83 lines
1.6 KiB
Rust
83 lines
1.6 KiB
Rust
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use crate::{
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canvas::{layer::Drawable, Frame, Layer},
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triangle,
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};
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use iced_native::Size;
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use std::cell::RefCell;
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use std::marker::PhantomData;
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use std::sync::Arc;
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#[derive(Debug)]
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pub struct Cached<T: Drawable> {
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input: PhantomData<T>,
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cache: RefCell<Cache>,
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}
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#[derive(Debug)]
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enum Cache {
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Empty,
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Filled {
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mesh: Arc<triangle::Mesh2D>,
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bounds: Size,
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},
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}
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impl<T> Cached<T>
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where
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T: Drawable + std::fmt::Debug,
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{
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pub fn new() -> Self {
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Cached {
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input: PhantomData,
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cache: RefCell::new(Cache::Empty),
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}
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}
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pub fn clear(&mut self) {
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*self.cache.borrow_mut() = Cache::Empty;
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}
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pub fn with<'a>(&'a self, input: &'a T) -> impl Layer + 'a {
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Bind {
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layer: self,
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input: input,
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}
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}
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}
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#[derive(Debug)]
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struct Bind<'a, T: Drawable> {
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layer: &'a Cached<T>,
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input: &'a T,
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}
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impl<'a, T> Layer for Bind<'a, T>
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where
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T: Drawable + std::fmt::Debug,
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{
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fn draw(&self, current_bounds: Size) -> Arc<triangle::Mesh2D> {
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use std::ops::Deref;
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if let Cache::Filled { mesh, bounds } =
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self.layer.cache.borrow().deref()
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{
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if *bounds == current_bounds {
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return mesh.clone();
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}
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}
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let mut frame = Frame::new(current_bounds.width, current_bounds.height);
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self.input.draw(&mut frame);
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let mesh = Arc::new(frame.into_mesh());
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*self.layer.cache.borrow_mut() = Cache::Filled {
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mesh: mesh.clone(),
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bounds: current_bounds,
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};
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mesh
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}
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}
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