Bug 1836703 - Fix drop-shadow not invalidating correctly. r=gfx-reviewers,lsalzman

There is still a remaining issue in some cases with the color of
the drop-shadow when moving the slider, but this seems to be a
different problem. This patch fixes the main issue.

Differential Revision: https://phabricator.services.mozilla.com/D183314

gfx/wr/webrender/src/picture.rs

@@ -3889,6 +3889,7 @@ impl SurfaceInfo {
 
 /// Information from `get_surface_rects` about the allocated size, UV sampling
 /// parameters etc for an off-screen surface
+#[derive(Debug)]
 struct SurfaceAllocInfo {
     task_size: DeviceIntSize,
     needs_scissor_rect: bool,
@@ -7004,10 +7005,9 @@ fn get_surface_rects(
         PictureCompositeMode::Filter(Filter::DropShadows(ref shadows)) => {
             let local_prim_rect = surface.clipped_local_rect;
 
-            let mut required_local_rect = match local_prim_rect.intersection(&local_clip_rect) {
-                Some(rect) => rect,
-                None => return None,
-            };
+            let mut required_local_rect = local_prim_rect
+                .intersection(&local_clip_rect)
+                .unwrap_or(PictureRect::zero());
 
             for shadow in shadows {
                 let (blur_radius_x, blur_radius_y) = surface.clamp_blur_radius(
@@ -7018,7 +7018,8 @@ fn get_surface_rects(
                 let blur_inflation_y = blur_radius_y * BLUR_SAMPLE_SCALE;
 
                 let local_shadow_rect = local_prim_rect
-                    .translate(shadow.offset.cast_unit());
+                    .translate(shadow.offset.cast_unit())
+                    .inflate(blur_inflation_x, blur_inflation_y);
 
                 if let Some(clipped_shadow_rect) = local_clip_rect.intersection(&local_shadow_rect) {
                     let required_shadow_rect = clipped_shadow_rect.inflate(blur_inflation_x, blur_inflation_y);
@@ -7228,3 +7229,103 @@ fn test_large_surface_scale_1() {
         false,
     );
 }
+
+#[test]
+fn test_drop_filter_dirty_region_outside_prim() {
+    // Ensure that if we have a drop-filter where the content of the
+    // shadow is outside the dirty rect, but blurred pixels from that
+    // content will affect the dirty rect, that we correctly calculate
+    // the required region of the drop-filter input
+
+    use api::Shadow;
+    use crate::spatial_tree::{SceneSpatialTree, SpatialTree};
+
+    let mut cst = SceneSpatialTree::new();
+    let root_reference_frame_index = cst.root_reference_frame_index();
+
+    let mut spatial_tree = SpatialTree::new();
+    spatial_tree.apply_updates(cst.end_frame_and_get_pending_updates());
+    spatial_tree.update_tree(&SceneProperties::new());
+
+    let map_local_to_surface = SpaceMapper::new_with_target(
+        root_reference_frame_index,
+        root_reference_frame_index,
+        PictureRect::max_rect(),
+        &spatial_tree,
+    );
+
+    let mut surfaces = vec![
+        SurfaceInfo {
+            unclipped_local_rect: PictureRect::max_rect(),
+            clipped_local_rect: PictureRect::max_rect(),
+            is_opaque: true,
+            clipping_rect: PictureRect::max_rect(),
+            map_local_to_surface: map_local_to_surface.clone(),
+            raster_spatial_node_index: root_reference_frame_index,
+            surface_spatial_node_index: root_reference_frame_index,
+            device_pixel_scale: DevicePixelScale::new(1.0),
+            world_scale_factors: (1.0, 1.0),
+            local_scale: (1.0, 1.0),
+            allow_snapping: true,
+            force_scissor_rect: false,
+        },
+        SurfaceInfo {
+            unclipped_local_rect: PictureRect::new(
+                PicturePoint::new(0.0, 0.0),
+                PicturePoint::new(750.0, 450.0),
+            ),
+            clipped_local_rect: PictureRect::new(
+                PicturePoint::new(0.0, 0.0),
+                PicturePoint::new(750.0, 450.0),
+            ),
+            is_opaque: true,
+            clipping_rect: PictureRect::max_rect(),
+            map_local_to_surface,
+            raster_spatial_node_index: root_reference_frame_index,
+            surface_spatial_node_index: root_reference_frame_index,
+            device_pixel_scale: DevicePixelScale::new(1.0),
+            world_scale_factors: (1.0, 1.0),
+            local_scale: (1.0, 1.0),
+            allow_snapping: true,
+            force_scissor_rect: false,
+        },
+    ];
+
+    let shadows = smallvec![
+        Shadow {
+            offset: LayoutVector2D::zero(),
+            color: ColorF::BLACK,
+            blur_radius: 75.0,
+        },
+    ];
+
+    let composite_mode = PictureCompositeMode::Filter(Filter::DropShadows(shadows));
+
+    // Ensure we get a valid and correct render task size when dirty region covers entire screen
+    let info = get_surface_rects(
+        SurfaceIndex(1),
+        &composite_mode,
+        SurfaceIndex(0),
+        &mut surfaces,
+        &spatial_tree,
+        MAX_SURFACE_SIZE as f32,
+        false,
+    ).expect("No surface rect");
+    assert_eq!(info.task_size, DeviceIntSize::new(1200, 900));
+
+    // Ensure we get a valid and correct render task size when dirty region is outside filter content
+    surfaces[0].clipping_rect = PictureRect::new(
+        PicturePoint::new(768.0, 128.0),
+        PicturePoint::new(1024.0, 256.0),
+    );
+    let info = get_surface_rects(
+        SurfaceIndex(1),
+        &composite_mode,
+        SurfaceIndex(0),
+        &mut surfaces,
+        &spatial_tree,
+        MAX_SURFACE_SIZE as f32,
+        false,
+    ).expect("No surface rect");
+    assert_eq!(info.task_size, DeviceIntSize::new(432, 578));
+}

layout/reftests/bugs/reftest.list

@@ -1801,9 +1801,9 @@ pref(layout.css.moz-document.content.enabled,false) == 1035091-2.html 1035091-re
 == 1053035-1-flex.html 1053035-1-ref.html
 == 1053035-1-grid.html 1053035-1-ref.html
 == 1059167-1.html 1059167-1-ref.html
-fails-if(!useDrawSnapshot) == 1059498-1.html 1059498-1-ref.html # WebRender: see bug 1504290
-fails-if(!useDrawSnapshot) == 1059498-2.html 1059498-1-ref.html # WebRender: see bug 1504290
-fails-if(!useDrawSnapshot) == 1059498-3.html 1059498-1-ref.html # WebRender: see bug 1499113
+== 1059498-1.html 1059498-1-ref.html # WebRender: see bug 1504290
+== 1059498-2.html 1059498-1-ref.html # WebRender: see bug 1504290
+== 1059498-3.html 1059498-1-ref.html # WebRender: see bug 1499113
 == 1062108-1.html 1062108-1-ref.html
 == 1062792-1.html 1062792-1-ref.html
 == 1066554-1.html 1066554-1-ref.html

testing/web-platform/meta/css/filter-effects/filters-drop-shadow-003.html.ini

@@ -1,2 +0,0 @@
-[filters-drop-shadow-003.html]
-  expected: FAIL