refactor: centralize editor interaction state

Move timeline and preview gestures into dedicated controllers so hooks stay thin around editor state and DOM events.

This also routes drag and playback synchronization through manager APIs and reuses persistent wasm surfaces so scrubbing, seeking, and preview rendering stay in sync.

Made-with: Cursor

rust/crates/compositor/src/compositor.rs

@@ -348,7 +348,6 @@ impl Compositor {
     ) -> Result<(), CompositorError> {
         let frame = options.frame;
         self.texture_pool.recycle_frame();
-        context.configure_surface(options.surface, frame.width, frame.height)?;
         let surface_texture = context.acquire_surface_texture(options.surface)?;
         let surface_view = surface_texture
             .texture

rust/crates/gpu/src/context.rs

@@ -1,5 +1,8 @@
 use wgpu::util::DeviceExt;
 
+#[cfg(all(feature = "wasm", target_arch = "wasm32"))]
+use std::cell::RefCell;
+
 #[cfg(all(feature = "wasm", target_arch = "wasm32"))]
 use wasm_bindgen::JsCast;
 
@@ -17,6 +20,12 @@ impl wgpu::rwh::HasDisplayHandle for WebDisplay {
     }
 }
 
+#[cfg(all(feature = "wasm", target_arch = "wasm32"))]
+struct CachedCanvasSurface {
+    surface: wgpu::Surface<'static>,
+    size: (u32, u32),
+}
+
 const BLIT_SHADER_SOURCE: &str = include_str!("shaders/blit.wgsl");
 
 const FULLSCREEN_QUAD_POSITIONS: [[f32; 2]; 6] = [
@@ -44,6 +53,8 @@ pub struct GpuContext {
     /// fallback path. Used by render_texture_via_gl_canvas to output frames on WebGL.
     #[cfg(all(feature = "wasm", target_arch = "wasm32"))]
     gl_canvas: Option<web_sys::HtmlCanvasElement>,
+    #[cfg(all(feature = "wasm", target_arch = "wasm32"))]
+    gl_surface: RefCell<Option<CachedCanvasSurface>>,
 }
 
 impl GpuContext {
@@ -170,6 +181,8 @@ impl GpuContext {
             supports_external_texture_copies,
             #[cfg(all(feature = "wasm", target_arch = "wasm32"))]
             gl_canvas,
+            #[cfg(all(feature = "wasm", target_arch = "wasm32"))]
+            gl_surface: RefCell::new(None),
         })
     }
 
@@ -184,17 +197,15 @@ impl GpuContext {
         ),
         GpuError,
     > {
-        // Temporary fix: force the wasm renderer onto the WebGL backend even when
-        // WebGPU is available while a WebGPU bug is being investigated.
-        // let instance = wgpu::util::new_instance_with_webgpu_detection(
-        //     wgpu::InstanceDescriptor::new_without_display_handle(),
-        // )
-        // .await;
+        let instance = wgpu::util::new_instance_with_webgpu_detection(
+            wgpu::InstanceDescriptor::new_without_display_handle(),
+        )
+        .await;
 
-        // match Self::try_request_device(&instance, None).await {
-        //     Ok((adapter, device, queue)) => return Ok((instance, adapter, device, queue, None)),
-        //     Err(_) => {}
-        // }
+        match Self::try_request_device(&instance, None).await {
+            Ok((adapter, device, queue)) => return Ok((instance, adapter, device, queue, None)),
+            Err(_) => {}
+        }
         let (gl_instance, adapter, device, queue, canvas) = Self::try_gl_fallback().await?;
         Ok((gl_instance, adapter, device, queue, Some(canvas)))
     }
@@ -369,6 +380,14 @@ impl GpuContext {
         height: u32,
     ) -> Result<(), GpuError> {
         self.configure_surface(surface, width, height)?;
+        self.present_texture_to_surface(texture, surface)
+    }
+
+    pub fn present_texture_to_surface(
+        &self,
+        texture: &wgpu::Texture,
+        surface: &wgpu::Surface<'_>,
+    ) -> Result<(), GpuError> {
         let surface_texture = self.acquire_surface_texture(surface)?;
         let target_view = surface_texture
             .texture
@@ -390,16 +409,38 @@ impl GpuContext {
         width: u32,
         height: u32,
     ) -> Result<(), GpuError> {
-        let Some(config) = surface.get_default_config(&self.adapter, width, height) else {
-            return Err(GpuError::UnsupportedSurfaceFormat);
-        };
-        if config.format != self.texture_format {
-            return Err(GpuError::UnsupportedSurfaceFormat);
-        }
+        let config = self.build_surface_configuration(surface, width, height)?;
         surface.configure(&self.device, &config);
         Ok(())
     }
 
+    fn build_surface_configuration(
+        &self,
+        surface: &wgpu::Surface<'_>,
+        width: u32,
+        height: u32,
+    ) -> Result<wgpu::SurfaceConfiguration, GpuError> {
+        let caps = surface.get_capabilities(&self.adapter);
+        if !caps.formats.contains(&self.texture_format) {
+            return Err(GpuError::UnsupportedSurfaceFormat);
+        }
+
+        Ok(wgpu::SurfaceConfiguration {
+            usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
+            format: self.texture_format,
+            width,
+            height,
+            present_mode: wgpu::PresentMode::Fifo,
+            alpha_mode: caps
+                .alpha_modes
+                .first()
+                .copied()
+                .unwrap_or(wgpu::CompositeAlphaMode::Auto),
+            view_formats: vec![],
+            desired_maximum_frame_latency: 2,
+        })
+    }
+
     pub fn acquire_surface_texture(
         &self,
         surface: &wgpu::Surface<'_>,
@@ -593,57 +634,29 @@ impl GpuContext {
         gl_canvas.set_width(width);
         gl_canvas.set_height(height);
 
-        let surface = self
-            .instance
-            .create_surface(wgpu::SurfaceTarget::Canvas(gl_canvas.clone()))?;
-
-        let caps = surface.get_capabilities(&self.adapter);
-        let surface_format = if caps.formats.contains(&self.texture_format) {
-            self.texture_format
-        } else if !caps.formats.is_empty() {
-            caps.formats[0]
-        } else {
-            return Err(GpuError::UnsupportedSurfaceFormat);
+        let mut cached_surface = self.gl_surface.borrow_mut();
+        let cached_surface = match cached_surface.as_mut() {
+            Some(cached_surface) => cached_surface,
+            None => {
+                let surface = self
+                    .instance
+                    .create_surface(wgpu::SurfaceTarget::Canvas(gl_canvas.clone()))?;
+                cached_surface.replace(CachedCanvasSurface {
+                    surface,
+                    size: (0, 0),
+                });
+                cached_surface
+                    .as_mut()
+                    .expect("gl_surface cache should exist after initialization")
+            }
         };
 
-        if surface_format != self.texture_format {
-            return Err(GpuError::UnsupportedSurfaceFormat);
+        if cached_surface.size != (width, height) {
+            self.configure_surface(&cached_surface.surface, width, height)?;
+            cached_surface.size = (width, height);
         }
 
-        let config = wgpu::SurfaceConfiguration {
-            usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
-            format: surface_format,
-            width,
-            height,
-            present_mode: wgpu::PresentMode::Fifo,
-            alpha_mode: caps
-                .alpha_modes
-                .first()
-                .copied()
-                .unwrap_or(wgpu::CompositeAlphaMode::Auto),
-            view_formats: vec![],
-            desired_maximum_frame_latency: 2,
-        };
-        surface.configure(&self.device, &config);
-
-        let surface_texture = self.acquire_surface_texture(&surface)?;
-        let surface_view = surface_texture
-            .texture
-            .create_view(&wgpu::TextureViewDescriptor::default());
-
-        let mut encoder = self
-            .device
-            .create_command_encoder(&wgpu::CommandEncoderDescriptor {
-                label: Some("gpu-gl-canvas-blit-encoder"),
-            });
-        self.encode_texture_blit_to_view(
-            &mut encoder,
-            texture,
-            &surface_view,
-            "gpu-gl-canvas-blit",
-        );
-        self.queue.submit([encoder.finish()]);
-        surface_texture.present();
+        self.present_texture_to_surface(texture, &cached_surface.surface)?;
 
         Ok(gl_canvas)
     }