Remove Layer trait and simplify Canvas

wgpu/src/widget/canvas/layer/cache.rs

@@ -1,120 +0,0 @@
-use crate::{
-    canvas::{Drawable, Frame, Layer},
-    Primitive,
-};
-
-use iced_native::Size;
-use std::{borrow::Borrow, cell::RefCell, marker::PhantomData, sync::Arc};
-
-enum State {
-    Empty,
-    Filled {
-        bounds: Size,
-        primitive: Arc<Primitive>,
-    },
-}
-
-impl Default for State {
-    fn default() -> Self {
-        State::Empty
-    }
-}
-/// A simple cache that stores generated geometry to avoid recomputation.
-///
-/// A [`Cache`] will not redraw its geometry unless the dimensions of its layer
-/// change or it is explicitly cleared.
-///
-/// [`Layer`]: ../trait.Layer.html
-/// [`Cache`]: struct.Cache.html
-#[derive(Debug, Default)]
-pub struct Cache {
-    state: RefCell<State>,
-}
-
-impl Cache {
-    /// Creates a new empty [`Cache`].
-    ///
-    /// [`Cache`]: struct.Cache.html
-    pub fn new() -> Self {
-        Cache {
-            state: Default::default(),
-        }
-    }
-
-    /// Clears the cache, forcing a redraw the next time it is used.
-    ///
-    /// [`Cached`]: struct.Cached.html
-    pub fn clear(&mut self) {
-        *self.state.borrow_mut() = State::Empty;
-    }
-
-    /// Binds the [`Cache`] with some data, producing a [`Layer`] that can be
-    /// added to a [`Canvas`].
-    ///
-    /// [`Cache`]: struct.Cache.html
-    /// [`Layer`]: ../trait.Layer.html
-    /// [`Canvas`]: ../../struct.Canvas.html
-    pub fn with<'a, T>(
-        &'a self,
-        input: impl Borrow<T> + std::fmt::Debug + 'a,
-    ) -> impl Layer + 'a
-    where
-        T: Drawable + std::fmt::Debug + 'a,
-    {
-        Bind {
-            cache: self,
-            input: input,
-            drawable: PhantomData,
-        }
-    }
-}
-
-#[derive(Debug)]
-struct Bind<'a, T: Drawable, I: Borrow<T> + 'a> {
-    cache: &'a Cache,
-    input: I,
-    drawable: PhantomData<T>,
-}
-
-impl<'a, T, I> Layer for Bind<'a, T, I>
-where
-    T: Drawable + std::fmt::Debug,
-    I: Borrow<T> + std::fmt::Debug + 'a,
-{
-    fn draw(&self, current_bounds: Size) -> Arc<Primitive> {
-        use std::ops::Deref;
-
-        if let State::Filled { bounds, primitive } =
-            self.cache.state.borrow().deref()
-        {
-            if *bounds == current_bounds {
-                return primitive.clone();
-            }
-        }
-
-        let mut frame = Frame::new(current_bounds.width, current_bounds.height);
-        self.input.borrow().draw(&mut frame);
-
-        let primitive = Arc::new(frame.into_primitive());
-
-        *self.cache.state.borrow_mut() = State::Filled {
-            bounds: current_bounds,
-            primitive: primitive.clone(),
-        };
-
-        primitive
-    }
-}
-
-impl std::fmt::Debug for State {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            State::Empty => write!(f, "Empty"),
-            State::Filled { primitive, bounds } => f
-                .debug_struct("Filled")
-                .field("primitive", primitive)
-                .field("bounds", bounds)
-                .finish(),
-        }
-    }
-}