Reintroduce damage tracking for `iced_tiny_skia`

1 files changed, 17 insertions, 14 deletions

diff --git a/tiny_skia/src/window/compositor.rs b/tiny_skia/src/window/compositor.rs
index e1a9dfec..153af6d5 100644
--- a/tiny_skia/src/window/compositor.rs
+++ b/tiny_skia/src/window/compositor.rs
@@ -1,5 +1,6 @@
 use crate::core::{Color, Rectangle, Size};
 use crate::graphics::compositor::{self, Information};
+use crate::graphics::damage;
 use crate::graphics::error::{self, Error};
 use crate::graphics::{self, Viewport};
 use crate::{Layer, Renderer, Settings};
@@ -154,7 +155,7 @@ pub fn present<T: AsRef<str>>(
         .buffer_mut()
         .map_err(|_| compositor::SurfaceError::Lost)?;
 
-    let _last_layers = {
+    let last_layers = {
         let age = buffer.age();
 
         surface.max_age = surface.max_age.max(age);
@@ -167,26 +168,28 @@ pub fn present<T: AsRef<str>>(
         }
     };
 
-    // TODO
-    // let damage = last_layers
-    //     .and_then(|last_layers| {
-    //         (surface.background_color == background_color)
-    //             .then(|| damage::layers(last_layers, renderer.layers()))
-    //     })
-    //     .unwrap_or_else(|| vec![Rectangle::with_size(viewport.logical_size())]);
-
-    let damage = vec![Rectangle::with_size(viewport.logical_size())];
+    let damage = last_layers
+        .and_then(|last_layers| {
+            (surface.background_color == background_color).then(|| {
+                damage::diff(
+                    last_layers,
+                    renderer.layers(),
+                    |layer| vec![layer.bounds],
+                    Layer::damage,
+                )
+            })
+        })
+        .unwrap_or_else(|| vec![Rectangle::with_size(viewport.logical_size())]);
 
     if damage.is_empty() {
         return Ok(());
     }
 
-    surface
-        .layer_stack
-        .push_front(renderer.layers().cloned().collect());
+    surface.layer_stack.push_front(renderer.layers().to_vec());
     surface.background_color = background_color;
 
-    // let damage = damage::group(damage, viewport.logical_size());
+    let damage =
+        damage::group(damage, Rectangle::with_size(viewport.logical_size()));
 
     let mut pixels = tiny_skia::PixmapMut::from_bytes(
         bytemuck::cast_slice_mut(&mut buffer),