+    pub r: WidgetRef<W>,
+}
+
+impl<W: Widget + ?Sized + Unsize<dyn Widget>> WidgetHandle<W> {
+    pub fn any(self) -> WidgetHandle<dyn Widget> {
+        self
+    }
+}
+
+impl<W: ?Sized> WidgetHandle<W> {
+    pub(crate) fn new(id: WidgetId, send: Sender<WidgetId>) -> Self {
+        Self {
+            id,
+            counter: RefCounter::new(),
+            send,
+            ty: null_ptr(),
+        }
+    }
+
+    pub fn id(&self) -> WidgetId {
+        self.id
+    }
+
+    pub fn refs(&self) -> u32 {
+        self.counter.refs()
+    }
+
+    pub fn weak(&self) -> WidgetRef<W> {
+        let Self { ty, id, .. } = *self;
+        WidgetRef { ty, id }
+    }
+
+    pub fn handles(self) -> WidgetHandles<W> {
+        let r = self.weak();
+        WidgetHandles { h: self, r }
+    }
+}
+
+impl<W: ?Sized> WidgetRef<W> {
+    pub(crate) fn new(id: WidgetId) -> Self {
+        Self { id, ty: null_ptr() }
+    }
+
+    pub fn id(&self) -> WidgetId {
+        self.id
+    }
+
+    #[track_caller]
+    pub fn upgrade(self, ui: &mut impl HasUi) -> WidgetHandle<W> {
+        ui.ui_mut().widgets.upgrade(self)
+    }
+}
+
+impl<W: ?Sized> Drop for WidgetHandle<W> {
+    fn drop(&mut self) {
+        if self.counter.drop() {
+            let _ = self.send.send(self.id);
+        }
+    }
+}
+
+pub trait WidgetIdFn<State, W: ?Sized = dyn Widget>: FnOnce(&mut State) -> WidgetRef<W> {}
+impl<State, W: ?Sized, F: FnOnce(&mut State) -> WidgetRef<W>> WidgetIdFn<State, W> for F {}
+
+pub trait IdLike {
+    type Widget: ?Sized;
+    fn id(&self) -> WidgetId;
+}
+
+impl<W: ?Sized> IdLike for &WidgetHandle<W> {
+    type Widget = W;
+    fn id(&self) -> WidgetId {
+        self.id
+    }
+}
+
+impl<W: ?Sized> IdLike for WidgetHandle<W> {
+    type Widget = W;
+    fn id(&self) -> WidgetId {
+        self.id
+    }
+}
+
+impl<W: ?Sized> IdLike for WidgetRef<W> {
+    type Widget = W;
+    fn id(&self) -> WidgetId {
+        self.id
+    }
+}
+
+impl IdLike for WidgetId {
+    type Widget = dyn Widget;
+    fn id(&self) -> WidgetId {
+        *self
+    }
+}
+
+impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<WidgetHandle<U>> for WidgetHandle<T> {}
+impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<WidgetRef<U>> for WidgetRef<T> {}
+
+impl<W: ?Sized> Clone for WidgetRef<W> {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+impl<W: ?Sized> Copy for WidgetRef<W> {}
+impl<W: ?Sized> PartialEq for WidgetRef<W> {
+    fn eq(&self, other: &Self) -> bool {
+        self.id == other.id
+    }
+}
+
+impl<W> PartialEq for WidgetHandle<W> {
+    fn eq(&self, other: &Self) -> bool {
+        self.id == other.id
+    }
+}
+
+impl<W> std::fmt::Debug for WidgetHandle<W> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.id.fmt(f)
+    }
+}
+
+impl<'a, W: Widget + 'a, State: HasUi> FnOnce<(&'a mut State,)> for WidgetRef<W> {
+    type Output = &'a mut W;
+
+    extern "rust-call" fn call_once(self, args: (&'a mut State,)) -> Self::Output {
+        &mut args.0.ui_mut()[self]
+    }
+}
+
+fn null_ptr<W: ?Sized>() -> *const W {
+    if size_of::<&W>() == size_of::<*const dyn Widget>() {
+        let w: *const dyn Widget = &();
+        unsafe { std::mem::transmute_copy(&w) }
+    } else {
+        unsafe { std::mem::transmute_copy(&[0usize; 1]) }
+    }
+}

core/src/widget/like.rs

@@ -0,0 +1,86 @@
+use crate::{HasUi, Ui};
+
+use super::*;
+use std::marker::Unsize;
+
+pub trait StateLike<State> {
+    fn as_state(&mut self) -> &mut State;
+}
+
+impl StateLike<Ui> for Ui {
+    fn as_state(&mut self) -> &mut Ui {
+        self
+    }
+}
+
+pub trait WidgetLike<State: HasUi + StateLike<State>, Tag>: Sized {
+    type Widget: Widget + ?Sized + Unsize<dyn Widget>;
+
+    fn add(self, state: &mut impl StateLike<State>) -> WidgetRef<Self::Widget>;
+
+    fn add_strong(self, state: &mut impl StateLike<State>) -> WidgetHandle<Self::Widget> {
+        self.add(state).upgrade(state.as_state().ui_mut())
+    }
+
+    fn with_id<W2>(
+        self,
+        f: impl FnOnce(&mut State, WidgetRef<Self::Widget>) -> WidgetRef<W2>,
+    ) -> impl WidgetIdFn<State, W2> {
+        move |state| {
+            let id = self.add(state);
+            f(state, id)
+        }
+    }
+
+    fn set_root(self, state: &mut impl StateLike<State>) {
+        let id = self.add(state);
+        let ui = state.as_state().ui_mut();
+        ui.root = Some(id.upgrade(ui));
+    }
+
+    fn handles(self, state: &mut impl StateLike<State>) -> WidgetHandles<Self::Widget> {
+        self.add(state).upgrade(state.as_state().ui_mut()).handles()
+    }
+}
+
+pub trait WidgetArrLike<State, const LEN: usize, Tag> {
+    #[track_caller]
+    fn add(self, state: &mut impl StateLike<State>) -> WidgetArr<LEN>;
+}
+
+impl<State, const LEN: usize> WidgetArrLike<State, LEN, ArrTag> for WidgetArr<LEN> {
+    fn add(self, _: &mut impl StateLike<State>) -> WidgetArr<LEN> {
+        self
+    }
+}
+
+// variadic generics please save us
+macro_rules! impl_widget_arr {
+    ($n:expr;$($W:ident)*) => {
+        impl_widget_arr!($n;$($W)*;$(${concat($W,Tag)})*);
+    };
+    ($n:expr;$($W:ident)*;$($Tag:ident)*) => {
+        impl<State: HasUi + StateLike<State>, $($W: WidgetLike<State, $Tag>,$Tag,)*> WidgetArrLike<State, $n, ($($Tag,)*)> for ($($W,)*) {
+            fn add(self, state: &mut impl StateLike<State>) -> WidgetArr<$n> {
+                #[allow(non_snake_case)]
+                let ($($W,)*) = self;
+                WidgetArr::new(
+                    [$($W.add(state).upgrade(state.as_state().ui_mut()),)*],
+                )
+            }
+        }
+    };
+}
+
+impl_widget_arr!(1;A);
+impl_widget_arr!(2;A B);
+impl_widget_arr!(3;A B C);
+impl_widget_arr!(4;A B C D);
+impl_widget_arr!(5;A B C D E);
+impl_widget_arr!(6;A B C D E F);
+impl_widget_arr!(7;A B C D E F G);
+impl_widget_arr!(8;A B C D E F G H);
+impl_widget_arr!(9;A B C D E F G H I);
+impl_widget_arr!(10;A B C D E F G H I J);
+impl_widget_arr!(11;A B C D E F G H I J K);
+impl_widget_arr!(12;A B C D E F G H I J K L);

core/src/widget/mod.rs

@@ -0,0 +1,85 @@
+use crate::{Axis, AxisT, Len, Painter, SizeCtx};
+use std::any::Any;
+
+mod data;
+mod handle;
+mod like;
+mod tag;
+mod widgets;
+
+pub use data::*;
+pub use handle::*;
+pub use like::*;
+pub use tag::*;
+pub use widgets::*;
+
+pub trait Widget: Any {
+    fn draw(&mut self, painter: &mut Painter);
+    fn desired_width(&mut self, ctx: &mut SizeCtx) -> Len;
+    fn desired_height(&mut self, ctx: &mut SizeCtx) -> Len;
+}
+
+pub trait WidgetAxisFns {
+    fn desired_len<A: AxisT>(&mut self, ctx: &mut SizeCtx) -> Len;
+}
+
+impl<W: Widget + ?Sized> WidgetAxisFns for W {
+    fn desired_len<A: AxisT>(&mut self, ctx: &mut SizeCtx) -> Len {
+        match A::get() {
+            Axis::X => self.desired_width(ctx),
+            Axis::Y => self.desired_height(ctx),
+        }
+    }
+}
+
+impl Widget for () {
+    fn draw(&mut self, _: &mut Painter) {}
+    fn desired_width(&mut self, _: &mut SizeCtx) -> Len {
+        Len::ZERO
+    }
+    fn desired_height(&mut self, _: &mut SizeCtx) -> Len {
+        Len::ZERO
+    }
+}
+
+impl dyn Widget {
+    pub fn as_any(&self) -> &dyn Any {
+        self
+    }
+
+    pub fn as_any_mut(&mut self) -> &mut dyn Any {
+        self
+    }
+}
+
+/// A function that returns a widget given a UI.
+/// Useful for defining trait functions on widgets that create a parent widget so that the children
+/// don't need to be IDs yet
+pub trait WidgetFn<State, W: Widget + ?Sized>: FnOnce(&mut State) -> W {}
+impl<State, W: Widget + ?Sized, F: FnOnce(&mut State) -> W> WidgetFn<State, W> for F {}
+
+pub struct WidgetArr<const LEN: usize> {
+    pub arr: [WidgetHandle; LEN],
+}
+
+impl<const LEN: usize> WidgetArr<LEN> {
+    pub fn new(arr: [WidgetHandle; LEN]) -> Self {
+        Self { arr }
+    }
+}
+
+pub trait WidgetOption<State> {
+    fn get(self, state: &mut State) -> Option<WidgetHandle>;
+}
+
+impl<State> WidgetOption<State> for () {
+    fn get(self, _: &mut State) -> Option<WidgetHandle> {
+        None
+    }
+}
+
+impl<State, F: FnOnce(&mut State) -> Option<WidgetHandle>> WidgetOption<State> for F {
+    fn get(self, state: &mut State) -> Option<WidgetHandle> {
+        self(state)
+    }
+}

core/src/widget/tag.rs

@@ -0,0 +1,59 @@
+use super::*;
+use crate::HasUi;
+use std::marker::Unsize;
+
+pub struct WidgetTag;
+impl<State: HasUi + StateLike<State>, W: Widget> WidgetLike<State, WidgetTag> for W {
+    type Widget = W;
+    fn add(self, state: &mut impl StateLike<State>) -> WidgetRef<W> {
+        state.as_state().get_mut().widgets.add_weak(self)
+    }
+}
+
+pub struct FnTag;
+impl<State: HasUi + StateLike<State>, W: Widget, F: FnOnce(&mut State) -> W>
+    WidgetLike<State, FnTag> for F
+{
+    type Widget = W;
+    fn add(self, state: &mut impl StateLike<State>) -> WidgetRef<W> {
+        self(state.as_state()).add(state)
+    }
+}
+
+pub trait WidgetFnTrait<State> {
+    type Widget: Widget;
+    fn run(self, state: &mut State) -> Self::Widget;
+}
+pub struct FnTraitTag;
+impl<State: HasUi + StateLike<State>, T: WidgetFnTrait<State>> WidgetLike<State, FnTraitTag> for T {
+    type Widget = T::Widget;
+    #[track_caller]
+    fn add(self, state: &mut impl StateLike<State>) -> WidgetRef<T::Widget> {
+        self.run(state.as_state()).add(state)
+    }
+}
+
+pub struct IdTag;
+impl<State: HasUi + StateLike<State>, W: ?Sized + Widget + Unsize<dyn Widget>>
+    WidgetLike<State, IdTag> for WidgetRef<W>
+{
+    type Widget = W;
+    fn add(self, _: &mut impl StateLike<State>) -> WidgetRef<W> {
+        self
+    }
+}
+
+pub struct IdFnTag;
+impl<
+    State: HasUi + StateLike<State>,
+    W: ?Sized + Widget + Unsize<dyn Widget>,
+    F: FnOnce(&mut State) -> WidgetRef<W>,
+> WidgetLike<State, IdFnTag> for F
+{
+    type Widget = W;
+    fn add(self, state: &mut impl StateLike<State>) -> WidgetRef<W> {
+        self(state.as_state())
+    }
+}
+
+pub struct ArrTag;

core/src/widget/widgets.rs

@@ -0,0 +1,109 @@
+use std::sync::mpsc::Sender;
+
+use crate::{
+    IdLike, Widget, WidgetData, WidgetHandle, WidgetId, WidgetRef,
+    util::{DynBorrower, HashSet, SlotVec, forget_mut, to_mut},
+};
+
+pub struct Widgets {
+    pub needs_redraw: HashSet<WidgetId>,
+    vec: SlotVec<WidgetData>,
+    send: Sender<WidgetId>,
+    pub(crate) waiting: HashSet<WidgetId>,
+}
+
+impl Widgets {
+    pub fn new(send: Sender<WidgetId>) -> Self {
+        Self {
+            needs_redraw: Default::default(),
+            vec: Default::default(),
+            waiting: Default::default(),
+            send,
+        }
+    }
+
+    pub fn has_updates(&self) -> bool {
+        !self.needs_redraw.is_empty()
+    }
+
+    pub fn get_dyn(&self, id: WidgetId) -> Option<&dyn Widget> {
+        Some(self.vec.get(id)?.widget.as_ref())
+    }
+
+    pub fn get_dyn_mut(&mut self, id: WidgetId) -> Option<&mut dyn Widget> {
+        self.needs_redraw.insert(id);
+        Some(self.vec.get_mut(id)?.widget.as_mut())
+    }
+
+    /// get_dyn but dynamic borrow checking of widgets
+    /// lets you do recursive (tree) operations, like the painter does
+    pub(crate) fn get_dyn_dynamic<'a>(&self, id: WidgetId) -> WidgetWrapper<'a> {
+        // SAFETY: must guarantee no other mutable references to this widget exist
+        // done through the borrow variable
+        let data = unsafe { forget_mut(to_mut(self.vec.get(id).unwrap())) };
+        if data.borrowed {
+            panic!("tried to mutably borrow the same widget twice");
+        }
+        WidgetWrapper::new(data.widget.as_mut(), &mut data.borrowed)
+    }
+
+    pub fn get<I: IdLike>(&self, id: &I) -> Option<&I::Widget>
+    where
+        I::Widget: Sized + Widget,
+    {
+        self.get_dyn(id.id())?.as_any().downcast_ref()
+    }
+
+    pub fn get_mut<I: IdLike>(&mut self, id: &I) -> Option<&mut I::Widget>
+    where
+        I::Widget: Sized + Widget,
+    {
+        self.get_dyn_mut(id.id())?.as_any_mut().downcast_mut()
+    }
+
+    pub fn add_strong<W: Widget>(&mut self, widget: W) -> WidgetHandle<W> {
+        let id = self.vec.add(WidgetData::new(widget));
+        WidgetHandle::new(id, self.send.clone())
+    }
+
+    pub fn add_weak<W: Widget>(&mut self, widget: W) -> WidgetRef<W> {
+        let id = self.vec.add(WidgetData::new(widget));
+        self.waiting.insert(id);
+        WidgetRef::new(id)
+    }
+
+    #[track_caller]
+    pub fn upgrade<W: ?Sized>(&mut self, rf: WidgetRef<W>) -> WidgetHandle<W> {
+        if !self.waiting.remove(&rf.id()) {
+            let label = self.label(rf);
+            let id = rf.id();
+            panic!("widget '{label}' ({id:?}) was already added\ncannot add a widget twice; consider creating two")
+        }
+        WidgetHandle::new(rf.id(), self.send.clone())
+    }
+
+    pub fn data(&self, id: impl IdLike) -> Option<&WidgetData> {
+        self.vec.get(id.id())
+    }
+
+    pub fn label(&self, id: impl IdLike) -> &String {
+        &self.data(id.id()).unwrap().label
+    }
+
+    pub fn data_mut(&mut self, id: impl IdLike) -> Option<&mut WidgetData> {
+        self.vec.get_mut(id.id())
+    }
+
+    pub fn delete(&mut self, id: impl IdLike) {
+        self.vec.free(id.id());
+        // not sure if there's any point in this
+        // self.updates.remove(&id);
+    }
+
+    #[allow(clippy::len_without_is_empty)]
+    pub fn len(&self) -> usize {
+        self.vec.len()
+    }
+}
+
+pub type WidgetWrapper<'a> = DynBorrower<'a, dyn Widget>;

examples/minimal.rs

@@ -0,0 +1,20 @@
+use iris::prelude::*;
+
+fn main() {
+    App::<State>::run();
+}
+
+#[default_ui_state]
+struct State {}
+
+impl DefaultAppState for State {
+    fn new(ui_state: DefaultUiState, _proxy: Proxy<Self::Event>) -> Self {
+        let mut ui = Ui::new();
+        rect(Color::RED).set_root(&mut ui);
+        Self {
+            ui,
+            ui_state,
+            events: EventManager::default(),
+        }
+    }
+}

macro/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "iris-macro"
+version.workspace = true
+edition.workspace = true
+
+[dependencies]
+proc-macro2 = "1.0.103"
+quote = "1.0.42"
+syn = { version = "2.0.111", features = ["full"] }
+
+[lib]
+proc-macro = true

macro/src/lib.rs

@@ -0,0 +1,192 @@
+extern crate proc_macro;
+use proc_macro::TokenStream;
+use quote::quote;
+use syn::{
+    Attribute, Block, Error, Fields, FieldsNamed, GenericParam, Generics, Ident, ItemStruct,
+    ItemTrait, Meta, Signature, Token, Visibility,
+    parse::{Parse, ParseStream, Result},
+    parse_macro_input, parse_quote,
+    spanned::Spanned,
+};
+
+struct Input {
+    attrs: Vec<Attribute>,
+    vis: Visibility,
+    name: Ident,
+    generics: Generics,
+    fns: Vec<InputFn>,
+}
+
+struct InputFn {
+    sig: Signature,
+    body: Block,
+}
+
+impl Parse for Input {
+    fn parse(input: ParseStream) -> Result<Self> {
+        let attrs = input.call(Attribute::parse_outer)?;
+        let vis = input.parse()?;
+        input.parse::<Token![trait]>()?;
+        let name = input.parse()?;
+        let generics = input.parse::<Generics>()?;
+        input.parse::<Token![;]>()?;
+        let mut fns = Vec::new();
+        while !input.is_empty() {
+            let sig = input.parse()?;
+            let body = input.parse()?;
+            fns.push(InputFn { sig, body })
+        }
+        if !input.is_empty() {
+            input.error("function expected");
+        }
+        Ok(Input {
+            attrs,
+            vis,
+            name,
+            generics,
+            fns,
+        })
+    }
+}
+
+#[proc_macro]
+pub fn widget_trait(input: TokenStream) -> TokenStream {
+    let Input {
+        attrs,
+        vis,
+        name,
+        mut generics,
+        fns,
+    } = parse_macro_input!(input as Input);
+
+    let sigs: Vec<_> = fns.iter().map(|f| f.sig.clone()).collect();
+    let impls: Vec<_> = fns
+        .iter()
+        .map(|InputFn { sig, body }| quote! { #sig #body })
+        .collect();
+
+    let Some(GenericParam::Type(state)) = generics.params.first() else {
+        return Error::new(name.span(), "expected state generic parameter")
+            .into_compile_error()
+            .into();
+    };
+
+    let state = &state.ident;
+
+    generics
+        .params
+        .push(parse_quote!(WL: WidgetLike<#state, Tag>));
+    generics.params.push(parse_quote!(Tag));
+
+    let mut trai: ItemTrait = parse_quote!(
+        #vis trait #name #generics {
+            #(#sigs;)*
+        }
+    );
+
+    trai.attrs = attrs;
+
+    quote! {
+        #trai
+
+        impl #generics #name<State, WL, Tag> for WL {
+            #(#impls)*
+        }
+    }
+    .into()
+}
+
+#[proc_macro_derive(UiState, attributes(rsc))]
+pub fn derive_ui_state(input: TokenStream) -> TokenStream {
+    let mut output = proc_macro2::TokenStream::new();
+
+    let state: ItemStruct = parse_macro_input!(input);
+    let sname = state.ident;
+    let rscname = Ident::new(&(sname.to_string() + "Rsc"), sname.span());
+    let mut rsc_fields = Vec::new();
+
+    for field in state.fields {
+        let Some(attr) = field.attrs.iter().find(|a| a.path().is_ident("rsc")) else {
+            continue;
+        };
+        let Meta::List(list) = &attr.meta else {
+            output.extend(Error::new(attr.span(), "invalid attr syntax").into_compile_error());
+            continue;
+        };
+        let tname: Ident = match list.parse_args::<Ident>() {
+            Ok(ident) => ident,
+            Err(err) => {
+                output.extend(err.to_compile_error());
+                continue;
+            }
+        };
+        let fty = &field.ty;
+        let fname = &field.ident.unwrap();
+        rsc_fields.extend(quote! {#fname: #fty,});
+        output.extend(quote! {
+            impl #tname for #sname {
+                fn get(&self) -> &#fty {
+                    &self.#fname
+                }
+                fn get_mut(&mut self) -> &mut #fty {
+                    &mut self.#fname
+                }
+            }
+            impl #tname for #rscname {
+                fn get(&self) -> &#fty {
+                    &self.#fname
+                }
+                fn get_mut(&mut self) -> &mut #fty {
+                    &mut self.#fname
+                }
+            }
+        });
+    }
+    let vis = state.vis;
+    output.extend(quote! {
+        #vis struct #rscname {
+            #(#rsc_fields)*
+        }
+
+        impl HasState for #sname {
+            type State = #sname;
+        }
+
+        impl HasState for #rscname {
+            type State = #sname;
+        }
+
+        impl StateLike<#sname> for #sname {
+            fn as_state(&mut self) -> &mut Self {
+                self
+            }
+        }
+
+        impl StateLike<#rscname> for #rscname {
+            fn as_state(&mut self) -> &mut Self {
+                self
+            }
+        }
+    });
+    output.into()
+}
+
+#[proc_macro_attribute]
+pub fn default_ui_state(_attr: TokenStream, input: TokenStream) -> TokenStream {
+    let mut state: ItemStruct = parse_macro_input!(input);
+    let Fields::Named(fields) = &mut state.fields else {
+        panic!("must be on named fields struct");
+    };
+    let name = &state.ident;
+    state.attrs.push(parse_quote! {#[derive(UiState)]});
+    let new: FieldsNamed = parse_quote! {{
+        #[rsc(HasUi)]
+        pub ui: Ui,
+        #[rsc(HasDefaultUiState)]
+        pub ui_state: DefaultUiState,
+        #[rsc(HasEvents)]
+        pub events: iris::prelude::EventManager<#name>,
+    }};
+    fields.named.extend(new.named);
+    quote! {#state}.into()
+}

readme.md

@@ -0,0 +1,31 @@
+# iris
+
+My experimental attempt at a rust ui library (also my first ui library).
+
+It's currently designed around using retained data structures (widgets), rather than diffing generated trees from data like xilem or iced. This is an experiment and I'm not sure if it's a good idea or not.
+
+There's a `main.rs` that runs a testing window, so you can just `cargo run` to see it working.
+
+Goals, in general order:
+1. does what I want it to (text, images, video, animations)
+2. very easy to use ignoring ergonomic ref counting
+3. reasonably fast / efficient (a lot faster than electron, save battery life)
+
+## dev details
+
+not targeting web rn cause wanna use actual nice gpu features & entire point of this is to make desktop apps / not need a web browser
+
+general ideas trynna use rn / experiment with:
+- retained mode
+- specifically designed around wgpu so there's no translation
+- postfix functions for most things to prevent unreadable indentation (going very well)
+- events can be done directly where you draw the widgets
+- almost no macros in user code & actual LSP typechecking (variadic generics if you can hear me please save us)
+- relative anchor + absolute offset coord system (+ "rest" / leftover during widget layout)
+- single threaded ui & pass context around to make non async usage straightforward (pretty unsure about this)
+- widgets store outside of the actual rendering so they can be moved around and swapped easily (unsure about this but seems to work good for now)
+
+under heavy initial development so not gonna try to explain status, maybe check TODO for that;
+sizable chance it gets a rewrite once I know everything I need and what seems to work best
+
+it's called iris because it's the structure around what you actually want to display and colorful

src/base/mod.rs

@@ -1,165 +0,0 @@
-use std::ops::Range;
-
-use crate::{
-    primitive::{Axis, Painter, RoundedRectData, UIRegion},
-    UIColor, Widget, WidgetArrLike, WidgetFn, WidgetId, WidgetLike,
-};
-
-#[derive(Clone, Copy)]
-pub struct RoundedRect {
-    pub color: UIColor,
-    pub radius: f32,
-    pub thickness: f32,
-    pub inner_radius: f32,
-}
-
-impl RoundedRect {
-    pub fn color(mut self, color: UIColor) -> Self {
-        self.color = color;
-        self
-    }
-}
-
-impl Widget for RoundedRect {
-    fn draw(&self, painter: &mut Painter) {
-        painter.write(RoundedRectData {
-            color: self.color,
-            radius: self.radius,
-            thickness: self.thickness,
-            inner_radius: self.inner_radius,
-        });
-    }
-}
-
-pub struct Span {
-    pub elements: Vec<(Range<f32>, WidgetId)>,
-    pub axis: Axis,
-}
-
-impl Widget for Span {
-    fn draw(&self, painter: &mut Painter) {
-        for (span, child) in &self.elements {
-            let mut sub_region = UIRegion::full();
-            let view = sub_region.axis_mut(self.axis);
-            *view.top_left.anchor = span.start;
-            *view.bot_right.anchor = span.end;
-            painter.draw_within(child, sub_region);
-        }
-    }
-}
-
-impl Span {
-    pub fn proportioned(
-        axis: Axis,
-        elements: impl IntoIterator<Item = (WidgetId, impl UINum)>,
-    ) -> Self {
-        // TODO: update
-        let elements = elements
-            .into_iter()
-            .map(|(w, r)| (w, r.to_f32()))
-            .collect::<Vec<_>>();
-        let total: f32 = elements.iter().map(|(_, r)| r).sum();
-        let mut start = 0.0;
-        Self {
-            elements: elements
-                .into_iter()
-                .map(|(e, r)| {
-                    let end = start + r / total;
-                    let res = (start..end, e);
-                    start = end;
-                    res
-                })
-                .collect(),
-            axis,
-        }
-    }
-}
-
-pub struct Regioned {
-    region: UIRegion,
-    inner: WidgetId,
-}
-
-impl Widget for Regioned {
-    fn draw(&self, painter: &mut Painter) {
-        painter.region.select(&self.region);
-        painter.draw(&self.inner);
-    }
-}
-
-pub struct Padding {
-    left: f32,
-    right: f32,
-    top: f32,
-    bottom: f32,
-}
-
-impl Padding {
-    pub fn uniform(amt: f32) -> Self {
-        Self {
-            left: amt,
-            right: amt,
-            top: amt,
-            bottom: amt,
-        }
-    }
-    pub fn region(&self) -> UIRegion {
-        let mut region = UIRegion::full();
-        region.top_left.offset.x += self.left;
-        region.top_left.offset.y += self.top;
-        region.bot_right.offset.x -= self.right;
-        region.bot_right.offset.y -= self.bottom;
-        region
-    }
-}
-
-impl<T: UINum> From<T> for Padding {
-    fn from(amt: T) -> Self {
-        Self::uniform(amt.to_f32())
-    }
-}
-
-pub trait WidgetUtil<W> {
-    fn pad(self, padding: impl Into<Padding>) -> impl WidgetLike<Widget = Regioned>;
-}
-
-impl<W: WidgetLike> WidgetUtil<W::Widget> for W {
-    fn pad(self, padding: impl Into<Padding>) -> impl WidgetLike<Widget = Regioned> {
-        WidgetFn(|ui| Regioned {
-            region: padding.into().region(),
-            inner: self.id(ui).erase_type(),
-        })
-    }
-}
-
-pub trait WidgetArrUtil<Wa: WidgetArrLike> {
-    fn span(self, axis: Axis, ratios: [impl UINum; Wa::LEN]) -> impl WidgetLike<Widget = Span>;
-}
-
-impl<Wa: WidgetArrLike> WidgetArrUtil<Wa> for Wa {
-    fn span(self, axis: Axis, ratios: [impl UINum; Wa::LEN]) -> impl WidgetLike<Widget = Span> {
-        WidgetFn(move |ui| Span::proportioned(axis, self.ui(ui).ids().into_iter().zip(ratios)))
-    }
-}
-
-pub trait UINum {
-    fn to_f32(self) -> f32;
-}
-
-impl UINum for f32 {
-    fn to_f32(self) -> f32 {
-        self
-    }
-}
-
-impl UINum for u32 {
-    fn to_f32(self) -> f32 {
-        self as f32
-    }
-}
-
-impl UINum for i32 {
-    fn to_f32(self) -> f32 {
-        self as f32
-    }
-}

src/bin/test/main.rs

@@ -0,0 +1,224 @@
+use cosmic_text::Family;
+use std::{cell::RefCell, rc::Rc};
+use winit::event::WindowEvent;
+
+iris::state_prelude!(ClientRsc);
+
+fn main() {
+    App::<Client>::run();
+}
+
+#[default_ui_state]
+pub struct Client {
+    info: WidgetRef<Text>,
+}
+
+impl DefaultAppState for Client {
+    fn new(ui_state: DefaultUiState, _proxy: Proxy<Self::Event>) -> Self {
+        let mut rsc = ClientRsc {
+            ui: Ui::new(),
+            ui_state,
+            events: EventManager::default(),
+        };
+
+        let rrect = rect(Color::WHITE).radius(20);
+        let pad_test = (
+            rrect.color(Color::BLUE),
+            (
+                rrect
+                    .color(Color::RED)
+                    .sized((100, 100))
+                    .center()
+                    .width(rest(2)),
+                (
+                    rrect.color(Color::ORANGE),
+                    rrect.color(Color::LIME).pad(10.0),
+                )
+                    .span(Dir::RIGHT)
+                    .width(rest(2)),
+                rrect.color(Color::YELLOW),
+            )
+                .span(Dir::RIGHT)
+                .pad(10)
+                .width(rest(3)),
+        )
+            .span(Dir::RIGHT)
+            .add(&mut rsc);
+
+        let span_test = (
+            rrect.color(Color::GREEN).width(100),
+            rrect.color(Color::ORANGE),
+            rrect.color(Color::CYAN),
+            rrect.color(Color::BLUE).width(rel(0.5)),
+            rrect.color(Color::MAGENTA).width(100),
+            rrect.color(Color::RED).width(100),
+        )
+            .span(Dir::LEFT)
+            .add(&mut rsc);
+
+        let span_add = Span::empty(Dir::RIGHT).add(&mut rsc);
+
+        let add_button = rect(Color::LIME)
+            .radius(30)
+            .on(CursorSense::click(), move |ctx| {
+                let child = image(include_bytes!("assets/sungals.png"))
+                    .center()
+                    .add_strong(ctx);
+                span_add(ctx).push(child);
+            })
+            .sized((150, 150))
+            .align(Align::BOT_RIGHT);
+
+        let del_button = rect(Color::RED)
+            .radius(30)
+            .on(CursorSense::click(), move |ctx| {
+                span_add(ctx).pop();
+            })
+            .sized((150, 150))
+            .align(Align::BOT_LEFT);
+
+        let span_add_test = (span_add, add_button, del_button).stack().add(&mut rsc);
+
+        let btext = |content| wtext(content).size(30);
+
+        let text_test = (
+            btext("this is a").align(Align::LEFT),
+            btext("teeeeeeeest").align(Align::RIGHT),
+            btext("okkk\nokkkkkk!").align(Align::LEFT),
+            btext("hmm"),
+            btext("a"),
+            (
+                btext("'").family(Family::Monospace).align(Align::TOP),
+                btext("'").family(Family::Monospace),
+                btext(":gamer mode").family(Family::Monospace),
+                rect(Color::CYAN).sized((10, 10)).center(),
+                rect(Color::RED).sized((100, 100)).center(),
+                rect(Color::PURPLE).sized((50, 50)).align(Align::TOP),
+            )
+                .span(Dir::RIGHT)
+                .center(),
+            wtext("pretty cool right?").size(50),
+        )
+            .span(Dir::DOWN)
+            .add(&mut rsc);
+
+        let texts = Span::empty(Dir::DOWN).gap(10).add(&mut rsc);
+        let msg_area = texts.scrollable().masked().background(rect(Color::SKY));
+        let add_text = wtext("add")
+            .editable(EditMode::MultiLine)
+            .text_align(Align::LEFT)
+            .size(30)
+            .attr::<Selectable>(())
+            .on(Submit, move |ctx| {
+                let w = ctx.widget;
+                let content = w.edit(ctx).take();
+                let text = wtext(content)
+                    .editable(EditMode::MultiLine)
+                    .size(30)
+                    .text_align(Align::LEFT)
+                    .wrap(true)
+                    .attr::<Selectable>(());
+                let msg_box = text
+                    .background(rect(Color::WHITE.darker(0.5)))
+                    .add_strong(ctx);
+                texts(ctx).push(msg_box);
+            })
+            .add(&mut rsc);
+        let text_edit_scroll = (
+            msg_area.height(rest(1)),
+            (
+                Rect::new(Color::WHITE.darker(0.9)),
+                (
+                    add_text.width(rest(1)),
+                    Rect::new(Color::GREEN)
+                        .on(CursorSense::click(), move |ctx| {
+                            ctx.state.run_event::<Submit>(add_text, &mut ());
+                        })
+                        .sized((40, 40)),
+                )
+                    .span(Dir::RIGHT)
+                    .pad(10),
+            )
+                .stack()
+                .size(StackSize::Child(1))
+                .layer_offset(1)
+                .align(Align::BOT),
+        )
+            .span(Dir::DOWN)
+            .add(&mut rsc);
+
+        let main = WidgetPtr::new().add(&mut rsc);
+
+        let vals = Rc::new(RefCell::new((0, Vec::new())));
+        let mut switch_button = |color, to: WidgetRef, label| {
+            let to = to.upgrade(&mut rsc);
+            let vec = &mut vals.borrow_mut().1;
+            let i = vec.len();
+            if vec.is_empty() {
+                vec.push(None);
+                rsc.ui[main].set(to);
+            } else {
+                vec.push(Some(to));
+            }
+            let vals = vals.clone();
+            let rect = rect(color)
+                .on(CursorSense::click(), move |ctx| {
+                    let (prev, vec) = &mut *vals.borrow_mut();
+                    if let Some(h) = vec[i].take() {
+                        vec[*prev] = main(ctx).replace(h);
+                        *prev = i;
+                    }
+                    ctx.widget().color = color.darker(0.3);
+                })
+                .on(
+                    CursorSense::HoverStart | CursorSense::unclick(),
+                    move |ctx| {
+                        ctx.widget().color = color.brighter(0.2);
+                    },
+                )
+                .on(CursorSense::HoverEnd, move |ctx| {
+                    ctx.widget().color = color;
+                });
+            (rect, wtext(label).size(30).text_align(Align::CENTER)).stack()
+        };
+
+        let tabs = (
+            switch_button(Color::RED, pad_test, "pad"),
+            switch_button(Color::GREEN, span_test, "span"),
+            switch_button(Color::BLUE, span_add_test, "image span"),
+            switch_button(Color::MAGENTA, text_test, "text layout"),
+            switch_button(
+                Color::YELLOW.mul_rgb(0.5),
+                text_edit_scroll,
+                "text edit scroll",
+            ),
+        )
+            .span(Dir::RIGHT);
+
+        let info = wtext("").add(&mut rsc);
+        let info_sect = info.pad(10).align(Align::RIGHT);
+
+        ((tabs.height(40), main.pad(10)).span(Dir::DOWN), info_sect)
+            .stack()
+            .set_root(&mut rsc);
+
+        Self {
+            ui: rsc.ui,
+            ui_state: rsc.ui_state,
+            events: rsc.events,
+            info,
+        }
+    }
+
+    fn window_event(&mut self, _: WindowEvent) {
+        let new = format!(
+            "widgets: {}\nactive:{}\nviews: {}",
+            self.ui.num_widgets(),
+            self.ui.active_widgets(),
+            self.ui_state.renderer.ui.view_count()
+        );
+        if new != *self.ui[self.info].content {
+            *self.ui[self.info].content = new;
+        }
+    }
+}

src/default/app.rs

@@ -0,0 +1,53 @@
+use winit::{
+    application::ApplicationHandler,
+    event::WindowEvent,
+    event_loop::{ActiveEventLoop, EventLoop, EventLoopProxy},
+    window::WindowId,
+};
+
+pub trait AppState {
+    type Event: 'static;
+    fn new(event_loop: &ActiveEventLoop, proxy: EventLoopProxy<Self::Event>) -> Self;
+    fn window_event(&mut self, event: WindowEvent, event_loop: &ActiveEventLoop);
+    fn event(&mut self, event: Self::Event, event_loop: &ActiveEventLoop);
+    fn exit(&mut self);
+}
+
+pub struct App<State: AppState> {
+    state: Option<State>,
+    proxy: EventLoopProxy<State::Event>,
+}
+
+impl<State: AppState> App<State> {
+    pub fn run() {
+        let event_loop = EventLoop::with_user_event().build().unwrap();
+        let proxy = event_loop.create_proxy();
+        event_loop
+            .run_app(&mut App::<State> { state: None, proxy })
+            .unwrap();
+    }
+}
+
+impl<State: AppState> ApplicationHandler<State::Event> for App<State> {
+    fn resumed(&mut self, event_loop: &ActiveEventLoop) {
+        if self.state.is_none() {
+            let state = State::new(event_loop, self.proxy.clone());
+            self.state = Some(state);
+        }
+    }
+
+    fn window_event(&mut self, event_loop: &ActiveEventLoop, _id: WindowId, event: WindowEvent) {
+        let state = self.state.as_mut().unwrap();
+        state.window_event(event, event_loop);
+    }
+
+    fn user_event(&mut self, event_loop: &ActiveEventLoop, event: State::Event) {
+        let state = self.state.as_mut().unwrap();
+        state.event(event, event_loop);
+    }
+
+    fn exiting(&mut self, _: &ActiveEventLoop) {
+        let state = self.state.as_mut().unwrap();
+        state.exit();
+    }
+}

src/default/attr.rs

@@ -0,0 +1,66 @@
+use crate::prelude::*;
+use std::time::{Duration, Instant};
+use winit::dpi::{LogicalPosition, LogicalSize};
+
+pub struct Selector;
+
+impl<State: HasEvents, W: Widget + 'static> WidgetAttr<State, W> for Selector
+where
+    State::State: HasDefaultUiState,
+{
+    type Input = WidgetRef<TextEdit>;
+
+    fn run(state: &mut State, container: WidgetRef<W>, id: Self::Input) {
+        state.register_event(container, CursorSense::click_or_drag(), move |ctx| {
+            let region = ctx.ui().window_region(&id).unwrap();
+            let id_pos = region.top_left;
+            let container_pos = ctx.state.ui().window_region(&container).unwrap().top_left;
+            let pos = ctx.data.pos + container_pos - id_pos;
+            let size = region.size();
+            select(ctx.state, id, pos, size, ctx.data.sense.is_dragging());
+        });
+    }
+}
+
+pub struct Selectable;
+
+impl<State: HasEvents> WidgetAttr<State, TextEdit> for Selectable
+where
+    State::State: HasDefaultUiState,
+{
+    type Input = ();
+
+    fn run(state: &mut State, id: WidgetRef<TextEdit>, _: Self::Input) {
+        state.register_event(id, CursorSense::click_or_drag(), move |ctx| {
+            select(
+                ctx.state,
+                id,
+                ctx.data.pos,
+                ctx.data.size,
+                ctx.data.sense.is_dragging(),
+            );
+        });
+    }
+}
+
+fn select(
+    state: &mut impl HasDefaultUiState,
+    id: WidgetRef<TextEdit>,
+    pos: Vec2,
+    size: Vec2,
+    dragging: bool,
+) {
+    let (ui, state) = HasDefaultUiState::ui_with_state(state);
+    let now = Instant::now();
+    let recent = (now - state.last_click) < Duration::from_millis(300);
+    state.last_click = now;
+    id.edit(ui).select(pos, size, dragging, recent);
+    if let Some(region) = ui.window_region(&id) {
+        state.window.set_ime_allowed(true);
+        state.window.set_ime_cursor_area(
+            LogicalPosition::<f32>::from(region.top_left.tuple()),
+            LogicalSize::<f32>::from(region.size().tuple()),
+        );
+    }
+    state.focus = Some(id);
+}

src/default/event.rs

@@ -0,0 +1,9 @@
+use iris_core::Event;
+
+#[derive(Eq, PartialEq, Hash, Clone)]
+pub struct Submit;
+impl Event for Submit {}
+
+#[derive(Eq, PartialEq, Hash, Clone)]
+pub struct Edited;
+impl Event for Edited {}

src/default/input.rs

@@ -0,0 +1,78 @@
+use crate::prelude::*;
+use winit::{
+    event::{MouseButton, MouseScrollDelta, WindowEvent},
+    keyboard::{Key, NamedKey},
+};
+
+#[derive(Default)]
+pub struct Input {
+    cursor: CursorState,
+    pub modifiers: Modifiers,
+}
+
+impl Input {
+    pub fn event(&mut self, event: &WindowEvent) -> bool {
+        match event {
+            WindowEvent::CursorMoved { position, .. } => {
+                self.cursor.pos = Vec2::new(position.x as f32, position.y as f32);
+                self.cursor.exists = true;
+            }
+            WindowEvent::MouseInput { state, button, .. } => {
+                let buttons = &mut self.cursor.buttons;
+                let pressed = state.is_pressed();
+                match button {
+                    MouseButton::Left => buttons.left.update(pressed),
+                    MouseButton::Right => buttons.right.update(pressed),
+                    MouseButton::Middle => buttons.middle.update(pressed),
+                    _ => (),
+                }
+            }
+            WindowEvent::MouseWheel { delta, .. } => {
+                let mut delta = match *delta {
+                    MouseScrollDelta::LineDelta(x, y) => Vec2::new(x, y),
+                    MouseScrollDelta::PixelDelta(pos) => Vec2::new(pos.x as f32, pos.y as f32),
+                };
+                if delta.x == 0.0 && self.modifiers.shift {
+                    delta.x = delta.y;
+                    delta.y = 0.0;
+                }
+                self.cursor.scroll_delta = delta;
+            }
+            WindowEvent::CursorLeft { .. } => {
+                self.cursor.exists = false;
+                self.modifiers.clear();
+            }
+            WindowEvent::KeyboardInput { event, .. } => {
+                if let Key::Named(named) = event.logical_key {
+                    let pressed = event.state.is_pressed();
+                    match named {
+                        NamedKey::Control => {
+                            self.modifiers.control = pressed;
+                        }
+                        NamedKey::Shift => {
+                            self.modifiers.shift = pressed;
+                        }
+                        _ => (),
+                    }
+                }
+            }
+            _ => return false,
+        }
+        true
+    }
+
+    pub fn end_frame(&mut self) {
+        self.cursor.end_frame();
+    }
+}
+
+impl DefaultUiState {
+    pub fn window_size(&self) -> Vec2 {
+        let size = self.renderer.window().inner_size();
+        (size.width, size.height).into()
+    }
+
+    pub fn cursor_state(&self) -> &CursorState {
+        &self.input.cursor
+    }
+}

src/default/mod.rs

@@ -0,0 +1,186 @@
+use crate::prelude::*;
+use arboard::Clipboard;
+use iris_core::util::forget_mut;
+use std::{marker::Sized, sync::Arc, time::Instant};
+use winit::{
+    event::{Ime, WindowEvent},
+    event_loop::{ActiveEventLoop, EventLoopProxy},
+    window::{Window, WindowAttributes},
+};
+
+mod app;
+mod attr;
+mod event;
+mod input;
+mod render;
+mod sense;
+
+pub use app::*;
+pub use attr::*;
+pub use event::*;
+pub use input::*;
+pub use render::*;
+pub use sense::*;
+
+pub type Proxy<Event> = EventLoopProxy<Event>;
+
+pub struct DefaultUiState {
+    pub renderer: UiRenderer,
+    pub input: Input,
+    pub focus: Option<WidgetRef<TextEdit>>,
+    pub clipboard: Clipboard,
+    pub window: Arc<Window>,
+    pub ime: usize,
+    pub last_click: Instant,
+}
+
+impl DefaultUiState {
+    pub fn new(window: impl Into<Arc<Window>>) -> Self {
+        let window = window.into();
+        Self {
+            renderer: UiRenderer::new(window.clone()),
+            window,
+            input: Input::default(),
+            clipboard: Clipboard::new().unwrap(),
+            ime: 0,
+            last_click: Instant::now(),
+            focus: None,
+        }
+    }
+}
+
+pub trait HasDefaultUiState: Sized + 'static + HasUi {
+    fn get(&self) -> &DefaultUiState;
+    fn get_mut(&mut self) -> &mut DefaultUiState;
+    fn ui_state(&self) -> &DefaultUiState {
+        HasDefaultUiState::get(self)
+    }
+    fn ui_state_mut(&mut self) -> &mut DefaultUiState {
+        HasDefaultUiState::get_mut(self)
+    }
+    fn ui_with_state(&mut self) -> (&mut Ui, &mut DefaultUiState) {
+        // as long as you're not doing anything actually unhinged this should always work safely
+        (
+            unsafe { forget_mut(self.ui_mut()) },
+            HasDefaultUiState::get_mut(self),
+        )
+    }
+}
+
+pub trait DefaultAppState: RunEvents + HasDefaultUiState {
+    type Event: 'static = ();
+    fn new(ui_state: DefaultUiState, proxy: Proxy<Self::Event>) -> Self;
+    #[allow(unused_variables)]
+    fn event(&mut self, event: Self::Event) {}
+    #[allow(unused_variables)]
+    fn exit(&mut self) {}
+    #[allow(unused_variables)]
+    fn window_event(&mut self, event: WindowEvent) {}
+    fn window_attributes() -> WindowAttributes {
+        Default::default()
+    }
+}
+
+impl<State: DefaultAppState> AppState for State {
+    type Event = State::Event;
+
+    fn new(event_loop: &ActiveEventLoop, proxy: EventLoopProxy<Self::Event>) -> Self {
+        let window = event_loop.create_window(Self::window_attributes()).unwrap();
+        Self::new(DefaultUiState::new(window), proxy)
+    }
+
+    fn event(&mut self, event: Self::Event, _: &ActiveEventLoop) {
+        self.event(event);
+    }
+
+    fn window_event(&mut self, event: WindowEvent, event_loop: &ActiveEventLoop) {
+        let events = unsafe { forget_mut(self.events_mut()) };
+        let ui_state = HasDefaultUiState::get_mut(self);
+        let input_changed = ui_state.input.event(&event);
+        let cursor_state = ui_state.cursor_state().clone();
+        let old = ui_state.focus;
+        if cursor_state.buttons.left.is_start() {
+            ui_state.focus = None;
+        }
+        if input_changed {
+            let window_size = ui_state.window_size();
+            self.run_sensors(&cursor_state, window_size);
+        }
+        let (mut ui, mut ui_state) = self.ui_with_state();
+        if old != ui_state.focus
+            && let Some(old) = old
+        {
+            old.edit(ui).deselect();
+        }
+        match &event {
+            WindowEvent::CloseRequested => event_loop.exit(),
+            WindowEvent::RedrawRequested => {
+                ui.update(events);
+                ui_state.renderer.update(ui);
+                ui_state.renderer.draw();
+            }
+            WindowEvent::Resized(size) => {
+                ui.resize((size.width, size.height));
+                ui_state.renderer.resize(size)
+            }
+            WindowEvent::KeyboardInput { event, .. } => {
+                if let Some(sel) = ui_state.focus
+                    && event.state.is_pressed()
+                {
+                    let mut text = sel.edit(ui);
+                    match text.apply_event(event, &ui_state.input.modifiers) {
+                        TextInputResult::Unfocus => {
+                            ui_state.focus = None;
+                            ui_state.window.set_ime_allowed(false);
+                        }
+                        TextInputResult::Submit => {
+                            self.run_event::<Submit>(sel, &mut ());
+                        }
+                        TextInputResult::Paste => {
+                            if let Ok(t) = ui_state.clipboard.get_text() {
+                                text.insert(&t);
+                            }
+                            self.run_event::<Edited>(sel, &mut ());
+                        }
+                        TextInputResult::Copy(text) => {
+                            if let Err(err) = ui_state.clipboard.set_text(text) {
+                                eprintln!("failed to copy text to clipboard: {err}")
+                            }
+                        }
+                        TextInputResult::Used => {
+                            self.run_event::<Edited>(sel, &mut ());
+                        }
+                        TextInputResult::Unused => {}
+                    }
+                }
+            }
+            WindowEvent::Ime(ime) => {
+                if let Some(sel) = ui_state.focus {
+                    let mut text = sel.edit(ui);
+                    match ime {
+                        Ime::Enabled | Ime::Disabled => (),
+                        Ime::Preedit(content, _pos) => {
+                            // TODO: highlight once that's real
+                            text.replace(ui_state.ime, content);
+                            ui_state.ime = content.chars().count();
+                        }
+                        Ime::Commit(content) => {
+                            text.insert(content);
+                        }
+                    }
+                }
+            }
+            _ => (),
+        }
+        self.window_event(event);
+        (ui, ui_state) = self.ui_with_state();
+        if ui.needs_redraw() {
+            ui_state.renderer.window().request_redraw();
+        }
+        ui_state.input.end_frame();
+    }
+
+    fn exit(&mut self) {
+        self.exit();
+    }
+}

src/default/render.rs

@@ -1,47 +1,48 @@
-use gui::{UIRenderNode, UI};
+use iris_core::{Ui, UiLimits, UiRenderNode};
 use pollster::FutureExt;
 use std::sync::Arc;
-use wgpu::util::StagingBelt;
+use wgpu::{util::StagingBelt, *};
 use winit::{dpi::PhysicalSize, window::Window};
 
-pub const CLEAR_COLOR: wgpu::Color = wgpu::Color::BLACK;
+pub const CLEAR_COLOR: Color = Color::BLACK;
 
-pub struct Renderer {
-    surface: wgpu::Surface<'static>,
-    device: wgpu::Device,
-    queue: wgpu::Queue,
-    config: wgpu::SurfaceConfiguration,
-    encoder: wgpu::CommandEncoder,
+pub struct UiRenderer {
+    window: Arc<Window>,
+    surface: Surface<'static>,
+    device: Device,
+    queue: Queue,
+    config: SurfaceConfiguration,
+    encoder: CommandEncoder,
     staging_belt: StagingBelt,
-    ui_node: UIRenderNode,
+    pub ui: UiRenderNode,
 }
 
-impl Renderer {
-    pub fn update(&mut self, ui: &UI) {
-        self.ui_node.update(&self.device, &self.queue, ui);
+impl UiRenderer {
+    pub fn update(&mut self, ui: &mut Ui) {
+        self.ui.update(&self.device, &self.queue, ui);
     }
 
     pub fn draw(&mut self) {
         let output = self.surface.get_current_texture().unwrap();
         let view = output
             .texture
-            .create_view(&wgpu::TextureViewDescriptor::default());
+            .create_view(&TextureViewDescriptor::default());
 
         let mut encoder = std::mem::replace(&mut self.encoder, Self::create_encoder(&self.device));
         {
-            let render_pass = &mut encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
-                color_attachments: &[Some(wgpu::RenderPassColorAttachment {
+            let render_pass = &mut encoder.begin_render_pass(&RenderPassDescriptor {
+                color_attachments: &[Some(RenderPassColorAttachment {
                     view: &view,
                     resolve_target: None,
-                    ops: wgpu::Operations {
-                        load: wgpu::LoadOp::Clear(CLEAR_COLOR),
-                        store: wgpu::StoreOp::Store,
+                    ops: Operations {
+                        load: LoadOp::Clear(CLEAR_COLOR),
+                        store: StoreOp::Store,
                     },
                     depth_slice: None,
                 })],
                 ..Default::default()
             });
-            self.ui_node.draw(render_pass);
+            self.ui.draw(render_pass);
         }
 
         self.queue.submit(std::iter::once(encoder.finish()));
@@ -54,11 +55,11 @@ impl Renderer {
         self.config.width = size.width;
         self.config.height = size.height;
         self.surface.configure(&self.device, &self.config);
-        self.ui_node.resize(size, &self.queue);
+        self.ui.resize(size, &self.queue);
     }
 
-    fn create_encoder(device: &wgpu::Device) -> wgpu::CommandEncoder {
-        device.create_command_encoder(&wgpu::CommandEncoderDescriptor {
+    fn create_encoder(device: &Device) -> CommandEncoder {
+        device.create_command_encoder(&CommandEncoderDescriptor {
             label: Some("Render Encoder"),
         })
     }
@@ -66,8 +67,8 @@ impl Renderer {
     pub fn new(window: Arc<Window>) -> Self {
         let size = window.inner_size();
 
-        let instance = wgpu::Instance::new(&wgpu::InstanceDescriptor {
-            backends: wgpu::Backends::PRIMARY,
+        let instance = Instance::new(&InstanceDescriptor {
+            backends: Backends::PRIMARY,
             ..Default::default()
         });
 
@@ -76,18 +77,29 @@ impl Renderer {
             .expect("Could not create window surface!");
 
         let adapter = instance
-            .request_adapter(&wgpu::RequestAdapterOptions {
-                power_preference: wgpu::PowerPreference::default(),
+            .request_adapter(&RequestAdapterOptions {
+                power_preference: PowerPreference::default(),
                 compatible_surface: Some(&surface),
                 force_fallback_adapter: false,
             })
             .block_on()
             .expect("Could not get adapter!");
 
+        let ui_limits = UiLimits::default();
+
         let (device, queue) = adapter
-            .request_device(&wgpu::DeviceDescriptor {
-                required_features: wgpu::Features::empty(),
-                required_limits: wgpu::Limits::default(),
+            .request_device(&DeviceDescriptor {
+                required_features: Features::TEXTURE_BINDING_ARRAY
+                    | Features::PARTIALLY_BOUND_BINDING_ARRAY
+                    | Features::SAMPLED_TEXTURE_AND_STORAGE_BUFFER_ARRAY_NON_UNIFORM_INDEXING,
+                required_limits: Limits {
+                    max_binding_array_elements_per_shader_stage: ui_limits
+                        .max_binding_array_elements_per_shader_stage(),
+                    max_binding_array_sampler_elements_per_shader_stage: ui_limits
+                        .max_binding_array_sampler_elements_per_shader_stage(),
+                    max_buffer_size: 1 << 30,
+                    ..Default::default()
+                },
                 ..Default::default()
             })
             .block_on()
@@ -101,12 +113,12 @@ impl Renderer {
             .find(|f| f.is_srgb())
             .unwrap_or(surface_caps.formats[0]);
 
-        let config = wgpu::SurfaceConfiguration {
-            usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
+        let config = SurfaceConfiguration {
+            usage: TextureUsages::RENDER_ATTACHMENT,
             format: surface_format,
             width: size.width,
             height: size.height,
-            present_mode: wgpu::PresentMode::AutoVsync,
+            present_mode: PresentMode::AutoNoVsync,
             alpha_mode: surface_caps.alpha_modes[0],
             desired_maximum_frame_latency: 2,
             view_formats: vec![],
@@ -117,7 +129,7 @@ impl Renderer {
         let staging_belt = StagingBelt::new(4096 * 4);
         let encoder = Self::create_encoder(&device);
 
-        let shape_pipeline = UIRenderNode::new(&device, &config);
+        let shape_pipeline = UiRenderNode::new(&device, &queue, &config, ui_limits);
 
         Self {
             surface,
@@ -126,7 +138,12 @@ impl Renderer {
             config,
             encoder,
             staging_belt,
-            ui_node: shape_pipeline,
+            ui: shape_pipeline,
+            window,
         }
     }
+
+    pub fn window(&self) -> &Window {
+        self.window.as_ref()
+    }
 }

src/default/sense.rs

@@ -0,0 +1,288 @@
+use crate::prelude::*;
+use std::{
+    ops::{BitOr, Deref, DerefMut},
+    rc::Rc,
+};
+
+#[derive(Clone, Copy, PartialEq)]
+pub enum CursorButton {
+    Left,
+    Right,
+    Middle,
+}
+
+#[derive(Clone, Copy, PartialEq)]
+pub enum CursorSense {
+    PressStart(CursorButton),
+    Pressing(CursorButton),
+    PressEnd(CursorButton),
+    HoverStart,
+    Hovering,
+    HoverEnd,
+    Scroll,
+}
+
+#[derive(Clone)]
+pub struct CursorSenses(Vec<CursorSense>);
+
+impl Event for CursorSenses {
+    type Data<'a> = CursorData<'a>;
+    type State = SensorState;
+    fn should_run(&self, data: &mut Self::Data<'_>) -> bool {
+        if let Some(sense) = should_run(self, data.cursor, data.hover) {
+            data.sense = sense;
+            true
+        } else {
+            false
+        }
+    }
+}
+
+impl CursorSense {
+    pub fn click() -> Self {
+        Self::PressStart(CursorButton::Left)
+    }
+    pub fn click_or_drag() -> CursorSenses {
+        Self::click() | Self::Pressing(CursorButton::Left)
+    }
+    pub fn unclick() -> Self {
+        Self::PressEnd(CursorButton::Left)
+    }
+    pub fn is_dragging(&self) -> bool {
+        matches!(self, CursorSense::Pressing(CursorButton::Left))
+    }
+}
+
+#[derive(Default, Clone)]
+pub struct CursorState {
+    pub pos: Vec2,
+    pub exists: bool,
+    pub buttons: CursorButtons,
+    pub scroll_delta: Vec2,
+}
+
+#[derive(Default, Clone)]
+pub struct CursorButtons {
+    pub left: ActivationState,
+    pub middle: ActivationState,
+    pub right: ActivationState,
+}
+
+impl CursorButtons {
+    pub fn select(&self, button: &CursorButton) -> &ActivationState {
+        match button {
+            CursorButton::Left => &self.left,
+            CursorButton::Right => &self.right,
+            CursorButton::Middle => &self.middle,
+        }
+    }
+
+    pub fn end_frame(&mut self) {
+        self.left.end_frame();
+        self.middle.end_frame();
+        self.right.end_frame();
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = (CursorButton, &ActivationState)> {
+        [
+            CursorButton::Left,
+            CursorButton::Middle,
+            CursorButton::Right,
+        ]
+        .into_iter()
+        .map(|b| (b, self.select(&b)))
+    }
+}
+
+impl CursorState {
+    pub fn end_frame(&mut self) {
+        self.buttons.end_frame();
+        self.scroll_delta = Vec2::ZERO;
+    }
+}
+
+#[derive(Debug, Clone, Copy, Default, PartialEq)]
+pub enum ActivationState {
+    Start,
+    On,
+    End,
+    #[default]
+    Off,
+}
+
+/// this and other similar stuff has a generic
+/// because I kind of want to make CursorModule generic
+/// or basically have some way to have custom senses
+/// that depend on active widget positions
+/// but I'm not sure how or if worth it
+pub struct Sensor<Ctx, Data> {
+    pub senses: CursorSenses,
+    pub f: Rc<dyn EventFn<Ctx, Data>>,
+}
+
+pub type SenseShape = UiRegion;
+
+#[derive(Default, Debug)]
+pub struct SensorState {
+    pub hover: ActivationState,
+}
+
+pub struct CursorData<'a> {
+    /// where this widget was hit
+    pub pos: Vec2,
+    pub size: Vec2,
+    pub scroll_delta: Vec2,
+    pub hover: ActivationState,
+    pub cursor: &'a CursorState,
+    /// the first sense that triggered this
+    pub sense: CursorSense,
+}
+
+pub trait SensorUi<State> {
+    fn run_sensors(&mut self, cursor: &CursorState, window_size: Vec2);
+}
+
+impl<State: RunEvents> SensorUi<State> for State {
+    fn run_sensors(&mut self, cursor: &CursorState, window_size: Vec2) {
+        let layers = std::mem::take(&mut self.ui_mut().layers);
+        let mut active = std::mem::take(&mut self.events_mut().get_type::<CursorSense>().active);
+        for layer in layers.indices().rev() {
+            let mut sensed = false;
+            for (id, sensor) in active.get_mut(&layer).into_iter().flatten() {
+                let shape = self.ui().active.get(id).unwrap().region;
+                let region = shape.to_px(window_size);
+                let in_shape = cursor.exists && region.contains(cursor.pos);
+                sensor.hover.update(in_shape);
+                if sensor.hover == ActivationState::Off {
+                    continue;
+                }
+                sensed = true;
+
+                let mut data = CursorData {
+                    pos: cursor.pos - region.top_left,
+                    size: region.bot_right - region.top_left,
+                    scroll_delta: cursor.scroll_delta,
+                    hover: sensor.hover,
+                    cursor,
+                    // this does not have any meaning;
+                    // might wanna set up Event to have a prepare stage
+                    sense: CursorSense::Hovering,
+                };
+                self.run_event::<CursorSense>(*id, &mut data);
+            }
+            if sensed {
+                break;
+            }
+        }
+        self.events_mut().get_type::<CursorSense>().active = active;
+        self.ui_mut().layers = layers;
+    }
+}
+
+pub fn should_run(
+    senses: &CursorSenses,
+    cursor: &CursorState,
+    hover: ActivationState,
+) -> Option<CursorSense> {
+    for sense in senses.iter() {
+        if match sense {
+            CursorSense::PressStart(button) => cursor.buttons.select(button).is_start(),
+            CursorSense::Pressing(button) => cursor.buttons.select(button).is_on(),
+            CursorSense::PressEnd(button) => cursor.buttons.select(button).is_end(),
+            CursorSense::HoverStart => hover.is_start(),
+            CursorSense::Hovering => hover.is_on(),
+            CursorSense::HoverEnd => hover.is_end(),
+            CursorSense::Scroll => cursor.scroll_delta != Vec2::ZERO,
+        } {
+            return Some(*sense);
+        }
+    }
+    None
+}
+
+impl ActivationState {
+    pub fn is_start(&self) -> bool {
+        *self == Self::Start
+    }
+    pub fn is_on(&self) -> bool {
+        *self == Self::Start || *self == Self::On
+    }
+    pub fn is_end(&self) -> bool {
+        *self == Self::End
+    }
+    pub fn is_off(&self) -> bool {
+        *self == Self::End || *self == Self::Off
+    }
+    pub fn update(&mut self, on: bool) {
+        *self = match *self {
+            Self::Start => match on {
+                true => Self::On,
+                false => Self::End,
+            },
+            Self::On => match on {
+                true => Self::On,
+                false => Self::End,
+            },
+            Self::End => match on {
+                true => Self::Start,
+                false => Self::Off,
+            },
+            Self::Off => match on {
+                true => Self::Start,
+                false => Self::Off,
+            },
+        }
+    }
+
+    pub fn end_frame(&mut self) {
+        match self {
+            Self::Start => *self = Self::On,
+            Self::End => *self = Self::Off,
+            _ => (),
+        }
+    }
+}
+
+impl EventLike for CursorSense {
+    type Event = CursorSenses;
+    fn into_event(self) -> Self::Event {
+        self.into()
+    }
+}
+
+impl Deref for CursorSenses {
+    type Target = Vec<CursorSense>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for CursorSenses {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+impl From<CursorSense> for CursorSenses {
+    fn from(val: CursorSense) -> Self {
+        CursorSenses(vec![val])
+    }
+}
+
+impl BitOr for CursorSense {
+    type Output = CursorSenses;
+
+    fn bitor(self, rhs: Self) -> Self::Output {
+        CursorSenses(vec![self, rhs])
+    }
+}
+
+impl BitOr<CursorSense> for CursorSenses {
+    type Output = Self;
+
+    fn bitor(mut self, rhs: CursorSense) -> Self::Output {
+        self.0.push(rhs);
+        self
+    }
+}

src/event.rs

@@ -0,0 +1,25 @@
+use crate::prelude::*;
+
+pub mod eventable {
+    use super::*;
+    widget_trait! {
+        pub trait Eventable<State: HasEvents + StateLike<State> + 'static>;
+        fn on<E: EventLike>(
+            self,
+            event: E,
+            f: impl for<'a> WidgetEventFn<State::State, <E::Event as Event>::Data<'a>, WL::Widget>,
+        ) -> impl WidgetIdFn<State, WL::Widget> {
+            move |state| {
+                let id = self.add(state);
+                state.register_event(id, event.into_event(), move |ctx| {
+                    f(&mut EventIdCtx {
+                        widget: id,
+                        state: ctx.state,
+                        data: ctx.data,
+                    });
+                });
+                id
+            }
+        }
+    }
+}

src/layout/mod.rs

@@ -1,8 +0,0 @@
-mod ui;
-mod widget;
-
-pub use ui::*;
-pub use widget::*;
-
-use crate::primitive::Color;
-pub type UIColor = Color<u8>;

src/layout/ui.rs

@@ -1,101 +0,0 @@
-use crate::{
-    primitive::{Painter, Primitives},
-    util::{IDTracker, ID},
-    HashMap, Widget, WidgetId, WidgetLike, WidgetRef,
-};
-use std::{
-    any::{Any, TypeId},
-    cell::RefCell,
-    rc::Rc,
-};
-
-pub struct UI {
-    ids: IDTracker,
-    base: Option<WidgetId>,
-    pub widgets: Widgets,
-}
-
-pub struct Widgets(HashMap<ID, Box<dyn Widget>>);
-
-#[derive(Clone)]
-pub struct UIBuilder {
-    ui: Rc<RefCell<UI>>,
-}
-
-impl From<UI> for UIBuilder {
-    fn from(ui: UI) -> Self {
-        UIBuilder {
-            ui: Rc::new(RefCell::new(ui)),
-        }
-    }
-}
-
-impl UIBuilder {
-    pub fn add<W: Widget>(&mut self, w: W) -> WidgetRef<W> {
-        WidgetRef::new(self.clone(), (self.push(w), ()))
-    }
-
-    pub fn push<W: Widget>(&mut self, w: W) -> WidgetId<W> {
-        let mut ui = self.ui.borrow_mut();
-        let id = ui.ids.next();
-        ui.widgets.insert(id.duplicate(), w);
-        WidgetId::new(id, TypeId::of::<W>())
-    }
-
-    pub fn finish<WL: WidgetLike>(mut self, base: WL) -> UI {
-        let base = base.id(&mut self).erase_type();
-        let mut ui = Rc::into_inner(self.ui).unwrap().into_inner();
-        ui.base = Some(base);
-        ui
-    }
-}
-
-impl UI {
-    pub fn build() -> UIBuilder {
-        Self::empty().into()
-    }
-
-    pub fn empty() -> Self {
-        Self {
-            ids: IDTracker::new(),
-            base: None,
-            widgets: Widgets::new(),
-        }
-    }
-
-    pub fn to_primitives(&self) -> Primitives {
-        let mut painter = Painter::new(&self.widgets);
-        if let Some(base) = &self.base {
-            painter.draw(base);
-        }
-        painter.finish()
-    }
-}
-
-impl Widgets {
-    fn new() -> Self {
-        Self(HashMap::new())
-    }
-
-    pub fn get(&self, id: &WidgetId) -> &dyn Widget {
-        self.0.get(&id.id).unwrap().as_ref()
-    }
-
-    pub fn get_mut<W: Widget>(&mut self, id: &WidgetId<W>) -> Option<&mut W> {
-        self.0.get_mut(&id.id).unwrap().as_any_mut().downcast_mut()
-    }
-
-    pub fn insert(&mut self, id: ID, widget: impl Widget) {
-        self.0.insert(id, Box::new(widget));
-    }
-
-    pub fn insert_any(&mut self, id: ID, widget: Box<dyn Widget>) {
-        self.0.insert(id, widget);
-    }
-}
-
-impl dyn Widget {
-    pub fn as_any_mut(&mut self) -> &mut dyn Any {
-        self
-    }
-}

src/layout/widget.rs

@@ -1,186 +0,0 @@
-use std::{
-    any::{Any, TypeId},
-    marker::PhantomData,
-};
-
-use crate::{
-    primitive::Painter,
-    util::{IntoTupleList, TupleList, ID},
-    UIBuilder,
-};
-
-pub trait Widget: 'static + Any {
-    fn draw(&self, painter: &mut Painter);
-}
-
-impl<W: Widget> Widget for (W,) {
-    fn draw(&self, painter: &mut Painter) {
-        self.0.draw(painter);
-    }
-}
-
-#[derive(Eq, Hash, PartialEq, Debug)]
-pub struct WidgetId<W = ()> {
-    pub(super) ty: TypeId,
-    pub(super) id: ID,
-    _pd: PhantomData<W>,
-}
-
-// TODO: temp
-impl<W> Clone for WidgetId<W> {
-    fn clone(&self) -> Self {
-        Self {
-            ty: self.ty,
-            id: self.id.duplicate(),
-            _pd: self._pd,
-        }
-    }
-}
-
-impl<W> WidgetId<W> {
-    pub(super) fn new(id: ID, ty: TypeId) -> Self {
-        Self {
-            ty,
-            id,
-            _pd: PhantomData,
-        }
-    }
-    pub fn erase_type(self) -> WidgetId<()> {
-        self.cast_type()
-    }
-
-    fn cast_type<W2>(self) -> WidgetId<W2> {
-        WidgetId {
-            ty: self.ty,
-            id: self.id,
-            _pd: PhantomData,
-        }
-    }
-}
-
-pub trait WidgetLike {
-    type Widget;
-    fn id(self, ui: &mut UIBuilder) -> WidgetId<Self::Widget>;
-}
-
-/// wouldn't be needed if negative trait bounds & disjoint impls existed
-pub struct WidgetFn<F: FnOnce(&mut UIBuilder) -> W, W>(pub F);
-
-impl<W: Widget, F: FnOnce(&mut UIBuilder) -> W> WidgetLike for WidgetFn<F, W> {
-    type Widget = W;
-    fn id(self, ui: &mut UIBuilder) -> WidgetId<W> {
-        let w = (self.0)(ui);
-        ui.add(w).to_id()
-    }
-}
-
-impl<W: Widget> WidgetLike for W {
-    type Widget = W;
-    fn id(self, ui: &mut UIBuilder) -> WidgetId<W> {
-        ui.add(self).to_id()
-    }
-}
-
-impl<W> WidgetLike for WidgetId<W> {
-    type Widget = W;
-    fn id(self, _: &mut UIBuilder) -> WidgetId<W> {
-        self
-    }
-}
-
-pub struct WidgetArr<Ws: WidgetList> {
-    pub ui: UIBuilder,
-    pub arr: Ws::Ids,
-}
-
-impl<Ws: WidgetList> WidgetArr<Ws> {
-    pub fn new(ui: UIBuilder, arr: Ws::Ids) -> Self {
-        Self { ui, arr }
-    }
-    pub fn ids(self) -> Vec<WidgetId> {
-        self.arr.all()
-    }
-}
-
-pub type WidgetRef<W> = WidgetArr<(W, ())>;
-
-impl<W> WidgetRef<W> {
-    pub fn handle(&self) -> WidgetId<W> {
-        self.arr.head().clone()
-    }
-    pub fn to_id(self) -> WidgetId<W> {
-        self.arr.into_head()
-    }
-}
-
-impl<W> WidgetLike for WidgetRef<W> {
-    type Widget = W;
-    fn id(self, _: &mut UIBuilder) -> WidgetId<W> {
-        self.arr.into_head()
-    }
-}
-
-pub trait WidgetArrLike {
-    const LEN: usize;
-    type Ws: WidgetList;
-    fn ui(self, ui: &mut UIBuilder) -> WidgetArr<Self::Ws>;
-}
-
-impl<Ws: WidgetList> WidgetArrLike for WidgetArr<Ws> {
-    const LEN: usize = Ws::LEN;
-    type Ws = Ws;
-    fn ui(self, _: &mut UIBuilder) -> WidgetArr<Ws> {
-        self
-    }
-}
-
-impl<W: WidgetLike> WidgetArrLike for (W, ())
-where
-    Self: TupleList,
-{
-    const LEN: usize = <Self as TupleList>::LEN;
-    type Ws = (W::Widget, ());
-    fn ui(self, ui: &mut UIBuilder) -> WidgetArr<(W::Widget, ())> {
-        WidgetArr::new(ui.clone(), (self.0.id(ui), ()))
-    }
-}
-impl<W: WidgetLike, T: WidgetArrLike> WidgetArrLike for (W, T)
-where
-    Self: TupleList,
-{
-    const LEN: usize = <Self as TupleList>::LEN;
-    type Ws = (W::Widget, T::Ws);
-    fn ui(self, ui: &mut UIBuilder) -> WidgetArr<(W::Widget, T::Ws)> {
-        WidgetArr::new(ui.clone(), (self.0.id(ui), self.1.ui(ui).arr))
-    }
-}
-
-pub trait WidgetList: TupleList {
-    type Ids: IdList;
-}
-impl<H> WidgetList for (H, ()) {
-    type Ids = (WidgetId<H>, ());
-}
-impl<H, T: WidgetList> WidgetList for (H, T) {
-    type Ids = (WidgetId<H>, T::Ids);
-}
-
-pub trait IdList: TupleList {
-    fn iter(self) -> impl Iterator<Item = WidgetId>;
-    fn all(self) -> Vec<WidgetId>
-    where
-        Self: Sized,
-    {
-        self.iter().collect::<Vec<_>>()
-    }
-}
-impl<H> IdList for (WidgetId<H>, ()) {
-    fn iter(self) -> impl Iterator<Item = WidgetId> {
-        core::iter::once(self.0.erase_type())
-    }
-}
-impl<H, T: IdList> IdList for (WidgetId<H>, T) {
-    fn iter(self) -> impl Iterator<Item = WidgetId> {
-        core::iter::once(self.0.erase_type()).chain(self.1.iter())
-    }
-}

src/lib.rs

@@ -1,17 +1,38 @@
-#![feature(macro_metavar_expr_concat)]
-#![feature(const_ops)]
-#![feature(const_trait_impl)]
-#![feature(const_from)]
-#![feature(trait_alias)]
-#![feature(generic_const_exprs)]
+#![feature(unboxed_closures)]
+#![feature(fn_traits)]
+#![feature(gen_blocks)]
+#![feature(associated_type_defaults)]
+#![feature(unsize)]
 
-mod layout;
-mod render;
-pub mod util;
-mod base;
+pub mod default;
+pub mod event;
+pub mod typed;
+pub mod widget;
 
-pub use layout::*;
-pub use render::*;
-pub use base::*;
+pub use iris_core as core;
+pub use iris_macro as macros;
 
-pub type HashMap<K, V> = std::collections::HashMap<K, V>;
+#[macro_export]
+macro_rules! state_prelude {
+    ($vis:vis $state:ty) => {
+        iris::event_state!($vis $state);
+        $vis use iris::{
+            default::*,
+            core::{len_fns::*, util::Vec2, *},
+            macros::*,
+            widget::*,
+        };
+    };
+}
+
+pub mod prelude {
+    use super::*;
+    pub use default::*;
+    pub use event::*;
+    pub use iris_core::*;
+    pub use iris_macro::*;
+    pub use widget::*;
+
+    pub use iris_core::util::Vec2;
+    pub use typed::*;
+}

src/main.rs

@@ -1,5 +0,0 @@
-mod testing;
-
-fn main() {
-    testing::main();
-}

src/render/data.rs

@@ -1,34 +0,0 @@
-use crate::primitive::UIRegion;
-use wgpu::VertexAttribute;
-
-#[repr(C)]
-#[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
-pub struct PrimitiveInstance {
-    pub region: UIRegion,
-    pub ptr: u32,
-}
-
-#[repr(C)]
-#[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable, Default)]
-pub struct WindowUniform {
-    pub width: f32,
-    pub height: f32,
-}
-
-impl PrimitiveInstance {
-    const ATTRIBS: [VertexAttribute; 5] = wgpu::vertex_attr_array![
-        0 => Float32x2,
-        1 => Float32x2,
-        2 => Float32x2,
-        3 => Float32x2,
-        4 => Uint32,
-    ];
-
-    pub fn desc() -> wgpu::VertexBufferLayout<'static> {
-        wgpu::VertexBufferLayout {
-            array_stride: std::mem::size_of::<Self>() as wgpu::BufferAddress,
-            step_mode: wgpu::VertexStepMode::Instance,
-            attributes: &Self::ATTRIBS,
-        }
-    }
-}

src/render/mod.rs

@@ -1,184 +0,0 @@
-use crate::{
-    render::{data::PrimitiveInstance, util::ArrBuf},
-    UI,
-};
-use data::WindowUniform;
-use wgpu::{
-    util::{BufferInitDescriptor, DeviceExt},
-    *,
-};
-use winit::dpi::PhysicalSize;
-
-mod data;
-pub mod primitive;
-mod util;
-
-const SHAPE_SHADER: &str = include_str!("./shader.wgsl");
-
-pub struct UIRenderNode {
-    bind_group_layout: BindGroupLayout,
-    bind_group: BindGroup,
-    pipeline: RenderPipeline,
-
-    window_buffer: Buffer,
-    instance: ArrBuf<PrimitiveInstance>,
-    data: ArrBuf<u32>,
-}
-
-impl UIRenderNode {
-    pub fn draw<'a>(&'a self, pass: &mut RenderPass<'a>) {
-        pass.set_pipeline(&self.pipeline);
-        pass.set_bind_group(0, &self.bind_group, &[]);
-        if self.instance.len() != 0 {
-            pass.set_vertex_buffer(0, self.instance.buffer.slice(..));
-            pass.draw(0..4, 0..self.instance.len() as u32);
-        }
-    }
-
-    pub fn update(&mut self, device: &Device, queue: &Queue, ui: &UI) {
-        let primitives = ui.to_primitives();
-        self.instance.update(device, queue, &primitives.instances);
-        self.data.update(device, queue, &primitives.data);
-        self.bind_group = Self::bind_group(
-            device,
-            &self.bind_group_layout,
-            &self.window_buffer,
-            &self.data.buffer,
-        )
-    }
-
-    pub fn resize(&mut self, size: &PhysicalSize<u32>, queue: &Queue) {
-        let slice = &[WindowUniform {
-            width: size.width as f32,
-            height: size.height as f32,
-        }];
-        queue.write_buffer(&self.window_buffer, 0, bytemuck::cast_slice(slice));
-    }
-
-    pub fn new(device: &Device, config: &SurfaceConfiguration) -> Self {
-        let shader = device.create_shader_module(ShaderModuleDescriptor {
-            label: Some("UI Shape Shader"),
-            source: ShaderSource::Wgsl(SHAPE_SHADER.into()),
-        });
-
-        let window_uniform = WindowUniform::default();
-        let window_buffer = device.create_buffer_init(&BufferInitDescriptor {
-            label: Some("Camera Buffer"),
-            contents: bytemuck::cast_slice(&[window_uniform]),
-            usage: BufferUsages::UNIFORM | BufferUsages::COPY_DST,
-        });
-
-        let instance = ArrBuf::new(
-            device,
-            BufferUsages::VERTEX | BufferUsages::COPY_DST,
-            "instance",
-        );
-        let data = ArrBuf::new(
-            device,
-            BufferUsages::STORAGE | BufferUsages::COPY_DST,
-            "data",
-        );
-
-        let bind_group_layout = device.create_bind_group_layout(&BindGroupLayoutDescriptor {
-            entries: &[
-                BindGroupLayoutEntry {
-                    binding: 0,
-                    visibility: ShaderStages::VERTEX,
-                    ty: BindingType::Buffer {
-                        ty: BufferBindingType::Uniform,
-                        has_dynamic_offset: false,
-                        min_binding_size: None,
-                    },
-                    count: None,
-                },
-                BindGroupLayoutEntry {
-                    binding: 1,
-                    visibility: ShaderStages::FRAGMENT,
-                    ty: BindingType::Buffer {
-                        ty: BufferBindingType::Storage { read_only: true },
-                        has_dynamic_offset: false,
-                        min_binding_size: None,
-                    },
-                    count: None,
-                },
-            ],
-            label: Some("camera_bind_group_layout"),
-        });
-
-        let bind_group = Self::bind_group(device, &bind_group_layout, &window_buffer, &data.buffer);
-
-        let pipeline_layout = device.create_pipeline_layout(&PipelineLayoutDescriptor {
-            label: Some("UI Shape Pipeline Layout"),
-            bind_group_layouts: &[&bind_group_layout],
-            push_constant_ranges: &[],
-        });
-        let pipeline = device.create_render_pipeline(&RenderPipelineDescriptor {
-            label: Some("UI Shape Pipeline"),
-            layout: Some(&pipeline_layout),
-            vertex: VertexState {
-                module: &shader,
-                entry_point: Some("vs_main"),
-                buffers: &[PrimitiveInstance::desc()],
-                compilation_options: Default::default(),
-            },
-            fragment: Some(FragmentState {
-                module: &shader,
-                entry_point: Some("fs_main"),
-                targets: &[Some(ColorTargetState {
-                    format: config.format,
-                    blend: Some(BlendState::ALPHA_BLENDING),
-                    write_mask: ColorWrites::ALL,
-                })],
-                compilation_options: Default::default(),
-            }),
-            primitive: PrimitiveState {
-                topology: PrimitiveTopology::TriangleStrip,
-                strip_index_format: None,
-                front_face: FrontFace::Cw,
-                cull_mode: Some(Face::Back),
-                polygon_mode: PolygonMode::Fill,
-                unclipped_depth: false,
-                conservative: false,
-            },
-            depth_stencil: None,
-            multisample: MultisampleState {
-                count: 1,
-                mask: !0,
-                alpha_to_coverage_enabled: false,
-            },
-            multiview: None,
-            cache: None,
-        });
-
-        Self {
-            bind_group_layout,
-            bind_group,
-            pipeline,
-            window_buffer,
-            instance,
-            data,
-        }
-    }
-
-    pub fn bind_group(
-        device: &Device,
-        layout: &BindGroupLayout,
-        window_buffer: &Buffer,
-        data: &Buffer,
-    ) -> BindGroup {
-        device.create_bind_group(&BindGroupDescriptor {
-            layout,
-            entries: &[
-                BindGroupEntry {
-                    binding: 0,
-                    resource: window_buffer.as_entire_binding(),
-                },
-                BindGroupEntry {
-                    binding: 1,
-                    resource: data.as_entire_binding(),
-                },
-            ],
-            label: Some("ui_bind_group"),
-        })
-    }
-}

src/render/primitive/color.rs

@@ -1,47 +0,0 @@
-#![allow(clippy::multiple_bound_locations)]
-
-#[repr(C)]
-#[derive(Clone, Copy, bytemuck::Zeroable)]
-pub struct Color<T: ColorNum> {
-    r: T,
-    g: T,
-    b: T,
-    a: T,
-}
-
-impl<T: ColorNum> Color<T> {
-    pub const BLACK: Self = Self::rgb(T::MIN, T::MIN, T::MIN);
-    pub const WHITE: Self = Self::rgb(T::MAX, T::MAX, T::MAX);
-
-    pub const RED: Self = Self::rgb(T::MAX, T::MIN, T::MIN);
-    pub const ORANGE: Self = Self::rgb(T::MAX, T::MID, T::MIN);
-    pub const YELLOW: Self = Self::rgb(T::MAX, T::MAX, T::MIN);
-    pub const LIME: Self = Self::rgb(T::MID, T::MAX, T::MIN);
-    pub const GREEN: Self = Self::rgb(T::MIN, T::MAX, T::MIN);
-    pub const CYAN: Self = Self::rgb(T::MIN, T::MAX, T::MAX);
-    pub const BLUE: Self = Self::rgb(T::MIN, T::MIN, T::MAX);
-    pub const MAGENTA: Self = Self::rgb(T::MAX, T::MIN, T::MAX);
-}
-
-impl<T: ColorNum> Color<T> {
-    pub const fn new(r: T, g: T, b: T, a: T) -> Self {
-        Self { r, g, b, a }
-    }
-    pub const fn rgb(r: T, g: T, b: T) -> Self {
-        Self { r, g, b, a: T::MAX }
-    }
-}
-
-pub trait ColorNum {
-    const MIN: Self;
-    const MID: Self;
-    const MAX: Self;
-}
-
-impl ColorNum for u8 {
-    const MIN: Self = u8::MIN;
-    const MID: Self = u8::MAX / 2;
-    const MAX: Self = u8::MAX;
-}
-
-unsafe impl bytemuck::Pod for Color<u8> {}

src/render/primitive/def.rs

@@ -1,14 +0,0 @@
-use crate::primitive::{Color, PrimitiveData};
-
-#[repr(C)]
-#[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
-pub struct RoundedRectData {
-    pub color: Color<u8>,
-    pub radius: f32,
-    pub thickness: f32,
-    pub inner_radius: f32,
-}
-
-impl PrimitiveData for RoundedRectData {
-    const DISCRIM: u32 = 0;
-}

src/render/primitive/format.rs

@@ -1,97 +0,0 @@
-use crate::primitive::{point::point, Point};
-
-#[repr(C)]
-#[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable, Default)]
-pub struct UIPos {
-    pub anchor: Point,
-    pub offset: Point,
-}
-
-impl UIPos {
-    pub const fn anchor_offset(anchor_x: f32, anchor_y: f32, offset_x: f32, offset_y: f32) -> Self {
-        Self {
-            anchor: point(anchor_x, anchor_y),
-            offset: point(offset_x, offset_y),
-        }
-    }
-
-    pub const fn top_left() -> Self {
-        Self::anchor_offset(0.0, 0.0, 0.0, 0.0)
-    }
-
-    pub const fn bottom_right() -> Self {
-        Self::anchor_offset(1.0, 1.0, 0.0, 0.0)
-    }
-
-    pub const fn within(&self, region: &UIRegion) -> UIPos {
-        let range = region.bot_right.anchor - region.top_left.anchor;
-        let region_offset = region
-            .top_left
-            .offset
-            .lerp(region.bot_right.offset, self.anchor);
-        UIPos {
-            anchor: region.top_left.anchor + self.anchor * range,
-            offset: self.offset + region_offset,
-        }
-    }
-
-    pub fn axis_mut(&mut self, axis: Axis) -> UIPosAxisView<'_> {
-        match axis {
-            Axis::X => UIPosAxisView {
-                anchor: &mut self.anchor.x,
-                offset: &mut self.offset.x,
-            },
-            Axis::Y => UIPosAxisView {
-                anchor: &mut self.anchor.y,
-                offset: &mut self.offset.y,
-            },
-        }
-    }
-}
-
-pub struct UIPosAxisView<'a> {
-    pub anchor: &'a mut f32,
-    pub offset: &'a mut f32,
-}
-
-#[repr(C)]
-#[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
-pub struct UIRegion {
-    pub top_left: UIPos,
-    pub bot_right: UIPos,
-}
-
-impl UIRegion {
-    pub const fn full() -> Self {
-        Self {
-            top_left: UIPos::top_left(),
-            bot_right: UIPos::bottom_right(),
-        }
-    }
-    pub fn within(&self, parent: &Self) -> Self {
-        Self {
-            top_left: self.top_left.within(parent),
-            bot_right: self.bot_right.within(parent),
-        }
-    }
-    pub fn select(&mut self, inner: &Self) {
-        *self = inner.within(self);
-    }
-    pub fn axis_mut(&mut self, axis: Axis) -> UIRegionAxisView<'_> {
-        UIRegionAxisView {
-            top_left: self.top_left.axis_mut(axis),
-            bot_right: self.bot_right.axis_mut(axis),
-        }
-    }
-}
-
-pub struct UIRegionAxisView<'a> {
-    pub top_left: UIPosAxisView<'a>,
-    pub bot_right: UIPosAxisView<'a>,
-}
-
-#[derive(Copy, Clone)]
-pub enum Axis {
-    X,
-    Y,
-}

src/render/primitive/mod.rs

@@ -1,63 +0,0 @@
-mod color;
-mod def;
-mod format;
-mod point;
-
-pub use color::*;
-pub use def::*;
-pub use format::*;
-pub use point::*;
-
-use crate::{render::data::PrimitiveInstance, WidgetId, Widgets};
-use bytemuck::Pod;
-
-#[derive(Default)]
-pub struct Primitives {
-    pub instances: Vec<PrimitiveInstance>,
-    pub data: Vec<u32>,
-}
-
-pub struct Painter<'a> {
-    nodes: &'a Widgets,
-    primitives: Primitives,
-    pub region: UIRegion,
-}
-
-/// NOTE: Self must have at least u32 alignment
-pub trait PrimitiveData: Pod {
-    const DISCRIM: u32;
-}
-
-impl<'a> Painter<'a> {
-    pub fn new(nodes: &'a Widgets) -> Self {
-        Self {
-            nodes,
-            primitives: Primitives::default(),
-            region: UIRegion::full(),
-        }
-    }
-    pub fn write<Data: PrimitiveData>(&mut self, data: Data) {
-        let ptr = self.primitives.data.len() as u32;
-        let region = self.region;
-        self.primitives
-            .instances
-            .push(PrimitiveInstance { region, ptr });
-        self.primitives.data.push(Data::DISCRIM);
-        self.primitives
-            .data
-            .extend_from_slice(bytemuck::cast_slice::<_, u32>(&[data]));
-    }
-    pub fn draw(&mut self, node: &WidgetId) {
-        self.nodes.get(node).draw(self);
-    }
-    pub fn draw_within(&mut self, node: &WidgetId, region: UIRegion) {
-        let old = self.region;
-        self.region.select(&region);
-        self.draw(node);
-        self.region = old;
-    }
-
-    pub fn finish(self) -> Primitives {
-        self.primitives
-    }
-}

src/render/primitive/point.rs

@@ -1,84 +0,0 @@
-use std::ops::*;
-
-#[repr(C)]
-#[derive(Clone, Copy, PartialEq, Default, bytemuck::Pod, bytemuck::Zeroable)]
-pub struct Point {
-    pub x: f32,
-    pub y: f32,
-}
-
-pub const fn point(x: f32, y: f32) -> Point {
-    Point::new(x, y)
-}
-
-impl Point {
-    pub const fn new(x: f32, y: f32) -> Self {
-        Self { x, y }
-    }
-
-    pub const fn lerp(self, to: Self, amt: impl const Into<Self>) -> Self {
-        let amt = amt.into();
-        Self {
-            x: lerp(self.x, to.x, amt.x),
-            y: lerp(self.y, to.y, amt.y),
-        }
-    }
-}
-
-const fn lerp(x: f32, y: f32, amt: f32) -> f32 {
-    (1.0 - amt) * x + y * amt
-}
-
-impl const From<f32> for Point {
-    fn from(v: f32) -> Self {
-        Self { x: v, y: v }
-    }
-}
-
-macro_rules! impl_op_inner {
-    ($op:ident $fn:ident $opa:ident $fna:ident) => {
-        impl const $op for Point {
-            type Output = Self;
-
-            fn $fn(self, rhs: Self) -> Self::Output {
-                Self {
-                    x: self.x.$fn(rhs.x),
-                    y: self.y.$fn(rhs.y),
-                }
-            }
-        }
-        impl $opa for Point {
-            fn $fna(&mut self, rhs: Self) {
-                self.x.$fna(rhs.x);
-                self.y.$fna(rhs.y);
-            }
-        }
-        impl const $op<f32> for Point {
-            type Output = Self;
-
-            fn $fn(self, rhs: f32) -> Self::Output {
-                Self {
-                    x: self.x.$fn(rhs),
-                    y: self.y.$fn(rhs),
-                }
-            }
-        }
-        impl $opa<f32> for Point {
-            fn $fna(&mut self, rhs: f32) {
-                self.x.$fna(rhs);
-                self.y.$fna(rhs);
-            }
-        }
-    };
-}
-
-macro_rules! impl_op {
-    ($op:ident $fn:ident) => {
-        impl_op_inner!($op $fn ${concat($op,Assign)} ${concat($fn,_assign)});
-    };
-}
-
-impl_op!(Add add);
-impl_op!(Sub sub);
-impl_op!(Mul mul);
-impl_op!(Div div);

src/render/shader.wgsl

@@ -1,110 +0,0 @@
-@group(0) @binding(0)
-var<uniform> window: WindowUniform;
-@group(0) @binding(1)
-var<storage> data: array<u32>;
-
-struct WindowUniform {
-    dim: vec2<f32>,
-};
-
-struct InstanceInput {
-    @location(0) top_left_anchor: vec2<f32>,
-    @location(1) top_left_offset: vec2<f32>,
-    @location(2) bottom_right_anchor: vec2<f32>,
-    @location(3) bottom_right_offset: vec2<f32>,
-    @location(4) pointer: u32,
-}
-
-struct RoundedRect {
-    color: u32,
-    radius: f32,
-    thickness: f32,
-    inner_radius: f32,
-}
-
-struct VertexOutput {
-    @location(0) pointer: u32,
-    @location(1) top_left: vec2<f32>,
-    @location(2) bot_right: vec2<f32>,
-    @builtin(position) clip_position: vec4<f32>,
-};
-
-struct Region {
-    pos: vec2<f32>,
-    top_left: vec2<f32>,
-    bot_right: vec2<f32>,
-}
-
-@vertex
-fn vs_main(
-    @builtin(vertex_index) vi: u32,
-    in: InstanceInput,
-) -> VertexOutput {
-    var out: VertexOutput;
-
-    let top_left = in.top_left_anchor * window.dim + in.top_left_offset;
-    let bot_right = in.bottom_right_anchor * window.dim + in.bottom_right_offset;
-    let size = bot_right - top_left;
-
-    var pos = top_left + vec2<f32>(
-        f32(vi % 2u),
-        f32(vi / 2u)
-    ) * size;
-    pos = pos / window.dim * 2.0 - 1.0;
-    out.clip_position = vec4<f32>(pos.x, -pos.y, 0.0, 1.0);
-    out.pointer = in.pointer;
-    out.top_left = top_left;
-    out.bot_right = bot_right;
-
-    return out;
-}
-
-@fragment
-fn fs_main(
-    in: VertexOutput
-) -> @location(0) vec4<f32> {
-    let pos = in.clip_position.xy;
-    let ty = data[in.pointer];
-    let dp = in.pointer + 1u;
-    let region = Region(pos, in.top_left, in.bot_right);
-    switch ty {
-        case 0u: {
-            return draw_rounded_rect(region, RoundedRect(
-                data[dp + 0u],
-                bitcast<f32>(data[dp + 1u]),
-                bitcast<f32>(data[dp + 2u]),
-                bitcast<f32>(data[dp + 3u]),
-            ));
-        }
-        default: {}
-    }
-    return vec4(1.0, 0.0, 1.0, 1.0);
-}
-
-fn draw_rounded_rect(region: Region, rect: RoundedRect) -> vec4<f32> {
-    var color = unpack4x8unorm(rect.color);
-
-    let edge = 0.5;
-
-    let size = region.bot_right - region.top_left;
-    let corner = size / 2.0;
-    let center = region.top_left + corner;
-
-    let dist = distance_from_rect(region.pos, center, corner, rect.radius);
-    color.a *= 1.0 - smoothstep(-min(edge, rect.radius), edge, dist);
-
-    if rect.thickness > 0.0 {
-        let dist2 = distance_from_rect(region.pos, center, corner - rect.thickness, rect.inner_radius);
-        color.a *= smoothstep(-min(edge, rect.inner_radius), edge, dist2);
-    }
-
-    return color;
-}
-
-fn distance_from_rect(pixel_pos: vec2<f32>, rect_center: vec2<f32>, rect_corner: vec2<f32>, radius: f32) -> f32 {
-    // vec from center to pixel
-    let p = pixel_pos - rect_center;
-    // vec from inner rect corner to pixel
-    let q = abs(p) - (rect_corner - radius);
-    return length(max(q, vec2<f32>(0.0, 0.0))) - radius;
-}

src/testing/app.rs

@@ -1,36 +0,0 @@
-use winit::{
-    application::ApplicationHandler,
-    event::WindowEvent,
-    event_loop::{ActiveEventLoop, EventLoop},
-    window::{Window, WindowId},
-};
-
-use super::Client;
-
-#[derive(Default)]
-pub struct App {
-    client: Option<Client>,
-}
-
-impl App {
-    pub fn run() {
-        let event_loop = EventLoop::new().unwrap();
-        event_loop.run_app(&mut App::default()).unwrap();
-    }
-}
-
-impl ApplicationHandler for App {
-    fn resumed(&mut self, event_loop: &ActiveEventLoop) {
-        if self.client.is_none() {
-            let window = event_loop
-                .create_window(Window::default_attributes())
-                .unwrap();
-            let client = Client::new(window.into());
-            self.client = Some(client);
-        }
-    }
-
-    fn window_event(&mut self, event_loop: &ActiveEventLoop, _id: WindowId, event: WindowEvent) {
-        self.client.as_mut().unwrap().event(event, event_loop);
-    }
-}

src/testing/mod.rs

@@ -1,71 +0,0 @@
-use gui::util::IntoTupleList;
-use std::sync::Arc;
-
-use app::App;
-use gui::{primitive::Axis, RoundedRect, UIColor, WidgetArrUtil, WidgetUtil, UI};
-use render::Renderer;
-use winit::{event::WindowEvent, event_loop::ActiveEventLoop, window::Window};
-
-mod app;
-mod render;
-
-pub fn main() {
-    App::run();
-}
-
-pub struct Client {
-    renderer: Renderer,
-}
-
-impl Client {
-    pub fn new(window: Arc<Window>) -> Self {
-        let mut renderer = Renderer::new(window);
-        let rect = RoundedRect {
-            color: UIColor::WHITE,
-            radius: 10.0,
-            thickness: 0.0,
-            inner_radius: 0.0,
-        };
-        let mut ui = UI::build();
-        let blue = ui.add(rect.color(UIColor::BLUE));
-        let handle = blue.handle();
-        let mut ui = ui.finish(
-            (
-                (
-                    blue,
-                    (
-                        rect.color(UIColor::RED),
-                        (
-                            rect.color(UIColor::ORANGE),
-                            rect.color(UIColor::LIME).pad(10.0),
-                        )
-                            .into_list()
-                            .span(Axis::Y, [1, 1].into()),
-                        rect.color(UIColor::YELLOW),
-                    )
-                        .into_list()
-                        .span(Axis::X, [2, 2, 1])
-                        .pad(10),
-                )
-                    .into_list()
-                    .span(Axis::X, [1, 3]),
-                rect.color(UIColor::GREEN),
-            )
-                .into_list()
-                .span(Axis::Y, [3, 1])
-                .pad(10),
-        );
-        ui.widgets.get_mut(&handle).unwrap().color = UIColor::MAGENTA;
-        renderer.update(&ui);
-        Self { renderer }
-    }
-
-    pub fn event(&mut self, event: WindowEvent, event_loop: &ActiveEventLoop) {
-        match event {
-            WindowEvent::CloseRequested => event_loop.exit(),
-            WindowEvent::RedrawRequested => self.renderer.draw(),
-            WindowEvent::Resized(size) => self.renderer.resize(&size),
-            _ => (),
-        }
-    }
-}

src/typed.rs

@@ -0,0 +1,37 @@
+#[macro_export]
+macro_rules! event_state {
+    ($vis:vis $state:ty) => {
+        mod local_event_trait {
+            use super::*;
+            #[allow(unused_imports)]
+            use $crate::prelude::*;
+            pub trait EventableCtx<WL: WidgetLike<$state, Tag>, Tag> {
+                fn on<E: EventLike>(
+                    self,
+                    event: E,
+                    f: impl for<'a> WidgetEventFn<
+                        <$state as HasState>::State,
+                        <E::Event as Event>::Data<'a>,
+                        WL::Widget
+                    >,
+                ) -> impl WidgetIdFn<$state, WL::Widget>;
+            }
+            impl<WL: WidgetLike<$state, Tag>, Tag> EventableCtx<WL, Tag> for WL {
+                fn on<E: EventLike>(
+                    self,
+                    event: E,
+                    f: impl for<'a> WidgetEventFn<
+                        <$state as HasState>::State,
+                        <E::Event as Event>::Data<'a>,
+                        WL::Widget
+                    >,
+                ) -> impl WidgetIdFn<$state, WL::Widget> {
+                    eventable::Eventable::on(self, event, f)
+                }
+            }
+        }
+        $vis type EventManager = $crate::prelude::EventManager<<$state as HasState>::State>;
+        $vis use local_event_trait::*;
+    };
+}
+pub use event_state;

src/util/id.rs

@@ -1,44 +0,0 @@
-/// intentionally does not implement copy or clone
-/// which should make it harder to misuse;
-/// the idea is to generally try to guarantee all IDs
-/// point to something valid, although duplicate
-/// gets around this if needed
-#[derive(Eq, Hash, PartialEq, Debug)]
-pub struct ID(usize);
-
-#[derive(Default)]
-pub struct IDTracker {
-    free: Vec<ID>,
-    cur: usize,
-}
-
-impl IDTracker {
-    pub fn new() -> Self {
-        Self::default()
-    }
-
-    #[allow(clippy::should_implement_trait)]
-    pub fn next(&mut self) -> ID {
-        if let Some(id) = self.free.pop() {
-            return id;
-        }
-        let id = ID(self.cur);
-        self.cur += 1;
-        id
-    }
-
-    #[allow(dead_code)]
-    pub fn free(&mut self, id: ID) {
-        self.free.push(id);
-    }
-}
-
-impl ID {
-    /// this must be used carefully to make sure
-    /// all IDs are still valid references;
-    /// named weirdly to indicate this.
-    /// generally should not be used in "user" code
-    pub fn duplicate(&self) -> Self {
-        Self(self.0)
-    }
-}

src/util/mod.rs

@@ -1,5 +0,0 @@
-mod id;
-mod tuple;
-
-pub use id::*;
-pub use tuple::*;

src/util/tuple.rs

@@ -1,70 +0,0 @@
-pub trait TupleList {
-    const LEN: usize;
-    type Head;
-    type Tail;
-    fn into_head(self) -> Self::Head;
-    fn head(&self) -> &Self::Head;
-    fn split(self) -> (Self::Head, Self::Tail);
-}
-impl TupleList for () {
-    const LEN: usize = 0;
-    type Head = ();
-    type Tail = ();
-    fn head(&self) -> &Self::Head {
-        &()
-    }
-    fn into_head(self) -> Self::Head {}
-    fn split(self) -> (Self::Head, Self::Tail) {
-        ((), ())
-    }
-}
-impl<T, Rest: TupleList> TupleList for (T, Rest) {
-    const LEN: usize = Rest::LEN + 1;
-    type Head = T;
-    type Tail = Rest;
-    fn head(&self) -> &Self::Head {
-        &self.0
-    }
-    fn into_head(self) -> Self::Head {
-        self.0
-    }
-    fn split(self) -> (Self::Head, Self::Tail) {
-        (self.0, self.1)
-    }
-}
-
-pub trait IntoTupleList {
-    type List;
-    fn into_list(self) -> Self::List;
-}
-
-impl IntoTupleList for () {
-    type List = ();
-    fn into_list(self) -> Self::List {}
-}
-
-macro_rules! impl_tuple {
-    ($H:tt $($T:tt)*) => {
-        impl<$H, $($T,)*> IntoTupleList for ($H, $($T,)*) {
-            type List = ($H, <($($T,)*) as IntoTupleList>::List);
-            fn into_list(self) -> Self::List {
-                #[allow(non_snake_case)]
-                let ($H, $($T,)*) = self;
-                ($H, ($($T,)*).into_list())
-            }
-        }
-    };
-}
-
-impl_tuple!(A);
-impl_tuple!(A B);
-impl_tuple!(A B C);
-impl_tuple!(A B C D);
-impl_tuple!(A B C D E);
-impl_tuple!(A B C D E F);
-impl_tuple!(A B C D E F G);
-impl_tuple!(A B C D E F G H);
-impl_tuple!(A B C D E F G H I);
-impl_tuple!(A B C D E F G H I J);
-impl_tuple!(A B C D E F G H I J K);
-impl_tuple!(A B C D E F G H I J K L);

src/widget/image.rs

@@ -0,0 +1,55 @@
+use crate::prelude::*;
+use image::DynamicImage;
+
+pub struct Image {
+    handle: TextureHandle,
+}
+
+impl Widget for Image {
+    fn draw(&mut self, painter: &mut Painter) {
+        painter.texture(&self.handle);
+    }
+
+    fn desired_width(&mut self, _: &mut SizeCtx) -> Len {
+        Len::abs(self.handle.size().x)
+    }
+
+    fn desired_height(&mut self, _: &mut SizeCtx) -> Len {
+        Len::abs(self.handle.size().y)
+    }
+}
+
+pub fn image<State: HasUi>(image: impl LoadableImage) -> impl WidgetFn<State, Image> {
+    let image = image.get_image().expect("Failed to load image");
+    move |state| Image {
+        handle: state.get_mut().add_texture(image),
+    }
+}
+
+pub trait LoadableImage {
+    fn get_image(self) -> Result<DynamicImage, String>;
+}
+
+impl LoadableImage for &str {
+    fn get_image(self) -> Result<DynamicImage, String> {
+        image::open(self).map_err(|e| format!("{e:?}"))
+    }
+}
+
+impl LoadableImage for String {
+    fn get_image(self) -> Result<DynamicImage, String> {
+        image::open(self).map_err(|e| format!("{e:?}"))
+    }
+}
+
+impl<const LEN: usize> LoadableImage for &[u8; LEN] {
+    fn get_image(self) -> Result<DynamicImage, String> {
+        image::load_from_memory(self).map_err(|e| format!("{e:?}"))
+    }
+}
+
+impl LoadableImage for DynamicImage {
+    fn get_image(self) -> Result<DynamicImage, String> {
+        Ok(self)
+    }
+}

src/widget/mask.rs

@@ -0,0 +1,20 @@
+use crate::prelude::*;
+
+pub struct Masked {
+    pub inner: WidgetHandle,
+}
+
+impl Widget for Masked {
+    fn draw(&mut self, painter: &mut Painter) {
+        painter.set_mask(painter.region());
+        painter.widget(&self.inner);
+    }
+
+    fn desired_width(&mut self, ctx: &mut SizeCtx) -> Len {
+        ctx.width(&self.inner)
+    }
+
+    fn desired_height(&mut self, ctx: &mut SizeCtx) -> Len {
+        ctx.height(&self.inner)
+    }
+}

src/widget/mod.rs

@@ -0,0 +1,15 @@
+mod image;
+mod mask;
+mod position;
+mod ptr;
+mod rect;
+mod text;
+mod trait_fns;
+
+pub use image::*;
+pub use mask::*;
+pub use position::*;
+pub use ptr::*;
+pub use rect::*;
+pub use text::*;
+pub use trait_fns::*;

src/widget/position/align.rs

@@ -0,0 +1,35 @@
+use crate::prelude::*;
+
+pub struct Aligned {
+    pub inner: WidgetHandle,
+    pub align: Align,
+}
+
+impl Widget for Aligned {
+    fn draw(&mut self, painter: &mut Painter) {
+        let region = match self.align.tuple() {
+            (Some(x), Some(y)) => painter
+                .size(&self.inner)
+                .to_uivec2()
+                .align(RegionAlign { x, y }),
+            (Some(x), None) => {
+                let x = painter.size_ctx().width(&self.inner).apply_rest().align(x);
+                UiRegion::new(x, UiSpan::FULL)
+            }
+            (None, Some(y)) => {
+                let y = painter.size_ctx().height(&self.inner).apply_rest().align(y);
+                UiRegion::new(UiSpan::FULL, y)
+            }
+            (None, None) => UiRegion::FULL,
+        };
+        painter.widget_within(&self.inner, region);
+    }
+
+    fn desired_width(&mut self, ctx: &mut SizeCtx) -> Len {
+        ctx.width(&self.inner)
+    }
+
+    fn desired_height(&mut self, ctx: &mut SizeCtx) -> Len {
+        ctx.height(&self.inner)
+    }
+}

src/widget/position/layer.rs

@@ -0,0 +1,23 @@
+use crate::prelude::*;
+
+pub struct LayerOffset {
+    pub inner: WidgetHandle,
+    pub offset: usize,
+}
+
+impl Widget for LayerOffset {
+    fn draw(&mut self, painter: &mut Painter) {
+        for _ in 0..self.offset {
+            painter.next_layer();
+        }
+        painter.widget(&self.inner);
+    }
+
+    fn desired_width(&mut self, ctx: &mut SizeCtx) -> Len {
+        ctx.width(&self.inner)
+    }
+
+    fn desired_height(&mut self, ctx: &mut SizeCtx) -> Len {
+        ctx.height(&self.inner)
+    }
+}

src/widget/position/max_size.rs

@@ -0,0 +1,48 @@
+use crate::prelude::*;
+
+pub struct MaxSize {
+    pub inner: WidgetHandle,
+    pub x: Option<Len>,
+    pub y: Option<Len>,
+}
+
+impl MaxSize {
+    fn apply_to_outer(&self, ctx: &mut SizeCtx) {
+        if let Some(x) = self.x {
+            ctx.outer.x.select_len(x.apply_rest());
+        }
+        if let Some(y) = self.y {
+            ctx.outer.y.select_len(y.apply_rest());
+        }
+    }
+}
+
+impl Widget for MaxSize {
+    fn draw(&mut self, painter: &mut Painter) {
+        painter.widget(&self.inner);
+    }
+
+    fn desired_width(&mut self, ctx: &mut SizeCtx) -> Len {
+        self.apply_to_outer(ctx);
+        let width = ctx.width(&self.inner);
+        if let Some(x) = self.x {
+            let width_px = width.apply_rest().to_abs(ctx.output_size().x);
+            let x_px = x.apply_rest().to_abs(ctx.output_size().x);
+            if width_px > x_px { x } else { width }
+        } else {
+            width
+        }
+    }
+
+    fn desired_height(&mut self, ctx: &mut SizeCtx) -> Len {
+        self.apply_to_outer(ctx);
+        let height = ctx.height(&self.inner);
+        if let Some(y) = self.y {
+            let height_px = height.apply_rest().to_abs(ctx.output_size().y);
+            let y_px = y.apply_rest().to_abs(ctx.output_size().y);
+            if height_px > y_px { y } else { height }
+        } else {
+            height
+        }
+    }
+}

src/widget/position/mod.rs

@@ -0,0 +1,19 @@
+mod align;
+mod layer;
+mod max_size;
+mod offset;
+mod pad;
+mod scroll;
+mod sized;
+mod span;
+mod stack;
+
+pub use align::*;
+pub use layer::*;
+pub use max_size::*;
+pub use offset::*;
+pub use pad::*;
+pub use scroll::*;
+pub use sized::*;
+pub use span::*;
+pub use stack::*;

src/widget/position/offset.rs

@@ -0,0 +1,21 @@
+use crate::prelude::*;
+
+pub struct Offset {
+    pub inner: WidgetHandle,
+    pub amt: UiVec2,
+}
+
+impl Widget for Offset {
+    fn draw(&mut self, painter: &mut Painter) {
+        let region = UiRegion::FULL.offset(self.amt);
+        painter.widget_within(&self.inner, region);
+    }
+
+    fn desired_width(&mut self, ctx: &mut SizeCtx) -> Len {
+        ctx.width(&self.inner)
+    }
+
+    fn desired_height(&mut self, ctx: &mut SizeCtx) -> Len {
+        ctx.height(&self.inner)
+    }
+}

src/widget/position/pad.rs

@@ -0,0 +1,134 @@
+use crate::prelude::*;
+
+pub struct Pad {
+    pub padding: Padding,
+    pub inner: WidgetHandle,
+}
+
+impl Widget for Pad {
+    fn draw(&mut self, painter: &mut Painter) {
+        painter.widget_within(&self.inner, self.padding.region());
+    }
+
+    fn desired_width(&mut self, ctx: &mut SizeCtx) -> Len {
+        let width = self.padding.left + self.padding.right;
+        let height = self.padding.top + self.padding.bottom;
+        ctx.outer.x.abs -= width;
+        ctx.outer.y.abs -= height;
+        let mut size = ctx.width(&self.inner);
+        size.abs += width;
+        size
+    }
+
+    fn desired_height(&mut self, ctx: &mut SizeCtx) -> Len {
+        let width = self.padding.left + self.padding.right;
+        let height = self.padding.top + self.padding.bottom;
+        ctx.outer.x.abs -= width;
+        ctx.outer.y.abs -= height;
+        let mut size = ctx.height(&self.inner);
+        size.abs += height;
+        size
+    }
+}
+
+pub struct Padding {
+    pub left: f32,
+    pub right: f32,
+    pub top: f32,
+    pub bottom: f32,
+}
+
+impl Padding {
+    pub const ZERO: Self = Self {
+        left: 0.0,
+        right: 0.0,
+        top: 0.0,
+        bottom: 0.0,
+    };
+
+    pub fn uniform(amt: impl UiNum) -> Self {
+        let amt = amt.to_f32();
+        Self {
+            left: amt,
+            right: amt,
+            top: amt,
+            bottom: amt,
+        }
+    }
+    pub fn region(&self) -> UiRegion {
+        let mut region = UiRegion::FULL;
+        region.x.start.abs += self.left;
+        region.y.start.abs += self.top;
+        region.x.end.abs -= self.right;
+        region.y.end.abs -= self.bottom;
+        region
+    }
+    pub fn x(amt: impl UiNum) -> Self {
+        let amt = amt.to_f32();
+        Self {
+            left: amt,
+            right: amt,
+            top: 0.0,
+            bottom: 0.0,
+        }
+    }
+    pub fn y(amt: impl UiNum) -> Self {
+        let amt = amt.to_f32();
+        Self {
+            left: 0.0,
+            right: 0.0,
+            top: amt,
+            bottom: amt,
+        }
+    }
+
+    pub fn top(amt: impl UiNum) -> Self {
+        let mut s = Self::ZERO;
+        s.top = amt.to_f32();
+        s
+    }
+
+    pub fn bottom(amt: impl UiNum) -> Self {
+        let mut s = Self::ZERO;
+        s.bottom = amt.to_f32();
+        s
+    }
+
+    pub fn left(amt: impl UiNum) -> Self {
+        let mut s = Self::ZERO;
+        s.left = amt.to_f32();
+        s
+    }
+
+    pub fn right(amt: impl UiNum) -> Self {
+        let mut s = Self::ZERO;
+        s.right = amt.to_f32();
+        s
+    }
+
+    pub fn with_top(mut self, amt: impl UiNum) -> Self {
+        self.top = amt.to_f32();
+        self
+    }
+
+    pub fn with_bottom(mut self, amt: impl UiNum) -> Self {
+        self.bottom = amt.to_f32();
+        self
+    }
+
+    pub fn with_left(mut self, amt: impl UiNum) -> Self {
+        self.left = amt.to_f32();
+        self
+    }
+
+    pub fn with_right(mut self, amt: impl UiNum) -> Self {
+        self.right = amt.to_f32();
+        self
+    }
+}
+
+impl<T: UiNum> From<T> for Padding {
+    fn from(amt: T) -> Self {
+        Self::uniform(amt.to_f32())
+    }
+}

src/widget/position/scroll.rs

@@ -0,0 +1,66 @@
+use crate::prelude::*;
+
+pub struct Scroll {
+    inner: WidgetHandle,
+    axis: Axis,
+    amt: f32,
+    snap_end: bool,
+    container_len: f32,
+    content_len: f32,
+}
+
+impl Widget for Scroll {
+    fn draw(&mut self, painter: &mut Painter) {
+        let output_len = painter.output_size().axis(self.axis);
+        let container_len = painter.region().axis(self.axis).len();
+        let content_len = painter
+            .len_axis(&self.inner, self.axis)
+            .apply_rest()
+            .within_len(container_len)
+            .to_abs(output_len);
+        self.container_len = container_len.to_abs(output_len);
+        self.content_len = content_len;
+
+        if self.snap_end {
+            self.amt = self.content_len - self.container_len;
+        }
+        self.update_amt();
+
+        let mut region = UiRegion::FULL.offset(Vec2::from_axis(self.axis, -self.amt, 0.0));
+        region.axis_mut(self.axis).end = region.axis(self.axis).start.offset(self.content_len);
+        painter.widget_within(&self.inner, region);
+    }
+
+    fn desired_width(&mut self, ctx: &mut SizeCtx) -> Len {
+        ctx.width(&self.inner)
+    }
+
+    fn desired_height(&mut self, ctx: &mut SizeCtx) -> Len {
+        ctx.height(&self.inner)
+    }
+}
+
+impl Scroll {
+    pub fn new(inner: WidgetHandle, axis: Axis) -> Self {
+        Self {
+            inner,
+            axis,
+            amt: 0.0,
+            snap_end: true,
+            container_len: 0.0,
+            content_len: 0.0,
+        }
+    }
+
+    pub fn update_amt(&mut self) {
+        self.amt = self.amt.max(0.0);
+        let len = (self.content_len - self.container_len).max(0.0);
+        self.amt = self.amt.min(len);
+        self.snap_end = self.amt == len;
+    }
+
+    pub fn scroll(&mut self, amt: f32) {
+        self.amt -= amt;
+        self.update_amt();
+    }
+}

src/widget/position/sized.rs

@@ -0,0 +1,34 @@
+use crate::prelude::*;
+
+pub struct Sized {
+    pub inner: WidgetHandle,
+    pub x: Option<Len>,
+    pub y: Option<Len>,
+}
+
+impl Sized {
+    fn apply_to_outer(&self, ctx: &mut SizeCtx) {
+        if let Some(x) = self.x {
+            ctx.outer.x.select_len(x.apply_rest());
+        }
+        if let Some(y) = self.y {
+            ctx.outer.y.select_len(y.apply_rest());
+        }
+    }
+}
+
+impl Widget for Sized {
+    fn draw(&mut self, painter: &mut Painter) {
+        painter.widget(&self.inner);
+    }
+
+    fn desired_width(&mut self, ctx: &mut SizeCtx) -> Len {
+        self.apply_to_outer(ctx);
+        self.x.unwrap_or_else(|| ctx.width(&self.inner))
+    }
+
+    fn desired_height(&mut self, ctx: &mut SizeCtx) -> Len {
+        self.apply_to_outer(ctx);
+        self.y.unwrap_or_else(|| ctx.height(&self.inner))
+    }
+}

src/widget/position/span.rs

@@ -0,0 +1,207 @@
+use crate::prelude::*;
+use std::marker::PhantomData;
+
+pub struct Span {
+    pub children: Vec<WidgetHandle>,
+    pub dir: Dir,
+    pub gap: f32,
+}
+
+impl Widget for Span {
+    fn draw(&mut self, painter: &mut Painter) {
+        let total = self.len_sum(&mut painter.size_ctx());
+        let mut start = UiScalar::rel_min();
+        for child in &self.children {
+            let mut span = UiSpan::FULL;
+            span.start = start;
+            let len = painter.len_axis(child, self.dir.axis);
+            if len.rest > 0.0 {
+                let offset = UiScalar::new(total.rel, total.abs);
+                let rel_end = UiScalar::rel(len.rest / total.rest);
+                let end = (UiScalar::rel_max() + start) - offset;
+                start = rel_end.within(&start.to(end));
+            }
+            start.abs += len.abs;
+            start.rel += len.rel;
+            span.end = start;
+            let mut child_region = UiRegion::from_axis(self.dir.axis, span, UiSpan::FULL);
+            if self.dir.sign == Sign::Neg {
+                child_region.flip(self.dir.axis);
+            }
+            painter.widget_within(child, child_region);
+            start.abs += self.gap;
+        }
+    }
+
+    fn desired_width(&mut self, ctx: &mut SizeCtx) -> Len {
+        match self.dir.axis {
+            Axis::X => self.desired_len(ctx),
+            Axis::Y => self.desired_ortho(ctx),
+        }
+    }
+
+    fn desired_height(&mut self, ctx: &mut SizeCtx) -> Len {
+        match self.dir.axis {
+            Axis::X => self.desired_ortho(ctx),
+            Axis::Y => self.desired_len(ctx),
+        }
+    }
+}
+
+impl Span {
+    pub fn empty(dir: Dir) -> Self {
+        Self {
+            children: Vec::new(),
+            dir,
+            gap: 0.0,
+        }
+    }
+
+    pub fn gap(mut self, gap: impl UiNum) -> Self {
+        self.gap = gap.to_f32();
+        self
+    }
+
+    pub fn push(&mut self, w: WidgetHandle) {
+        self.children.push(w);
+    }
+
+    pub fn pop(&mut self) -> Option<WidgetHandle> {
+        self.children.pop()
+    }
+
+    fn len_sum(&mut self, ctx: &mut SizeCtx) -> Len {
+        let gap = self.gap * self.children.len().saturating_sub(1) as f32;
+        self.children.iter().fold(Len::abs(gap), |mut s, id| {
+            // it's tempting to subtract the abs & rel from the ctx outer,
+            // but that would create inconsistent sizing if you put
+            // a rest first vs last & only speed up in one direction.
+            // I think this is only solvable by restricting how you can
+            // compute size, bc currently you need child to define parent's
+            // sectioning and you need parent's sectioning to define child.
+            // Fortunately, that doesn't matter in most cases
+            let len = ctx.len_axis(id, self.dir.axis);
+            s += len;
+            s
+        })
+    }
+
+    fn desired_len(&mut self, ctx: &mut SizeCtx) -> Len {
+        let len = self.len_sum(ctx);
+        if len.rest == 0.0 && len.rel == 0.0 {
+            len
+        } else {
+            Len::default()
+        }
+    }
+
+    fn desired_ortho(&mut self, ctx: &mut SizeCtx) -> Len {
+        // this is a weird hack to get text wrapping to work properly when in a downward span
+        // the correct solution here is to add a function to widget that lets them
+        // request that ctx.outer has an axis "resolved" before checking the other,
+        // and panicking or warning if two request opposite axis (unsolvable in that case)
+        let outer = ctx.outer.axis(self.dir.axis);
+        if self.dir.axis == Axis::X {
+            // so....... this literally copies draw so that the lengths are correctly set in the
+            // context, which makes this slow and not cool
+            let total = self.len_sum(ctx);
+            let mut start = UiScalar::rel_min();
+            let mut ortho_len = Len::ZERO;
+            for child in &self.children {
+                let mut span = UiSpan::FULL;
+                span.start = start;
+                let len = ctx.len_axis(child, self.dir.axis);
+                if len.rest > 0.0 {
+                    let offset = UiScalar::new(total.rel, total.abs);
+                    let rel_end = UiScalar::rel(len.rest / total.rest);
+                    let end = (UiScalar::rel_max() + start) - offset;
+                    start = rel_end.within(&start.to(end));
+                }
+                start.abs += len.abs;
+                start.rel += len.rel;
+                span.end = start;
+
+                let scalar = span.len();
+                *ctx.outer.axis_mut(self.dir.axis) = outer.select_len(scalar);
+                let ortho = ctx.len_axis(child, !self.dir.axis);
+                // TODO: rel shouldn't do this, but no easy way before actually calculating pixels
+                if ortho.rel > 0.0 || ortho.rest > 0.0 {
+                    ortho_len.rest = 1.0;
+                    ortho_len.abs = 0.0;
+                    break;
+                }
+                ortho_len.abs = ortho_len.abs.max(ortho.abs);
+                start.abs += self.gap;
+            }
+            ortho_len
+        } else {
+            let mut ortho_len = Len::ZERO;
+            let ortho = !self.dir.axis;
+            for child in &self.children {
+                let len = ctx.len_axis(child, ortho);
+                // TODO: rel shouldn't do this, but no easy way before actually calculating pixels
+                if len.rel > 0.0 || len.rest > 0.0 {
+                    ortho_len.rest = 1.0;
+                    ortho_len.abs = 0.0;
+                    break;
+                }
+                ortho_len.abs = ortho_len.abs.max(len.abs);
+            }
+            ortho_len
+        }
+    }
+}
+
+pub struct SpanBuilder<State, const LEN: usize, Wa: WidgetArrLike<State, LEN, Tag>, Tag> {
+    pub children: Wa,
+    pub dir: Dir,
+    pub gap: f32,
+    _pd: PhantomData<(State, Tag)>,
+}
+
+impl<State: StateLike<State>, const LEN: usize, Wa: WidgetArrLike<State, LEN, Tag>, Tag>
+    WidgetFnTrait<State> for SpanBuilder<State, LEN, Wa, Tag>
+{
+    type Widget = Span;
+
+    #[track_caller]
+    fn run(self, state: &mut State) -> Self::Widget {
+        Span {
+            children: self.children.add(state).arr.into_iter().collect(),
+            dir: self.dir,
+            gap: self.gap,
+        }
+    }
+}
+
+impl<State, const LEN: usize, Wa: WidgetArrLike<State, LEN, Tag>, Tag>
+    SpanBuilder<State, LEN, Wa, Tag>
+{
+    pub fn new(children: Wa, dir: Dir) -> Self {
+        Self {
+            children,
+            dir,
+            gap: 0.0,
+            _pd: PhantomData,
+        }
+    }
+
+    pub fn gap(mut self, gap: impl UiNum) -> Self {
+        self.gap = gap.to_f32();
+        self
+    }
+}
+
+impl std::ops::Deref for Span {
+    type Target = Vec<WidgetHandle>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.children
+    }
+}
+
+impl std::ops::DerefMut for Span {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.children
+    }
+}

src/widget/position/stack.rs

@@ -0,0 +1,79 @@
+use std::marker::PhantomData;
+
+use crate::prelude::*;
+
+pub struct Stack {
+    pub children: Vec<WidgetHandle>,
+    pub size: StackSize,
+}
+
+impl Widget for Stack {
+    fn draw(&mut self, painter: &mut Painter) {
+        let mut iter = self.children.iter();
+        if let Some(child) = iter.next() {
+            painter.child_layer();
+            painter.widget(child);
+        }
+        for child in iter {
+            painter.next_layer();
+            painter.widget(child);
+        }
+    }
+
+    fn desired_width(&mut self, ctx: &mut SizeCtx) -> Len {
+        match self.size {
+            StackSize::Default => Len::default(),
+            StackSize::Child(i) => ctx.width(&self.children[i]),
+        }
+    }
+
+    fn desired_height(&mut self, ctx: &mut SizeCtx) -> Len {
+        match self.size {
+            StackSize::Default => Len::default(),
+            StackSize::Child(i) => ctx.height(&self.children[i]),
+        }
+    }
+}
+
+#[derive(Default, Debug)]
+pub enum StackSize {
+    #[default]
+    Default,
+    Child(usize),
+}
+
+pub struct StackBuilder<State, const LEN: usize, Wa: WidgetArrLike<State, LEN, Tag>, Tag> {
+    pub children: Wa,
+    pub size: StackSize,
+    _pd: PhantomData<(State, Tag)>,
+}
+
+impl<State: StateLike<State>, const LEN: usize, Wa: WidgetArrLike<State, LEN, Tag>, Tag> FnOnce<(&mut State,)>
+    for StackBuilder<State, LEN, Wa, Tag>
+{
+    type Output = Stack;
+
+    extern "rust-call" fn call_once(self, args: (&mut State,)) -> Self::Output {
+        Stack {
+            children: self.children.add(args.0).arr.into_iter().collect(),
+            size: self.size,
+        }
+    }
+}
+
+impl<State, const LEN: usize, Wa: WidgetArrLike<State, LEN, Tag>, Tag>
+    StackBuilder<State, LEN, Wa, Tag>
+{
+    pub fn new(children: Wa) -> Self {
+        Self {
+            children,
+            size: StackSize::default(),
+            _pd: PhantomData,
+        }
+    }
+
+    pub fn size(mut self, size: StackSize) -> Self {
+        self.size = size;
+        self
+    }
+}