Update WR (gradients, batching, text run, border changes).

- Tidy and optimize the batching code.
- Support tiling / repeat for linear and radial gradients.
- Fix some edge cases of subpixel text AA.
- Add clip mask support to border shaders.
- Optimization to text run creation on CPU.
- Handle more box-shadow clipping cases.
- Fix a panic that could occur when window size is 0.
- Clip / scroll API improvements.

components/compositing/compositor.rs

@@ -39,7 +39,7 @@ use style_traits::viewport::ViewportConstraints;
 use time::{precise_time_ns, precise_time_s};
 use touch::{TouchHandler, TouchAction};
 use webrender;
-use webrender_traits::{self, LayoutPoint, ScrollEventPhase, ScrollLayerId, ScrollLocation};
+use webrender_traits::{self, LayoutPoint, ScrollEventPhase, ClipId, ScrollLocation};
 use windowing::{self, MouseWindowEvent, WindowEvent, WindowMethods, WindowNavigateMsg};
 
 #[derive(Debug, PartialEq)]
@@ -797,8 +797,8 @@ impl<Window: WindowMethods> IOCompositor<Window> {
                                 pipeline_id: PipelineId,
                                 scroll_root_id: ScrollRootId,
                                 point: Point2D<f32>) {
-        let id = ScrollLayerId::new(scroll_root_id.0 as u64, pipeline_id.to_webrender());
-        self.webrender_api.scroll_layer_with_id(LayoutPoint::from_untyped(&point), id);
+        let id = ClipId::new(scroll_root_id.0 as u64, pipeline_id.to_webrender());
+        self.webrender_api.scroll_node_with_id(LayoutPoint::from_untyped(&point), id);
     }
 
     fn handle_window_message(&mut self, event: WindowEvent) {
@@ -1389,7 +1389,7 @@ impl<Window: WindowMethods> IOCompositor<Window> {
 
     fn send_viewport_rects(&self) {
         let mut stacking_context_scroll_states_per_pipeline = HashMap::new();
-        for scroll_layer_state in self.webrender_api.get_scroll_layer_state() {
+        for scroll_layer_state in self.webrender_api.get_scroll_node_state() {
             let external_id = match scroll_layer_state.id.external_id() {
                 Some(id) => id,
                 None => continue,

components/layout/display_list_builder.rs

@@ -985,8 +985,8 @@ impl FragmentDisplayListBuilding for Fragment {
             })
         }
 
-        let center = Point2D::new(absolute_bounds.origin.x + absolute_bounds.size.width / 2,
-                                  absolute_bounds.origin.y + absolute_bounds.size.height / 2);
+        let center = Point2D::new(absolute_bounds.size.width / 2,
+                                  absolute_bounds.size.height / 2);
 
         Some(display_list::Gradient {
             start_point: center - delta,

components/layout/webrender_helpers.rs

@@ -16,7 +16,7 @@ use msg::constellation_msg::PipelineId;
 use style::computed_values::{image_rendering, mix_blend_mode};
 use style::computed_values::filter::{self, Filter};
 use style::values::computed::BorderStyle;
-use webrender_traits::{self, DisplayListBuilder, ExtendMode, LayoutTransform, ScrollLayerId};
+use webrender_traits::{self, DisplayListBuilder, ExtendMode, LayoutTransform, ClipId};
 
 pub trait WebRenderDisplayListConverter {
     fn convert_to_webrender(&self, pipeline_id: PipelineId) -> DisplayListBuilder;
@@ -374,7 +374,11 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                                                        end_point,
                                                        item.gradient.stops.clone(),
                                                        ExtendMode::Clamp);
-                builder.push_gradient(rect, clip, gradient);
+                builder.push_gradient(rect,
+                                      clip,
+                                      gradient,
+                                      rect.size,
+                                      webrender_traits::LayoutSize::zero());
             }
             DisplayItem::Line(..) => {
                 println!("TODO DisplayItem::Line");
@@ -421,7 +425,7 @@ impl WebRenderDisplayItemConverter for DisplayItem {
             }
             DisplayItem::PopStackingContext(_) => builder.pop_stacking_context(),
             DisplayItem::PushScrollRoot(ref item) => {
-                let our_id = ScrollLayerId::new(item.scroll_root.id.0 as u64, builder.pipeline_id);
+                let our_id = ClipId::new(item.scroll_root.id.0 as u64, builder.pipeline_id);
                 let clip = item.scroll_root.clip.to_clip_region(builder);
                 let content_rect = item.scroll_root.content_rect.to_rectf();
                 let webrender_id = builder.define_clip(content_rect, clip, Some(our_id));
@@ -432,15 +436,15 @@ impl WebRenderDisplayItemConverter for DisplayItem {
     }
 }
 trait WebRenderScrollRootIdConverter {
-    fn convert_to_webrender(&self, pipeline_id: webrender_traits::PipelineId) -> ScrollLayerId;
+    fn convert_to_webrender(&self, pipeline_id: webrender_traits::PipelineId) -> ClipId;
 }
 
 impl WebRenderScrollRootIdConverter for ScrollRootId {
-    fn convert_to_webrender(&self, pipeline_id: webrender_traits::PipelineId) -> ScrollLayerId {
+    fn convert_to_webrender(&self, pipeline_id: webrender_traits::PipelineId) -> ClipId {
         if *self == ScrollRootId::root() {
-            ScrollLayerId::root_scroll_layer(pipeline_id)
+            ClipId::root_scroll_node(pipeline_id)
         } else {
-            ScrollLayerId::new(self.0 as u64, pipeline_id)
+            ClipId::new(self.0 as u64, pipeline_id)
         }
     }
 }