From e41970287d3e7b745551f9dab82454b5aa41aa9e Mon Sep 17 00:00:00 2001
From: Shadow Cat <shadowcatzero@protonmail.com>
Date: Thu, 14 Aug 2025 12:21:26 -0400
Subject: [PATCH] TAG TECHNOLOGY

---
 src/base/trait_fns.rs       |  37 -------------
 src/{base => core}/frame.rs |  12 ++--
 src/{base => core}/mod.rs   |   2 +
 src/{base => core}/num.rs   |   0
 src/{base => core}/rect.rs  |   4 +-
 src/core/sense.rs           |  35 ++++++++++++
 src/{base => core}/span.rs  |   8 +--
 src/core/trait_fns.rs       |  39 +++++++++++++
 src/layout/mod.rs           |   2 +-
 src/layout/painter.rs       |  28 ++++++----
 src/layout/region.rs        |   6 +-
 src/layout/ui.rs            |  99 +++++++++++++++++++++++----------
 src/layout/widget.rs        | 106 ++++++++++++++++++------------------
 src/lib.rs                  |   6 +-
 src/render/data.rs          |   4 +-
 src/render/mod.rs           |  14 ++++-
 src/testing/mod.rs          |  12 +++-
 src/testing/render/mod.rs   |   6 +-
 src/util/id.rs              |  12 ++--
 19 files changed, 267 insertions(+), 165 deletions(-)
 delete mode 100644 src/base/trait_fns.rs
 rename src/{base => core}/frame.rs (73%)
 rename src/{base => core}/mod.rs (83%)
 rename src/{base => core}/num.rs (100%)
 rename src/{base => core}/rect.rs (89%)
 create mode 100644 src/core/sense.rs
 rename src/{base => core}/span.rs (92%)
 create mode 100644 src/core/trait_fns.rs

diff --git a/src/base/trait_fns.rs b/src/base/trait_fns.rs
deleted file mode 100644
index 90627c3..0000000
--- a/src/base/trait_fns.rs
+++ /dev/null
@@ -1,37 +0,0 @@
-use super::*;
-use crate::{UIRegion, Ui, Vec2, WidgetArrLike, WidgetFn, WidgetFnRet, WidgetLike};
-
-pub trait BaseWidget {
-    fn pad(self, padding: impl Into<Padding>) -> WidgetFnRet!(Regioned);
-    fn center(self, size: impl Into<Vec2>) -> WidgetFnRet!(Regioned);
-}
-
-impl<W: WidgetLike> BaseWidget for W {
-    fn pad(self, padding: impl Into<Padding>) -> WidgetFnRet!(Regioned) {
-        WidgetFn(|ui| Regioned {
-            region: padding.into().region(),
-            inner: self.add(ui).erase_type(),
-        })
-    }
-
-    fn center(self, size: impl Into<Vec2>) -> WidgetFnRet!(Regioned) {
-        WidgetFn(|ui| Regioned {
-            region: UIRegion::center(size.into()),
-            inner: self.add(ui).erase_type(),
-        })
-    }
-}
-
-pub trait BaseWidgetArr<const LEN: usize> {
-    fn span(self, dir: Dir, lengths: [impl Into<SpanLen>; LEN]) -> WidgetFnRet!(Span);
-}
-
-impl<const LEN: usize, Wa: WidgetArrLike<LEN>> BaseWidgetArr<LEN> for Wa {
-    fn span(self, dir: Dir, lengths: [impl Into<SpanLen>; LEN]) -> WidgetFnRet!(Span) {
-        let lengths = lengths.map(Into::into);
-        WidgetFn(move |ui| Span {
-            dir,
-            children: self.ui(ui).arr.into_iter().zip(lengths).collect(),
-        })
-    }
-}
diff --git a/src/base/frame.rs b/src/core/frame.rs
similarity index 73%
rename from src/base/frame.rs
rename to src/core/frame.rs
index eaf4dce..7b9bd15 100644
--- a/src/base/frame.rs
+++ b/src/core/frame.rs
@@ -1,12 +1,12 @@
-use crate::{Painter, UINum, UIRegion, Widget, WidgetId};
+use crate::{Painter, UINum, UiRegion, Widget, WidgetId};
 
 pub struct Regioned {
-    pub region: UIRegion,
+    pub region: UiRegion,
     pub inner: WidgetId,
 }
 
-impl Widget for Regioned {
-    fn draw(&self, painter: &mut Painter) {
+impl<Ctx: 'static> Widget<Ctx> for Regioned {
+    fn draw(&self, painter: &mut Painter<Ctx>) {
         painter.region.select(&self.region);
         painter.draw(&self.inner);
     }
@@ -28,8 +28,8 @@ impl Padding {
             bottom: amt,
         }
     }
-    pub fn region(&self) -> UIRegion {
-        let mut region = UIRegion::full();
+    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;
diff --git a/src/base/mod.rs b/src/core/mod.rs
similarity index 83%
rename from src/base/mod.rs
rename to src/core/mod.rs
index 647220b..2136c32 100644
--- a/src/base/mod.rs
+++ b/src/core/mod.rs
@@ -1,11 +1,13 @@
 mod frame;
 mod num;
 mod rect;
+mod sense;
 mod span;
 mod trait_fns;
 
 pub use frame::*;
 pub use num::*;
 pub use rect::*;
+pub use sense::*;
 pub use span::*;
 pub use trait_fns::*;
diff --git a/src/base/num.rs b/src/core/num.rs
similarity index 100%
rename from src/base/num.rs
rename to src/core/num.rs
diff --git a/src/base/rect.rs b/src/core/rect.rs
similarity index 89%
rename from src/base/rect.rs
rename to src/core/rect.rs
index a719af4..e27510e 100644
--- a/src/base/rect.rs
+++ b/src/core/rect.rs
@@ -23,8 +23,8 @@ impl Rect {
     }
 }
 
-impl Widget for Rect {
-    fn draw(&self, painter: &mut Painter) {
+impl<Ctx> Widget<Ctx> for Rect {
+    fn draw(&self, painter: &mut Painter<Ctx>) {
         painter.write(RoundedRectData {
             color: self.color,
             radius: self.radius,
diff --git a/src/core/sense.rs b/src/core/sense.rs
new file mode 100644
index 0000000..c598b04
--- /dev/null
+++ b/src/core/sense.rs
@@ -0,0 +1,35 @@
+use std::marker::PhantomData;
+
+use crate::{Painter, Widget, WidgetFn, WidgetId, WidgetLike};
+
+pub struct Sensor<F: SenseFn<Ctx>, Ctx> {
+    inner: WidgetId,
+    f: F,
+    _pd: PhantomData<Ctx>,
+}
+
+impl<F: SenseFn<Ctx>, Ctx: 'static> Widget<Ctx> for Sensor<F, Ctx> {
+    fn draw(&self, painter: &mut Painter<Ctx>) {
+        (self.f)(painter.ctx_mut());
+        painter.draw(&self.inner);
+    }
+}
+
+pub trait SenseFn<Ctx> = Fn(&mut Ctx) + 'static;
+
+pub trait Sensable<Ctx: 'static, Tag> {
+    fn sense<F: SenseFn<Ctx>>(self, f: F) -> impl WidgetFn<Sensor<F, Ctx>, Ctx>;
+}
+
+impl<W: WidgetLike<Ctx, Tag>, Ctx: 'static, Tag> Sensable<Ctx, Tag> for W {
+    fn sense<F: SenseFn<Ctx>>(self, f: F) -> impl WidgetFn<Sensor<F, Ctx>, Ctx> {
+        |ui| {
+            let inner = self.add(ui).erase_type();
+            Sensor {
+                inner,
+                f,
+                _pd: PhantomData,
+            }
+        }
+    }
+}
diff --git a/src/base/span.rs b/src/core/span.rs
similarity index 92%
rename from src/base/span.rs
rename to src/core/span.rs
index f596eb0..67d7fd5 100644
--- a/src/base/span.rs
+++ b/src/core/span.rs
@@ -1,16 +1,16 @@
-use crate::{Dir, Painter, Sign, UINum, UIRegion, UIScalar, Widget, WidgetId};
+use crate::{Dir, Painter, Sign, UINum, UiRegion, UIScalar, Widget, WidgetId};
 
 pub struct Span {
     pub children: Vec<(WidgetId, SpanLen)>,
     pub dir: Dir,
 }
 
-impl Widget for Span {
-    fn draw(&self, painter: &mut Painter) {
+impl<Ctx: 'static> Widget<Ctx> for Span {
+    fn draw(&self, painter: &mut Painter<Ctx>) {
         let total = self.sums();
         let mut start = UIScalar::min();
         for (child, length) in &self.children {
-            let mut child_region = UIRegion::full();
+            let mut child_region = UiRegion::full();
             let mut axis = child_region.axis_mut(self.dir.axis);
             axis.top_left.set(start);
             match *length {
diff --git a/src/core/trait_fns.rs b/src/core/trait_fns.rs
new file mode 100644
index 0000000..e81e26a
--- /dev/null
+++ b/src/core/trait_fns.rs
@@ -0,0 +1,39 @@
+use super::*;
+use crate::{UiRegion, Vec2, WidgetArrLike, WidgetFn, WidgetLike};
+
+pub trait CoreWidget<Ctx: 'static, Tag> {
+    fn pad(self, padding: impl Into<Padding>) -> impl WidgetFn<Regioned, Ctx>;
+    fn center(self, size: impl Into<Vec2>) -> impl WidgetFn<Regioned, Ctx>;
+}
+
+impl<W: WidgetLike<Ctx, Tag>, Ctx: 'static, Tag> CoreWidget<Ctx, Tag> for W {
+    fn pad(self, padding: impl Into<Padding>) -> impl WidgetFn<Regioned, Ctx> {
+        |ui| Regioned {
+            region: padding.into().region(),
+            inner: self.add(ui).erase_type(),
+        }
+    }
+
+    fn center(self, size: impl Into<Vec2>) -> impl WidgetFn<Regioned, Ctx> {
+        |ui| Regioned {
+            region: UiRegion::center(size.into()),
+            inner: self.add(ui).erase_type(),
+        }
+    }
+}
+
+pub trait CoreWidgetArr<const LEN: usize, Ctx: 'static, Tag> {
+    fn span(self, dir: Dir, lengths: [impl Into<SpanLen>; LEN]) -> impl WidgetFn<Span, Ctx>;
+}
+
+impl<const LEN: usize, Wa: WidgetArrLike<LEN, Ctx, Tag>, Ctx: 'static, Tag> CoreWidgetArr<LEN, Ctx, Tag>
+    for Wa
+{
+    fn span(self, dir: Dir, lengths: [impl Into<SpanLen>; LEN]) -> impl WidgetFn<Span, Ctx> {
+        let lengths = lengths.map(Into::into);
+        move |ui| Span {
+            dir,
+            children: self.ui(ui).arr.into_iter().zip(lengths).collect(),
+        }
+    }
+}
diff --git a/src/layout/mod.rs b/src/layout/mod.rs
index fab6dcc..6891c09 100644
--- a/src/layout/mod.rs
+++ b/src/layout/mod.rs
@@ -6,10 +6,10 @@ mod vec2;
 mod widget;
 
 pub use color::*;
+pub use painter::*;
 pub use region::*;
 pub use ui::*;
 pub use vec2::*;
 pub use widget::*;
-pub use painter::*;
 
 pub type UiColor = Color<u8>;
diff --git a/src/layout/painter.rs b/src/layout/painter.rs
index 24d9c2c..4003291 100644
--- a/src/layout/painter.rs
+++ b/src/layout/painter.rs
@@ -1,20 +1,22 @@
 use crate::{
-    UIRegion, WidgetId, Widgets,
+    UiRegion, WidgetId, Widgets,
     primitive::{PrimitiveData, PrimitiveInstance, Primitives},
 };
 
-pub struct Painter<'a> {
-    nodes: &'a Widgets,
+pub struct Painter<'a, Ctx> {
+    nodes: &'a Widgets<Ctx>,
+    ctx: &'a mut Ctx,
     primitives: Primitives,
-    pub region: UIRegion,
+    pub region: UiRegion,
 }
 
-impl<'a> Painter<'a> {
-    pub fn new(nodes: &'a Widgets) -> Self {
+impl<'a, Ctx> Painter<'a, Ctx> {
+    pub fn new(nodes: &'a Widgets<Ctx>, ctx: &'a mut Ctx) -> Self {
         Self {
             nodes,
+            ctx,
             primitives: Primitives::default(),
-            region: UIRegion::full(),
+            region: UiRegion::full(),
         }
     }
     pub fn write<Data: PrimitiveData>(&mut self, data: Data) {
@@ -28,10 +30,12 @@ impl<'a> Painter<'a> {
             .data
             .extend_from_slice(bytemuck::cast_slice::<_, u32>(&[data]));
     }
-    pub fn draw(&mut self, node: &WidgetId) {
-        self.nodes.get_dyn(node).draw(self);
+
+    pub fn draw(&mut self, id: &WidgetId) where Ctx: 'static {
+        self.nodes.get_dyn(id).draw(self);
     }
-    pub fn draw_within(&mut self, node: &WidgetId, region: UIRegion) {
+
+    pub fn draw_within(&mut self, node: &WidgetId, region: UiRegion) where Ctx: 'static {
         let old = self.region;
         self.region.select(&region);
         self.draw(node);
@@ -41,4 +45,8 @@ impl<'a> Painter<'a> {
     pub fn finish(self) -> Primitives {
         self.primitives
     }
+
+    pub fn ctx_mut(&mut self) -> &mut Ctx {
+        &mut self.ctx
+    }
 }
diff --git a/src/layout/region.rs b/src/layout/region.rs
index 76427fe..bc61169 100644
--- a/src/layout/region.rs
+++ b/src/layout/region.rs
@@ -36,7 +36,7 @@ impl UIPos {
         self
     }
 
-    pub const fn within(&self, region: &UIRegion) -> UIPos {
+    pub const fn within(&self, region: &UiRegion) -> UIPos {
         let anchor = self
             .anchor
             .lerp(region.top_left.anchor, region.bot_right.anchor);
@@ -110,12 +110,12 @@ impl UIScalar {
 
 #[repr(C)]
 #[derive(Debug, Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
-pub struct UIRegion {
+pub struct UiRegion {
     pub top_left: UIPos,
     pub bot_right: UIPos,
 }
 
-impl UIRegion {
+impl UiRegion {
     pub const fn full() -> Self {
         Self {
             top_left: UIPos::top_left(),
diff --git a/src/layout/ui.rs b/src/layout/ui.rs
index 1987298..766db67 100644
--- a/src/layout/ui.rs
+++ b/src/layout/ui.rs
@@ -1,46 +1,60 @@
 use crate::{
-    HashMap, Painter, Widget, WidgetId, WidgetLike,
+    HashMap, Painter, Vec2, Widget, WidgetId, WidgetLike,
     primitive::Primitives,
-    util::{ID, IDTracker},
+    util::{IDTracker, Id},
 };
 use std::{
     any::{Any, TypeId},
     ops::{Index, IndexMut},
 };
 
-#[derive(Default)]
-pub struct Ui {
+pub struct Ui<Ctx> {
     ids: IDTracker,
     base: Option<WidgetId>,
-    widgets: Widgets,
+    widgets: Widgets<Ctx>,
     updates: Vec<WidgetId>,
     primitives: Primitives,
     full_redraw: bool,
 }
 
-#[derive(Default)]
-pub struct Widgets(HashMap<ID, Box<dyn Widget>>);
+pub struct MouseState {
+    pos: Vec2,
+    primary: ButtonState,
+    secondary: ButtonState,
+}
 
-impl Ui {
-    pub fn add<W: Widget>(&mut self, w: impl WidgetLike<Widget = W>) -> WidgetId<W> {
+pub enum ButtonState {
+    JustPressed,
+    Pressed,
+    Released,
+}
+
+#[derive(Default)]
+pub struct Widgets<Ctx>(HashMap<Id, Box<dyn Widget<Ctx>>>);
+
+impl<Ctx> Ui<Ctx> {
+    pub fn add<W: Widget<Ctx>, Tag>(
+        &mut self,
+        w: impl WidgetLike<Ctx, Tag, Widget = W>,
+    ) -> WidgetId<W> {
         w.add(self)
     }
 
-    pub fn add_widget<W: Widget>(&mut self, w: W) -> WidgetId<W> {
+    pub fn add_widget<W: Widget<Ctx>>(&mut self, w: W) -> WidgetId<W> {
         self.push(w)
     }
 
-    pub fn push<W: Widget>(&mut self, w: W) -> WidgetId<W> {
+    pub fn push<W: Widget<Ctx>>(&mut self, w: W) -> WidgetId<W> {
         let id = self.ids.next();
         self.widgets.insert(id.duplicate(), w);
         WidgetId::new(id, TypeId::of::<W>())
     }
 
-    pub fn set<W: Widget>(&mut self, i: &WidgetId<W>, w: W) {
+    pub fn set<W: Widget<Ctx>>(&mut self, i: &WidgetId<W>, w: W) {
         self.widgets.insert(i.id.duplicate(), w);
     }
 
-    pub fn set_base(&mut self, w: impl WidgetLike) {
+    pub fn set_base<Tag>(&mut self, w: impl WidgetLike<Ctx, Tag>) {
         self.base = Some(w.add(self).erase_type());
         self.full_redraw = true;
     }
@@ -49,36 +63,42 @@ impl Ui {
         Self::default()
     }
 
-    pub fn get<W: Widget>(&self, id: &WidgetId<W>) -> Option<&W> {
+    pub fn get<W: Widget<Ctx>>(&self, id: &WidgetId<W>) -> Option<&W> {
         self.widgets.get(id)
     }
 
-    pub fn get_mut<W: Widget>(&mut self, id: &WidgetId<W>) -> Option<&mut W> {
+    pub fn get_mut<W: Widget<Ctx>>(&mut self, id: &WidgetId<W>) -> Option<&mut W> {
         self.widgets.get_mut(id)
     }
 
-    pub fn id<W: Widget>(&mut self) -> WidgetId<W> {
+    pub fn id<W: Widget<Ctx>>(&mut self) -> WidgetId<W> {
         WidgetId::new(self.ids.next(), TypeId::of::<W>())
     }
 
-    pub fn redraw_all(&mut self) {
-        let mut painter = Painter::new(&self.widgets);
+    pub fn redraw_all(&mut self, ctx: &mut Ctx)
+    where
+        Ctx: 'static,
+    {
+        let mut painter = Painter::new(&self.widgets, ctx);
         if let Some(base) = &self.base {
             painter.draw(base);
         }
         self.primitives = painter.finish();
     }
 
-    pub fn update(&mut self) -> Option<&Primitives> {
+    pub fn update(&mut self, ctx: &mut Ctx) -> Option<&Primitives>
+    where
+        Ctx: 'static,
+    {
         if self.full_redraw {
-            self.redraw_all();
+            self.redraw_all(ctx);
             self.full_redraw = false;
             return Some(&self.primitives);
         }
         if self.updates.is_empty() {
             return None;
         }
-        self.redraw_all();
+        self.redraw_all(ctx);
         self.updates.drain(..);
         Some(&self.primitives)
     }
@@ -86,9 +106,11 @@ impl Ui {
     pub fn needs_redraw(&self) -> bool {
         self.full_redraw || !self.updates.is_empty()
     }
+
+    pub fn set_mouse_pos(&mut self) {}
 }
 
-impl<W: Widget> Index<&WidgetId<W>> for Ui {
+impl<W: Widget<Ctx>, Ctx> Index<&WidgetId<W>> for Ui<Ctx> {
     type Output = W;
 
     fn index(&self, id: &WidgetId<W>) -> &Self::Output {
@@ -96,36 +118,40 @@ impl<W: Widget> Index<&WidgetId<W>> for Ui {
     }
 }
 
-impl<W: Widget> IndexMut<&WidgetId<W>> for Ui {
+impl<W: Widget<Ctx>, Ctx> IndexMut<&WidgetId<W>> for Ui<Ctx> {
     fn index_mut(&mut self, id: &WidgetId<W>) -> &mut Self::Output {
         self.updates.push(id.clone().erase_type());
         self.get_mut(id).unwrap()
     }
 }
 
-impl Widgets {
-    pub fn get_dyn(&self, id: &WidgetId) -> &dyn Widget {
+impl<Ctx> Widgets<Ctx> {
+    pub fn new() -> Self {
+        Self(HashMap::new())
+    }
+
+    pub fn get_dyn(&self, id: &WidgetId) -> &dyn Widget<Ctx> {
         self.0.get(&id.id).unwrap().as_ref()
     }
 
-    pub fn get<W: Widget>(&self, id: &WidgetId<W>) -> Option<&W> {
+    pub fn get<W: Widget<Ctx>>(&self, id: &WidgetId<W>) -> Option<&W> {
         self.0.get(&id.id).unwrap().as_any().downcast_ref()
     }
 
-    pub fn get_mut<W: Widget>(&mut self, id: &WidgetId<W>) -> Option<&mut W> {
+    pub fn get_mut<W: Widget<Ctx>>(&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) {
+    pub fn insert(&mut self, id: Id, widget: impl Widget<Ctx>) {
         self.0.insert(id, Box::new(widget));
     }
 
-    pub fn insert_any(&mut self, id: ID, widget: Box<dyn Widget>) {
+    pub fn insert_any(&mut self, id: Id, widget: Box<dyn Widget<Ctx>>) {
         self.0.insert(id, widget);
     }
 }
 
-impl dyn Widget {
+impl<Ctx> dyn Widget<Ctx> {
     pub fn as_any(&self) -> &dyn Any {
         self
     }
@@ -134,3 +160,16 @@ impl dyn Widget {
         self
     }
 }
+
+impl<Ctx> Default for Ui<Ctx> {
+    fn default() -> Self {
+        Self {
+            ids: Default::default(),
+            base: Default::default(),
+            widgets: Widgets::new(),
+            updates: Default::default(),
+            primitives: Default::default(),
+            full_redraw: Default::default(),
+        }
+    }
+}
diff --git a/src/layout/widget.rs b/src/layout/widget.rs
index 7f1eebb..f8d3df4 100644
--- a/src/layout/widget.rs
+++ b/src/layout/widget.rs
@@ -3,10 +3,10 @@ use std::{
     marker::PhantomData,
 };
 
-use crate::{Painter, Ui, util::ID};
+use crate::{Painter, Ui, util::Id};
 
-pub trait Widget: 'static + Any {
-    fn draw(&self, painter: &mut Painter);
+pub trait Widget<Ctx>: Any {
+    fn draw(&self, painter: &mut Painter<Ctx>);
 }
 
 pub struct AnyWidget;
@@ -19,7 +19,7 @@ pub struct AnyWidget;
 #[derive(Eq, Hash, PartialEq, Debug)]
 pub struct WidgetId<W = AnyWidget> {
     pub(super) ty: TypeId,
-    pub(super) id: ID,
+    pub(super) id: Id,
     _pd: PhantomData<W>,
 }
 
@@ -31,7 +31,7 @@ impl<W> Clone for WidgetId<W> {
 }
 
 impl<W> WidgetId<W> {
-    pub(super) fn new(id: ID, ty: TypeId) -> Self {
+    pub(super) fn new(id: Id, ty: TypeId) -> Self {
         Self {
             ty,
             id,
@@ -51,85 +51,81 @@ impl<W> WidgetId<W> {
     }
 }
 
-pub trait WidgetLike {
+pub struct WidgetTag;
+pub struct FnTag;
+pub struct IdTag;
+
+pub trait WidgetLike<Ctx, Tag> {
     type Widget;
-    fn add(self, ui: &mut Ui) -> WidgetId<Self::Widget>;
+    fn add(self, ui: &mut Ui<Ctx>) -> WidgetId<Self::Widget>;
 }
 
 /// 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 WFn<W> = FnOnce(&mut Ui) -> W;
-pub struct WidgetFn<F: FnOnce(&mut Ui) -> W, W>(pub F);
-pub struct WidgetIdFn<F: FnOnce(&mut Ui) -> WidgetId<W>, W>(pub F);
+pub trait WidgetFn<W: Widget<Ctx>, Ctx> = FnOnce(&mut Ui<Ctx>) -> W;
+pub trait WidgetIdFn<W: Widget<Ctx>, Ctx> = FnOnce(&mut Ui<Ctx>) -> WidgetId<W>;
 
-macro_rules! WidgetFnRet {
-    ($W:ident) => {
-        WidgetFn<impl FnOnce(&mut Ui) -> $W, $W>
-    };
-}
-pub(crate) use WidgetFnRet;
-
-pub trait Idable {
-    type Widget: Widget;
-    fn set(self, ui: &mut Ui, id: &WidgetId<Self::Widget>);
+pub trait Idable<Ctx, Tag> {
+    type Widget: Widget<Ctx>;
+    fn set(self, ui: &mut Ui<Ctx>, id: &WidgetId<Self::Widget>);
 }
 
-pub trait WidgetFns<W> {
-    fn id(self, id: &WidgetId<W>) -> impl WidgetLike<Widget = W>;
+pub trait WidgetFns<W: Widget<Ctx>, Ctx, Tag> {
+    fn id(self, id: &WidgetId<W>) -> impl WidgetIdFn<W, Ctx>;
 }
 
-impl<I: Idable> WidgetFns<I::Widget> for I {
-    fn id(self, id: &WidgetId<I::Widget>) -> impl WidgetLike<Widget = I::Widget> {
-        WidgetIdFn(|ui| {
+impl<I: Idable<Ctx, Tag>, Ctx, Tag> WidgetFns<I::Widget, Ctx, Tag> for I {
+    fn id(self, id: &WidgetId<I::Widget>) -> impl WidgetIdFn<I::Widget, Ctx> {
+        |ui| {
             self.set(ui, id);
             id.clone()
-        })
+        }
     }
 }
 
-impl<W: Widget> Idable for W {
+impl<W: Widget<Ctx>, Ctx> Idable<Ctx, WidgetTag> for W {
     type Widget = W;
 
-    fn set(self, ui: &mut Ui, id: &WidgetId<Self::Widget>) {
+    fn set(self, ui: &mut Ui<Ctx>, id: &WidgetId<Self::Widget>) {
         ui.set(id, self);
     }
 }
 
-impl<F: for<'a> FnOnce(&'a mut Ui) -> W, W: Widget> Idable for WidgetFn<F, W> {
+impl<F: FnOnce(&mut Ui<Ctx>) -> W, W: Widget<Ctx>, Ctx> Idable<Ctx, FnTag> for F {
     type Widget = W;
 
-    fn set(self, ui: &mut Ui, id: &WidgetId<Self::Widget>) {
-        let w = self.0(ui);
+    fn set(self, ui: &mut Ui<Ctx>, id: &WidgetId<Self::Widget>) {
+        let w = self(ui);
         ui.set(id, w);
     }
 }
 
-impl<W: Widget, F: FnOnce(&mut Ui) -> W> WidgetLike for WidgetFn<F, W> {
+impl<W: Widget<Ctx>, Ctx, F: FnOnce(&mut Ui<Ctx>) -> W> WidgetLike<Ctx, FnTag> for F {
     type Widget = W;
-    fn add(self, ui: &mut Ui) -> WidgetId<W> {
-        let w = (self.0)(ui);
+    fn add(self, ui: &mut Ui<Ctx>) -> WidgetId<W> {
+        let w = self(ui);
         ui.add(w)
     }
 }
 
-impl<W: Widget, F: FnOnce(&mut Ui) -> WidgetId<W>> WidgetLike for WidgetIdFn<F, W> {
+impl<W: Widget<Ctx>, F: FnOnce(&mut Ui<Ctx>) -> WidgetId<W>, Ctx> WidgetLike<Ctx, IdTag> for F {
     type Widget = W;
-    fn add(self, ui: &mut Ui) -> WidgetId<W> {
-        (self.0)(ui)
+    fn add(self, ui: &mut Ui<Ctx>) -> WidgetId<W> {
+        self(ui)
     }
 }
 
-impl<W: Widget> WidgetLike for W {
+impl<W: Widget<Ctx>, Ctx> WidgetLike<Ctx, WidgetTag> for W {
     type Widget = W;
-    fn add(self, ui: &mut Ui) -> WidgetId<W> {
+    fn add(self, ui: &mut Ui<Ctx>) -> WidgetId<W> {
         ui.add_widget(self)
     }
 }
 
-impl<W> WidgetLike for WidgetId<W> {
+impl<W: Widget<Ctx>, Ctx> WidgetLike<Ctx, FnTag> for WidgetId<W> {
     type Widget = W;
-    fn add(self, _: &mut Ui) -> WidgetId<W> {
+    fn add(self, _: &mut Ui<Ctx>) -> WidgetId<W> {
         self
     }
 }
@@ -148,35 +144,39 @@ impl<const LEN: usize, Ws> WidgetArr<LEN, Ws> {
     }
 }
 
-pub trait WidgetArrLike<const LEN: usize> {
+pub struct ArrTag;
+pub trait WidgetArrLike<const LEN: usize, Ctx, Tags> {
     type Ws;
-    fn ui(self, ui: &mut Ui) -> WidgetArr<LEN, Self::Ws>;
+    fn ui(self, ui: &mut Ui<Ctx>) -> WidgetArr<LEN, Self::Ws>;
 }
 
-impl<const LEN: usize, Ws> WidgetArrLike<LEN> for WidgetArr<LEN, Ws> {
+impl<const LEN: usize, Ws, Ctx> WidgetArrLike<LEN, Ctx, ArrTag> for WidgetArr<LEN, Ws> {
     type Ws = Ws;
-    fn ui(self, _: &mut Ui) -> WidgetArr<LEN, Ws> {
+    fn ui(self, _: &mut Ui<Ctx>) -> WidgetArr<LEN, Ws> {
         self
     }
 }
 
-impl<W: WidgetLike> WidgetArrLike<1> for W {
+impl<W: WidgetLike<Ctx, WidgetTag>, Ctx> WidgetArrLike<1, Ctx, WidgetTag> for W {
     type Ws = (W::Widget,);
-    fn ui(self, ui: &mut Ui) -> WidgetArr<1, (W::Widget,)> {
+    fn ui(self, ui: &mut Ui<Ctx>) -> WidgetArr<1, (W::Widget,)> {
         WidgetArr::new([self.add(ui).erase_type()])
     }
 }
 
 // I hate this language it's so bad why do I even use it
 macro_rules! impl_widget_arr {
-    ($n:expr;$($T:tt)*) => {
-        impl<$($T: WidgetLike,)*> WidgetArrLike<$n> for ($($T,)*) {
-            type Ws = ($($T::Widget,)*);
-            fn ui(self, ui: &mut Ui) -> WidgetArr<$n, ($($T::Widget,)*)> {
+    ($n:expr;$($W:ident)*) => {
+        impl_widget_arr!($n;$($W)*;$(${concat($W,Tag)})*);
+    };
+    ($n:expr;$($W:ident)*;$($Tag:ident)*) => {
+        impl<$($W: WidgetLike<Ctx, $Tag>,$Tag,)* Ctx> WidgetArrLike<$n, Ctx, ($($Tag,)*)> for ($($W,)*) {
+            type Ws = ($($W::Widget,)*);
+            fn ui(self, ui: &mut Ui<Ctx>) -> WidgetArr<$n, ($($W::Widget,)*)> {
                 #[allow(non_snake_case)]
-                let ($($T,)*) = self;
+                let ($($W,)*) = self;
                 WidgetArr::new(
-                    [$($T.add(ui).cast_type(),)*],
+                    [$($W.add(ui).cast_type(),)*],
                 )
             }
         }
diff --git a/src/lib.rs b/src/lib.rs
index 89d2b0e..5ba7372 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,14 +3,16 @@
 #![feature(const_trait_impl)]
 #![feature(const_from)]
 #![feature(trait_alias)]
+#![feature(negative_impls)]
 
 mod layout;
 mod render;
 mod util;
-mod base;
+mod core;
 
 pub use layout::*;
 pub use render::*;
-pub use base::*;
+pub use core::*;
 
 pub type HashMap<K, V> = std::collections::HashMap<K, V>;
+pub type HashSet<K> = std::collections::HashSet<K>;
diff --git a/src/render/data.rs b/src/render/data.rs
index c0e02b9..299299b 100644
--- a/src/render/data.rs
+++ b/src/render/data.rs
@@ -1,6 +1,6 @@
 use wgpu::VertexAttribute;
 
-use crate::UIRegion;
+use crate::UiRegion;
 
 #[repr(C)]
 #[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable, Default)]
@@ -12,7 +12,7 @@ pub struct WindowUniform {
 #[repr(C)]
 #[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
 pub struct PrimitiveInstance {
-    pub region: UIRegion,
+    pub region: UiRegion,
     pub ptr: u32,
 }
 
diff --git a/src/render/mod.rs b/src/render/mod.rs
index 0dc36fc..cc963e4 100644
--- a/src/render/mod.rs
+++ b/src/render/mod.rs
@@ -1,4 +1,7 @@
-use crate::{Ui, primitive::PrimitiveInstance, render::util::ArrBuf};
+use crate::{
+    primitive::{PrimitiveInstance, Primitives},
+    render::util::ArrBuf,
+};
 use data::WindowUniform;
 use wgpu::{
     util::{BufferInitDescriptor, DeviceExt},
@@ -32,8 +35,13 @@ impl UIRenderNode {
         }
     }
 
-    pub fn update(&mut self, device: &Device, queue: &Queue, ui: &mut Ui) {
-        if let Some(primitives) = ui.update() {
+    pub fn update(
+        &mut self,
+        device: &Device,
+        queue: &Queue,
+        primitives: Option<&Primitives>,
+    ) {
+        if let Some(primitives) = primitives {
             self.instance.update(device, queue, &primitives.instances);
             self.data.update(device, queue, &primitives.data);
             self.bind_group = Self::bind_group(
diff --git a/src/testing/mod.rs b/src/testing/mod.rs
index d1cdd8c..a530518 100644
--- a/src/testing/mod.rs
+++ b/src/testing/mod.rs
@@ -12,9 +12,13 @@ pub fn main() {
     App::run();
 }
 
+struct Data {
+    x: u32,
+}
+
 pub struct Client {
     renderer: Renderer,
-    ui: Ui,
+    ui: Ui<Data>,
     test: WidgetId<Span>,
 }
 
@@ -32,7 +36,8 @@ impl Client {
         ui.set_base(
             (
                 (
-                    rect.color(UiColor::BLUE),
+                    rect.color(UiColor::BLUE)
+                        .sense(|d: &mut Data| println!("{}", d.x)),
                     (
                         rect.color(UiColor::RED).center((100.0, 100.0)),
                         (
@@ -77,7 +82,8 @@ impl Client {
         match event {
             WindowEvent::CloseRequested => event_loop.exit(),
             WindowEvent::RedrawRequested => {
-                self.renderer.update(&mut self.ui);
+                let primitives = self.ui.update(&mut Data { x: 39 });
+                self.renderer.update(primitives);
                 self.renderer.draw()
             }
             WindowEvent::Resized(size) => self.renderer.resize(&size),
diff --git a/src/testing/render/mod.rs b/src/testing/render/mod.rs
index a353d28..3069b0a 100644
--- a/src/testing/render/mod.rs
+++ b/src/testing/render/mod.rs
@@ -1,4 +1,4 @@
-use gui::{UIRenderNode, Ui};
+use gui::{primitive::Primitives, UIRenderNode, Ui};
 use pollster::FutureExt;
 use std::sync::Arc;
 use wgpu::util::StagingBelt;
@@ -18,8 +18,8 @@ pub struct Renderer {
 }
 
 impl Renderer {
-    pub fn update(&mut self, ui: &mut Ui) {
-        self.ui_node.update(&self.device, &self.queue, ui);
+    pub fn update(&mut self, primitives: Option<&Primitives>) {
+        self.ui_node.update(&self.device, &self.queue, primitives);
     }
 
     pub fn draw(&mut self) {
diff --git a/src/util/id.rs b/src/util/id.rs
index d5fd9ae..cdb8b9f 100644
--- a/src/util/id.rs
+++ b/src/util/id.rs
@@ -4,11 +4,11 @@
 /// point to something valid, although duplicate
 /// gets around this if needed
 #[derive(Eq, Hash, PartialEq, Debug)]
-pub struct ID(u64);
+pub struct Id(u64);
 
 #[derive(Default)]
 pub struct IDTracker {
-    free: Vec<ID>,
+    free: Vec<Id>,
     cur: u64,
 }
 
@@ -18,22 +18,22 @@ impl IDTracker {
     }
 
     #[allow(clippy::should_implement_trait)]
-    pub fn next(&mut self) -> ID {
+    pub fn next(&mut self) -> Id {
         if let Some(id) = self.free.pop() {
             return id;
         }
-        let id = ID(self.cur);
+        let id = Id(self.cur);
         self.cur += 1;
         id
     }
 
     #[allow(dead_code)]
-    pub fn free(&mut self, id: ID) {
+    pub fn free(&mut self, id: Id) {
         self.free.push(id);
     }
 }
 
-impl ID {
+impl Id {
     /// this must be used carefully to make sure
     /// all IDs are still valid references;
     /// named weirdly to indicate this.