Implement Canvas::request_redraw

src/platform_impl/web/web_sys/canvas.rs

@@ -9,6 +9,7 @@ use web_sys::{HtmlCanvasElement, PointerEvent, WheelEvent};
 
 pub struct Canvas {
     raw: HtmlCanvasElement,
+    on_redraw: Closure<dyn Fn()>,
     on_mouse_out: Option<Closure<dyn FnMut(PointerEvent)>>,
     on_mouse_over: Option<Closure<dyn FnMut(PointerEvent)>>,
     on_mouse_up: Option<Closure<dyn FnMut(PointerEvent)>>,
@@ -24,7 +25,10 @@ impl Drop for Canvas {
 }
 
 impl Canvas {
-    pub fn create() -> Result<Self, RootOE> {
+    pub fn create<F>(on_redraw: F) -> Result<Self, RootOE>
+    where
+        F: 'static + Fn(),
+    {
         let window = web_sys::window().expect("Failed to obtain window");
         let document = window.document().expect("Failed to obtain document");
 
@@ -41,6 +45,7 @@ impl Canvas {
 
         Ok(Canvas {
             raw: canvas,
+            on_redraw: Closure::wrap(Box::new(on_redraw) as Box<dyn Fn()>),
             on_mouse_out: None,
             on_mouse_over: None,
             on_mouse_up: None,
@@ -79,6 +84,11 @@ impl Canvas {
         &self.raw
     }
 
+    pub fn request_redraw(&self) {
+        let window = web_sys::window().expect("Failed to obtain window");
+        window.request_animation_frame(&self.on_redraw.as_ref().unchecked_ref());
+    }
+
     pub fn on_mouse_out<F>(&mut self, mut handler: F)
     where
         F: 'static + FnMut(i32),

src/platform_impl/web/web_sys/mod.rs

@@ -11,12 +11,6 @@ use crate::platform::web::WindowExtWebSys;
 use crate::window::Window;
 use web_sys::HtmlCanvasElement;
 
-pub fn request_animation_frame<F>(f: F)
-where
-    F: Fn(),
-{
-}
-
 pub fn throw(msg: &str) {
     wasm_bindgen::throw_str(msg);
 }

src/platform_impl/web/window.rs

@@ -13,7 +13,6 @@ use std::collections::VecDeque;
 
 pub struct Window {
     canvas: backend::Canvas,
-    redraw: Box<dyn Fn()>,
     previous_pointer: RefCell<&'static str>,
     position: RefCell<LogicalPosition>,
 }
@@ -24,24 +23,19 @@ impl Window {
         attr: WindowAttributes,
         _: PlatformSpecificBuilderAttributes,
     ) -> Result<Self, RootOE> {
-        let mut canvas = backend::Canvas::create()?;
-
-        target.register(&mut canvas);
-
         let runner = target.runner.clone();
-        let redraw = Box::new(move || {
-            let runner = runner.clone();
-            backend::request_animation_frame(move || {
+
+        let mut canvas = backend::Canvas::create(move || {
             runner.send_event(Event::WindowEvent {
                 window_id: RootWI(Id),
                 event: WindowEvent::RedrawRequested,
             })
-            });
-        });
+        })?;
+
+        target.register(&mut canvas);
 
         let window = Window {
             canvas,
-            redraw,
             previous_pointer: RefCell::new("auto"),
             position: RefCell::new(LogicalPosition { x: 0.0, y: 0.0 }),
         };
@@ -71,7 +65,7 @@ impl Window {
     }
 
     pub fn request_redraw(&self) {
-        (self.redraw)();
+        self.canvas.request_redraw();
     }
 
     pub fn outer_position(&self) -> Result<LogicalPosition, NotSupportedError> {