feat(ui-gpui): render-driven pulse via request_animation_frame() (GPUI native)

ui-gpui/src/components/pulsing_dot.rs

@@ -1,10 +1,10 @@
-//! PulsingDot — GPU-native smooth pulse using GPUI's async runtime.
+//! PulsingDot — GPU-native animation using render-driven frame requests.
 //!
-//! Uses cx.spawn() + background_executor().timer() + entity.update() to
-//! smoothly cycle through opacity steps. GPUI only repaints the dirty view.
+//! Uses request_animation_frame() during render to schedule next frame.
+//! Only runs while the dot is visible. GPUI repaints only dirty views.
 
 use gpui::*;
-use std::time::Duration;
+use std::time::Instant;
 
 use crate::theme;
 
@@ -17,21 +17,18 @@ pub enum DotStatus {
     Error,
 }
 
-/// Pre-computed opacity values for smooth sine-wave pulse (6 steps)
-const OPACITIES: [f32; 6] = [1.0, 0.85, 0.6, 0.4, 0.6, 0.85];
-
 pub struct PulsingDot {
     status: DotStatus,
-    step: u8,
     size: f32,
+    start_time: Instant,
 }
 
 impl PulsingDot {
     pub fn new(status: DotStatus, size: f32) -> Self {
         Self {
             status,
-            step: 0,
             size,
+            start_time: Instant::now(),
         }
     }
 
@@ -49,35 +46,25 @@ impl PulsingDot {
         }
     }
 
-    /// Start the pulse animation. Call from Context after entity creation.
-    pub fn start_animation(&self, cx: &mut Context<Self>) {
+    fn current_opacity(&self) -> f32 {
         if !self.should_pulse() {
-            return;
+            return 1.0;
         }
-
-        cx.spawn(async move |weak: WeakEntity<Self>, cx: &mut AsyncApp| {
-            loop {
-                cx.background_executor().timer(Duration::from_millis(200)).await;
-                let ok = weak.update(cx, |dot, cx| {
-                    dot.step = (dot.step + 1) % 6;
-                    cx.notify();
-                });
-                if ok.is_err() {
-                    break; // Entity dropped
-                }
-            }
-        }).detach();
+        let elapsed = self.start_time.elapsed().as_secs_f32();
+        // Sine wave: 2s period, oscillates between 0.4 and 1.0
+        0.7 + 0.3 * (elapsed * std::f32::consts::PI).sin()
     }
 }
 
 impl Render for PulsingDot {
-    fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
+    fn render(&mut self, window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
         let base = self.base_color();
-        let alpha = if self.should_pulse() {
-            OPACITIES[self.step as usize % 6]
-        } else {
-            1.0
-        };
+        let alpha = self.current_opacity();
+
+        // Schedule next frame if pulsing — this is how GPUI does continuous animation
+        if self.should_pulse() {
+            window.request_animation_frame();
+        }
 
         let r = (base.r * 255.0) as u32;
         let g = (base.g * 255.0) as u32;