iced: Throttle resize updates

src/utils/iced.rs

@@ -3,6 +3,7 @@ use std::{
     fmt,
     hash::{Hash, Hasher},
     sync::{mpsc::Receiver, Arc, Mutex},
+    time::{Duration, Instant},
 };
 
 use cosmic::{
@@ -136,6 +137,7 @@ struct IcedElementInternal<P: Program + Send + 'static> {
     // draw buffer
     outputs: HashSet<Output>,
     buffers: HashMap<OrderedFloat<f64>, (MemoryRenderBuffer, Option<(Vec<Primitive>, Color)>)>,
+    pending_resize: Option<(Instant, Size<i32, Logical>)>,
 
     // state
     size: Size<i32, Logical>,
@@ -182,6 +184,7 @@ impl<P: Program + Send + Clone + 'static> Clone for IcedElementInternal<P> {
         IcedElementInternal {
             outputs: self.outputs.clone(),
             buffers: self.buffers.clone(),
+            pending_resize: self.pending_resize.clone(),
             size: self.size.clone(),
             cursor_pos: self.cursor_pos.clone(),
             theme: self.theme.clone(),
@@ -201,6 +204,7 @@ impl<P: Program + Send + 'static> fmt::Debug for IcedElementInternal<P> {
         f.debug_struct("IcedElementInternal")
             .field("buffers", &"...")
             .field("size", &self.size)
+            .field("pending_resize", &self.pending_resize)
             .field("cursor_pos", &self.cursor_pos)
             .field("theme", &self.theme)
             .field("renderer", &"...")
@@ -250,6 +254,7 @@ impl<P: Program + Send + 'static> IcedElement<P> {
         let mut internal = IcedElementInternal {
             outputs: HashSet::new(),
             buffers: HashMap::new(),
+            pending_resize: None,
             size,
             cursor_pos: None,
             theme: Theme::dark(), // TODO
@@ -282,18 +287,9 @@ impl<P: Program + Send + 'static> IcedElement<P> {
             return;
         }
 
-        internal_ref.size = size;
-        for (scale, (buffer, old_primitives)) in internal_ref.buffers.iter_mut() {
-            let buffer_size = internal_ref
-                .size
-                .to_f64()
-                .to_buffer(**scale, Transform::Normal)
-                .to_i32_round();
-            *buffer =
-                MemoryRenderBuffer::new(Fourcc::Argb8888, buffer_size, 1, Transform::Normal, None);
-            *old_primitives = None;
+        if internal_ref.pending_resize.is_none() {
+            internal_ref.pending_resize = Some((Instant::now(), size));
         }
-        internal_ref.update(true);
     }
 
     pub fn force_update(&self) {
@@ -706,10 +702,34 @@ where
         alpha: f32,
     ) -> Vec<C> {
         let mut internal = self.0.lock().unwrap();
-        let _ = internal.update(false);
+        let internal_ref = &mut *internal;
+        let force = if matches!(
+            internal_ref.pending_resize,
+            Some((instant, _)) if Instant::now().duration_since(instant) > Duration::from_millis(25)
+        ) {
+            internal_ref.size = internal_ref.pending_resize.take().unwrap().1;
+            for (scale, (buffer, old_primitives)) in internal_ref.buffers.iter_mut() {
+                let buffer_size = internal_ref
+                    .size
+                    .to_f64()
+                    .to_buffer(**scale, Transform::Normal)
+                    .to_i32_round();
+                *buffer = MemoryRenderBuffer::new(
+                    Fourcc::Argb8888,
+                    buffer_size,
+                    1,
+                    Transform::Normal,
+                    None,
+                );
+                *old_primitives = None;
+            }
+            true
+        } else {
+            false
+        };
+        let _ = internal_ref.update(force);
 
         // makes partial borrows easier
-        let internal_ref = &mut *internal;
         if let Some((buffer, ref mut old_primitives)) =
             internal_ref.buffers.get_mut(&OrderedFloat(scale.x))
         {