move everything out of layout

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()
+    }
+}