Overhaul resize presentation and wallpaper rendering

Coordinate native-pixel resize handoffs, fractional geometry and shared animation timing. Delegate wallpaper rendering to the compositor, advertise DMA-BUF device feedback, and improve callback pacing and render metrics.

Handle monitor-local shell surfaces, lid-driven output evacuation and workspace restoration.

compositor/src/handlers/compositor.rs

@@ -18,6 +18,30 @@ use smithay::{
 use super::{layer_shell, xdg_shell};
 use crate::{Ferese, state::ClientState};
 
+fn layer_affects_backdrop(layer: smithay::wayland::shell::wlr_layer::Layer) -> bool {
+    matches!(
+        layer,
+        smithay::wayland::shell::wlr_layer::Layer::Background
+            | smithay::wayland::shell::wlr_layer::Layer::Bottom
+    )
+}
+
+impl Ferese {
+    fn surface_affects_backdrop(&self, surface: &WlSurface) -> bool {
+        let mut root = surface.clone();
+        while let Some(parent) = get_parent(&root) {
+            root = parent;
+        }
+        if matches!(&self.cursor_status, smithay::input::pointer::CursorImageStatus::Surface(cursor) if cursor == &root)
+        {
+            return false;
+        }
+        self.space
+            .layer_for_surface(&root, smithay::desktop::WindowSurfaceType::ALL)
+            .is_none_or(|layer| layer_affects_backdrop(layer.cached_state().layer))
+    }
+}
+
 impl CompositorHandler for Ferese {
     fn compositor_state(&mut self) -> &mut CompositorState {
         &mut self.compositor_state
@@ -31,7 +55,10 @@ impl CompositorHandler for Ferese {
     }
 
     fn commit(&mut self, surface: &WlSurface) {
-        self.backdrop_generation = self.backdrop_generation.wrapping_add(1);
+        self.capture_resize_before_commit(surface);
+        if self.surface_affects_backdrop(surface) {
+            self.backdrop_generation = self.backdrop_generation.wrapping_add(1);
+        }
         on_commit_buffer_handler::<Self>(surface);
         if !is_sync_subsurface(surface) {
             let mut root = surface.clone();
@@ -77,6 +104,19 @@ impl CompositorHandler for Ferese {
     }
 }
 
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use smithay::wayland::shell::wlr_layer::Layer;
+    #[test]
+    fn panel_commits_do_not_invalidate_their_own_backdrop() {
+        assert!(!layer_affects_backdrop(Layer::Top));
+        assert!(!layer_affects_backdrop(Layer::Overlay));
+        assert!(layer_affects_backdrop(Layer::Bottom));
+        assert!(layer_affects_backdrop(Layer::Background));
+    }
+}
+
 impl BufferHandler for Ferese {
     fn buffer_destroyed(&mut self, _buffer: &wl_buffer::WlBuffer) {}
 }