Bug 1775369 - Make hit-test API use clip-chains rather than ClipId r=gfx-reviewers,lsalzman

Differential Revision: https://phabricator.services.mozilla.com/D149938

gfx/webrender_bindings/src/bindings.rs

@@ -3014,22 +3014,27 @@ pub extern "C" fn wr_dp_push_hit_test(
 ) {
     debug_assert!(unsafe { !is_in_render_thread() });
 
-    let space_and_clip = parent.to_webrender(state.pipeline_id);
-
     let clip_rect = clip.intersection(&rect);
     if clip_rect.is_none() {
         return;
     }
     let tag = (scroll_id, hit_info);
 
-    let prim_info = CommonItemProperties {
-        clip_rect: clip_rect.unwrap(),
-        clip_id: space_and_clip.clip_id,
-        spatial_id: space_and_clip.spatial_id,
-        flags: prim_flags(is_backface_visible, /* prefer_compositor_surface */ false),
+    let spatial_id = parent.space.to_webrender(state.pipeline_id);
+
+    let clip_chain_id = if parent.clip_chain == ROOT_CLIP_CHAIN {
+        ClipChainId::INVALID
+    } else {
+        ClipChainId(parent.clip_chain, state.pipeline_id)
     };
 
-    state.frame_builder.dl_builder.push_hit_test(&prim_info, tag);
+    state.frame_builder.dl_builder.push_hit_test(
+        clip_rect.unwrap(),
+        clip_chain_id,
+        spatial_id,
+        prim_flags(is_backface_visible, false),
+        tag,
+    );
 }
 
 #[no_mangle]

gfx/wr/examples/scrolling.rs

@@ -72,12 +72,24 @@ impl Example for App {
             // now put some content into it.
             // start with a white background
             let info = CommonItemProperties::new((0, 0).to(1000, 1000), space_and_clip1);
-            builder.push_hit_test(&info, (0, 1));
+            builder.push_hit_test(
+                info.clip_rect,
+                ClipChainId::INVALID,
+                info.spatial_id,
+                info.flags,
+                (0, 1)
+            );
             builder.push_rect(&info, info.clip_rect, ColorF::new(1.0, 1.0, 1.0, 1.0));
 
             // let's make a 50x50 blue square as a visual reference
             let info = CommonItemProperties::new((0, 0).to(50, 50), space_and_clip1);
-            builder.push_hit_test(&info, (0, 2));
+            builder.push_hit_test(
+                info.clip_rect,
+                ClipChainId::INVALID,
+                info.spatial_id,
+                info.flags,
+                (0, 2)
+            );
             builder.push_rect(&info, info.clip_rect, ColorF::new(0.0, 0.0, 1.0, 1.0));
 
             // and a 50x50 green square next to it with an offset clip
@@ -86,7 +98,13 @@ impl Example for App {
                 (50, 0).to(100, 50).intersection(&(60, 10).to(110, 60)).unwrap(),
                 space_and_clip1,
             );
-            builder.push_hit_test(&info, (0, 3));
+            builder.push_hit_test(
+                info.clip_rect,
+                ClipChainId::INVALID,
+                info.spatial_id,
+                info.flags,
+                (0, 3)
+            );
             builder.push_rect(&info, info.clip_rect, ColorF::new(0.0, 1.0, 0.0, 1.0));
 
             // Below the above rectangles, set up a nested scrollbox. It's still in
@@ -113,13 +131,25 @@ impl Example for App {
                 (-1000, -1000).to(5000, 5000),
                 space_and_clip2,
             );
-            builder.push_hit_test(&info, (0, 4));
+            builder.push_hit_test(
+                info.clip_rect,
+                ClipChainId::INVALID,
+                info.spatial_id,
+                info.flags,
+                (0, 4)
+            );
             builder.push_rect(&info, info.clip_rect, ColorF::new(0.5, 0.5, 0.5, 1.0));
 
             // add a teal square to visualize the scrolling/clipping behaviour
             // as you scroll the nested scrollbox
             let info = CommonItemProperties::new((0, 200).to(50, 250), space_and_clip2);
-            builder.push_hit_test(&info, (0, 5));
+            builder.push_hit_test(
+                info.clip_rect,
+                ClipChainId::INVALID,
+                info.spatial_id,
+                info.flags,
+                (0, 5)
+            );
             builder.push_rect(&info, info.clip_rect, ColorF::new(0.0, 1.0, 1.0, 1.0));
 
             // Add a sticky frame. It will "stick" twice while scrolling, once
@@ -143,7 +173,13 @@ impl Example for App {
                     clip_id: space_and_clip2.clip_id,
                 },
             );
-            builder.push_hit_test(&info, (0, 6));
+            builder.push_hit_test(
+                info.clip_rect,
+                ClipChainId::INVALID,
+                info.spatial_id,
+                info.flags,
+                (0, 6)
+            );
             builder.push_rect(
                 &info,
                 info.clip_rect,
@@ -156,7 +192,13 @@ impl Example for App {
                 (250, 350).to(300, 400),
                 space_and_clip2,
             );
-            builder.push_hit_test(&info, (0, 7));
+            builder.push_hit_test(
+                info.clip_rect,
+                ClipChainId::INVALID,
+                info.spatial_id,
+                info.flags,
+                (0, 7)
+            );
             builder.push_rect(&info, info.clip_rect, ColorF::new(0.0, 1.0, 1.0, 1.0));
 
             builder.pop_stacking_context();

gfx/wr/webrender/src/scene_building.rs

@@ -762,6 +762,13 @@ impl<'a> SceneBuilder<'a> {
             kind: ContextKind<'a>,
         }
 
+        let invalid_clip_chain_id = ClipId::ClipChain(api::ClipChainId::INVALID);
+        self.clip_store.register_clip_template(
+            invalid_clip_chain_id,
+            invalid_clip_chain_id,
+            &[],
+        );
+
         let root_clip_id = ClipId::root(root_pipeline.pipeline_id);
         self.clip_store.register_clip_template(root_clip_id, root_clip_id, &[]);
         self.clip_store.push_clip_root(Some(root_clip_id), false);
@@ -1356,20 +1363,28 @@ impl<'a> SceneBuilder<'a> {
             DisplayItem::HitTest(ref info) => {
                 profile_scope!("hit_test");
 
-                // TODO(gw): We could skip building the clip-chain here completely, as it's not used by
-                //           hit-test items.
-                let (layout, _, spatial_node_index, _) = self.process_common_properties(
-                    &info.common,
-                    None,
+                let spatial_node_index = self.get_space(info.spatial_id);
+                let current_offset = self.current_offset(spatial_node_index);
+                let unsnapped_rect = info.rect.translate(current_offset);
+
+                let rect = self.snap_rect(
+                    &unsnapped_rect,
+                    spatial_node_index,
                 );
 
-                // Don't add transparent rectangles to the draw list,
-                // but do consider them for hit testing. This allows
-                // specifying invisible hit testing areas.
+                let layout = LayoutPrimitiveInfo {
+                    rect,
+                    clip_rect: rect,
+                    flags: info.flags,
+                };
+
+                // TODO(gw): Port internal API to be ClipChain based, rather than ClipId once all callers updated
+                let clip_id = ClipId::ClipChain(info.clip_chain_id);
+
                 self.add_primitive_to_hit_testing_list(
                     &layout,
                     spatial_node_index,
-                    info.common.clip_id,
+                    clip_id,
                     info.tag,
                 );
             }

gfx/wr/webrender_api/src/display_item.rs

@@ -365,7 +365,10 @@ pub struct ClearRectangleDisplayItem {
 /// distinct item also makes it easier to inspect/debug display items.
 #[derive(Clone, Copy, Debug, Default, Deserialize, PartialEq, Serialize, PeekPoke)]
 pub struct HitTestDisplayItem {
-    pub common: CommonItemProperties,
+    pub rect: LayoutRect,
+    pub clip_chain_id: ClipChainId,
+    pub spatial_id: SpatialId,
+    pub flags: PrimitiveFlags,
     pub tag: ItemTag,
 }
 
@@ -1633,6 +1636,10 @@ impl From<FillRule> for u8 {
 #[derive(Clone, Copy, Debug, Default, Deserialize, Eq, Hash, PartialEq, Serialize, PeekPoke)]
 pub struct ClipChainId(pub u64, pub PipelineId);
 
+impl ClipChainId {
+    pub const INVALID: Self = ClipChainId(!0, PipelineId::INVALID);
+}
+
 /// A reference to a clipping node defining how an item is clipped.
 #[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, PartialEq, Serialize, PeekPoke)]
 pub enum ClipId {

gfx/wr/webrender_api/src/display_list.rs

@@ -1350,11 +1350,17 @@ impl DisplayListBuilder {
 
     pub fn push_hit_test(
         &mut self,
-        common: &di::CommonItemProperties,
+        rect: LayoutRect,
+        clip_chain_id: di::ClipChainId,
+        spatial_id: di::SpatialId,
+        flags: di::PrimitiveFlags,
         tag: di::ItemTag,
     ) {
         let item = di::DisplayItem::HitTest(di::HitTestDisplayItem {
-            common: *common,
+            rect,
+            clip_chain_id,
+            spatial_id,
+            flags,
             tag,
         });
         self.push_item(&item);

gfx/wr/webrender_api/src/lib.rs

@@ -159,6 +159,8 @@ impl PipelineId {
     pub fn dummy() -> Self {
         PipelineId(!0, !0)
     }
+
+    pub const INVALID: Self = PipelineId(!0, !0);
 }
 
 

gfx/wr/wrench/src/rawtest.rs

@@ -1331,24 +1331,27 @@ impl<'a> RawtestHarness<'a> {
         builder.begin();
 
         // Add a rectangle that covers the entire scene.
-        let info = self.make_common_properties(LayoutRect::from_size(layout_size));
+        let space_and_clip = SpaceAndClipInfo::root_scroll(self.wrench.root_pipeline_id);
         builder.push_hit_test(
-            &info,
+            LayoutRect::from_size(layout_size),
+            ClipChainId::INVALID,
+            space_and_clip.spatial_id,
+            PrimitiveFlags::default(),
             (0, 1),
         );
 
         // Add a simple 100x100 rectangle at 100,0.
-        let info = self.make_common_properties(LayoutRect::from_origin_and_size(
-            LayoutPoint::new(100., 0.),
-            LayoutSize::new(100., 100.)
-        ));
         builder.push_hit_test(
-            &info,
+            LayoutRect::from_origin_and_size(
+                LayoutPoint::new(100., 0.),
+                LayoutSize::new(100., 100.)
+            ),
+            ClipChainId::INVALID,
+            space_and_clip.spatial_id,
+            PrimitiveFlags::default(),
             (0, 2),
         );
 
-        let space_and_clip = SpaceAndClipInfo::root_scroll(self.wrench.root_pipeline_id);
-
         let make_rounded_complex_clip = |rect: &LayoutRect, radius: f32| -> ComplexClipRegion {
             ComplexClipRegion::new(
                 *rect,
@@ -1363,13 +1366,12 @@ impl<'a> RawtestHarness<'a> {
             &space_and_clip,
             make_rounded_complex_clip(&rect, 20.),
         );
+        let clip_chain_id = builder.define_clip_chain(None, vec![temp_clip_id]);
         builder.push_hit_test(
-            &CommonItemProperties {
-                clip_rect: rect,
-                clip_id: temp_clip_id,
-                spatial_id: space_and_clip.spatial_id,
-                flags: PrimitiveFlags::default(),
-            },
+            rect,
+            clip_chain_id,
+            space_and_clip.spatial_id,
+            PrimitiveFlags::default(),
             (0, 4),
         );
 
@@ -1381,12 +1383,10 @@ impl<'a> RawtestHarness<'a> {
         );
         let clip_chain_id = builder.define_clip_chain(None, vec![clip_id]);
         builder.push_hit_test(
-            &CommonItemProperties {
-                clip_rect: rect,
-                clip_id: ClipId::ClipChain(clip_chain_id),
-                spatial_id: space_and_clip.spatial_id,
-                flags: PrimitiveFlags::default(),
-            },
+            rect,
+            clip_chain_id,
+            space_and_clip.spatial_id,
+            PrimitiveFlags::default(),
             (0, 5),
         );
 

gfx/wr/wrench/src/yaml_frame_reader.rs

@@ -878,9 +878,17 @@ impl YamlFrameReader {
             &info.clip_rect
         );
 
+        let clip_chain_id = match info.clip_id {
+            ClipId::Clip(..) => panic!("bug: must be a clip-chain"),
+            ClipId::ClipChain(id) => id,
+        };
+
         if let Some(tag) = self.to_hit_testing_tag(&item["hit-testing-tag"]) {
             dl.push_hit_test(
-                info,
+                info.clip_rect,
+                clip_chain_id,
+                info.spatial_id,
+                info.flags,
                 tag,
             );
         }