Bug 1429806 - Update webrender to commit eb9e1702df4b6dc036b649b3dd32ccc4bfbe43bf. r=jrmuizel

MozReview-Commit-ID: 7m0P5kgiWZF

--HG--
extra : rebase_source : 4543ca28be94c735c24120892b5eb254afabd677

gfx/doc/README.webrender

@@ -175,4 +175,4 @@ Troubleshooting tips:
 -------------------------------------------------------------------------------
 
 The version of WebRender currently in the tree is:
-722e8b104bf99d29d61ecb1fe456eebe89ad81fd
+eb9e1702df4b6dc036b649b3dd32ccc4bfbe43bf

gfx/webrender/Cargo.toml

@@ -35,7 +35,7 @@ serde_json = { optional = true, version = "1.0" }
 serde = { optional = true, version = "1.0", features = ["serde_derive"] }
 image = { optional = true, version = "0.17" }
 base64 = { optional = true, version = "0.3.0" }
-ron = { optional = true, version = "0.1.3" }
+ron = { optional = true, version = "0.1.5" }
 
 [dev-dependencies]
 angle = {git = "https://github.com/servo/angle", branch = "servo"}

gfx/webrender/examples/alpha_perf.rs

@@ -0,0 +1,86 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+extern crate euclid;
+extern crate gleam;
+extern crate glutin;
+extern crate webrender;
+
+#[path = "common/boilerplate.rs"]
+mod boilerplate;
+
+use boilerplate::{Example, HandyDandyRectBuilder};
+use std::cmp;
+use webrender::api::*;
+
+struct App {
+    rect_count: usize,
+}
+
+impl Example for App {
+    fn render(
+        &mut self,
+        _api: &RenderApi,
+        builder: &mut DisplayListBuilder,
+        _resources: &mut ResourceUpdates,
+        _framebuffer_size: DeviceUintSize,
+        _pipeline_id: PipelineId,
+        _document_id: DocumentId,
+    ) {
+        let bounds = (0, 0).to(1920, 1080);
+        let info = LayoutPrimitiveInfo {
+            local_clip: LocalClip::Rect(bounds),
+            .. LayoutPrimitiveInfo::new(bounds)
+        };
+
+        builder.push_stacking_context(
+            &info,
+            ScrollPolicy::Scrollable,
+            None,
+            TransformStyle::Flat,
+            None,
+            MixBlendMode::Normal,
+            Vec::new(),
+        );
+
+        for _ in 0 .. self.rect_count {
+            builder.push_rect(&info, ColorF::new(1.0, 1.0, 1.0, 0.05));
+        }
+
+        builder.pop_stacking_context();
+    }
+
+    fn on_event(
+        &mut self,
+        event: glutin::Event,
+        _api: &RenderApi,
+        _document_id: DocumentId
+    ) -> bool {
+        match event {
+            glutin::Event::KeyboardInput(glutin::ElementState::Pressed, _, Some(key)) => {
+                match key {
+                    glutin::VirtualKeyCode::Right => {
+                        self.rect_count += 1;
+                        println!("rects = {}", self.rect_count);
+                    }
+                    glutin::VirtualKeyCode::Left => {
+                        self.rect_count = cmp::max(self.rect_count, 1) - 1;
+                        println!("rects = {}", self.rect_count);
+                    }
+                    _ => {}
+                };
+            }
+            _ => (),
+        }
+
+        true
+    }
+}
+
+fn main() {
+    let mut app = App {
+        rect_count: 1,
+    };
+    boilerplate::main_wrapper(&mut app, None);
+}

gfx/webrender/examples/basic.rs

@@ -212,7 +212,7 @@ impl Example for App {
         let image_mask_key = api.generate_image_key();
         resources.add_image(
             image_mask_key,
-            ImageDescriptor::new(2, 2, ImageFormat::A8, true),
+            ImageDescriptor::new(2, 2, ImageFormat::R8, true),
             ImageData::new(vec![0, 80, 180, 255]),
             None,
         );

gfx/webrender/examples/blob.rs

@@ -85,7 +85,7 @@ fn render_blob(
                     texels.push(color.r * checker + tc);
                     texels.push(color.a * checker + tc);
                 }
-                api::ImageFormat::A8 => {
+                api::ImageFormat::R8 => {
                     texels.push(color.a * checker + tc);
                 }
                 _ => {
@@ -265,6 +265,7 @@ impl Example for App {
             api::LayoutSize::new(500.0, 500.0),
             api::LayoutSize::new(0.0, 0.0),
             api::ImageRendering::Auto,
+            api::AlphaType::PremultipliedAlpha,
             blob_img1,
         );
 
@@ -274,6 +275,7 @@ impl Example for App {
             api::LayoutSize::new(200.0, 200.0),
             api::LayoutSize::new(0.0, 0.0),
             api::ImageRendering::Auto,
+            api::AlphaType::PremultipliedAlpha,
             blob_img2,
         );
 

gfx/webrender/examples/common/boilerplate.rs

@@ -64,6 +64,9 @@ impl HandyDandyRectBuilder for (i32, i32) {
 pub trait Example {
     const TITLE: &'static str = "WebRender Sample App";
     const PRECACHE_SHADERS: bool = false;
+    const WIDTH: u32 = 1920;
+    const HEIGHT: u32 = 1080;
+
     fn render(
         &mut self,
         api: &RenderApi,
@@ -103,6 +106,7 @@ pub fn main_wrapper<E: Example>(
     let window = glutin::WindowBuilder::new()
         .with_title(E::TITLE)
         .with_multitouch()
+        .with_dimensions(E::WIDTH, E::HEIGHT)
         .with_gl(glutin::GlRequest::GlThenGles {
             opengl_version: (3, 2),
             opengles_version: (3, 0),
@@ -224,6 +228,13 @@ pub fn main_wrapper<E: Example>(
                 ) => {
                     renderer.toggle_debug_flags(webrender::DebugFlags::ALPHA_PRIM_DBG);
                 }
+                glutin::Event::KeyboardInput(
+                    glutin::ElementState::Pressed,
+                    _,
+                    Some(glutin::VirtualKeyCode::S),
+                ) => {
+                    renderer.toggle_debug_flags(webrender::DebugFlags::COMPACT_PROFILER);
+                }
                 glutin::Event::KeyboardInput(
                     glutin::ElementState::Pressed,
                     _,

gfx/webrender/examples/frame_output.rs

@@ -164,6 +164,7 @@ impl Example for App {
             info.rect.size,
             LayoutSize::zero(),
             ImageRendering::Auto,
+            AlphaType::PremultipliedAlpha,
             self.external_image_key.unwrap()
         );
 

gfx/webrender/examples/image_resize.rs

@@ -59,6 +59,7 @@ impl Example for App {
             image_size,
             LayoutSize::zero(),
             ImageRendering::Auto,
+            AlphaType::PremultipliedAlpha,
             self.image_key,
         );
 
@@ -71,6 +72,7 @@ impl Example for App {
             image_size,
             LayoutSize::zero(),
             ImageRendering::Pixelated,
+            AlphaType::PremultipliedAlpha,
             self.image_key,
         );
 

gfx/webrender/examples/texture_cache_stress.rs

@@ -147,6 +147,7 @@ impl Example for App {
                 image_size,
                 LayoutSize::zero(),
                 ImageRendering::Auto,
+                AlphaType::PremultipliedAlpha,
                 *key,
             );
         }
@@ -162,6 +163,7 @@ impl Example for App {
                 image_size,
                 LayoutSize::zero(),
                 ImageRendering::Auto,
+                AlphaType::PremultipliedAlpha,
                 image_key,
             );
         }
@@ -177,6 +179,7 @@ impl Example for App {
             image_size,
             LayoutSize::zero(),
             ImageRendering::Auto,
+            AlphaType::PremultipliedAlpha,
             swap_key,
         );
         self.swap_index = 1 - self.swap_index;

gfx/webrender/examples/yuv.rs

@@ -192,7 +192,7 @@ impl Example for App {
         let yuv_chanel3 = api.generate_image_key();
         resources.add_image(
             yuv_chanel1,
-            ImageDescriptor::new(100, 100, ImageFormat::A8, true),
+            ImageDescriptor::new(100, 100, ImageFormat::R8, true),
             ImageData::new(vec![127; 100 * 100]),
             None,
         );
@@ -204,13 +204,13 @@ impl Example for App {
         );
         resources.add_image(
             yuv_chanel2_1,
-            ImageDescriptor::new(100, 100, ImageFormat::A8, true),
+            ImageDescriptor::new(100, 100, ImageFormat::R8, true),
             ImageData::new(vec![127; 100 * 100]),
             None,
         );
         resources.add_image(
             yuv_chanel3,
-            ImageDescriptor::new(100, 100, ImageFormat::A8, true),
+            ImageDescriptor::new(100, 100, ImageFormat::R8, true),
             ImageData::new(vec![127; 100 * 100]),
             None,
         );

gfx/webrender/res/brush.glsl

@@ -23,6 +23,7 @@ struct BrushInstance {
     int clip_address;
     int z;
     int segment_index;
+    int edge_mask;
     ivec2 user_data;
 };
 
@@ -35,7 +36,8 @@ BrushInstance load_brush() {
     bi.scroll_node_id = aData0.z % 65536;
     bi.clip_address = aData0.w;
     bi.z = aData1.x;
-    bi.segment_index = aData1.y;
+    bi.segment_index = aData1.y & 0xffff;
+    bi.edge_mask = aData1.y >> 16;
     bi.user_data = aData1.zw;
 
     return bi;
@@ -125,7 +127,7 @@ void main(void) {
             vLocalBounds = vec4(vec2(-1000000.0), vec2(1000000.0));
 #endif
         } else {
-            bvec4 edge_mask = notEqual(int(segment_data[1].x) & ivec4(1, 2, 4, 8), ivec4(0));
+            bvec4 edge_mask = notEqual(brush.edge_mask & ivec4(1, 2, 4, 8), ivec4(0));
             vi = write_transform_vertex(
                 local_segment_rect,
                 brush_prim.local_rect,

gfx/webrender/res/brush_image.glsl

@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#define VECS_PER_SPECIFIC_BRUSH 0
+#define VECS_PER_SPECIFIC_BRUSH 1
 
 #include shared,prim_shared,brush
 
@@ -25,6 +25,16 @@ flat varying vec4 vColor;
 #define BRUSH_IMAGE_MIRROR      2
 
 #ifdef WR_VERTEX_SHADER
+
+struct Picture {
+    vec4 color;
+};
+
+Picture fetch_picture(int address) {
+    vec4 data = fetch_from_resource_cache_1(address);
+    return Picture(data);
+}
+
 void brush_vs(
     int prim_address,
     vec2 local_pos,
@@ -32,29 +42,35 @@ void brush_vs(
     ivec2 user_data,
     PictureTask pic_task
 ) {
-    // TODO(gw): For now, this brush_image shader is only
-    //           being used to draw items from the intermediate
-    //           surface cache (render tasks). In the future
-    //           we can expand this to support items from
-    //           the normal texture cache and unify this
-    //           with the normal image shader.
-    BlurTask blur_task = fetch_blur_task(user_data.x);
-    vUv.z = blur_task.common_data.texture_layer_index;
     vImageKind = user_data.y;
 
-#if defined WR_FEATURE_COLOR_TARGET
+    // TODO(gw): There's quite a bit of code duplication here,
+    //           depending on which variation of brush image
+    //           this is being used for. This is because only
+    //           box-shadow pictures are currently supported
+    //           as texture cacheable items. Once we port the
+    //           drop-shadows and text-shadows to be cacheable,
+    //           most of this code can be merged together.
+#if defined WR_FEATURE_COLOR_TARGET || defined WR_FEATURE_COLOR_TARGET_ALPHA_MASK
+    BlurTask blur_task = fetch_blur_task(user_data.x);
+    vUv.z = blur_task.common_data.texture_layer_index;
     vec2 texture_size = vec2(textureSize(sColor0, 0).xy);
-#elif defined WR_FEATURE_COLOR_TARGET_ALPHA_MASK
-    vec2 texture_size = vec2(textureSize(sColor0, 0).xy);
-    vColor = blur_task.color;
-#else
-    vec2 texture_size = vec2(textureSize(sColor1, 0).xy);
+#if defined WR_FEATURE_COLOR_TARGET_ALPHA_MASK
     vColor = blur_task.color;
 #endif
-
     vec2 uv0 = blur_task.common_data.task_rect.p0;
     vec2 src_size = blur_task.common_data.task_rect.size * blur_task.scale_factor;
     vec2 uv1 = uv0 + blur_task.common_data.task_rect.size;
+#else
+    Picture pic = fetch_picture(prim_address);
+    ImageResource uv_rect = fetch_image_resource(user_data.x);
+    vec2 texture_size = vec2(textureSize(sColor1, 0).xy);
+    vColor = pic.color;
+    vec2 uv0 = uv_rect.uv_rect.xy;
+    vec2 uv1 = uv_rect.uv_rect.zw;
+    vec2 src_size = (uv1 - uv0) * uv_rect.user_data.x;
+    vUv.z = uv_rect.layer;
+#endif
 
     // TODO(gw): In the future we'll probably draw these as segments
     //           with the brush shader. When that occurs, we can

gfx/webrender/res/cs_blur.glsl

@@ -20,7 +20,6 @@ flat varying int vBlurRadius;
 in int aBlurRenderTaskAddress;
 in int aBlurSourceTaskAddress;
 in int aBlurDirection;
-in vec4 aBlurRegion;
 
 void main(void) {
     BlurTask blur_task = fetch_blur_task(aBlurRenderTaskAddress);
@@ -51,13 +50,6 @@ void main(void) {
                    src_rect.p0 + src_rect.size - vec2(0.5));
     vUvRect /= texture_size.xyxy;
 
-    if (aBlurRegion.z > 0.0) {
-        vec4 blur_region = aBlurRegion * uDevicePixelRatio;
-        src_rect = RectWithSize(src_rect.p0 + blur_region.xy, blur_region.zw);
-        target_rect.p0 = target_rect.p0 + blur_region.xy;
-        target_rect.size = blur_region.zw;
-    }
-
     vec2 pos = target_rect.p0 + target_rect.size * aPosition.xy;
 
     vec2 uv0 = src_rect.p0 / texture_size;

gfx/webrender/res/prim_shared.glsl

@@ -694,17 +694,18 @@ GlyphResource fetch_glyph_resource(int address) {
 struct ImageResource {
     vec4 uv_rect;
     float layer;
+    vec3 user_data;
 };
 
 ImageResource fetch_image_resource(int address) {
     //Note: number of blocks has to match `renderer::BLOCKS_PER_UV_RECT`
     vec4 data[2] = fetch_from_resource_cache_2(address);
-    return ImageResource(data[0], data[1].x);
+    return ImageResource(data[0], data[1].x, data[1].yzw);
 }
 
 ImageResource fetch_image_resource_direct(ivec2 address) {
     vec4 data[2] = fetch_from_resource_cache_2_direct(address);
-    return ImageResource(data[0], data[1].x);
+    return ImageResource(data[0], data[1].x, data[1].yzw);
 }
 
 struct TextRun {

gfx/webrender/res/shared_border.glsl

@@ -47,7 +47,7 @@ vec4 get_effective_border_widths(Border border, int style) {
             // for now - we can adjust this if we find other browsers pick
             // different values in some cases.
             // SEE: https://drafts.csswg.org/css-backgrounds-3/#double
-            return floor(0.5 + border.widths / 3.0);
+            return max(floor(0.5 + border.widths / 3.0), 1.0);
         case BORDER_STYLE_GROOVE:
         case BORDER_STYLE_RIDGE:
             return floor(0.5 + border.widths * 0.5);

gfx/webrender/src/batch.rs

@@ -2,11 +2,11 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use api::{DeviceIntRect, DeviceIntSize, ImageKey, LayerToWorldScale};
+use api::{AlphaType, DeviceIntRect, DeviceIntSize, ImageKey, LayerToWorldScale};
 use api::{ExternalImageType, FilterOp, ImageRendering, LayerRect};
 use api::{SubpixelDirection, TileOffset, YuvColorSpace, YuvFormat};
 use api::{LayerToWorldTransform, WorldPixel};
-use border::{BorderCornerInstance, BorderCornerSide};
+use border::{BorderCornerInstance, BorderCornerSide, BorderEdgeKind};
 use clip::{ClipSource, ClipStore};
 use clip_scroll_tree::{CoordinateSystemId};
 use euclid::{TypedTransform3D, vec3};
@@ -16,10 +16,10 @@ use gpu_types::{BrushImageKind, BrushInstance, ClipChainRectIndex};
 use gpu_types::{ClipMaskInstance, ClipScrollNodeIndex, PictureType};
 use gpu_types::{CompositePrimitiveInstance, PrimitiveInstance, SimplePrimitiveInstance};
 use internal_types::{FastHashMap, SourceTexture};
-use picture::{PictureCompositeMode, PictureKind, PicturePrimitive};
+use picture::{PictureCompositeMode, PictureKind, PicturePrimitive, PictureSurface};
 use plane_split::{BspSplitter, Polygon, Splitter};
 use prim_store::{PrimitiveIndex, PrimitiveKind, PrimitiveMetadata, PrimitiveStore};
-use prim_store::{BrushPrimitive, BrushKind, DeferredResolve, PrimitiveRun};
+use prim_store::{BrushPrimitive, BrushKind, DeferredResolve, EdgeAaSegmentMask, PrimitiveRun};
 use render_task::{ClipWorkItem};
 use render_task::{RenderTaskAddress, RenderTaskId, RenderTaskKind};
 use render_task::{RenderTaskTree};
@@ -109,7 +109,7 @@ impl BatchTextures {
 
     pub fn color(texture: SourceTexture) -> Self {
         BatchTextures {
-            colors: [texture, SourceTexture::Invalid, SourceTexture::Invalid],
+            colors: [texture, texture, SourceTexture::Invalid],
         }
     }
 }
@@ -344,6 +344,7 @@ impl BatchList {
                 self.opaque_batch_list
                     .get_suitable_batch(key, item_bounding_rect)
             }
+            BlendMode::Alpha |
             BlendMode::PremultipliedAlpha |
             BlendMode::PremultipliedDestOut |
             BlendMode::SubpixelConstantTextColor(..) |
@@ -365,7 +366,6 @@ impl BatchList {
 pub struct AlphaBatcher {
     pub batch_list: BatchList,
     pub text_run_cache_prims: FastHashMap<SourceTexture, Vec<PrimitiveInstance>>,
-    pub line_cache_prims: Vec<PrimitiveInstance>,
     glyph_fetch_buffer: Vec<GlyphFetchResult>,
 }
 
@@ -375,7 +375,6 @@ impl AlphaBatcher {
             batch_list: BatchList::new(screen_size),
             glyph_fetch_buffer: Vec::new(),
             text_run_cache_prims: FastHashMap::default(),
-            line_cache_prims: Vec::new(),
         }
     }
 
@@ -468,7 +467,12 @@ impl AlphaBatcher {
             let pic_metadata = &ctx.prim_store.cpu_metadata[prim_index.0];
             let pic = &ctx.prim_store.cpu_pictures[pic_metadata.cpu_prim_index.0];
             let batch = self.batch_list.get_suitable_batch(key, pic_metadata.screen_rect.as_ref().expect("bug"));
-            let source_task_address = render_tasks.get_task_address(pic.render_task_id.expect("bug"));
+
+            let render_task_id = match pic.surface {
+                Some(PictureSurface::RenderTask(render_task_id)) => render_task_id,
+                Some(PictureSurface::TextureCache(..)) | None => panic!("BUG: unexpected surface in splitting"),
+            };
+            let source_task_address = render_tasks.get_task_address(render_task_id);
             let gpu_address = gpu_handle.as_int(gpu_cache);
 
             let instance = CompositePrimitiveInstance::new(
@@ -646,37 +650,13 @@ impl AlphaBatcher {
                 }
 
                 let batch = self.batch_list.get_suitable_batch(edge_key, item_bounding_rect);
-                for border_segment in 0 .. 4 {
-                    batch.push(base_instance.build(border_segment, 0, 0));
+                for (border_segment, instance_kind) in border_cpu.edges.iter().enumerate() {
+                    match *instance_kind {
+                        BorderEdgeKind::None => {},
+                        _ => {
+                          batch.push(base_instance.build(border_segment as i32, 0, 0));
                         }
                     }
-            PrimitiveKind::Line => {
-                let base_instance = BrushInstance {
-                    picture_address: task_address,
-                    prim_address: prim_cache_address,
-                    clip_chain_rect_index,
-                    scroll_id,
-                    clip_task_address,
-                    z,
-                    segment_index: 0,
-                    user_data0: 0,
-                    user_data1: 0,
-                };
-
-                let instance = PrimitiveInstance::from(base_instance);
-
-                match pic_type {
-                    PictureType::TextShadow => {
-                        self.line_cache_prims.push(instance);
-                    }
-                    PictureType::Image => {
-                        let kind =
-                            BatchKind::Brush(BrushBatchKind::Line);
-                        let key = BatchKey::new(kind, blend_mode, no_textures);
-                        let batch = self.batch_list.get_suitable_batch(key, item_bounding_rect);
-                        batch.push(instance);
-                    }
-                    PictureType::BoxShadow => unreachable!(),
                 }
             }
             PrimitiveKind::Image => {
@@ -806,7 +786,7 @@ impl AlphaBatcher {
                                     } else if ctx.use_dual_source_blending {
                                         BlendMode::SubpixelDualSource
                                     } else {
-                                        BlendMode::SubpixelConstantTextColor(text_cpu.font.color.into())
+                                        BlendMode::SubpixelConstantTextColor(text_cpu.get_color())
                                     }
                                 }
                                 GlyphFormat::Alpha |
@@ -833,8 +813,39 @@ impl AlphaBatcher {
                 let picture =
                     &ctx.prim_store.cpu_pictures[prim_metadata.cpu_prim_index.0];
 
-                match picture.render_task_id {
-                    Some(cache_task_id) => {
+                match picture.surface {
+                    Some(PictureSurface::TextureCache(ref cache_item)) => {
+                        match picture.kind {
+                            PictureKind::TextShadow { .. } |
+                            PictureKind::Image { .. } => {
+                                panic!("BUG: only supported as render tasks for now");
+                            }
+                            PictureKind::BoxShadow { image_kind, .. } => {
+                                let textures = BatchTextures::color(cache_item.texture_id);
+                                let kind = BatchKind::Brush(
+                                    BrushBatchKind::Image(
+                                        BrushImageSourceKind::from_render_target_kind(picture.target_kind())),
+                                );
+                                let key = BatchKey::new(kind, blend_mode, textures);
+                                let batch = self.batch_list.get_suitable_batch(key, item_bounding_rect);
+
+                                let instance = BrushInstance {
+                                    picture_address: task_address,
+                                    prim_address: prim_cache_address,
+                                    clip_chain_rect_index,
+                                    scroll_id,
+                                    clip_task_address,
+                                    z,
+                                    segment_index: 0,
+                                    edge_flags: EdgeAaSegmentMask::empty(),
+                                    user_data0: cache_item.uv_rect_handle.as_int(gpu_cache),
+                                    user_data1: image_kind as i32,
+                                };
+                                batch.push(PrimitiveInstance::from(instance));
+                            }
+                        }
+                    }
+                    Some(PictureSurface::RenderTask(cache_task_id)) => {
                         let cache_task_address = render_tasks.get_task_address(cache_task_id);
                         let textures = BatchTextures::render_target_cache();
 
@@ -855,31 +866,14 @@ impl AlphaBatcher {
                                     clip_task_address,
                                     z,
                                     segment_index: 0,
+                                    edge_flags: EdgeAaSegmentMask::empty(),
                                     user_data0: cache_task_address.0 as i32,
                                     user_data1: BrushImageKind::Simple as i32,
                                 };
                                 batch.push(PrimitiveInstance::from(instance));
                             }
-                            PictureKind::BoxShadow { image_kind, .. } => {
-                                let kind = BatchKind::Brush(
-                                    BrushBatchKind::Image(
-                                        BrushImageSourceKind::from_render_target_kind(picture.target_kind())),
-                                );
-                                let key = BatchKey::new(kind, blend_mode, textures);
-                                let batch = self.batch_list.get_suitable_batch(key, item_bounding_rect);
-
-                                let instance = BrushInstance {
-                                    picture_address: task_address,
-                                    prim_address: prim_cache_address,
-                                    clip_chain_rect_index,
-                                    scroll_id,
-                                    clip_task_address,
-                                    z,
-                                    segment_index: 0,
-                                    user_data0: cache_task_address.0 as i32,
-                                    user_data1: image_kind as i32,
-                                };
-                                batch.push(PrimitiveInstance::from(instance));
+                            PictureKind::BoxShadow { .. } => {
+                                panic!("BUG: should be handled as a texture cache surface");
                             }
                             PictureKind::Image {
                                 composite_mode,
@@ -914,7 +908,7 @@ impl AlphaBatcher {
                                 // This will allow us to unify some of the shaders, apply clip masks
                                 // when compositing pictures, and also correctly apply pixel snapping
                                 // to picture compositing operations.
-                                let source_id = picture.render_task_id.expect("no source!?");
+                                let source_id = cache_task_id;
 
                                 match composite_mode.expect("bug: only composites here") {
                                     PictureCompositeMode::Filter(filter) => {
@@ -954,6 +948,7 @@ impl AlphaBatcher {
                                                     clip_task_address,
                                                     z,
                                                     segment_index: 0,
+                                                    edge_flags: EdgeAaSegmentMask::empty(),
                                                     user_data0: cache_task_address.0 as i32,
                                                     user_data1: BrushImageKind::Simple as i32,
                                                 };
@@ -1244,6 +1239,7 @@ impl AlphaBatcher {
             clip_task_address,
             z,
             segment_index: 0,
+            edge_flags: EdgeAaSegmentMask::empty(),
             user_data0: 0,
             user_data1: 0,
         };
@@ -1275,6 +1271,7 @@ impl AlphaBatcher {
 
                     let instance = PrimitiveInstance::from(BrushInstance {
                         segment_index: i as i32,
+                        edge_flags: segment.edge_flags,
                         clip_task_address,
                         ..base_instance
                     });
@@ -1297,6 +1294,13 @@ impl AlphaBatcher {
 impl BrushPrimitive {
     fn get_batch_key(&self, blend_mode: BlendMode) -> BatchKey {
         match self.kind {
+            BrushKind::Line { .. } => {
+                BatchKey::new(
+                    BatchKind::Brush(BrushBatchKind::Line),
+                    blend_mode,
+                    BatchTextures::no_texture(),
+                )
+            }
             BrushKind::Solid { .. } => {
                 BatchKey::new(
                     BatchKind::Brush(BrushBatchKind::Solid),
@@ -1339,18 +1343,25 @@ impl AlphaBatchHelpers for PrimitiveStore {
             // Can only resolve the TextRun's blend mode once glyphs are fetched.
             PrimitiveKind::TextRun => BlendMode::PremultipliedAlpha,
             PrimitiveKind::Border |
-            PrimitiveKind::Image |
             PrimitiveKind::YuvImage |
             PrimitiveKind::AlignedGradient |
             PrimitiveKind::AngleGradient |
             PrimitiveKind::RadialGradient |
-            PrimitiveKind::Line |
             PrimitiveKind::Brush |
             PrimitiveKind::Picture => if needs_blending {
                 BlendMode::PremultipliedAlpha
             } else {
                 BlendMode::None
             },
+            PrimitiveKind::Image => if needs_blending {
+                let image_cpu = &self.cpu_images[metadata.cpu_prim_index.0];
+                match image_cpu.alpha_type {
+                    AlphaType::PremultipliedAlpha => BlendMode::PremultipliedAlpha,
+                    AlphaType::Alpha => BlendMode::Alpha,
+                }
+            } else {
+                BlendMode::None
+            },
         }
     }
 }

gfx/webrender/src/border.rs

@@ -149,6 +149,14 @@ impl NormalBorderHelpers for NormalBorder {
                 BorderCornerKind::None
             }
 
+            // If one of the edges is none or hidden, we just draw one style.
+            (BorderStyle::None, _) |
+            (_, BorderStyle::None) |
+            (BorderStyle::Hidden, _) |
+            (_, BorderStyle::Hidden) => {
+                BorderCornerKind::Clip(BorderCornerInstance::Single)
+            }
+
             // If both borders are solid, we can draw them with a simple rectangle if
             // both the colors match and there is no radius.
             (BorderStyle::Solid, BorderStyle::Solid) => {
@@ -237,12 +245,12 @@ pub fn ensure_no_corner_overlap(
     let bottom_right_radius = &mut radius.bottom_right;
     let bottom_left_radius = &mut radius.bottom_left;
 
-    let sum = top_left_radius.width + bottom_left_radius.width;
+    let sum = top_left_radius.width + top_right_radius.width;
     if rect.size.width < sum {
         ratio = f32::min(ratio, rect.size.width / sum);
     }
 
-    let sum = top_right_radius.width + bottom_right_radius.width;
+    let sum = bottom_left_radius.width + bottom_right_radius.width;
     if rect.size.width < sum {
         ratio = f32::min(ratio, rect.size.width / sum);
     }
@@ -280,6 +288,7 @@ impl FrameBuilder {
         widths: &BorderWidths,
         clip_and_scroll: ClipAndScrollInfo,
         corner_instances: [BorderCornerInstance; 4],
+        edges: [BorderEdgeKind; 4],
         clip_sources: Vec<ClipSource>,
     ) {
         let radius = &border.radius;
@@ -296,6 +305,7 @@ impl FrameBuilder {
 
         let prim_cpu = BorderPrimitiveCpu {
             corner_instances,
+            edges,
 
             // TODO(gw): In the future, we will build these on demand
             //           from the deserialized display list, rather
@@ -536,6 +546,7 @@ impl FrameBuilder {
                 widths,
                 clip_and_scroll,
                 corner_instances,
+                edges,
                 extra_clips,
             );
         }

gfx/webrender/src/box_shadow.rs

@@ -83,6 +83,9 @@ impl FrameBuilder {
             .inflate(spread_amount, spread_amount);
 
         if blur_radius == 0.0 {
+            if box_offset.x == 0.0 && box_offset.y == 0.0 && spread_amount == 0.0 {
+                return;
+            }
             let mut clips = Vec::new();
 
             let fast_info = match clip_mode {
@@ -242,7 +245,6 @@ impl FrameBuilder {
                     let mut pic_prim = PicturePrimitive::new_box_shadow(
                         blur_radius,
                         *color,
-                        Vec::new(),
                         clip_mode,
                         image_kind,
                         cache_key,
@@ -301,7 +303,7 @@ impl FrameBuilder {
                         inflate_size *= 2.0;
                     }
 
-                    let brush_rect = brush_rect.inflate(inflate_size, inflate_size);
+                    let brush_rect = brush_rect.inflate(inflate_size + box_offset.x.abs(), inflate_size + box_offset.y.abs());
                     let brush_prim = BrushPrimitive::new(
                         BrushKind::Mask {
                             clip_mode: brush_clip_mode,
@@ -321,7 +323,6 @@ impl FrameBuilder {
                     let mut pic_prim = PicturePrimitive::new_box_shadow(
                         blur_radius,
                         *color,
-                        Vec::new(),
                         BoxShadowClipMode::Inset,
                         // TODO(gw): Make use of optimization for inset.
                         BrushImageKind::NinePatch,
@@ -337,7 +338,7 @@ impl FrameBuilder {
                     // rect to account for the inflate above. This
                     // extra edge will be clipped by the local clip
                     // rect set below.
-                    let pic_rect = prim_info.rect.inflate(inflate_size, inflate_size);
+                    let pic_rect = prim_info.rect.inflate(inflate_size + box_offset.x.abs(), inflate_size + box_offset.y.abs());
                     let pic_info = LayerPrimitiveInfo::with_clip_rect(
                         pic_rect,
                         prim_info.rect

gfx/webrender/src/clip_scroll_node.rs

@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use api::{ClipId, DeviceIntRect, DevicePixelScale, LayerPixel, LayerPoint, LayerRect, LayerSize};
+use api::{ClipId, DevicePixelScale, LayerPixel, LayerPoint, LayerRect, LayerSize};
 use api::{LayerToWorldTransform, LayerTransform, LayerVector2D, LayoutTransform, LayoutVector2D};
 use api::{PipelineId, PropertyBinding, ScrollClamping, ScrollEventPhase, ScrollLocation};
 use api::{ScrollSensitivity, StickyOffsetBounds, WorldPoint};
@@ -12,11 +12,10 @@ use euclid::SideOffsets2D;
 use geometry::ray_intersects_rect;
 use gpu_cache::GpuCache;
 use gpu_types::{ClipScrollNodeIndex, ClipScrollNodeData};
-use render_task::{ClipChain, ClipChainNode, ClipWorkItem};
+use render_task::{ClipChain, ClipWorkItem};
 use resource_cache::ResourceCache;
 use scene::SceneProperties;
 use spring::{DAMPING, STIFFNESS, Spring};
-use std::rc::Rc;
 use util::{MatrixHelpers, TransformOrOffset, TransformedRectKind};
 
 #[cfg(target_os = "macos")]
@@ -107,10 +106,8 @@ pub struct ClipScrollNode {
     /// The type of this node and any data associated with that node type.
     pub node_type: NodeType,
 
-    /// The node in the chain of clips that are necessary to clip display items
-    /// that have this ClipScrollNode as their clip parent. This will be used to
-    /// generate clip tasks.
-    pub clip_chain_node: ClipChain,
+    /// The ClipChain that will be used if this node is used as the 'clipping node.'
+    pub clip_chain: Option<ClipChain>,
 
     /// True if this node is transformed by an invertible transform.  If not, display items
     /// transformed by this node will not be displayed and display items not transformed by this
@@ -145,7 +142,7 @@ impl ClipScrollNode {
             children: Vec::new(),
             pipeline_id,
             node_type: node_type,
-            clip_chain_node: None,
+            clip_chain: None,
             invertible: true,
             coordinate_system_id: CoordinateSystemId(0),
             coordinate_system_relative_transform: TransformOrOffset::zero(),
@@ -272,7 +269,7 @@ impl ClipScrollNode {
         self.invertible = false;
         self.world_content_transform = LayerToWorldTransform::identity();
         self.world_viewport_transform = LayerToWorldTransform::identity();
-        self.clip_chain_node = None;
+        self.clip_chain = None;
     }
 
     pub fn push_gpu_node_data(&mut self, node_data: &mut Vec<ClipScrollNodeData>) {
@@ -300,7 +297,6 @@ impl ClipScrollNode {
         &mut self,
         state: &mut TransformUpdateState,
         next_coordinate_system_id: &mut CoordinateSystemId,
-        screen_rect: &DeviceIntRect,
         device_pixel_scale: DevicePixelScale,
         clip_store: &mut ClipStore,
         resource_cache: &mut ResourceCache,
@@ -329,7 +325,6 @@ impl ClipScrollNode {
 
         self.update_clip_work_item(
             state,
-            screen_rect,
             device_pixel_scale,
             clip_store,
             resource_cache,
@@ -340,21 +335,15 @@ impl ClipScrollNode {
     pub fn update_clip_work_item(
         &mut self,
         state: &mut TransformUpdateState,
-        screen_rect: &DeviceIntRect,
         device_pixel_scale: DevicePixelScale,
         clip_store: &mut ClipStore,
         resource_cache: &mut ResourceCache,
         gpu_cache: &mut GpuCache,
     ) {
-        let current_clip_chain = state.parent_clip_chain.clone();
-        let combined_outer_screen_rect = current_clip_chain.as_ref().map_or(
-            *screen_rect, |clip| clip.combined_outer_screen_rect,
-        );
-
         let clip_sources_handle = match self.node_type {
             NodeType::Clip(ref handle) => handle,
             _ => {
-                self.clip_chain_node = current_clip_chain.clone();
+                self.clip_chain = Some(state.parent_clip_chain.clone());
                 self.invertible = true;
                 return;
             }
@@ -376,8 +365,8 @@ impl ClipScrollNode {
         // If this clip's inner rectangle completely surrounds the existing clip
         // chain's outer rectangle, we can discard this clip entirely since it isn't
         // going to affect anything.
-        if screen_inner_rect.contains_rect(&combined_outer_screen_rect) {
-            self.clip_chain_node = current_clip_chain;
+        if screen_inner_rect.contains_rect(&state.parent_clip_chain.combined_outer_screen_rect) {
+            self.clip_chain = Some(state.parent_clip_chain.clone());
             return;
         }
 
@@ -387,16 +376,15 @@ impl ClipScrollNode {
             coordinate_system_id: state.current_coordinate_system_id,
         };
 
-        let clip_chain_node = ClipChainNode::new(
+        let clip_chain = state.parent_clip_chain.new_with_added_node(
             work_item,
             self.coordinate_system_relative_transform.apply(&local_outer_rect),
             screen_outer_rect,
             screen_inner_rect,
-            current_clip_chain
         );
 
-        self.clip_chain_node = Some(Rc::new(clip_chain_node));
-        state.parent_clip_chain = self.clip_chain_node.clone();
+        self.clip_chain = Some(clip_chain.clone());
+        state.parent_clip_chain = clip_chain;
     }
 
     pub fn update_transform(
@@ -613,7 +601,6 @@ impl ClipScrollNode {
     pub fn prepare_state_for_children(&self, state: &mut TransformUpdateState) {
         if !self.invertible {
             state.invertible = false;
-            state.parent_clip_chain = None;
             return;
         }
 
@@ -778,16 +765,6 @@ impl ClipScrollNode {
             _ => false,
         }
     }
-
-    pub fn is_visible(&self) -> bool {
-        if !self.invertible {
-            return false;
-        }
-        match self.clip_chain_node {
-            Some(ref node) if node.combined_outer_screen_rect.is_empty() => false,
-            _ => true,
-        }
-    }
 }
 
 #[derive(Copy, Clone, Debug)]

gfx/webrender/src/clip_scroll_tree.rs

@@ -2,9 +2,9 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use api::{ClipId, DeviceIntRect, DevicePixelScale, LayerPoint, LayerRect};
-use api::{LayerToWorldTransform, LayerVector2D, PipelineId, ScrollClamping, ScrollEventPhase};
-use api::{PropertyBinding, LayoutTransform, ScrollLayerState, ScrollLocation, WorldPoint};
+use api::{ClipId, ClipChainId, DeviceIntRect, DevicePixelScale, LayerPoint, LayerRect};
+use api::{LayerToWorldTransform, LayerVector2D, LayoutTransform, PipelineId, PropertyBinding};
+use api::{ScrollClamping, ScrollEventPhase, ScrollLayerState, ScrollLocation, WorldPoint};
 use clip::ClipStore;
 use clip_scroll_node::{ClipScrollNode, NodeType, ScrollingState, StickyFrameInfo};
 use gpu_cache::GpuCache;
@@ -40,8 +40,23 @@ impl CoordinateSystemId {
     }
 }
 
+struct ClipChainDescriptor {
+    id: ClipChainId,
+    parent: Option<ClipChainId>,
+    clips: Vec<ClipId>,
+}
+
 pub struct ClipScrollTree {
     pub nodes: FastHashMap<ClipId, ClipScrollNode>,
+
+    /// A Vec of all descriptors that describe ClipChains in the order in which they are
+    /// encountered during display list flattening. ClipChains are expected to never be
+    /// the children of ClipChains later in the list.
+    clip_chains_descriptors: Vec<ClipChainDescriptor>,
+
+    /// A HashMap of built ClipChains that are described by `clip_chains_descriptors`.
+    pub clip_chains: FastHashMap<ClipChainId, ClipChain>,
+
     pub pending_scroll_offsets: FastHashMap<ClipId, (LayerPoint, ScrollClamping)>,
 
     /// The ClipId of the currently scrolling node. Used to allow the same
@@ -94,6 +109,8 @@ impl ClipScrollTree {
         let dummy_pipeline = PipelineId::dummy();
         ClipScrollTree {
             nodes: FastHashMap::default(),
+            clip_chains_descriptors: Vec::new(),
+            clip_chains: FastHashMap::default(),
             pending_scroll_offsets: FastHashMap::default(),
             currently_scrolling_node_id: None,
             root_reference_frame_id: ClipId::root_reference_frame(dummy_pipeline),
@@ -243,6 +260,8 @@ impl ClipScrollTree {
         }
 
         self.pipelines_to_discard.clear();
+        self.clip_chains.clear();
+        self.clip_chains_descriptors.clear();
         scroll_states
     }
 
@@ -359,7 +378,7 @@ impl ClipScrollTree {
             parent_accumulated_scroll_offset: LayerVector2D::zero(),
             nearest_scrolling_ancestor_offset: LayerVector2D::zero(),
             nearest_scrolling_ancestor_viewport: LayerRect::zero(),
-            parent_clip_chain: None,
+            parent_clip_chain: ClipChain::empty(screen_rect),
             current_coordinate_system_id: CoordinateSystemId::root(),
             coordinate_system_relative_transform: TransformOrOffset::zero(),
             invertible: true,
@@ -369,7 +388,6 @@ impl ClipScrollTree {
             root_reference_frame_id,
             &mut state,
             &mut next_coordinate_system_id,
-            screen_rect,
             device_pixel_scale,
             clip_store,
             resource_cache,
@@ -377,6 +395,8 @@ impl ClipScrollTree {
             node_data,
             scene_properties,
         );
+
+        self.build_clip_chains(screen_rect);
     }
 
     fn update_node(
@@ -384,7 +404,6 @@ impl ClipScrollTree {
         layer_id: ClipId,
         state: &mut TransformUpdateState,
         next_coordinate_system_id: &mut CoordinateSystemId,
-        screen_rect: &DeviceIntRect,
         device_pixel_scale: DevicePixelScale,
         clip_store: &mut ClipStore,
         resource_cache: &mut ResourceCache,
@@ -407,7 +426,6 @@ impl ClipScrollTree {
             node.update(
                 &mut state,
                 next_coordinate_system_id,
-                screen_rect,
                 device_pixel_scale,
                 clip_store,
                 resource_cache,
@@ -421,7 +439,6 @@ impl ClipScrollTree {
                 return;
             }
 
-
             node.prepare_state_for_children(&mut state);
             node.children.clone()
         };
@@ -431,7 +448,6 @@ impl ClipScrollTree {
                 child_node_id,
                 &mut state,
                 next_coordinate_system_id,
-                screen_rect,
                 device_pixel_scale,
                 clip_store,
                 resource_cache,
@@ -442,6 +458,25 @@ impl ClipScrollTree {
         }
     }
 
+    pub fn build_clip_chains(&mut self, screen_rect: &DeviceIntRect) {
+        for descriptor in &self.clip_chains_descriptors {
+            let mut chain = match descriptor.parent {
+                Some(id) => self.clip_chains[&id].clone(),
+                None => ClipChain::empty(screen_rect),
+            };
+
+            for clip_id in &descriptor.clips {
+                if let Some(ref node_chain) = self.nodes[&clip_id].clip_chain {
+                    if let Some(ref nodes) = node_chain.nodes {
+                        chain.add_node((**nodes).clone());
+                    }
+                }
+            }
+
+            self.clip_chains.insert(descriptor.id, chain);
+        }
+    }
+
     pub fn tick_scrolling_bounce_animations(&mut self) {
         for (_, node) in &mut self.nodes {
             node.tick_scrolling_bounce_animation()
@@ -512,6 +547,15 @@ impl ClipScrollTree {
         self.add_node(node, id);
     }
 
+    pub fn add_clip_chain_descriptor(
+        &mut self,
+        id: ClipChainId,
+        parent: Option<ClipChainId>,
+        clips: Vec<ClipId>
+    ) {
+        self.clip_chains_descriptors.push(ClipChainDescriptor { id, parent, clips });
+    }
+
     pub fn add_node(&mut self, node: ClipScrollNode, id: ClipId) {
         // When the parent node is None this means we are adding the root.
         match node.parent {
@@ -612,4 +656,12 @@ impl ClipScrollTree {
                    .unwrap_or_else(|| WorldPoint::new(point.x, point.y))
 
     }
+
+    pub fn get_clip_chain(&self, id: &ClipId) -> Option<&ClipChain> {
+        match id {
+            &ClipId::ClipChain(clip_chain_id) => Some(&self.clip_chains[&clip_chain_id]),
+            _ => self.nodes[id].clip_chain.as_ref(),
+        }
+    }
+
 }

gfx/webrender/src/debug_render.rs

@@ -121,7 +121,7 @@ impl DebugRenderer {
             &mut font_texture,
             debug_font_data::BMP_WIDTH,
             debug_font_data::BMP_HEIGHT,
-            ImageFormat::A8,
+            ImageFormat::R8,
             TextureFilter::Linear,
             None,
             1,

gfx/webrender/src/device.rs

@@ -12,7 +12,6 @@ use smallvec::SmallVec;
 use std::cell::RefCell;
 use std::fs::File;
 use std::io::Read;
-use std::iter::repeat;
 use std::marker::PhantomData;
 use std::mem;
 use std::ops::Add;
@@ -21,6 +20,11 @@ use std::ptr;
 use std::rc::Rc;
 use std::thread;
 
+// Apparently, in some cases calling `glTexImage3D` with
+// similar parameters that the texture already has confuses
+// Angle when running with optimizations.
+const WORK_AROUND_TEX_IMAGE: bool = cfg!(windows);
+
 #[derive(Debug, Copy, Clone, PartialEq, Ord, Eq, PartialOrd)]
 pub struct FrameId(usize);
 
@@ -38,12 +42,6 @@ impl Add<usize> for FrameId {
     }
 }
 
-#[cfg(not(any(target_arch = "arm", target_arch = "aarch64")))]
-const GL_FORMAT_A: gl::GLuint = gl::RED;
-
-#[cfg(any(target_arch = "arm", target_arch = "aarch64"))]
-const GL_FORMAT_A: gl::GLuint = gl::ALPHA;
-
 const GL_FORMAT_BGRA_GL: gl::GLuint = gl::BGRA;
 
 const GL_FORMAT_BGRA_GLES: gl::GLuint = gl::BGRA_EXT;
@@ -457,7 +455,7 @@ impl Texture {
 
     pub fn get_bpp(&self) -> u32 {
         match self.format {
-            ImageFormat::A8 => 1,
+            ImageFormat::R8 => 1,
             ImageFormat::BGRA8 => 4,
             ImageFormat::RG8 => 2,
             ImageFormat::RGBAF32 => 16,
@@ -468,6 +466,10 @@ impl Texture {
     pub fn has_depth(&self) -> bool {
         self.depth_rb.is_some()
     }
+
+    pub fn get_rt_info(&self) -> Option<&RenderTargetInfo> {
+        self.render_target.as_ref()
+    }
 }
 
 impl Drop for Texture {
@@ -962,7 +964,7 @@ impl Device {
 
         self.bind_texture(DEFAULT_TEXTURE, texture);
         self.set_texture_parameters(texture.target, texture.filter);
-        self.update_texture_storage(texture, &rt_info, true);
+        self.update_texture_storage(texture, &rt_info, true, false);
 
         let rect = DeviceIntRect::new(DeviceIntPoint::zero(), old_size.to_i32());
         for (read_fbo, &draw_fbo) in old_fbos.into_iter().zip(&texture.fbo_ids) {
@@ -984,13 +986,13 @@ impl Device {
         filter: TextureFilter,
         render_target: Option<RenderTargetInfo>,
         layer_count: i32,
+
         pixels: Option<&[u8]>,
     ) {
         debug_assert!(self.inside_frame);
 
-        let resized = texture.width != width ||
-            texture.height != height ||
-            texture.format != format;
+        let is_resized = texture.width != width || texture.height != height;
+        let is_format_changed = texture.format != format;
 
         texture.format = format;
         texture.width = width;
@@ -1005,26 +1007,12 @@ impl Device {
         match render_target {
             Some(info) => {
                 assert!(pixels.is_none());
-                self.update_texture_storage(texture, &info, resized);
+                self.update_texture_storage(texture, &info, is_resized, is_format_changed);
             }
             None => {
                 let (internal_format, gl_format) = gl_texture_formats_for_image_format(self.gl(), format);
                 let type_ = gl_type_for_texture_format(format);
 
-                let expanded_data: Vec<u8>;
-                let actual_pixels = if pixels.is_some() && format == ImageFormat::A8 &&
-                    cfg!(any(target_arch = "arm", target_arch = "aarch64"))
-                {
-                    expanded_data = pixels
-                        .unwrap()
-                        .iter()
-                        .flat_map(|&byte| repeat(byte).take(4))
-                        .collect();
-                    Some(expanded_data.as_slice())
-                } else {
-                    pixels
-                };
-
                 match texture.target {
                     gl::TEXTURE_2D_ARRAY => {
                         self.gl.tex_image_3d(
@@ -1037,7 +1025,7 @@ impl Device {
                             0,
                             gl_format,
                             type_,
-                            actual_pixels,
+                            pixels,
                         );
                     }
                     gl::TEXTURE_2D | gl::TEXTURE_RECTANGLE | gl::TEXTURE_EXTERNAL_OES => {
@@ -1050,7 +1038,7 @@ impl Device {
                             0,
                             gl_format,
                             type_,
-                            actual_pixels,
+                            pixels,
                         );
                     }
                     _ => panic!("BUG: Unexpected texture target!"),
@@ -1065,11 +1053,12 @@ impl Device {
         texture: &mut Texture,
         rt_info: &RenderTargetInfo,
         is_resized: bool,
+        is_format_changed: bool,
     ) {
         assert!(texture.layer_count > 0);
 
         let needed_layer_count = texture.layer_count - texture.fbo_ids.len() as i32;
-        let allocate_color = needed_layer_count != 0 || is_resized;
+        let allocate_color = needed_layer_count != 0 || is_resized || is_format_changed;
 
         if allocate_color {
             let (internal_format, gl_format) =
@@ -1078,6 +1067,19 @@ impl Device {
 
             match texture.target {
                 gl::TEXTURE_2D_ARRAY => {
+                    if WORK_AROUND_TEX_IMAGE {
+                        // reset the contents before resizing
+                        self.gl.tex_image_3d(
+                            texture.target,
+                            0,
+                            gl::RGBA32F as _,
+                            2, 2, 1,
+                            0,
+                            gl::RGBA,
+                            gl::FLOAT,
+                            None,
+                        )
+                    }
                     self.gl.tex_image_3d(
                         texture.target,
                         0,
@@ -1138,8 +1140,8 @@ impl Device {
                 self.gl.renderbuffer_storage(
                     gl::RENDERBUFFER,
                     gl::DEPTH_COMPONENT24,
-                    texture.width as gl::GLsizei,
-                    texture.height as gl::GLsizei,
+                    texture.width as _,
+                    texture.height as _,
                 );
             } else {
                 self.gl.delete_renderbuffers(&[depth_rb]);
@@ -1149,6 +1151,7 @@ impl Device {
         }
 
         if allocate_color || allocate_depth {
+            let original_bound_fbo = self.bound_draw_fbo;
             for (fbo_index, &fbo_id) in texture.fbo_ids.iter().enumerate() {
                 self.bind_external_draw_target(fbo_id);
                 match texture.target {
@@ -1158,7 +1161,7 @@ impl Device {
                             gl::COLOR_ATTACHMENT0,
                             texture.id,
                             0,
-                            fbo_index as gl::GLint,
+                            fbo_index as _,
                         )
                     }
                     _ => {
@@ -1180,9 +1183,7 @@ impl Device {
                     depth_rb,
                 );
             }
-            // restore the previous FBO
-            let bound_fbo = self.bound_draw_fbo;
-            self.bind_external_draw_target(bound_fbo);
+            self.bind_external_draw_target(original_bound_fbo);
         }
     }
 
@@ -1859,6 +1860,12 @@ impl Device {
         }
     }
 
+    pub fn set_blend_mode_alpha(&self) {
+        self.gl.blend_func_separate(gl::SRC_ALPHA, gl::ONE_MINUS_SRC_ALPHA,
+                                    gl::ONE, gl::ONE);
+        self.gl.blend_equation(gl::FUNC_ADD);
+    }
+
     pub fn set_blend_mode_premultiplied_alpha(&self) {
         self.gl.blend_func(gl::ONE, gl::ONE_MINUS_SRC_ALPHA);
         self.gl.blend_equation(gl::FUNC_ADD);
@@ -1924,11 +1931,7 @@ fn gl_texture_formats_for_image_format(
     format: ImageFormat,
 ) -> (gl::GLint, gl::GLuint) {
     match format {
-        ImageFormat::A8 => if cfg!(any(target_arch = "arm", target_arch = "aarch64")) {
-            (get_gl_format_bgra(gl) as gl::GLint, get_gl_format_bgra(gl))
-        } else {
-            (GL_FORMAT_A as gl::GLint, GL_FORMAT_A)
-        },
+        ImageFormat::R8 => (gl::RED as gl::GLint, gl::RED),
         ImageFormat::BGRA8 => match gl.get_type() {
             gl::GlType::Gl => (gl::RGBA as gl::GLint, get_gl_format_bgra(gl)),
             gl::GlType::Gles => (get_gl_format_bgra(gl) as gl::GLint, get_gl_format_bgra(gl)),
@@ -2053,7 +2056,7 @@ impl<'a, T> TextureUploader<'a, T> {
 impl<'a> UploadTarget<'a> {
     fn update_impl(&mut self, chunk: UploadChunk) {
         let (gl_format, bpp, data_type) = match self.texture.format {
-            ImageFormat::A8 => (GL_FORMAT_A, 1, gl::UNSIGNED_BYTE),
+            ImageFormat::R8 => (gl::RED, 1, gl::UNSIGNED_BYTE),
             ImageFormat::BGRA8 => (get_gl_format_bgra(self.gl), 4, gl::UNSIGNED_BYTE),
             ImageFormat::RG8 => (gl::RG, 2, gl::UNSIGNED_BYTE),
             ImageFormat::RGBAF32 => (gl::RGBA, 16, gl::FLOAT),

gfx/webrender/src/frame.rs

@@ -74,6 +74,24 @@ impl<'a> FlattenContext<'a> {
             .collect()
     }
 
+    fn get_clip_chain_items(
+        &self,
+        pipeline_id: PipelineId,
+        items: ItemRange<ClipId>,
+    ) -> Vec<ClipId> {
+        if items.is_empty() {
+            return vec![];
+        }
+
+        self.scene
+            .pipelines
+            .get(&pipeline_id)
+            .expect("No display list?")
+            .display_list
+            .get(items)
+            .collect()
+    }
+
     fn flatten_root(
         &mut self,
         traversal: &mut BuiltDisplayListIter<'a>,
@@ -405,6 +423,7 @@ impl<'a> FlattenContext<'a> {
                             None,
                             info.image_key,
                             info.image_rendering,
+                            info.alpha_type,
                             None,
                         );
                     }
@@ -558,6 +577,10 @@ impl<'a> FlattenContext<'a> {
                     clip_region,
                 );
             }
+            SpecificDisplayItem::ClipChain(ref info) => {
+                let items = self.get_clip_chain_items(pipeline_id, item.clip_chain_items());
+                self.clip_scroll_tree.add_clip_chain_descriptor(info.id, info.parent, items);
+            },
             SpecificDisplayItem::ScrollFrame(ref info) => {
                 let complex_clips = self.get_complex_clips(pipeline_id, item.complex_clip().0);
                 let clip_region = ClipRegion::create_for_clip_node(
@@ -915,6 +938,7 @@ impl<'a> FlattenContext<'a> {
                 None,
                 info.image_key,
                 info.image_rendering,
+                info.alpha_type,
                 Some(tile_offset),
             );
         }

gfx/webrender/src/frame_builder.rs

@@ -2,8 +2,8 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use api::{BorderDetails, BorderDisplayItem, BuiltDisplayList, ClipAndScrollInfo, ClipId, ColorF};
-use api::{ColorU, DeviceIntPoint, DevicePixelScale, DeviceUintPoint, DeviceUintRect};
+use api::{AlphaType, BorderDetails, BorderDisplayItem, BuiltDisplayList, ClipAndScrollInfo, ClipId};
+use api::{ColorF, ColorU, DeviceIntPoint, DevicePixelScale, DeviceUintPoint, DeviceUintRect};
 use api::{DeviceUintSize, DocumentLayer, ExtendMode, FontRenderMode, GlyphInstance, GlyphOptions};
 use api::{GradientStop, HitTestFlags, HitTestItem, HitTestResult, ImageKey, ImageRendering};
 use api::{ItemRange, ItemTag, LayerPoint, LayerPrimitiveInfo, LayerRect, LayerSize};
@@ -22,19 +22,18 @@ use glyph_rasterizer::FontInstance;
 use gpu_cache::GpuCache;
 use gpu_types::{ClipScrollNodeData, PictureType};
 use internal_types::{FastHashMap, FastHashSet, RenderPassIndex};
-use picture::{ContentOrigin, PictureCompositeMode, PictureKind, PicturePrimitive};
+use picture::{ContentOrigin, PictureCompositeMode, PictureKind, PicturePrimitive, PictureSurface};
 use prim_store::{BrushKind, BrushPrimitive, TexelRect, YuvImagePrimitiveCpu};
-use prim_store::{GradientPrimitiveCpu, ImagePrimitiveCpu, LinePrimitive, PrimitiveKind};
+use prim_store::{GradientPrimitiveCpu, ImagePrimitiveCpu, PrimitiveKind};
 use prim_store::{PrimitiveContainer, PrimitiveIndex, SpecificPrimitiveIndex};
 use prim_store::{PrimitiveStore, RadialGradientPrimitiveCpu};
 use prim_store::{BrushSegmentDescriptor, TextRunPrimitiveCpu};
 use profiler::{FrameProfileCounters, GpuCacheProfileCounters, TextureCacheProfileCounters};
-use render_task::{ClearMode, RenderTask, RenderTaskId, RenderTaskTree};
+use render_task::{ClearMode, ClipChain, RenderTask, RenderTaskId, RenderTaskTree};
 use resource_cache::ResourceCache;
 use scene::{ScenePipeline, SceneProperties};
 use std::{mem, usize, f32};
-use tiling::{CompositeOps, Frame};
-use tiling::{RenderPass, RenderTargetKind};
+use tiling::{CompositeOps, Frame, RenderPass, RenderTargetKind};
 use tiling::{RenderTargetContext, ScrollbarPrimitive};
 use util::{self, MaxRect, pack_as_float, RectHelpers, recycle_vec};
 
@@ -129,7 +128,7 @@ pub struct FrameBuilder {
 pub struct PrimitiveContext<'a> {
     pub device_pixel_scale: DevicePixelScale,
     pub display_list: &'a BuiltDisplayList,
-    pub clip_node: &'a ClipScrollNode,
+    pub clip_chain: Option<&'a ClipChain>,
     pub scroll_node: &'a ClipScrollNode,
 }
 
@@ -137,13 +136,13 @@ impl<'a> PrimitiveContext<'a> {
     pub fn new(
         device_pixel_scale: DevicePixelScale,
         display_list: &'a BuiltDisplayList,
-        clip_node: &'a ClipScrollNode,
+        clip_chain: Option<&'a ClipChain>,
         scroll_node: &'a ClipScrollNode,
     ) -> Self {
         PrimitiveContext {
             device_pixel_scale,
             display_list,
-            clip_node,
+            clip_chain,
             scroll_node,
         }
     }
@@ -819,12 +818,15 @@ impl FrameBuilder {
         line_color: &ColorF,
         style: LineStyle,
     ) {
-        let line = LinePrimitive {
+        let line = BrushPrimitive::new(
+            BrushKind::Line {
                 wavy_line_thickness,
                 color: line_color.premultiplied(),
                 style,
                 orientation,
-        };
+            },
+            None,
+        );
 
         let mut fast_shadow_prims = Vec::new();
         for (idx, &(shadow_prim_index, _)) in self.shadow_prim_stack.iter().enumerate() {
@@ -839,14 +841,21 @@ impl FrameBuilder {
         }
 
         for (idx, shadow_offset, shadow_color) in fast_shadow_prims {
-            let mut line = line.clone();
-            line.color = shadow_color.premultiplied();
+            let line = BrushPrimitive::new(
+                BrushKind::Line {
+                    wavy_line_thickness,
+                    color: shadow_color.premultiplied(),
+                    style,
+                    orientation,
+                },
+                None,
+            );
             let mut info = info.clone();
             info.rect = info.rect.translate(&shadow_offset);
             let prim_index = self.create_primitive(
                 &info,
                 Vec::new(),
-                PrimitiveContainer::Line(line),
+                PrimitiveContainer::Brush(line),
             );
             self.shadow_prim_stack[idx].1.push((prim_index, clip_and_scroll));
         }
@@ -854,7 +863,7 @@ impl FrameBuilder {
         let prim_index = self.create_primitive(
             &info,
             Vec::new(),
-            PrimitiveContainer::Line(line),
+            PrimitiveContainer::Brush(line),
         );
 
         if line_color.a > 0.0 {
@@ -1088,6 +1097,7 @@ impl FrameBuilder {
                         Some(segment.sub_rect),
                         border.image_key,
                         ImageRendering::Auto,
+                        AlphaType::PremultipliedAlpha,
                         None,
                     );
                 }
@@ -1283,8 +1293,10 @@ impl FrameBuilder {
         let mut render_mode = self.config
             .default_font_render_mode
             .limit_by(font.render_mode);
+        let mut flags = font.flags;
         if let Some(options) = glyph_options {
             render_mode = render_mode.limit_by(options.render_mode);
+            flags |= options.flags;
         }
 
         // There are some conditions under which we can't use
@@ -1309,7 +1321,7 @@ impl FrameBuilder {
             font.bg_color,
             render_mode,
             font.subpx_dir,
-            font.flags,
+            flags,
             font.platform_options,
             font.variations.clone(),
         );
@@ -1411,6 +1423,7 @@ impl FrameBuilder {
         sub_rect: Option<TexelRect>,
         image_key: ImageKey,
         image_rendering: ImageRendering,
+        alpha_type: AlphaType,
         tile: Option<TileOffset>,
     ) {
         let sub_rect_block = sub_rect.unwrap_or(TexelRect::invalid()).into();
@@ -1430,6 +1443,7 @@ impl FrameBuilder {
             image_rendering,
             tile_offset: tile,
             tile_spacing,
+            alpha_type,
             gpu_blocks: [
                 [
                     stretch_size.width,
@@ -1582,7 +1596,7 @@ impl FrameBuilder {
         let root_prim_context = PrimitiveContext::new(
             device_pixel_scale,
             display_list,
-            root_clip_scroll_node,
+            root_clip_scroll_node.clip_chain.as_ref(),
             root_clip_scroll_node,
         );
 
@@ -1620,12 +1634,12 @@ impl FrameBuilder {
             PremultipliedColorF::TRANSPARENT,
             ClearMode::Transparent,
             child_tasks,
-            None,
             PictureType::Image,
         );
 
-        pic.render_task_id = Some(render_tasks.add(root_render_task));
-        pic.render_task_id
+        let render_task_id = render_tasks.add(root_render_task);
+        pic.surface = Some(PictureSurface::RenderTask(render_task_id));
+        Some(render_task_id)
     }
 
     fn update_scroll_bars(&mut self, clip_scroll_tree: &ClipScrollTree, gpu_cache: &mut GpuCache) {

gfx/webrender/src/glyph_rasterizer.rs

@@ -114,6 +114,18 @@ impl FontTransform {
             self.scale_y - self.skew_y * skew_factor,
         )
     }
+
+    pub fn swap_xy(&self) -> Self {
+        FontTransform::new(self.skew_x, self.scale_x, self.scale_y, self.skew_y)
+    }
+
+    pub fn flip_x(&self) -> Self {
+        FontTransform::new(-self.scale_x, self.skew_x, -self.skew_y, self.scale_y)
+    }
+
+    pub fn flip_y(&self) -> Self {
+        FontTransform::new(self.scale_x, -self.skew_y, self.skew_y, -self.scale_y)
+    }
 }
 
 impl<'a> From<&'a LayerToWorldTransform> for FontTransform {
@@ -220,8 +232,6 @@ pub enum GlyphFormat {
 impl GlyphFormat {
     pub fn ignore_color(self) -> Self {
         match self {
-            GlyphFormat::Subpixel => GlyphFormat::Alpha,
-            GlyphFormat::TransformedSubpixel => GlyphFormat::TransformedAlpha,
             GlyphFormat::ColorBitmap => GlyphFormat::Bitmap,
             _ => self,
         }
@@ -400,7 +410,7 @@ impl GlyphRasterizer {
                                     offset: 0,
                                 },
                                 TextureFilter::Linear,
-                                ImageData::Raw(glyph_info.glyph_bytes.clone()),
+                                Some(ImageData::Raw(glyph_info.glyph_bytes.clone())),
                                 [glyph_info.offset.x, glyph_info.offset.y, glyph_info.scale],
                                 None,
                                 gpu_cache,
@@ -523,7 +533,7 @@ impl GlyphRasterizer {
                             offset: 0,
                         },
                         TextureFilter::Linear,
-                        ImageData::Raw(glyph_bytes.clone()),
+                        Some(ImageData::Raw(glyph_bytes.clone())),
                         [glyph.left, -glyph.top, glyph.scale],
                         None,
                         gpu_cache,

gfx/webrender/src/gpu_types.rs

@@ -2,8 +2,9 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use api::{LayerRect, LayerToWorldTransform};
+use api::{LayerToWorldTransform};
 use gpu_cache::GpuCacheAddress;
+use prim_store::EdgeAaSegmentMask;
 use render_task::RenderTaskAddress;
 
 // Contains type that must exactly match the same structures declared in GLSL.
@@ -21,7 +22,6 @@ pub struct BlurInstance {
     pub task_address: RenderTaskAddress,
     pub src_task_address: RenderTaskAddress,
     pub blur_direction: BlurDirection,
-    pub region: LayerRect,
 }
 
 /// A clipping primitive drawn into the clipping mask.
@@ -155,6 +155,7 @@ pub struct BrushInstance {
     pub clip_task_address: RenderTaskAddress,
     pub z: i32,
     pub segment_index: i32,
+    pub edge_flags: EdgeAaSegmentMask,
     pub user_data0: i32,
     pub user_data1: i32,
 }
@@ -168,7 +169,7 @@ impl From<BrushInstance> for PrimitiveInstance {
                 ((instance.clip_chain_rect_index.0 as i32) << 16) | instance.scroll_id.0 as i32,
                 instance.clip_task_address.0 as i32,
                 instance.z,
-                instance.segment_index,
+                instance.segment_index | ((instance.edge_flags.bits() as i32) << 16),
                 instance.user_data0,
                 instance.user_data1,
             ]

gfx/webrender/src/picture.rs

@@ -8,10 +8,12 @@ use api::{BoxShadowClipMode, LayerPoint, LayerRect, LayerVector2D, Shadow};
 use api::{ClipId, PremultipliedColorF};
 use box_shadow::{BLUR_SAMPLE_SCALE, BoxShadowCacheKey};
 use frame_builder::PrimitiveContext;
-use gpu_cache::GpuDataRequest;
+use gpu_cache::{GpuCache, GpuDataRequest};
 use gpu_types::{BrushImageKind, PictureType};
 use prim_store::{PrimitiveIndex, PrimitiveRun, PrimitiveRunLocalRect};
-use render_task::{ClearMode, RenderTask, RenderTaskId, RenderTaskTree};
+use render_task::{ClearMode, RenderTask, RenderTaskCacheKey};
+use render_task::{RenderTaskCacheKeyKind, RenderTaskId, RenderTaskTree};
+use resource_cache::{CacheItem, ResourceCache};
 use scene::{FilterOpHelpers, SceneProperties};
 use tiling::RenderTargetKind;
 
@@ -57,7 +59,6 @@ pub enum PictureKind {
     BoxShadow {
         blur_radius: f32,
         color: ColorF,
-        blur_regions: Vec<LayerRect>,
         clip_mode: BoxShadowClipMode,
         image_kind: BrushImageKind,
         content_rect: LayerRect,
@@ -88,11 +89,21 @@ pub enum PictureKind {
     },
 }
 
+// The type of surface that a picture can be drawn to.
+// RenderTask surfaces are not retained across frames.
+// TextureCache surfaces are stored across frames, and
+// also shared between display lists.
+#[derive(Debug)]
+pub enum PictureSurface {
+    RenderTask(RenderTaskId),
+    TextureCache(CacheItem),
+}
+
 #[derive(Debug)]
 pub struct PicturePrimitive {
     // If this picture is drawn to an intermediate surface,
-    // the associated render task.
-    pub render_task_id: Option<RenderTaskId>,
+    // the associated target information.
+    pub surface: Option<PictureSurface>,
 
     // Details specific to this type of picture.
     pub kind: PictureKind,
@@ -113,7 +124,7 @@ impl PicturePrimitive {
     pub fn new_text_shadow(shadow: Shadow, pipeline_id: PipelineId) -> Self {
         PicturePrimitive {
             runs: Vec::new(),
-            render_task_id: None,
+            surface: None,
             kind: PictureKind::TextShadow {
                 offset: shadow.offset,
                 color: shadow.color,
@@ -149,7 +160,6 @@ impl PicturePrimitive {
     pub fn new_box_shadow(
         blur_radius: f32,
         color: ColorF,
-        blur_regions: Vec<LayerRect>,
         clip_mode: BoxShadowClipMode,
         image_kind: BrushImageKind,
         cache_key: BoxShadowCacheKey,
@@ -157,11 +167,10 @@ impl PicturePrimitive {
     ) -> Self {
         PicturePrimitive {
             runs: Vec::new(),
-            render_task_id: None,
+            surface: None,
             kind: PictureKind::BoxShadow {
                 blur_radius,
                 color,
-                blur_regions,
                 clip_mode,
                 image_kind,
                 content_rect: LayerRect::zero(),
@@ -181,7 +190,7 @@ impl PicturePrimitive {
     ) -> Self {
         PicturePrimitive {
             runs: Vec::new(),
-            render_task_id: None,
+            surface: None,
             kind: PictureKind::Image {
                 secondary_render_task_id: None,
                 composite_mode,
@@ -303,6 +312,8 @@ impl PicturePrimitive {
         prim_local_rect: &LayerRect,
         child_tasks: Vec<RenderTaskId>,
         parent_tasks: &mut Vec<RenderTaskId>,
+        resource_cache: &mut ResourceCache,
+        gpu_cache: &mut GpuCache,
     ) {
         let content_scale = LayerToWorldScale::new(1.0) * prim_context.device_pixel_scale;
 
@@ -323,26 +334,24 @@ impl PicturePrimitive {
                             PremultipliedColorF::TRANSPARENT,
                             ClearMode::Transparent,
                             child_tasks,
-                            None,
                             PictureType::Image,
                         );
 
                         let blur_std_deviation = blur_radius * prim_context.device_pixel_scale.0;
                         let picture_task_id = render_tasks.add(picture_task);
 
-                        let blur_render_task = RenderTask::new_blur(
+                        let (blur_render_task, _) = RenderTask::new_blur(
                             blur_std_deviation,
                             picture_task_id,
                             render_tasks,
                             RenderTargetKind::Color,
-                            &[],
                             ClearMode::Transparent,
                             PremultipliedColorF::TRANSPARENT,
-                            None,
                         );
 
-                        let blur_render_task_id = render_tasks.add(blur_render_task);
-                        self.render_task_id = Some(blur_render_task_id);
+                        let render_task_id = render_tasks.add(blur_render_task);
+                        parent_tasks.push(render_task_id);
+                        self.surface = Some(PictureSurface::RenderTask(render_task_id));
                     }
                     Some(PictureCompositeMode::Filter(FilterOp::DropShadow(offset, blur_radius, color))) => {
                         let rect = (prim_local_rect.translate(&-offset) * content_scale).round().to_i32();
@@ -354,26 +363,26 @@ impl PicturePrimitive {
                             PremultipliedColorF::TRANSPARENT,
                             ClearMode::Transparent,
                             child_tasks,
-                            None,
                             PictureType::Image,
                         );
 
                         let blur_std_deviation = blur_radius * prim_context.device_pixel_scale.0;
                         let picture_task_id = render_tasks.add(picture_task);
 
-                        let blur_render_task = RenderTask::new_blur(
+                        let (blur_render_task, _) = RenderTask::new_blur(
                             blur_std_deviation.round(),
                             picture_task_id,
                             render_tasks,
                             RenderTargetKind::Color,
-                            &[],
                             ClearMode::Transparent,
                             color.premultiplied(),
-                            None,
                         );
 
                         *secondary_render_task_id = Some(picture_task_id);
-                        self.render_task_id = Some(render_tasks.add(blur_render_task));
+
+                        let render_task_id = render_tasks.add(blur_render_task);
+                        parent_tasks.push(render_task_id);
+                        self.surface = Some(PictureSurface::RenderTask(render_task_id));
                     }
                     Some(PictureCompositeMode::MixBlend(..)) => {
                         let picture_task = RenderTask::new_picture(
@@ -384,7 +393,6 @@ impl PicturePrimitive {
                             PremultipliedColorF::TRANSPARENT,
                             ClearMode::Transparent,
                             child_tasks,
-                            None,
                             PictureType::Image,
                         );
 
@@ -393,7 +401,9 @@ impl PicturePrimitive {
                         *secondary_render_task_id = Some(readback_task_id);
                         parent_tasks.push(readback_task_id);
 
-                        self.render_task_id = Some(render_tasks.add(picture_task));
+                        let render_task_id = render_tasks.add(picture_task);
+                        parent_tasks.push(render_task_id);
+                        self.surface = Some(PictureSurface::RenderTask(render_task_id));
                     }
                     Some(PictureCompositeMode::Filter(filter)) => {
                         // If this filter is not currently going to affect
@@ -403,7 +413,7 @@ impl PicturePrimitive {
                         // filters and be a significant performance win.
                         if filter.is_noop() {
                             parent_tasks.extend(child_tasks);
-                            self.render_task_id = None;
+                            self.surface = None;
                         } else {
                             let picture_task = RenderTask::new_picture(
                                 Some(prim_screen_rect.size),
@@ -413,11 +423,12 @@ impl PicturePrimitive {
                                 PremultipliedColorF::TRANSPARENT,
                                 ClearMode::Transparent,
                                 child_tasks,
-                                None,
                                 PictureType::Image,
                             );
 
-                            self.render_task_id = Some(render_tasks.add(picture_task));
+                            let render_task_id = render_tasks.add(picture_task);
+                            parent_tasks.push(render_task_id);
+                            self.surface = Some(PictureSurface::RenderTask(render_task_id));
                         }
                     }
                     Some(PictureCompositeMode::Blit) => {
@@ -429,15 +440,16 @@ impl PicturePrimitive {
                             PremultipliedColorF::TRANSPARENT,
                             ClearMode::Transparent,
                             child_tasks,
-                            None,
                             PictureType::Image,
                         );
 
-                        self.render_task_id = Some(render_tasks.add(picture_task));
+                        let render_task_id = render_tasks.add(picture_task);
+                        parent_tasks.push(render_task_id);
+                        self.surface = Some(PictureSurface::RenderTask(render_task_id));
                     }
                     None => {
                         parent_tasks.extend(child_tasks);
-                        self.render_task_id = None;
+                        self.surface = None;
                     }
                 }
             }
@@ -468,26 +480,25 @@ impl PicturePrimitive {
                     color.premultiplied(),
                     ClearMode::Transparent,
                     Vec::new(),
-                    None,
                     PictureType::TextShadow,
                 );
 
                 let picture_task_id = render_tasks.add(picture_task);
 
-                let render_task = RenderTask::new_blur(
+                let (blur_render_task, _) = RenderTask::new_blur(
                     blur_std_deviation,
                     picture_task_id,
                     render_tasks,
                     RenderTargetKind::Color,
-                    &[],
                     ClearMode::Transparent,
                     color.premultiplied(),
-                    None,
                 );
 
-                self.render_task_id = Some(render_tasks.add(render_task));
+                let render_task_id = render_tasks.add(blur_render_task);
+                parent_tasks.push(render_task_id);
+                self.surface = Some(PictureSurface::RenderTask(render_task_id));
             }
-            PictureKind::BoxShadow { blur_radius, clip_mode, ref blur_regions, color, content_rect, cache_key, .. } => {
+            PictureKind::BoxShadow { blur_radius, clip_mode, color, content_rect, cache_key, .. } => {
                 // TODO(gw): Rounding the content rect here to device pixels is not
                 // technically correct. Ideally we should ceil() here, and ensure that
                 // the extra part pixel in the case of fractional sizes is correctly
@@ -495,6 +506,17 @@ impl PicturePrimitive {
                 // Gecko tests.
                 let cache_size = (content_rect.size * content_scale).round().to_i32();
 
+                // Request the texture cache item for this box-shadow key. If it
+                // doesn't exist in the cache, the closure is invoked to build
+                // a render task chain to draw the cacheable result.
+                let cache_item = resource_cache.request_render_task(
+                    RenderTaskCacheKey {
+                        size: cache_size,
+                        kind: RenderTaskCacheKeyKind::BoxShadow(cache_key),
+                    },
+                    gpu_cache,
+                    render_tasks,
+                    |render_tasks| {
                         // Quote from https://drafts.csswg.org/css-backgrounds-3/#shadow-blur
                         // "the image that would be generated by applying to the shadow a
                         // Gaussian blur with a standard deviation equal to half the blur radius."
@@ -518,36 +540,48 @@ impl PicturePrimitive {
                             color.premultiplied(),
                             ClearMode::Zero,
                             Vec::new(),
-                    Some(cache_key),
                             PictureType::BoxShadow,
                         );
 
                         let picture_task_id = render_tasks.add(picture_task);
 
-                let render_task = RenderTask::new_blur(
+                        let (blur_render_task, scale_factor) = RenderTask::new_blur(
                             blur_std_deviation,
                             picture_task_id,
                             render_tasks,
                             RenderTargetKind::Alpha,
-                    blur_regions,
                             blur_clear_mode,
                             color.premultiplied(),
-                    Some(cache_key),
                         );
 
-                self.render_task_id = Some(render_tasks.add(render_task));
+                        let root_task_id = render_tasks.add(blur_render_task);
+                        parent_tasks.push(root_task_id);
+
+                        // TODO(gw): Remove the nastiness with having to pass
+                        //           the scale factor through the texture cache
+                        //           item user data. This will disappear once
+                        //           the brush_image shader is updated to draw
+                        //           segments, since the scale factor will not
+                        //           be used at all then during drawing.
+                        (root_task_id, [scale_factor, 0.0, 0.0])
+                    }
+                );
+
+                self.surface = Some(PictureSurface::TextureCache(cache_item));
+            }
         }
     }
 
-        if let Some(render_task_id) = self.render_task_id {
-            parent_tasks.push(render_task_id);
+    pub fn write_gpu_blocks(&self, request: &mut GpuDataRequest) {
+        match self.kind {
+            PictureKind::TextShadow { .. } |
+            PictureKind::Image { .. } => {
+                request.push([0.0; 4]);
+            }
+            PictureKind::BoxShadow { color, .. } => {
+                request.push(color.premultiplied());
             }
         }
-
-    pub fn write_gpu_blocks(&self, _request: &mut GpuDataRequest) {
-        // TODO(gw): We'll need to write the GPU blocks
-        //           here specific to a brush primitive
-        //           once we start drawing pictures as brushes!
     }
 
     pub fn target_kind(&self) -> RenderTargetKind {

gfx/webrender/src/platform/macos/font.rs

@@ -117,7 +117,6 @@ fn get_glyph_metrics(
 
     if let Some(transform) = transform {
         bounds = bounds.apply_transform(transform);
-        advance = advance.apply_transform(transform);
     }
 
     // First round out to pixel boundaries
@@ -361,8 +360,23 @@ impl FontContext {
                 let glyph = key.index as CGGlyph;
                 let bitmap = is_bitmap_font(ct_font);
                 let (x_offset, y_offset) = if bitmap { (0.0, 0.0) } else { font.get_subpx_offset(key) };
-                let transform = if font.flags.contains(FontInstanceFlags::SYNTHETIC_ITALICS) {
-                    let shape = FontTransform::identity().synthesize_italics(OBLIQUE_SKEW_FACTOR);
+                let transform = if font.flags.intersects(FontInstanceFlags::SYNTHETIC_ITALICS |
+                                                         FontInstanceFlags::TRANSPOSE |
+                                                         FontInstanceFlags::FLIP_X |
+                                                         FontInstanceFlags::FLIP_Y) {
+                    let mut shape = FontTransform::identity();
+                    if font.flags.contains(FontInstanceFlags::FLIP_X) {
+                        shape = shape.flip_x();
+                    }
+                    if font.flags.contains(FontInstanceFlags::FLIP_Y) {
+                        shape = shape.flip_y();
+                    }
+                    if font.flags.contains(FontInstanceFlags::TRANSPOSE) {
+                        shape = shape.swap_xy();
+                    }
+                    if font.flags.contains(FontInstanceFlags::SYNTHETIC_ITALICS) {
+                        shape = shape.synthesize_italics(OBLIQUE_SKEW_FACTOR);
+                    }
                     Some(CGAffineTransform {
                         a: shape.scale_x as f64,
                         b: -shape.skew_y as f64,
@@ -483,6 +497,15 @@ impl FontContext {
         } else {
             (font.transform.invert_scale(y_scale, y_scale), font.get_subpx_offset(key))
         };
+        if font.flags.contains(FontInstanceFlags::FLIP_X) {
+            shape = shape.flip_x();
+        }
+        if font.flags.contains(FontInstanceFlags::FLIP_Y) {
+            shape = shape.flip_y();
+        }
+        if font.flags.contains(FontInstanceFlags::TRANSPOSE) {
+            shape = shape.swap_xy();
+        }
         if font.flags.contains(FontInstanceFlags::SYNTHETIC_ITALICS) {
             shape = shape.synthesize_italics(OBLIQUE_SKEW_FACTOR);
         }

gfx/webrender/src/platform/unix/font.rs

@@ -105,6 +105,38 @@ fn skew_bitmap(bitmap: &[u8], width: usize, height: usize, left: i32, top: i32)
     (skew_buffer, skew_width, left + skew_min as i32)
 }
 
+fn transpose_bitmap(bitmap: &[u8], width: usize, height: usize) -> Vec<u8> {
+    let mut transposed = vec![0u8; width * height * 4];
+    for (y, row) in bitmap.chunks(width * 4).enumerate() {
+        let mut offset = y * 4;
+        for src in row.chunks(4) {
+            transposed[offset .. offset + 4].copy_from_slice(src);
+            offset += height * 4;
+        }
+    }
+    transposed
+}
+
+fn flip_bitmap_x(bitmap: &mut [u8], width: usize, height: usize) {
+    assert!(bitmap.len() == width * height * 4);
+    let pixels = unsafe { slice::from_raw_parts_mut(bitmap.as_mut_ptr() as *mut u32, width * height) };
+    for row in pixels.chunks_mut(width) {
+        row.reverse();
+    }
+}
+
+fn flip_bitmap_y(bitmap: &mut [u8], width: usize, height: usize) {
+    assert!(bitmap.len() == width * height * 4);
+    let pixels = unsafe { slice::from_raw_parts_mut(bitmap.as_mut_ptr() as *mut u32, width * height) };
+    for y in 0 .. height / 2 {
+        let low_row = y * width;
+        let high_row = (height - 1 - y) * width;
+        for x in 0 .. width {
+            pixels.swap(low_row + x, high_row + x);
+        }
+    }
+}
+
 impl FontContext {
     pub fn new() -> FontContext {
         let mut lib: FT_Library = ptr::null_mut();
@@ -250,6 +282,15 @@ impl FontContext {
             self.choose_bitmap_size(face.face, req_size * y_scale)
         } else {
             let mut shape = font.transform.invert_scale(x_scale, y_scale);
+            if font.flags.contains(FontInstanceFlags::FLIP_X) {
+                shape = shape.flip_x();
+            }
+            if font.flags.contains(FontInstanceFlags::FLIP_Y) {
+                shape = shape.flip_y();
+            }
+            if font.flags.contains(FontInstanceFlags::TRANSPOSE) {
+                shape = shape.swap_xy();
+            }
             if font.flags.contains(FontInstanceFlags::SYNTHETIC_ITALICS) {
                 shape = shape.synthesize_italics(OBLIQUE_SKEW_FACTOR);
             };
@@ -391,6 +432,18 @@ impl FontContext {
                         left += skew_min as i32;
                         width += (skew_max - skew_min) as u32;
                     }
+                    if font.flags.contains(FontInstanceFlags::TRANSPOSE) {
+                        mem::swap(&mut width, &mut height);
+                        mem::swap(&mut left, &mut top);
+                        left -= width as i32;
+                        top += height as i32;
+                    }
+                    if font.flags.contains(FontInstanceFlags::FLIP_X) {
+                        left = -(left + width as i32);
+                    }
+                    if font.flags.contains(FontInstanceFlags::FLIP_Y) {
+                        top = -(top - height as i32);
+                    }
                 }
                 Some(GlyphDimensions {
                     left,
@@ -570,7 +623,7 @@ impl FontContext {
 
         let bitmap = unsafe { &(*slot).bitmap };
         let pixel_mode = unsafe { mem::transmute(bitmap.pixel_mode as u32) };
-        let (mut actual_width, actual_height) = match pixel_mode {
+        let (mut actual_width, mut actual_height) = match pixel_mode {
             FT_Pixel_Mode::FT_PIXEL_MODE_LCD => {
                 assert!(bitmap.width % 3 == 0);
                 ((bitmap.width / 3) as usize, bitmap.rows as usize)
@@ -677,6 +730,21 @@ impl FontContext {
                     actual_width = skew_width;
                     left = skew_left;
                 }
+                if font.flags.contains(FontInstanceFlags::TRANSPOSE) {
+                    final_buffer = transpose_bitmap(&final_buffer, actual_width, actual_height);
+                    mem::swap(&mut actual_width, &mut actual_height);
+                    mem::swap(&mut left, &mut top);
+                    left -= actual_width as i32;
+                    top += actual_height as i32;
+                }
+                if font.flags.contains(FontInstanceFlags::FLIP_X) {
+                    flip_bitmap_x(&mut final_buffer, actual_width, actual_height);
+                    left = -(left + actual_width as i32);
+                }
+                if font.flags.contains(FontInstanceFlags::FLIP_Y) {
+                    flip_bitmap_y(&mut final_buffer, actual_width, actual_height);
+                    top = -(top - actual_height as i32);
+                }
             }
             FT_Glyph_Format::FT_GLYPH_FORMAT_OUTLINE => {
                 unsafe {

gfx/webrender/src/platform/windows/font.rs

@@ -236,8 +236,23 @@ impl FontContext {
     ) -> Option<GlyphDimensions> {
         let size = font.size.to_f32_px();
         let bitmaps = is_bitmap_font(font);
-        let transform = if font.flags.contains(FontInstanceFlags::SYNTHETIC_ITALICS) {
-            let shape = FontTransform::identity().synthesize_italics(OBLIQUE_SKEW_FACTOR);
+        let transform = if font.flags.intersects(FontInstanceFlags::SYNTHETIC_ITALICS |
+                                                 FontInstanceFlags::TRANSPOSE |
+                                                 FontInstanceFlags::FLIP_X |
+                                                 FontInstanceFlags::FLIP_Y) {
+            let mut shape = FontTransform::identity();
+            if font.flags.contains(FontInstanceFlags::FLIP_X) {
+                shape = shape.flip_x();
+            }
+            if font.flags.contains(FontInstanceFlags::FLIP_Y) {
+                shape = shape.flip_y();
+            }
+            if font.flags.contains(FontInstanceFlags::TRANSPOSE) {
+                shape = shape.swap_xy();
+            }
+            if font.flags.contains(FontInstanceFlags::SYNTHETIC_ITALICS) {
+                shape = shape.synthesize_italics(OBLIQUE_SKEW_FACTOR);
+            }
             Some(dwrote::DWRITE_MATRIX {
                 m11: shape.scale_x,
                 m12: shape.skew_y,
@@ -359,6 +374,15 @@ impl FontContext {
         } else {
             (font.transform.invert_scale(y_scale, y_scale), font.get_subpx_offset(key))
         };
+        if font.flags.contains(FontInstanceFlags::FLIP_X) {
+            shape = shape.flip_x();
+        }
+        if font.flags.contains(FontInstanceFlags::FLIP_Y) {
+            shape = shape.flip_y();
+        }
+        if font.flags.contains(FontInstanceFlags::TRANSPOSE) {
+            shape = shape.swap_xy();
+        }
         if font.flags.contains(FontInstanceFlags::SYNTHETIC_ITALICS) {
             shape = shape.synthesize_italics(OBLIQUE_SKEW_FACTOR);
         }

gfx/webrender/src/prim_store.rs

@@ -2,14 +2,14 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use api::{BorderRadius, BuiltDisplayList, ClipAndScrollInfo, ClipId, ClipMode, ColorF, ColorU};
-use api::{DeviceIntRect, DevicePixelScale, DevicePoint};
+use api::{AlphaType, BorderRadius, BuiltDisplayList, ClipAndScrollInfo, ClipId, ClipMode};
+use api::{ColorF, ColorU, DeviceIntRect, DevicePixelScale, DevicePoint};
 use api::{ComplexClipRegion, ExtendMode, FontRenderMode};
 use api::{GlyphInstance, GlyphKey, GradientStop, ImageKey, ImageRendering, ItemRange, ItemTag};
 use api::{LayerPoint, LayerRect, LayerSize, LayerToWorldTransform, LayerVector2D, LineOrientation};
 use api::{LineStyle, PipelineId, PremultipliedColorF, TileOffset, WorldToLayerTransform};
 use api::{YuvColorSpace, YuvFormat};
-use border::BorderCornerInstance;
+use border::{BorderCornerInstance, BorderEdgeKind};
 use clip_scroll_tree::{CoordinateSystemId, ClipScrollTree};
 use clip_scroll_node::ClipScrollNode;
 use clip::{ClipSource, ClipSourcesHandle, ClipStore};
@@ -21,8 +21,8 @@ use gpu_cache::{GpuBlockData, GpuCache, GpuCacheAddress, GpuCacheHandle, GpuData
 use gpu_types::{ClipChainRectIndex, ClipScrollNodeData};
 use picture::{PictureKind, PicturePrimitive};
 use profiler::FrameProfileCounters;
-use render_task::{ClipChain, ClipChainNode, ClipChainNodeIter, ClipWorkItem, RenderTask};
-use render_task::{RenderTaskId, RenderTaskTree};
+use render_task::{ClipChain, ClipChainNode, ClipChainNodeIter, ClipChainNodeRef, ClipWorkItem};
+use render_task::{RenderTask, RenderTaskId, RenderTaskTree};
 use renderer::{BLOCKS_PER_UV_RECT, MAX_VERTEX_TEXTURE_WIDTH};
 use resource_cache::{ImageProperties, ResourceCache};
 use scene::{ScenePipeline, SceneProperties};
@@ -151,7 +151,6 @@ pub enum PrimitiveKind {
     AlignedGradient,
     AngleGradient,
     RadialGradient,
-    Line,
     Picture,
     Brush,
 }
@@ -212,6 +211,12 @@ pub enum BrushKind {
         color: ColorF,
     },
     Clear,
+    Line {
+        color: PremultipliedColorF,
+        wavy_line_thickness: f32,
+        style: LineStyle,
+        orientation: LineOrientation,
+    }
 }
 
 impl BrushKind {
@@ -331,30 +336,18 @@ impl BrushPrimitive {
                     radii.bottom_left.height,
                 ]);
             }
-        }
-    }
-}
-
-#[derive(Debug, Clone)]
-#[repr(C)]
-pub struct LinePrimitive {
-    pub color: PremultipliedColorF,
-    pub wavy_line_thickness: f32,
-    pub style: LineStyle,
-    pub orientation: LineOrientation,
-}
-
-impl LinePrimitive {
-    fn write_gpu_blocks(&self, request: &mut GpuDataRequest) {
-        request.push(self.color);
+            BrushKind::Line { color, wavy_line_thickness, style, orientation } => {
+                request.push(color);
                 request.push([
-            self.wavy_line_thickness,
-            pack_as_float(self.style as u32),
-            pack_as_float(self.orientation as u32),
+                    wavy_line_thickness,
+                    pack_as_float(style as u32),
+                    pack_as_float(orientation as u32),
                     0.0,
                 ]);
             }
         }
+    }
+}
 
 #[derive(Debug)]
 pub struct ImagePrimitiveCpu {
@@ -362,6 +355,7 @@ pub struct ImagePrimitiveCpu {
     pub image_rendering: ImageRendering,
     pub tile_offset: Option<TileOffset>,
     pub tile_spacing: LayerSize,
+    pub alpha_type: AlphaType,
     // TODO(gw): Build on demand
     pub gpu_blocks: [GpuBlockData; BLOCKS_PER_UV_RECT],
 }
@@ -393,6 +387,7 @@ impl ToGpuBlocks for YuvImagePrimitiveCpu {
 #[derive(Debug)]
 pub struct BorderPrimitiveCpu {
     pub corner_instances: [BorderCornerInstance; 4],
+    pub edges: [BorderEdgeKind; 4],
     pub gpu_blocks: [GpuBlockData; 8],
 }
 
@@ -679,6 +674,14 @@ impl TextRunPrimitiveCpu {
         self.shadow_color.a != 0
     }
 
+    pub fn get_color(&self) -> ColorF {
+        ColorF::from(if self.is_shadow() {
+            self.shadow_color
+        } else {
+            self.font.color
+        })
+    }
+
     fn prepare_for_render(
         &mut self,
         resource_cache: &mut ResourceCache,
@@ -728,14 +731,9 @@ impl TextRunPrimitiveCpu {
     }
 
     fn write_gpu_blocks(&self, request: &mut GpuDataRequest) {
-        let bg_color = ColorF::from(self.font.bg_color);
-        let color = ColorF::from(if self.is_shadow() {
-            self.shadow_color
-        } else {
-            self.font.color
-        });
-        request.push(color.premultiplied());
+        request.push(self.get_color().premultiplied());
         // this is the only case where we need to provide plain color to GPU
+        let bg_color = ColorF::from(self.font.bg_color);
         request.extend_from_slice(&[
             GpuBlockData { data: [bg_color.r, bg_color.g, bg_color.b, 1.0] }
         ]);
@@ -944,7 +942,6 @@ pub enum PrimitiveContainer {
     AngleGradient(GradientPrimitiveCpu),
     RadialGradient(RadialGradientPrimitiveCpu),
     Picture(PicturePrimitive),
-    Line(LinePrimitive),
     Brush(BrushPrimitive),
 }
 
@@ -959,7 +956,6 @@ pub struct PrimitiveStore {
     pub cpu_radial_gradients: Vec<RadialGradientPrimitiveCpu>,
     pub cpu_metadata: Vec<PrimitiveMetadata>,
     pub cpu_borders: Vec<BorderPrimitiveCpu>,
-    pub cpu_lines: Vec<LinePrimitive>,
 }
 
 impl PrimitiveStore {
@@ -974,7 +970,6 @@ impl PrimitiveStore {
             cpu_gradients: Vec::new(),
             cpu_radial_gradients: Vec::new(),
             cpu_borders: Vec::new(),
-            cpu_lines: Vec::new(),
         }
     }
 
@@ -989,7 +984,6 @@ impl PrimitiveStore {
             cpu_gradients: recycle_vec(self.cpu_gradients),
             cpu_radial_gradients: recycle_vec(self.cpu_radial_gradients),
             cpu_borders: recycle_vec(self.cpu_borders),
-            cpu_lines: recycle_vec(self.cpu_lines),
         }
     }
 
@@ -1025,6 +1019,7 @@ impl PrimitiveStore {
                     BrushKind::Clear => PrimitiveOpacity::translucent(),
                     BrushKind::Solid { ref color } => PrimitiveOpacity::from_alpha(color.a),
                     BrushKind::Mask { .. } => PrimitiveOpacity::translucent(),
+                    BrushKind::Line { .. } => PrimitiveOpacity::translucent(),
                 };
 
                 let metadata = PrimitiveMetadata {
@@ -1038,17 +1033,6 @@ impl PrimitiveStore {
 
                 metadata
             }
-            PrimitiveContainer::Line(line) => {
-                let metadata = PrimitiveMetadata {
-                    opacity: PrimitiveOpacity::translucent(),
-                    prim_kind: PrimitiveKind::Line,
-                    cpu_prim_index: SpecificPrimitiveIndex(self.cpu_lines.len()),
-                    ..base_metadata
-                };
-
-                self.cpu_lines.push(line);
-                metadata
-            }
             PrimitiveContainer::TextRun(text_cpu) => {
                 let metadata = PrimitiveMetadata {
                     opacity: PrimitiveOpacity::translucent(),
@@ -1167,7 +1151,7 @@ impl PrimitiveStore {
     ) {
         let metadata = &mut self.cpu_metadata[prim_index.0];
         match metadata.prim_kind {
-            PrimitiveKind::Border | PrimitiveKind::Line => {}
+            PrimitiveKind::Border => {}
             PrimitiveKind::Picture => {
                 self.cpu_pictures[metadata.cpu_prim_index.0]
                     .prepare_for_render(
@@ -1178,6 +1162,8 @@ impl PrimitiveStore {
                         &metadata.local_rect,
                         child_tasks,
                         parent_tasks,
+                        resource_cache,
+                        gpu_cache,
                     );
             }
             PrimitiveKind::TextRun => {
@@ -1248,25 +1234,6 @@ impl PrimitiveStore {
             request.push(metadata.local_clip_rect);
 
             match metadata.prim_kind {
-                PrimitiveKind::Line => {
-                    let line = &self.cpu_lines[metadata.cpu_prim_index.0];
-                    line.write_gpu_blocks(&mut request);
-
-                    // TODO(gw): This is a bit of a hack. The Line type
-                    //           is drawn by the brush_line shader, so the
-                    //           layout here needs to conform to the same
-                    //           BrushPrimitive layout. We should tidy this
-                    //           up in the future so it's enforced that these
-                    //           types use a shared function to write out the
-                    //           GPU blocks...
-                    request.push(metadata.local_rect);
-                    request.push([
-                        EdgeAaSegmentMask::empty().bits() as f32,
-                        0.0,
-                        0.0,
-                        0.0
-                    ]);
-                }
                 PrimitiveKind::Border => {
                     let border = &self.cpu_borders[metadata.cpu_prim_index.0];
                     border.write_gpu_blocks(request);
@@ -1306,13 +1273,7 @@ impl PrimitiveStore {
                     //           up in the future so it's enforced that these
                     //           types use a shared function to write out the
                     //           GPU blocks...
-                    request.push(metadata.local_rect);
-                    request.push([
-                        EdgeAaSegmentMask::empty().bits() as f32,
-                        0.0,
-                        0.0,
-                        0.0
-                    ]);
+                    request.write_segment(metadata.local_rect);
                 }
                 PrimitiveKind::Brush => {
                     let brush = &self.cpu_brushes[metadata.cpu_prim_index.0];
@@ -1321,23 +1282,11 @@ impl PrimitiveStore {
                         Some(ref segment_desc) => {
                             for segment in &segment_desc.segments {
                                 // has to match VECS_PER_SEGMENT
-                                request.push(segment.local_rect);
-                                request.push([
-                                    segment.edge_flags.bits() as f32,
-                                    0.0,
-                                    0.0,
-                                    0.0
-                                ]);
+                                request.write_segment(segment.local_rect);
                             }
                         }
                         None => {
-                            request.push(metadata.local_rect);
-                            request.push([
-                                EdgeAaSegmentMask::empty().bits() as f32,
-                                0.0,
-                                0.0,
-                                0.0
-                            ]);
+                            request.write_segment(metadata.local_rect);
                         }
                     }
                 }
@@ -1513,7 +1462,6 @@ impl PrimitiveStore {
 
                 combined_outer_rect.intersection(&segment_screen_rect).map(|bounds| {
                     let clip_task = RenderTask::new_mask(
-                        None,
                         bounds,
                         clips.clone(),
                         prim_context.scroll_node.coordinate_system_id,
@@ -1555,12 +1503,13 @@ impl PrimitiveStore {
             }
         };
 
-        let clip_chain = prim_context.clip_node.clip_chain_node.clone();
-        let mut combined_outer_rect = match clip_chain {
-            Some(ref node) => prim_screen_rect.intersection(&node.combined_outer_screen_rect),
+        let mut combined_outer_rect = match prim_context.clip_chain {
+            Some(ref chain) => prim_screen_rect.intersection(&chain.combined_outer_screen_rect),
             None => Some(prim_screen_rect),
         };
 
+        let clip_chain = prim_context.clip_chain.map_or(None, |x| x.nodes.clone());
+
         let prim_coordinate_system_id = prim_context.scroll_node.coordinate_system_id;
         let transform = &prim_context.scroll_node.world_content_transform;
         let extra_clip =  {
@@ -1588,9 +1537,6 @@ impl PrimitiveStore {
                     local_clip_rect: LayerRect::zero(),
                     screen_inner_rect,
                     screen_outer_rect: screen_outer_rect.unwrap_or(prim_screen_rect),
-                    combined_outer_screen_rect:
-                        combined_outer_rect.unwrap_or_else(DeviceIntRect::zero),
-                    combined_inner_screen_rect: DeviceIntRect::zero(),
                     prev: None,
                 }))
             } else {
@@ -1653,7 +1599,6 @@ impl PrimitiveStore {
         }
 
         let clip_task = RenderTask::new_mask(
-            None,
             combined_outer_rect,
             clips,
             prim_coordinate_system_id,
@@ -1788,7 +1733,7 @@ impl PrimitiveStore {
                 prim_context.device_pixel_scale,
             );
 
-            let clip_bounds = match prim_context.clip_node.clip_chain_node {
+            let clip_bounds = match prim_context.clip_chain {
                 Some(ref node) => node.combined_outer_screen_rect,
                 None => *screen_rect,
             };
@@ -1871,13 +1816,24 @@ impl PrimitiveStore {
             //           a new primitive context for every run (if the hash
             //           lookups ever show up in a profile).
             let scroll_node = &clip_scroll_tree.nodes[&run.clip_and_scroll.scroll_node_id];
-            let clip_node = &clip_scroll_tree.nodes[&run.clip_and_scroll.clip_node_id()];
+            let clip_chain = clip_scroll_tree.get_clip_chain(&run.clip_and_scroll.clip_node_id());
 
-            if perform_culling && !clip_node.is_visible() {
-                debug!("{:?} of clipped out {:?}", run.base_prim_index, pipeline_id);
+            if perform_culling {
+                if !scroll_node.invertible {
+                    debug!("{:?} {:?}: position not invertible", run.base_prim_index, pipeline_id);
                     continue;
                 }
 
+                match clip_chain {
+                     Some(ref chain) if chain.combined_outer_screen_rect.is_empty() => {
+                        debug!("{:?} {:?}: clipped out", run.base_prim_index, pipeline_id);
+                        continue;
+                    }
+                    _ => {},
+                }
+            }
+
+
             let parent_relative_transform = parent_prim_context
                 .scroll_node
                 .world_content_transform
@@ -1905,13 +1861,13 @@ impl PrimitiveStore {
             let child_prim_context = PrimitiveContext::new(
                 parent_prim_context.device_pixel_scale,
                 display_list,
-                clip_node,
+                clip_chain,
                 scroll_node,
             );
 
 
             let clip_chain_rect = match perform_culling {
-                true => get_local_clip_rect_for_nodes(scroll_node, clip_node),
+                true => get_local_clip_rect_for_nodes(scroll_node, clip_chain),
                 false => None,
             };
 
@@ -1994,17 +1950,14 @@ impl InsideTest<ComplexClipRegion> for ComplexClipRegion {
 }
 
 fn convert_clip_chain_to_clip_vector(
-    clip_chain: ClipChain,
-    extra_clip: ClipChain,
+    clip_chain_nodes: ClipChainNodeRef,
+    extra_clip: ClipChainNodeRef,
     combined_outer_rect: &DeviceIntRect,
     combined_inner_rect: &mut DeviceIntRect,
 ) -> Vec<ClipWorkItem> {
     // Filter out all the clip instances that don't contribute to the result.
     ClipChainNodeIter { current: extra_clip }
-        .chain(ClipChainNodeIter { current: clip_chain })
-        .take_while(|node| {
-            !node.combined_inner_screen_rect.contains_rect(&combined_outer_rect)
-        })
+        .chain(ClipChainNodeIter { current: clip_chain_nodes })
         .filter_map(|node| {
             *combined_inner_rect = if !node.screen_inner_rect.is_empty() {
                 // If this clip's inner area contains the area of the primitive clipped
@@ -2025,9 +1978,14 @@ fn convert_clip_chain_to_clip_vector(
 
 fn get_local_clip_rect_for_nodes(
     scroll_node: &ClipScrollNode,
-    clip_node: &ClipScrollNode,
+    clip_chain: Option<&ClipChain>,
 ) -> Option<LayerRect> {
-    let local_rect = ClipChainNodeIter { current: clip_node.clip_chain_node.clone() }.fold(
+    let clip_chain_nodes = match clip_chain {
+        Some(ref clip_chain) => clip_chain.nodes.clone(),
+        None => return None,
+    };
+
+    let local_rect = ClipChainNodeIter { current: clip_chain_nodes }.fold(
         None,
         |combined_local_clip_rect: Option<LayerRect>, node| {
             if node.work_item.coordinate_system_id != scroll_node.coordinate_system_id {
@@ -2048,3 +2006,23 @@ fn get_local_clip_rect_for_nodes(
         None => None,
     }
 }
+
+impl<'a> GpuDataRequest<'a> {
+    // Write the GPU cache data for an individual segment.
+    // TODO(gw): The second block is currently unused. In
+    //           the future, it will be used to store a
+    //           UV rect, allowing segments to reference
+    //           part of an image.
+    fn write_segment(
+        &mut self,
+        local_rect: LayerRect,
+    ) {
+        self.push(local_rect);
+        self.push([
+            0.0,
+            0.0,
+            0.0,
+            0.0
+        ]);
+    }
+}

gfx/webrender/src/profiler.rs

@@ -944,6 +944,7 @@ impl Profiler {
                 &renderer_profile.color_targets,
                 &renderer_profile.alpha_targets,
                 &renderer_profile.draw_calls,
+                &renderer_profile.vertices,
                 &self.backend_time,
                 &self.compositor_time,
                 &self.gpu_time,

gfx/webrender/src/render_backend.rs

@@ -801,6 +801,7 @@ impl ToDebugString for SpecificDisplayItem {
             SpecificDisplayItem::PushStackingContext(..) => String::from("push_stacking_context"),
             SpecificDisplayItem::Iframe(..) => String::from("iframe"),
             SpecificDisplayItem::Clip(..) => String::from("clip"),
+            SpecificDisplayItem::ClipChain(..) => String::from("clip_chain"),
             SpecificDisplayItem::ScrollFrame(..) => String::from("scroll_frame"),
             SpecificDisplayItem::StickyFrame(..) => String::from("sticky_frame"),
             SpecificDisplayItem::SetGradientStops => String::from("set_gradient_stops"),
@@ -816,16 +817,17 @@ impl ToDebugString for SpecificDisplayItem {
 impl RenderBackend {
     // Note: the mutable `self` is only needed here for resolving blob images
     fn save_capture(&mut self, root: &PathBuf) -> Vec<ExternalCaptureImage> {
-        use ron::ser::pretty;
+        use ron::ser::{to_string_pretty, PrettyConfig};
         use std::fs;
         use std::io::Write;
 
         info!("capture: saving {}", root.to_string_lossy());
+        let ron_config = PrettyConfig::default();
         let (resources, deferred) = self.resource_cache.save_capture(root);
 
         for (&id, doc) in &self.documents {
             info!("\tdocument {:?}", id);
-            let ron = pretty::to_string(&doc.scene).unwrap();
+            let ron = to_string_pretty(&doc.scene, ron_config.clone()).unwrap();
             let file_name = format!("scene-{}-{}.ron", (id.0).0, id.1);
             let ron_path = root.clone().join(file_name);
             let mut file = fs::File::create(ron_path).unwrap();
@@ -844,7 +846,7 @@ impl RenderBackend {
             resources,
         };
 
-        let ron = pretty::to_string(&serial).unwrap();
+        let ron = to_string_pretty(&serial, ron_config).unwrap();
         let ron_path = root.clone().join("backend.ron");
         let mut file = fs::File::create(ron_path).unwrap();
         write!(file, "{}\n", ron).unwrap();

gfx/webrender/src/render_task.rs

@@ -2,19 +2,23 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use api::{ClipId, DeviceIntPoint, DeviceIntRect, DeviceIntSize};
-use api::{LayerRect, PremultipliedColorF};
+use api::{DeviceIntPoint, DeviceIntRect, DeviceIntSize};
+use api::{ImageDescriptor, ImageFormat, LayerRect, PremultipliedColorF};
 use box_shadow::BoxShadowCacheKey;
 use clip::{ClipSourcesWeakHandle};
 use clip_scroll_tree::CoordinateSystemId;
+use device::TextureFilter;
+use gpu_cache::GpuCache;
 use gpu_types::{ClipScrollNodeIndex, PictureType};
-use internal_types::RenderPassIndex;
+use internal_types::{FastHashMap, RenderPassIndex, SourceTexture};
 use picture::ContentOrigin;
 use prim_store::{PrimitiveIndex};
 #[cfg(feature = "debugger")]
 use print_tree::{PrintTreePrinter};
+use resource_cache::CacheItem;
 use std::{cmp, ops, usize, f32, i32};
 use std::rc::Rc;
+use texture_cache::{TextureCache, TextureCacheHandle};
 use tiling::{RenderPass, RenderTargetIndex};
 use tiling::{RenderTargetKind};
 
@@ -35,72 +39,82 @@ pub struct RenderTaskTree {
     pub task_data: Vec<RenderTaskData>,
 }
 
-pub type ClipChain = Option<Rc<ClipChainNode>>;
+pub type ClipChainNodeRef = Option<Rc<ClipChainNode>>;
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct ClipChainNode {
     pub work_item: ClipWorkItem,
     pub local_clip_rect: LayerRect,
     pub screen_outer_rect: DeviceIntRect,
     pub screen_inner_rect: DeviceIntRect,
-    pub combined_outer_screen_rect: DeviceIntRect,
-    pub combined_inner_screen_rect: DeviceIntRect,
-    pub prev: ClipChain,
+    pub prev: ClipChainNodeRef,
 }
 
-impl ClipChainNode {
-    pub fn new(
+#[derive(Debug, Clone)]
+pub struct ClipChain {
+    pub combined_outer_screen_rect: DeviceIntRect,
+    pub combined_inner_screen_rect: DeviceIntRect,
+    pub nodes: ClipChainNodeRef,
+}
+
+impl ClipChain {
+    pub fn empty(screen_rect: &DeviceIntRect) -> ClipChain {
+        ClipChain {
+            combined_inner_screen_rect: *screen_rect,
+            combined_outer_screen_rect: *screen_rect,
+            nodes: None,
+        }
+    }
+
+    pub fn new_with_added_node(
+        &self,
         work_item: ClipWorkItem,
         local_clip_rect: LayerRect,
         screen_outer_rect: DeviceIntRect,
         screen_inner_rect: DeviceIntRect,
-        parent_chain: ClipChain,
-    ) -> ClipChainNode {
-        let mut node = ClipChainNode {
+    ) -> ClipChain {
+        let new_node = ClipChainNode {
             work_item,
             local_clip_rect,
             screen_outer_rect,
             screen_inner_rect,
-            combined_outer_screen_rect: screen_outer_rect,
-            combined_inner_screen_rect: screen_inner_rect,
             prev: None,
         };
-        node.set_parent(parent_chain);
-        node
+
+        let mut new_chain = self.clone();
+        new_chain.add_node(new_node);
+        new_chain
     }
 
-    fn set_parent(&mut self, new_parent: ClipChain) {
-        self.prev = new_parent.clone();
-
-        let parent_node = match new_parent {
-            Some(ref parent_node) => parent_node,
-            None => return,
-        };
+    pub fn add_node(&mut self, mut new_node: ClipChainNode) {
+        new_node.prev = self.nodes.clone();
 
         // If this clip's outer rectangle is completely enclosed by the clip
         // chain's inner rectangle, then the only clip that matters from this point
         // on is this clip. We can disconnect this clip from the parent clip chain.
-        if parent_node.combined_inner_screen_rect.contains_rect(&self.screen_outer_rect) {
-            self.prev = None;
+        if self.combined_inner_screen_rect.contains_rect(&new_node.screen_outer_rect) {
+            new_node.prev = None;
         }
 
         self.combined_outer_screen_rect =
-            parent_node.combined_outer_screen_rect.intersection(&self.screen_outer_rect)
+            self.combined_outer_screen_rect.intersection(&new_node.screen_outer_rect)
             .unwrap_or_else(DeviceIntRect::zero);
         self.combined_inner_screen_rect =
-            parent_node.combined_inner_screen_rect.intersection(&self.screen_inner_rect)
+            self.combined_inner_screen_rect.intersection(&new_node.screen_inner_rect)
             .unwrap_or_else(DeviceIntRect::zero);
+
+        self.nodes = Some(Rc::new(new_node));
     }
 }
 
 pub struct ClipChainNodeIter {
-    pub current: ClipChain,
+    pub current: ClipChainNodeRef,
 }
 
 impl Iterator for ClipChainNodeIter {
     type Item = Rc<ClipChainNode>;
 
-    fn next(&mut self) -> ClipChain {
+    fn next(&mut self) -> ClipChainNodeRef {
         let previous = self.current.clone();
         self.current = match self.current {
             Some(ref item) => item.prev.clone(),
@@ -150,7 +164,8 @@ impl RenderTaskTree {
             RenderTaskLocation::Fixed => {
                 debug_assert!(pass_index == passes.len() - 1);
             }
-            RenderTaskLocation::Dynamic(..) => {
+            RenderTaskLocation::Dynamic(..) |
+            RenderTaskLocation::TextureCache(..) => {
                 debug_assert!(pass_index < passes.len() - 1);
             }
         }
@@ -170,10 +185,7 @@ impl RenderTaskTree {
     }
 
     pub fn get_task_address(&self, id: RenderTaskId) -> RenderTaskAddress {
-        match self[id].kind {
-            RenderTaskKind::Alias(alias_id) => RenderTaskAddress(alias_id.0),
-            _ => RenderTaskAddress(id.0),
-        }
+        RenderTaskAddress(id.0)
     }
 
     pub fn build(&mut self) {
@@ -196,19 +208,11 @@ impl ops::IndexMut<RenderTaskId> for RenderTaskTree {
     }
 }
 
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
-pub enum RenderTaskKey {
-    /// Draw the alpha mask for a shared clip.
-    CacheMask(ClipId),
-    CacheScaling(BoxShadowCacheKey, DeviceIntSize),
-    CacheBlur(BoxShadowCacheKey, i32),
-    CachePicture(BoxShadowCacheKey),
-}
-
 #[derive(Debug)]
 pub enum RenderTaskLocation {
     Fixed,
     Dynamic(Option<(DeviceIntPoint, RenderTargetIndex)>, DeviceIntSize),
+    TextureCache(SourceTexture, i32, DeviceIntRect),
 }
 
 #[derive(Debug, Clone)]
@@ -238,7 +242,6 @@ pub struct PictureTask {
 pub struct BlurTask {
     pub blur_std_deviation: f32,
     pub target_kind: RenderTargetKind,
-    pub regions: Vec<LayerRect>,
     pub color: PremultipliedColorF,
     pub scale_factor: f32,
 }
@@ -249,9 +252,6 @@ impl BlurTask {
         pt.add_item(format!("std deviation: {}", self.blur_std_deviation));
         pt.add_item(format!("target: {:?}", self.target_kind));
         pt.add_item(format!("scale: {}", self.scale_factor));
-        for region in &self.regions {
-            pt.add_item(format!("region {:?}", region));
-        }
     }
 }
 
@@ -267,7 +267,6 @@ pub enum RenderTaskKind {
     VerticalBlur(BlurTask),
     HorizontalBlur(BlurTask),
     Readback(DeviceIntRect),
-    Alias(RenderTaskId),
     Scaling(RenderTargetKind),
 }
 
@@ -283,7 +282,6 @@ pub enum ClearMode {
 
 #[derive(Debug)]
 pub struct RenderTask {
-    pub cache_key: Option<RenderTaskKey>,
     pub location: RenderTaskLocation,
     pub children: Vec<RenderTaskId>,
     pub kind: RenderTaskKind,
@@ -300,7 +298,6 @@ impl RenderTask {
         color: PremultipliedColorF,
         clear_mode: ClearMode,
         children: Vec<RenderTaskId>,
-        box_shadow_cache_key: Option<BoxShadowCacheKey>,
         pic_type: PictureType,
     ) -> Self {
         let location = match size {
@@ -309,10 +306,6 @@ impl RenderTask {
         };
 
         RenderTask {
-            cache_key: match box_shadow_cache_key {
-                Some(key) => Some(RenderTaskKey::CachePicture(key)),
-                None => None,
-            },
             children,
             location,
             kind: RenderTaskKind::Picture(PictureTask {
@@ -329,7 +322,6 @@ impl RenderTask {
 
     pub fn new_readback(screen_rect: DeviceIntRect) -> Self {
         RenderTask {
-            cache_key: None,
             children: Vec::new(),
             location: RenderTaskLocation::Dynamic(None, screen_rect.size),
             kind: RenderTaskKind::Readback(screen_rect),
@@ -339,13 +331,11 @@ impl RenderTask {
     }
 
     pub fn new_mask(
-        key: Option<ClipId>,
         outer_rect: DeviceIntRect,
         clips: Vec<ClipWorkItem>,
         prim_coordinate_system_id: CoordinateSystemId,
     ) -> RenderTask {
         RenderTask {
-            cache_key: key.map(RenderTaskKey::CacheMask),
             children: Vec::new(),
             location: RenderTaskLocation::Dynamic(None, outer_rect.size),
             kind: RenderTaskKind::CacheMask(CacheMaskTask {
@@ -381,11 +371,9 @@ impl RenderTask {
         src_task_id: RenderTaskId,
         render_tasks: &mut RenderTaskTree,
         target_kind: RenderTargetKind,
-        regions: &[LayerRect],
         clear_mode: ClearMode,
         color: PremultipliedColorF,
-        box_shadow_cache_key: Option<BoxShadowCacheKey>,
-    ) -> Self {
+    ) -> (Self, f32) {
         // Adjust large std deviation value.
         let mut adjusted_blur_std_deviation = blur_std_deviation;
         let blur_target_size = render_tasks[src_task_id].get_dynamic_size();
@@ -404,23 +392,17 @@ impl RenderTask {
                 target_kind,
                 downscaling_src_task_id,
                 adjusted_blur_target_size,
-                box_shadow_cache_key,
             );
             downscaling_src_task_id = render_tasks.add(downscaling_task);
         }
         scale_factor = blur_target_size.width as f32 / adjusted_blur_target_size.width as f32;
 
         let blur_task_v = RenderTask {
-            cache_key: match box_shadow_cache_key {
-                Some(key) => Some(RenderTaskKey::CacheBlur(key, 0)),
-                None => None,
-            },
             children: vec![downscaling_src_task_id],
             location: RenderTaskLocation::Dynamic(None, adjusted_blur_target_size),
             kind: RenderTaskKind::VerticalBlur(BlurTask {
                 blur_std_deviation: adjusted_blur_std_deviation,
                 target_kind,
-                regions: regions.to_vec(),
                 color,
                 scale_factor,
             }),
@@ -431,16 +413,11 @@ impl RenderTask {
         let blur_task_v_id = render_tasks.add(blur_task_v);
 
         let blur_task_h = RenderTask {
-            cache_key: match box_shadow_cache_key {
-                Some(key) => Some(RenderTaskKey::CacheBlur(key, 1)),
-                None => None,
-            },
             children: vec![blur_task_v_id],
             location: RenderTaskLocation::Dynamic(None, adjusted_blur_target_size),
             kind: RenderTaskKind::HorizontalBlur(BlurTask {
                 blur_std_deviation: adjusted_blur_std_deviation,
                 target_kind,
-                regions: regions.to_vec(),
                 color,
                 scale_factor,
             }),
@@ -448,20 +425,15 @@ impl RenderTask {
             pass_index: None,
         };
 
-        blur_task_h
+        (blur_task_h, scale_factor)
     }
 
     pub fn new_scaling(
         target_kind: RenderTargetKind,
         src_task_id: RenderTaskId,
         target_size: DeviceIntSize,
-        box_shadow_cache_key: Option<BoxShadowCacheKey>,
     ) -> Self {
         RenderTask {
-            cache_key: match box_shadow_cache_key {
-                Some(key) => Some(RenderTaskKey::CacheScaling(key, target_size)),
-                None => None,
-            },
             children: vec![src_task_id],
             location: RenderTaskLocation::Dynamic(None, target_size),
             kind: RenderTaskKind::Scaling(target_kind),
@@ -527,8 +499,7 @@ impl RenderTask {
                 )
             }
             RenderTaskKind::Readback(..) |
-            RenderTaskKind::Scaling(..) |
-            RenderTaskKind::Alias(..) => {
+            RenderTaskKind::Scaling(..) => {
                 (
                     [0.0; 3],
                     [0.0; 4],
@@ -560,6 +531,7 @@ impl RenderTask {
         match self.location {
             RenderTaskLocation::Fixed => DeviceIntSize::zero(),
             RenderTaskLocation::Dynamic(_, size) => size,
+            RenderTaskLocation::TextureCache(_, _, rect) => rect.size,
         }
     }
 
@@ -588,6 +560,9 @@ impl RenderTask {
             RenderTaskLocation::Dynamic(None, _) => {
                 (DeviceIntRect::zero(), RenderTargetIndex(0))
             }
+            RenderTaskLocation::TextureCache(_, layer, rect) => {
+                (rect, RenderTargetIndex(layer as usize))
+            }
         }
     }
 
@@ -611,10 +586,6 @@ impl RenderTask {
             RenderTaskKind::Picture(ref task_info) => {
                 task_info.target_kind
             }
-
-            RenderTaskKind::Alias(..) => {
-                panic!("BUG: target_kind() called on invalidated task");
-            }
         }
     }
 
@@ -633,10 +604,6 @@ impl RenderTask {
             RenderTaskKind::Scaling(..) => false,
 
             RenderTaskKind::CacheMask(..) => true,
-
-            RenderTaskKind::Alias(..) => {
-                panic!("BUG: is_shared() called on aliased task");
-            }
         }
     }
 
@@ -667,10 +634,6 @@ impl RenderTask {
                 pt.new_level("Scaling".to_owned());
                 pt.add_item(format!("kind: {:?}", kind));
             }
-            RenderTaskKind::Alias(ref alias_id) => {
-                pt.add_item(format!("Alias of {:?}", alias_id));
-                return false
-            }
         }
 
         pt.add_item(format!("clear to: {:?}", self.clear_mode));
@@ -685,3 +648,131 @@ impl RenderTask {
         true
     }
 }
+
+#[derive(Debug, Hash, PartialEq, Eq)]
+pub enum RenderTaskCacheKeyKind {
+    BoxShadow(BoxShadowCacheKey),
+}
+
+#[derive(Debug, Hash, PartialEq, Eq)]
+pub struct RenderTaskCacheKey {
+    pub size: DeviceIntSize,
+    pub kind: RenderTaskCacheKeyKind,
+}
+
+struct RenderTaskCacheEntry {
+    handle: TextureCacheHandle,
+}
+
+// A cache of render tasks that are stored in the texture
+// cache for usage across frames.
+pub struct RenderTaskCache {
+    entries: FastHashMap<RenderTaskCacheKey, RenderTaskCacheEntry>,
+}
+
+impl RenderTaskCache {
+    pub fn new() -> RenderTaskCache {
+        RenderTaskCache {
+            entries: FastHashMap::default(),
+        }
+    }
+
+    pub fn clear(&mut self) {
+        self.entries.clear();
+    }
+
+    pub fn begin_frame(
+        &mut self,
+        texture_cache: &mut TextureCache,
+    ) {
+        // Drop any items from the cache that have been
+        // evicted from the texture cache.
+        //
+        // This isn't actually necessary for the texture
+        // cache to be able to evict old render tasks.
+        // It will evict render tasks as required, since
+        // the access time in the texture cache entry will
+        // be stale if this task hasn't been requested
+        // for a while.
+        //
+        // Nonetheless, we should remove stale entries
+        // from here so that this hash map doesn't
+        // grow indefinitely!
+        self.entries.retain(|_, value| {
+            texture_cache.is_allocated(&value.handle)
+        });
+    }
+
+    pub fn request_render_task<F>(
+        &mut self,
+        key: RenderTaskCacheKey,
+        texture_cache: &mut TextureCache,
+        gpu_cache: &mut GpuCache,
+        render_tasks: &mut RenderTaskTree,
+        mut f: F,
+    ) -> CacheItem where F: FnMut(&mut RenderTaskTree) -> (RenderTaskId, [f32; 3]) {
+        // Get the texture cache handle for this cache key,
+        // or create one.
+        let cache_entry = self.entries
+                              .entry(key)
+                              .or_insert(RenderTaskCacheEntry {
+                                  handle: TextureCacheHandle::new(),
+                              });
+
+        // Check if this texture cache handle is valie.
+        if texture_cache.request(&mut cache_entry.handle, gpu_cache) {
+            // Invoke user closure to get render task chain
+            // to draw this into the texture cache.
+            let (render_task_id, user_data) = f(render_tasks);
+            let render_task = &mut render_tasks[render_task_id];
+
+            // Find out what size to alloc in the texture cache.
+            let size = match render_task.location {
+                RenderTaskLocation::Fixed |
+                RenderTaskLocation::TextureCache(..) => {
+                    panic!("BUG: dynamic task was expected");
+                }
+                RenderTaskLocation::Dynamic(_, size) => size,
+            };
+
+            // TODO(gw): Support color tasks in the texture cache,
+            //           and perhaps consider if we can determine
+            //           if some tasks are opaque as an optimization.
+            let descriptor = ImageDescriptor::new(
+                size.width as u32,
+                size.height as u32,
+                ImageFormat::R8,
+                false,
+            );
+
+            // Allocate space in the texture cache, but don't supply
+            // and CPU-side data to be uploaded.
+            texture_cache.update(
+                &mut cache_entry.handle,
+                descriptor,
+                TextureFilter::Linear,
+                None,
+                user_data,
+                None,
+                gpu_cache,
+            );
+
+            // Get the allocation details in the texture cache, and store
+            // this in the render task. The renderer will draw this
+            // task into the appropriate layer and rect of the texture
+            // cache on this frame.
+            let (texture_id, texture_layer, uv_rect) =
+                texture_cache.get_cache_location(&cache_entry.handle);
+
+            render_task.location = RenderTaskLocation::TextureCache(
+                texture_id,
+                texture_layer,
+                uv_rect.to_i32()
+            );
+        }
+
+        // Finally, return the texture cache handle that we know
+        // is now up to date.
+        texture_cache.get(&cache_entry.handle)
+    }
+}

gfx/webrender/src/renderer.rs

@@ -66,7 +66,7 @@ use texture_cache::TextureCache;
 use thread_profiler::{register_thread_with_profiler, write_profile};
 use tiling::{AlphaRenderTarget, ColorRenderTarget};
 use tiling::{RenderPass, RenderPassKind, RenderTargetList};
-use tiling::{Frame, RenderTarget, ScalingInfo};
+use tiling::{Frame, RenderTarget, ScalingInfo, TextureCacheRenderTarget};
 use time::precise_time_ns;
 use util::TransformedRectKind;
 
@@ -103,10 +103,6 @@ const GPU_TAG_CACHE_TEXT_RUN: GpuProfileTag = GpuProfileTag {
     label: "C_TextRun",
     color: debug_colors::MISTYROSE,
 };
-const GPU_TAG_CACHE_LINE: GpuProfileTag = GpuProfileTag {
-    label: "C_Line",
-    color: debug_colors::BROWN,
-};
 const GPU_TAG_SETUP_TARGET: GpuProfileTag = GpuProfileTag {
     label: "target init",
     color: debug_colors::SLATEGREY,
@@ -413,11 +409,6 @@ const DESC_BLUR: VertexDescriptor = VertexDescriptor {
             count: 1,
             kind: VertexAttributeKind::I32,
         },
-        VertexAttribute {
-            name: "aBlurRegion",
-            count: 4,
-            kind: VertexAttributeKind::F32
-        },
     ],
 };
 
@@ -769,6 +760,7 @@ impl SourceTextureResolver {
 #[allow(dead_code)] // SubpixelVariableTextColor is not used at the moment.
 pub enum BlendMode {
     None,
+    Alpha,
     PremultipliedAlpha,
     PremultipliedDestOut,
     SubpixelDualSource,
@@ -1299,6 +1291,7 @@ impl BrushShader {
             BlendMode::None => {
                 self.opaque.bind(device, projection, mode, renderer_errors)
             }
+            BlendMode::Alpha |
             BlendMode::PremultipliedAlpha |
             BlendMode::PremultipliedDestOut |
             BlendMode::SubpixelDualSource |
@@ -2099,7 +2092,7 @@ impl Renderer {
                 &mut texture,
                 8,
                 8,
-                ImageFormat::A8,
+                ImageFormat::R8,
                 TextureFilter::Nearest,
                 None,
                 1,
@@ -2553,11 +2546,6 @@ impl Renderer {
                 batch.len(),
             );
         }
-        debug_target.add(
-            debug_server::BatchKind::Cache,
-            "Lines",
-            target.alpha_batcher.line_cache_prims.len(),
-        );
 
         for batch in target
             .alpha_batcher
@@ -2585,6 +2573,19 @@ impl Renderer {
         debug_target
     }
 
+    #[cfg(feature = "debugger")]
+    fn debug_texture_cache_target(target: &TextureCacheRenderTarget) -> debug_server::Target {
+        let mut debug_target = debug_server::Target::new("Texture Cache");
+
+        debug_target.add(
+            debug_server::BatchKind::Cache,
+            "Horizontal Blur",
+            target.horizontal_blurs.len(),
+        );
+
+        debug_target
+    }
+
     #[cfg(feature = "debugger")]
     fn get_passes_for_debugger(&self) -> String {
         let mut debug_passes = debug_server::PassList::new();
@@ -2596,9 +2597,10 @@ impl Renderer {
                     RenderPassKind::MainFramebuffer(ref target) => {
                         debug_targets.push(Self::debug_color_target(target));
                     }
-                    RenderPassKind::OffScreen { ref alpha, ref color } => {
+                    RenderPassKind::OffScreen { ref alpha, ref color, ref texture_cache } => {
                         debug_targets.extend(alpha.targets.iter().map(Self::debug_alpha_target));
                         debug_targets.extend(color.targets.iter().map(Self::debug_color_target));
+                        debug_targets.extend(texture_cache.iter().map(|(_, target)| Self::debug_texture_cache_target(target)))
                     }
                 }
 
@@ -3444,27 +3446,6 @@ impl Renderer {
                 );
             }
         }
-        if !target.alpha_batcher.line_cache_prims.is_empty() {
-            // TODO(gw): Technically, we don't need blend for solid
-            //           lines. We could check that here?
-            self.device.set_blend(true);
-            self.device.set_blend_mode_premultiplied_alpha();
-
-            let _timer = self.gpu_profile.start_timer(GPU_TAG_CACHE_LINE);
-            self.brush_line.bind(
-                &mut self.device,
-                BlendMode::PremultipliedAlpha,
-                projection,
-                0,
-                &mut self.renderer_errors,
-            );
-            self.draw_instanced_batch(
-                &target.alpha_batcher.line_cache_prims,
-                VertexArrayKind::Primitive,
-                &BatchTextures::no_texture(),
-                stats,
-            );
-        }
 
         //TODO: record the pixel count for cached primitives
 
@@ -3512,6 +3493,7 @@ impl Renderer {
                 if self.debug_flags.contains(DebugFlags::ALPHA_PRIM_DBG) {
                     let color = match batch.key.blend_mode {
                         BlendMode::None => debug_colors::BLACK,
+                        BlendMode::Alpha |
                         BlendMode::PremultipliedAlpha => debug_colors::GREY,
                         BlendMode::PremultipliedDestOut => debug_colors::SALMON,
                         BlendMode::SubpixelConstantTextColor(..) => debug_colors::GREEN,
@@ -3538,6 +3520,7 @@ impl Renderer {
                         self.device.set_blend(true);
 
                         match batch.key.blend_mode {
+                            BlendMode::Alpha => panic!("Attempt to composite non-premultiplied text primitives."),
                             BlendMode::PremultipliedAlpha => {
                                 self.device.set_blend_mode_premultiplied_alpha();
 
@@ -3706,6 +3689,10 @@ impl Renderer {
                                 BlendMode::None => {
                                     self.device.set_blend(false);
                                 }
+                                BlendMode::Alpha => {
+                                    self.device.set_blend(true);
+                                    self.device.set_blend_mode_alpha();
+                                }
                                 BlendMode::PremultipliedAlpha => {
                                     self.device.set_blend(true);
                                     self.device.set_blend_mode_premultiplied_alpha();
@@ -3963,6 +3950,51 @@ impl Renderer {
         self.gpu_profile.finish_sampler(alpha_sampler);
     }
 
+    fn draw_texture_cache_target(
+        &mut self,
+        texture: &SourceTexture,
+        layer: i32,
+        target: &TextureCacheRenderTarget,
+        stats: &mut RendererStats,
+    ) {
+        let projection = {
+            let texture = self.texture_resolver
+                .resolve(texture)
+                .expect("BUG: invalid target texture");
+            let target_size = texture.get_dimensions();
+
+            self.device
+                .bind_draw_target(Some((texture, layer)), Some(target_size));
+            self.device.disable_depth();
+            self.device.disable_depth_write();
+            self.device.set_blend(false);
+
+            Transform3D::ortho(
+                0.0,
+                target_size.width as f32,
+                0.0,
+                target_size.height as f32,
+                ORTHO_NEAR_PLANE,
+                ORTHO_FAR_PLANE,
+            )
+        };
+
+        // Draw any blurs for this target.
+        if !target.horizontal_blurs.is_empty() {
+            let _timer = self.gpu_profile.start_timer(GPU_TAG_BLUR);
+
+            self.cs_blur_a8
+                .bind(&mut self.device, &projection, 0, &mut self.renderer_errors);
+
+            self.draw_instanced_batch(
+                &target.horizontal_blurs,
+                VertexArrayKind::Blur,
+                &BatchTextures::no_texture(),
+                stats,
+            );
+        }
+    }
+
     fn update_deferred_resolves(&mut self, frame: &Frame) -> Option<GpuCacheUpdateList> {
         // The first thing we do is run through any pending deferred
         // resolves, and use a callback to get the UV rect for this
@@ -4082,6 +4114,7 @@ impl Renderer {
             }
         } else {
             if list.texture.is_some() {
+                list.check_ready();
                 return
             }
             match self.texture_resolver.render_target_pool.pop() {
@@ -4103,13 +4136,14 @@ impl Renderer {
             None,
         );
         list.texture = Some(texture);
+        list.check_ready();
     }
 
     fn prepare_tile_frame(&mut self, frame: &mut Frame) {
         // Init textures and render targets to match this scene.
         // First pass grabs all the perfectly matching targets from the pool.
         for pass in &mut frame.passes {
-            if let RenderPassKind::OffScreen { ref mut alpha, ref mut color } = pass.kind {
+            if let RenderPassKind::OffScreen { ref mut alpha, ref mut color, .. } = pass.kind {
                 self.prepare_target_list(alpha, true);
                 self.prepare_target_list(color, true);
             }
@@ -4123,7 +4157,7 @@ impl Renderer {
         // Some of the textures are already assigned by `prepare_frame`.
         // Now re-allocate the space for the rest of the target textures.
         for pass in &mut frame.passes {
-            if let RenderPassKind::OffScreen { ref mut alpha, ref mut color } = pass.kind {
+            if let RenderPassKind::OffScreen { ref mut alpha, ref mut color, .. } = pass.kind {
                 self.prepare_target_list(alpha, false);
                 self.prepare_target_list(color, false);
             }
@@ -4216,9 +4250,17 @@ impl Renderer {
 
                     (None, None)
                 }
-                RenderPassKind::OffScreen { ref mut alpha, ref mut color } => {
-                    assert!(alpha.targets.is_empty() || alpha.texture.is_some());
-                    assert!(color.targets.is_empty() || color.texture.is_some());
+                RenderPassKind::OffScreen { ref mut alpha, ref mut color, ref mut texture_cache } => {
+                    alpha.check_ready();
+                    color.check_ready();
+                    for (&(texture_id, target_index), target) in texture_cache {
+                        self.draw_texture_cache_target(
+                            &texture_id,
+                            target_index,
+                            target,
+                            stats,
+                        );
+                    }
 
                     for (target_index, target) in alpha.targets.iter().enumerate() {
                         stats.alpha_target_count += 1;

gfx/webrender/src/resource_cache.rs

@@ -4,8 +4,7 @@
 
 use api::{AddFont, BlobImageData, BlobImageResources, ResourceUpdate, ResourceUpdates};
 use api::{BlobImageDescriptor, BlobImageError, BlobImageRenderer, BlobImageRequest};
-use api::ColorF;
-use api::{DevicePoint, DeviceUintRect, DeviceUintSize};
+use api::{ColorF, DevicePoint, DeviceUintRect, DeviceUintSize};
 use api::{Epoch, FontInstanceKey, FontKey, FontTemplate};
 use api::{ExternalImageData, ExternalImageType};
 use api::{FontInstanceOptions, FontInstancePlatformOptions, FontVariation};
@@ -25,6 +24,7 @@ use internal_types::{FastHashMap, FastHashSet, SourceTexture, TextureUpdateList}
 use internal_types::ExternalCaptureImage;
 use profiler::{ResourceProfileCounters, TextureCacheProfileCounters};
 use rayon::ThreadPool;
+use render_task::{RenderTaskCache, RenderTaskCacheKey, RenderTaskId, RenderTaskTree};
 use std::collections::hash_map::Entry::{self, Occupied, Vacant};
 use std::cmp;
 use std::fmt::Debug;
@@ -52,6 +52,7 @@ pub struct GlyphFetchResult {
 // storing the coordinates as texel values
 // we don't need to go through and update
 // various CPU-side structures.
+#[derive(Debug)]
 pub struct CacheItem {
     pub texture_id: SourceTexture,
     pub uv_rect_handle: GpuCacheHandle,
@@ -219,6 +220,7 @@ impl BlobImageResources for Resources {
 pub struct ResourceCache {
     cached_glyphs: GlyphCache,
     cached_images: ImageCache,
+    cached_render_tasks: RenderTaskCache,
 
     resources: Resources,
     state: State,
@@ -247,6 +249,7 @@ impl ResourceCache {
         ResourceCache {
             cached_glyphs: GlyphCache::new(),
             cached_images: ResourceClassCache::new(),
+            cached_render_tasks: RenderTaskCache::new(),
             resources: Resources {
                 font_templates: FastHashMap::default(),
                 font_instances: Arc::new(RwLock::new(FastHashMap::default())),
@@ -278,6 +281,27 @@ impl ResourceCache {
         }
     }
 
+    // Request the texture cache item for a cacheable render
+    // task. If the item is already cached, the texture cache
+    // handle will be returned. Otherwise, the user supplied
+    // closure will be invoked to generate the render task
+    // chain that is required to draw this task.
+    pub fn request_render_task<F>(
+        &mut self,
+        key: RenderTaskCacheKey,
+        gpu_cache: &mut GpuCache,
+        render_tasks: &mut RenderTaskTree,
+        f: F,
+    ) -> CacheItem where F: FnMut(&mut RenderTaskTree) -> (RenderTaskId, [f32; 3]) {
+        self.cached_render_tasks.request_render_task(
+            key,
+            &mut self.texture_cache,
+            gpu_cache,
+            render_tasks,
+            f
+        )
+    }
+
     pub fn update_resources(
         &mut self,
         updates: ResourceUpdates,
@@ -762,6 +786,7 @@ impl ResourceCache {
         debug_assert_eq!(self.state, State::Idle);
         self.state = State::AddResources;
         self.texture_cache.begin_frame(frame_id);
+        self.cached_render_tasks.begin_frame(&mut self.texture_cache);
         self.current_frame_id = frame_id;
     }
 
@@ -871,7 +896,7 @@ impl ResourceCache {
                 &mut entry.texture_cache_handle,
                 descriptor,
                 filter,
-                image_data,
+                Some(image_data),
                 [0.0; 3],
                 image_template.dirty_rect,
                 gpu_cache,
@@ -896,6 +921,7 @@ impl ResourceCache {
         // recently used resources.
         self.cached_images.clear();
         self.cached_glyphs.clear();
+        self.cached_render_tasks.clear();
     }
 
     pub fn clear_namespace(&mut self, namespace: IdNamespace) {
@@ -1127,6 +1153,7 @@ impl ResourceCache {
         info!("loading resource cache");
         self.cached_glyphs.clear();
         self.cached_images.clear();
+        self.cached_render_tasks.clear();
 
         self.state = State::Idle;
         self.current_frame_id = FrameId(0);

gfx/webrender/src/texture_cache.rs

@@ -206,7 +206,7 @@ impl TextureCache {
         TextureCache {
             max_texture_size,
             array_a8_linear: TextureArray::new(
-                ImageFormat::A8,
+                ImageFormat::R8,
                 TextureFilter::Linear,
                 TEXTURE_ARRAY_LAYERS_LINEAR,
             ),
@@ -284,7 +284,7 @@ impl TextureCache {
         handle: &mut TextureCacheHandle,
         descriptor: ImageDescriptor,
         filter: TextureFilter,
-        data: ImageData,
+        data: Option<ImageData>,
         user_data: [f32; 3],
         mut dirty_rect: Option<DeviceUintRect>,
         gpu_cache: &mut GpuCache,
@@ -337,6 +337,7 @@ impl TextureCache {
         // Create an update command, which the render thread processes
         // to upload the new image data into the correct location
         // in GPU memory.
+        if let Some(data) = data {
             let (layer_index, origin) = match entry.kind {
                 EntryKind::Standalone { .. } => (0, DeviceUintPoint::zero()),
                 EntryKind::Cache {
@@ -357,6 +358,7 @@ impl TextureCache {
             );
             self.pending_updates.push(op);
         }
+    }
 
     // Get a specific region by index from a shared texture array.
     fn get_region_mut(&mut self,
@@ -365,18 +367,26 @@ impl TextureCache {
         region_index: u16
     ) -> &mut TextureRegion {
         let texture_array = match (format, filter) {
-            (ImageFormat::A8, TextureFilter::Linear) => &mut self.array_a8_linear,
+            (ImageFormat::R8, TextureFilter::Linear) => &mut self.array_a8_linear,
             (ImageFormat::BGRA8, TextureFilter::Linear) => &mut self.array_rgba8_linear,
             (ImageFormat::BGRA8, TextureFilter::Nearest) => &mut self.array_rgba8_nearest,
             (ImageFormat::Invalid, _) |
             (ImageFormat::RGBAF32, _) |
             (ImageFormat::RG8, _) |
-            (ImageFormat::A8, TextureFilter::Nearest) => unreachable!(),
+            (ImageFormat::R8, TextureFilter::Nearest) => unreachable!(),
         };
 
         &mut texture_array.regions[region_index as usize]
     }
 
+    // Check if a given texture handle has a valid allocation
+    // in the texture cache.
+    pub fn is_allocated(&self, handle: &TextureCacheHandle) -> bool {
+        handle.entry.as_ref().map_or(false, |handle| {
+            self.entries.get_opt(handle).is_some()
+        })
+    }
+
     // Retrieve the details of an item in the cache. This is used
     // during batch creation to provide the resource rect address
     // to the shaders and texture ID to the batching logic.
@@ -398,6 +408,36 @@ impl TextureCache {
         }
     }
 
+    // A more detailed version of get(). This allows access to the actual
+    // device rect of the cache allocation.
+    pub fn get_cache_location(
+        &self,
+        handle: &TextureCacheHandle,
+    ) -> (SourceTexture, i32, DeviceUintRect) {
+        let handle = handle
+            .entry
+            .as_ref()
+            .expect("BUG: handle not requested earlier in frame");
+
+        let entry = self.entries
+            .get_opt(handle)
+            .expect("BUG: was dropped from cache or not updated!");
+        debug_assert_eq!(entry.last_access, self.frame_id);
+        let (layer_index, origin) = match entry.kind {
+            EntryKind::Standalone { .. } => {
+                (0, DeviceUintPoint::zero())
+            }
+            EntryKind::Cache {
+                layer_index,
+                origin,
+                ..
+            } => (layer_index, origin),
+        };
+        (SourceTexture::TextureCache(entry.texture_id),
+         layer_index as i32,
+         DeviceUintRect::new(origin, entry.size))
+    }
+
     // Expire old standalone textures.
     fn expire_old_standalone_entries(&mut self) {
         let mut eviction_candidates = Vec::new();
@@ -470,7 +510,7 @@ impl TextureCache {
         // want to evict everything we can, since that will result in
         // more items being uploaded than necessary.
         // Instead, we say we will keep evicting until both of these
-        // consitions are met:
+        // conditions are met:
         // - We have evicted some arbitrary number of items (512 currently).
         //   AND
         // - We have freed an item that will definitely allow us to
@@ -537,12 +577,12 @@ impl TextureCache {
     ) -> Option<CacheEntry> {
         // Work out which cache it goes in, based on format.
         let texture_array = match (descriptor.format, filter) {
-            (ImageFormat::A8, TextureFilter::Linear) => &mut self.array_a8_linear,
+            (ImageFormat::R8, TextureFilter::Linear) => &mut self.array_a8_linear,
             (ImageFormat::BGRA8, TextureFilter::Linear) => &mut self.array_rgba8_linear,
             (ImageFormat::BGRA8, TextureFilter::Nearest) => &mut self.array_rgba8_nearest,
             (ImageFormat::Invalid, _) |
             (ImageFormat::RGBAF32, _) |
-            (ImageFormat::A8, TextureFilter::Nearest) |
+            (ImageFormat::R8, TextureFilter::Nearest) |
             (ImageFormat::RG8, _) => unreachable!(),
         };
 

gfx/webrender/src/tiling.rs

@@ -14,16 +14,15 @@ use gpu_cache::{GpuCache, GpuCacheUpdateList};
 use gpu_types::{BlurDirection, BlurInstance, BrushInstance, ClipChainRectIndex};
 use gpu_types::{ClipScrollNodeData, ClipScrollNodeIndex};
 use gpu_types::{PrimitiveInstance};
-use internal_types::{FastHashMap, RenderPassIndex};
+use internal_types::{FastHashMap, RenderPassIndex, SourceTexture};
 use picture::{PictureKind};
 use prim_store::{PrimitiveIndex, PrimitiveKind, PrimitiveStore};
-use prim_store::{BrushMaskKind, BrushKind, DeferredResolve};
+use prim_store::{BrushMaskKind, BrushKind, DeferredResolve, EdgeAaSegmentMask};
 use profiler::FrameProfileCounters;
-use render_task::{RenderTaskAddress, RenderTaskId, RenderTaskKey, RenderTaskKind};
+use render_task::{RenderTaskAddress, RenderTaskId, RenderTaskKind};
 use render_task::{BlurTask, ClearMode, RenderTaskLocation, RenderTaskTree};
 use resource_cache::{ResourceCache};
 use std::{cmp, usize, f32, i32};
-use std::collections::hash_map::Entry;
 use texture_allocator::GuillotineAllocator;
 
 const MIN_TARGET_SIZE: u32 = 2048;
@@ -38,12 +37,6 @@ pub struct ScrollbarPrimitive {
 #[derive(Debug, Copy, Clone)]
 pub struct RenderTargetIndex(pub usize);
 
-#[derive(Debug)]
-struct DynamicTaskInfo {
-    task_id: RenderTaskId,
-    rect: DeviceIntRect,
-}
-
 pub struct RenderTargetContext<'a> {
     pub device_pixel_scale: DevicePixelScale,
     pub prim_store: &'a PrimitiveStore,
@@ -201,6 +194,22 @@ impl<T: RenderTarget> RenderTargetList<T> {
     pub fn needs_depth(&self) -> bool {
         self.targets.iter().any(|target| target.needs_depth())
     }
+
+    pub fn check_ready(&self) {
+        match self.texture {
+            Some(ref t) => {
+                assert_eq!(t.get_dimensions(), self.max_size);
+                assert_eq!(t.get_format(), self.format);
+                assert_eq!(t.get_render_target_layer_count(), self.targets.len());
+                assert_eq!(t.get_layer_count() as usize, self.targets.len());
+                assert_eq!(t.has_depth(), t.get_rt_info().unwrap().has_depth);
+                assert_eq!(t.has_depth(), self.needs_depth());
+            }
+            None => {
+                assert!(self.targets.is_empty())
+            }
+        }
+    }
 }
 
 /// Frame output information for a given pipeline ID.
@@ -282,9 +291,6 @@ impl RenderTarget for ColorRenderTarget {
         let task = &render_tasks[task_id];
 
         match task.kind {
-            RenderTaskKind::Alias(..) => {
-                panic!("BUG: add_task() called on invalidated task");
-            }
             RenderTaskKind::VerticalBlur(ref info) => {
                 info.add_instances(
                     &mut self.vertical_blurs,
@@ -409,9 +415,6 @@ impl RenderTarget for AlphaRenderTarget {
         }
 
         match task.kind {
-            RenderTaskKind::Alias(..) => {
-                panic!("BUG: add_task() called on invalidated task");
-            }
             RenderTaskKind::Readback(..) => {
                 panic!("Should not be added to alpha target!");
             }
@@ -465,13 +468,15 @@ impl RenderTarget for AlphaRenderTarget {
                                             clip_task_address: RenderTaskAddress(0),
                                             z: 0,
                                             segment_index: 0,
+                                            edge_flags: EdgeAaSegmentMask::empty(),
                                             user_data0: 0,
                                             user_data1: 0,
                                         };
                                         let brush = &ctx.prim_store.cpu_brushes[sub_metadata.cpu_prim_index.0];
                                         let batch = match brush.kind {
                                             BrushKind::Solid { .. } |
-                                            BrushKind::Clear => {
+                                            BrushKind::Clear |
+                                            BrushKind::Line { .. } => {
                                                 unreachable!("bug: unexpected brush here");
                                             }
                                             BrushKind::Mask { ref kind, .. } => {
@@ -525,12 +530,54 @@ impl RenderTarget for AlphaRenderTarget {
     }
 }
 
+pub struct TextureCacheRenderTarget {
+    pub horizontal_blurs: Vec<BlurInstance>,
+}
+
+impl TextureCacheRenderTarget {
+    fn new(
+        _size: Option<DeviceUintSize>,
+        _screen_size: DeviceIntSize,
+    ) -> Self {
+        TextureCacheRenderTarget {
+            horizontal_blurs: Vec::new(),
+        }
+    }
+
+    fn add_task(
+        &mut self,
+        task_id: RenderTaskId,
+        render_tasks: &RenderTaskTree,
+    ) {
+        let task = &render_tasks[task_id];
+
+        match task.kind {
+            RenderTaskKind::HorizontalBlur(ref info) => {
+                info.add_instances(
+                    &mut self.horizontal_blurs,
+                    task_id,
+                    task.children[0],
+                    BlurDirection::Horizontal,
+                    render_tasks,
+                );
+            }
+            RenderTaskKind::VerticalBlur(..) |
+            RenderTaskKind::Picture(..) |
+            RenderTaskKind::CacheMask(..) |
+            RenderTaskKind::Readback(..) |
+            RenderTaskKind::Scaling(..) => {
+                panic!("BUG: unexpected task kind for texture cache target");
+            }
+        }
+    }
+}
 
 pub enum RenderPassKind {
     MainFramebuffer(ColorRenderTarget),
     OffScreen {
         alpha: RenderTargetList<AlphaRenderTarget>,
         color: RenderTargetList<ColorRenderTarget>,
+        texture_cache: FastHashMap<(SourceTexture, i32), TextureCacheRenderTarget>,
     },
 }
 
@@ -542,7 +589,6 @@ pub enum RenderPassKind {
 pub struct RenderPass {
     pub kind: RenderPassKind,
     tasks: Vec<RenderTaskId>,
-    dynamic_tasks: FastHashMap<RenderTaskKey, DynamicTaskInfo>,
 }
 
 impl RenderPass {
@@ -551,7 +597,6 @@ impl RenderPass {
         RenderPass {
             kind: RenderPassKind::MainFramebuffer(target),
             tasks: vec![],
-            dynamic_tasks: FastHashMap::default(),
         }
     }
 
@@ -559,10 +604,10 @@ impl RenderPass {
         RenderPass {
             kind: RenderPassKind::OffScreen {
                 color: RenderTargetList::new(screen_size, ImageFormat::BGRA8),
-                alpha: RenderTargetList::new(screen_size, ImageFormat::A8),
+                alpha: RenderTargetList::new(screen_size, ImageFormat::R8),
+                texture_cache: FastHashMap::default(),
             },
             tasks: vec![],
-            dynamic_tasks: FastHashMap::default(),
         }
     }
 
@@ -572,7 +617,7 @@ impl RenderPass {
         size: DeviceIntSize,
         target_kind: RenderTargetKind,
     ) {
-        if let RenderPassKind::OffScreen { ref mut color, ref mut alpha } = self.kind {
+        if let RenderPassKind::OffScreen { ref mut color, ref mut alpha, .. } = self.kind {
             let max_size = match target_kind {
                 RenderTargetKind::Color => &mut color.max_size,
                 RenderTargetKind::Alpha => &mut alpha.max_size,
@@ -604,10 +649,10 @@ impl RenderPass {
                 }
                 target.build(ctx, gpu_cache, render_tasks, deferred_resolves);
             }
-            RenderPassKind::OffScreen { ref mut color, ref mut alpha } => {
+            RenderPassKind::OffScreen { ref mut color, ref mut alpha, ref mut texture_cache } => {
                 // Step through each task, adding to batches as appropriate.
                 for &task_id in &self.tasks {
-                    let target_kind = {
+                    let (target_kind, texture_target) = {
                         let task = &mut render_tasks[task_id];
                         task.pass_index = Some(pass_index);
                         let target_kind = task.target_kind();
@@ -615,22 +660,16 @@ impl RenderPass {
                         // Find a target to assign this task to, or create a new
                         // one if required.
                         match task.location {
-                            RenderTaskLocation::Fixed => {}
+                            RenderTaskLocation::TextureCache(texture_id, layer, _) => {
+                                // TODO(gw): When we support caching color items, we will
+                                //           need to calculate that here to get the
+                                //           correct target kind.
+                                (RenderTargetKind::Alpha, Some((texture_id, layer)))
+                            }
+                            RenderTaskLocation::Fixed => {
+                                (RenderTargetKind::Color, None)
+                            }
                             RenderTaskLocation::Dynamic(ref mut origin, size) => {
-                                let dynamic_entry = match task.cache_key {
-                                    // See if this task is a duplicate.
-                                    // If so, just skip adding it!
-                                    Some(cache_key) => match self.dynamic_tasks.entry(cache_key) {
-                                        Entry::Occupied(entry) => {
-                                            debug_assert_eq!(entry.get().rect.size, size);
-                                            task.kind = RenderTaskKind::Alias(entry.get().task_id);
-                                            continue;
-                                        },
-                                        Entry::Vacant(entry) => Some(entry),
-                                    },
-                                    None => None,
-                                };
-
                                 let alloc_size = DeviceUintSize::new(size.width as u32, size.height as u32);
                                 let (alloc_origin, target_index) =  match target_kind {
                                     RenderTargetKind::Color => color.allocate(alloc_size),
@@ -638,25 +677,28 @@ impl RenderPass {
                                 };
                                 *origin = Some((alloc_origin.to_i32(), target_index));
 
-                                // If this task is cacheable / sharable, store it in the task hash
-                                // for this pass.
-                                if let Some(entry) = dynamic_entry {
-                                    entry.insert(DynamicTaskInfo {
-                                        task_id,
-                                        rect: DeviceIntRect::new(alloc_origin.to_i32(), size),
-                                    });
+                                (target_kind, None)
                             }
                         }
-                        }
-
-                        target_kind
                     };
 
+                    match texture_target {
+                        Some(texture_target) => {
+                            let texture = texture_cache
+                                .entry(texture_target)
+                                .or_insert(
+                                    TextureCacheRenderTarget::new(None, DeviceIntSize::zero())
+                                );
+                            texture.add_task(task_id, render_tasks);
+                        }
+                        None => {
                             match target_kind {
                                 RenderTargetKind::Color => color.add_task(task_id, ctx, gpu_cache, render_tasks, clip_store),
                                 RenderTargetKind::Alpha => alpha.add_task(task_id, ctx, gpu_cache, render_tasks, clip_store),
                             }
                         }
+                    }
+                }
 
                 color.build(ctx, gpu_cache, render_tasks, deferred_resolves);
                 alpha.build(ctx, gpu_cache, render_tasks, deferred_resolves);
@@ -726,18 +768,8 @@ impl BlurTask {
             task_address: render_tasks.get_task_address(task_id),
             src_task_address: render_tasks.get_task_address(source_task_id),
             blur_direction,
-            region: LayerRect::zero(),
         };
 
-        if self.regions.is_empty() {
         instances.push(instance);
-        } else {
-            for region in &self.regions {
-                instances.push(BlurInstance {
-                    region: *region,
-                    ..instance
-                });
-            }
-        }
     }
 }

gfx/webrender_api/src/display_item.rs

@@ -111,6 +111,7 @@ pub enum SpecificDisplayItem {
     BoxShadow(BoxShadowDisplayItem),
     Gradient(GradientDisplayItem),
     RadialGradient(RadialGradientDisplayItem),
+    ClipChain(ClipChainItem),
     Iframe(IframeDisplayItem),
     PushStackingContext(PushStackingContextDisplayItem),
     PopStackingContext,
@@ -126,6 +127,7 @@ pub enum SpecificDisplayItem {
 #[derive(Deserialize, Serialize)]
 pub enum CompletelySpecificDisplayItem {
     Clip(ClipDisplayItem, Vec<ComplexClipRegion>),
+    ClipChain(ClipChainItem, Vec<ClipId>),
     ScrollFrame(ScrollFrameDisplayItem, Vec<ComplexClipRegion>),
     StickyFrame(StickyFrameDisplayItem),
     Rectangle(RectangleDisplayItem),
@@ -426,6 +428,12 @@ pub struct RadialGradient {
     pub extend_mode: ExtendMode,
 } // IMPLICIT stops: Vec<GradientStop>
 
+#[derive(Clone, Copy, Debug, Deserialize, PartialEq, Serialize)]
+pub struct ClipChainItem {
+    pub id: ClipChainId,
+    pub parent: Option<ClipChainId>,
+} // IMPLICIT stops: Vec<ClipId>
+
 #[derive(Clone, Copy, Debug, Deserialize, PartialEq, Serialize)]
 pub struct RadialGradientDisplayItem {
     pub gradient: RadialGradient,
@@ -507,6 +515,7 @@ pub struct ImageDisplayItem {
     pub stretch_size: LayoutSize,
     pub tile_spacing: LayoutSize,
     pub image_rendering: ImageRendering,
+    pub alpha_type: AlphaType,
 }
 
 #[repr(u32)]
@@ -517,6 +526,12 @@ pub enum ImageRendering {
     Pixelated = 2,
 }
 
+#[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, PartialEq, Serialize)]
+pub enum AlphaType {
+    Alpha = 0,
+    PremultipliedAlpha = 1,
+}
+
 #[derive(Clone, Copy, Debug, Deserialize, PartialEq, Serialize)]
 pub struct YuvImageDisplayItem {
     pub yuv_data: YuvData,
@@ -727,9 +742,14 @@ impl ComplexClipRegion {
     }
 }
 
+
+#[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, PartialEq, Serialize)]
+pub struct ClipChainId(pub u64, pub PipelineId);
+
 #[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, PartialEq, Serialize)]
 pub enum ClipId {
     Clip(u64, PipelineId),
+    ClipChain(ClipChainId),
     ClipExternalId(u64, PipelineId),
     DynamicallyAddedNode(u64, PipelineId),
 }
@@ -756,6 +776,7 @@ impl ClipId {
     pub fn pipeline_id(&self) -> PipelineId {
         match *self {
             ClipId::Clip(_, pipeline_id) |
+            ClipId::ClipChain(ClipChainId(_, pipeline_id)) |
             ClipId::ClipExternalId(_, pipeline_id) |
             ClipId::DynamicallyAddedNode(_, pipeline_id) => pipeline_id,
         }

gfx/webrender_api/src/display_list.rs

@@ -2,17 +2,17 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use {BorderDetails, BorderDisplayItem, BorderRadius, BorderWidths, BoxShadowClipMode};
-use {BoxShadowDisplayItem, ClipAndScrollInfo, ClipDisplayItem, ClipId, ColorF, ComplexClipRegion};
-use {DisplayItem, ExtendMode, FilterOp, FontInstanceKey, GlyphInstance, GlyphOptions, Gradient};
-use {GradientDisplayItem, GradientStop, IframeDisplayItem, ImageDisplayItem, ImageKey, ImageMask};
-use {ImageRendering, LayerPrimitiveInfo, LayoutPoint, LayoutPrimitiveInfo, LayoutRect, LayoutSize};
-use {LayoutTransform, LayoutVector2D, LineDisplayItem, LineOrientation, LineStyle, LocalClip};
-use {MixBlendMode, PipelineId, PropertyBinding, PushStackingContextDisplayItem, RadialGradient};
-use {RadialGradientDisplayItem, RectangleDisplayItem, ScrollFrameDisplayItem, ScrollPolicy};
-use {ScrollSensitivity, Shadow, SpecificDisplayItem, StackingContext, StickyFrameDisplayItem};
-use {StickyOffsetBounds, TextDisplayItem, TransformStyle, YuvColorSpace, YuvData};
-use YuvImageDisplayItem;
+use {AlphaType, BorderDetails, BorderDisplayItem, BorderRadius, BorderWidths, BoxShadowClipMode};
+use {BoxShadowDisplayItem, ClipAndScrollInfo, ClipChainId, ClipChainItem, ClipDisplayItem, ClipId};
+use {ColorF, ComplexClipRegion, DisplayItem, ExtendMode, FilterOp, FontInstanceKey, GlyphInstance};
+use {GlyphOptions, Gradient, GradientDisplayItem, GradientStop, IframeDisplayItem};
+use {ImageDisplayItem, ImageKey, ImageMask, ImageRendering, LayerPrimitiveInfo, LayoutPoint};
+use {LayoutPrimitiveInfo, LayoutRect, LayoutSize, LayoutTransform, LayoutVector2D};
+use {LineDisplayItem, LineOrientation, LineStyle, LocalClip, MixBlendMode, PipelineId};
+use {PropertyBinding, PushStackingContextDisplayItem, RadialGradient, RadialGradientDisplayItem};
+use {RectangleDisplayItem, ScrollFrameDisplayItem, ScrollPolicy, ScrollSensitivity, Shadow};
+use {SpecificDisplayItem, StackingContext, StickyFrameDisplayItem, StickyOffsetBounds};
+use {TextDisplayItem, TransformStyle, YuvColorSpace, YuvData, YuvImageDisplayItem};
 use bincode;
 use euclid::SideOffsets2D;
 use serde::{Deserialize, Serialize};
@@ -86,6 +86,7 @@ pub struct BuiltDisplayListIter<'a> {
     cur_stops: ItemRange<GradientStop>,
     cur_glyphs: ItemRange<GlyphInstance>,
     cur_filters: ItemRange<FilterOp>,
+    cur_clip_chain_items: ItemRange<ClipId>,
     cur_complex_clip: (ItemRange<ComplexClipRegion>, usize),
     peeking: Peek,
 }
@@ -197,6 +198,7 @@ impl<'a> BuiltDisplayListIter<'a> {
             cur_stops: ItemRange::default(),
             cur_glyphs: ItemRange::default(),
             cur_filters: ItemRange::default(),
+            cur_clip_chain_items: ItemRange::default(),
             cur_complex_clip: (ItemRange::default(), 0),
             peeking: Peek::NotPeeking,
         }
@@ -223,6 +225,7 @@ impl<'a> BuiltDisplayListIter<'a> {
         // Don't let these bleed into another item
         self.cur_stops = ItemRange::default();
         self.cur_complex_clip = (ItemRange::default(), 0);
+        self.cur_clip_chain_items = ItemRange::default();
 
         loop {
             if self.data.len() == 0 {
@@ -243,6 +246,9 @@ impl<'a> BuiltDisplayListIter<'a> {
                     // This is a dummy item, skip over it
                     continue;
                 }
+                ClipChain(_) => {
+                    self.cur_clip_chain_items = skip_slice::<ClipId>(self.list, &mut self.data).0;
+                }
                 Clip(_) | ScrollFrame(_) => {
                     self.cur_complex_clip = self.skip_slice::<ComplexClipRegion>()
                 }
@@ -356,6 +362,10 @@ impl<'a, 'b> DisplayItemRef<'a, 'b> {
         self.iter.cur_filters
     }
 
+    pub fn clip_chain_items(&self) -> ItemRange<ClipId> {
+        self.iter.cur_clip_chain_items
+    }
+
     pub fn display_list(&self) -> &BuiltDisplayList {
         self.iter.display_list()
     }
@@ -418,20 +428,27 @@ impl Serialize for BuiltDisplayList {
         let mut seq = serializer.serialize_seq(None)?;
         let mut traversal = self.iter();
         while let Some(item) = traversal.next() {
-            let di = item.display_item();
+            let display_item = item.display_item();
             let serial_di = GenericDisplayItem {
-                item: match di.item {
-                    SpecificDisplayItem::Clip(v) => Clip(v,
+                item: match display_item.item {
+                    SpecificDisplayItem::Clip(v) => Clip(
+                        v,
                         item.iter.list.get(item.iter.cur_complex_clip.0).collect()
                     ),
-                    SpecificDisplayItem::ScrollFrame(v) => ScrollFrame(v,
+                    SpecificDisplayItem::ClipChain(v) => ClipChain(
+                        v,
+                        item.iter.list.get(item.iter.cur_clip_chain_items).collect(),
+                    ),
+                    SpecificDisplayItem::ScrollFrame(v) => ScrollFrame(
+                        v,
                         item.iter.list.get(item.iter.cur_complex_clip.0).collect()
                     ),
                     SpecificDisplayItem::StickyFrame(v) => StickyFrame(v),
                     SpecificDisplayItem::Rectangle(v) => Rectangle(v),
                     SpecificDisplayItem::ClearRectangle => ClearRectangle,
                     SpecificDisplayItem::Line(v) => Line(v),
-                    SpecificDisplayItem::Text(v) => Text(v,
+                    SpecificDisplayItem::Text(v) => Text(
+                        v,
                         item.iter.list.get(item.iter.cur_glyphs).collect()
                     ),
                     SpecificDisplayItem::Image(v) => Image(v),
@@ -441,7 +458,8 @@ impl Serialize for BuiltDisplayList {
                     SpecificDisplayItem::Gradient(v) => Gradient(v),
                     SpecificDisplayItem::RadialGradient(v) => RadialGradient(v),
                     SpecificDisplayItem::Iframe(v) => Iframe(v),
-                    SpecificDisplayItem::PushStackingContext(v) => PushStackingContext(v,
+                    SpecificDisplayItem::PushStackingContext(v) => PushStackingContext(
+                        v,
                         item.iter.list.get(item.iter.cur_filters).collect()
                     ),
                     SpecificDisplayItem::PopStackingContext => PopStackingContext,
@@ -451,8 +469,8 @@ impl Serialize for BuiltDisplayList {
                     SpecificDisplayItem::PushShadow(v) => PushShadow(v),
                     SpecificDisplayItem::PopAllShadows => PopAllShadows,
                 },
-                clip_and_scroll: di.clip_and_scroll,
-                info: di.info,
+                clip_and_scroll: display_item.clip_and_scroll,
+                info: display_item.info,
             };
             seq.serialize_element(&serial_di)?
         }
@@ -492,39 +510,44 @@ impl<'de> Deserialize<'de> for BuiltDisplayList {
         for complete in list {
             let item = DisplayItem {
                 item: match complete.item {
-                    Clip(v, complex_clips) => {
+                    Clip(specific_item, complex_clips) => {
                         push_vec(&mut temp, complex_clips);
-                        SpecificDisplayItem::Clip(v)
+                        SpecificDisplayItem::Clip(specific_item)
                     },
-                    ScrollFrame(v, complex_clips) => {
+                    ClipChain(specific_item, clip_chain_ids) => {
+                        push_vec(&mut temp, clip_chain_ids);
+                        SpecificDisplayItem::ClipChain(specific_item)
+                    }
+                    ScrollFrame(specific_item, complex_clips) => {
                         push_vec(&mut temp, complex_clips);
-                        SpecificDisplayItem::ScrollFrame(v)
+                        SpecificDisplayItem::ScrollFrame(specific_item)
                     },
-                    StickyFrame(v) => SpecificDisplayItem::StickyFrame(v),
-                    Rectangle(v) => SpecificDisplayItem::Rectangle(v),
+                    StickyFrame(specific_item) => SpecificDisplayItem::StickyFrame(specific_item),
+                    Rectangle(specific_item) => SpecificDisplayItem::Rectangle(specific_item),
                     ClearRectangle => SpecificDisplayItem::ClearRectangle,
-                    Line(v) => SpecificDisplayItem::Line(v),
-                    Text(v, glyphs) => {
+                    Line(specific_item) => SpecificDisplayItem::Line(specific_item),
+                    Text(specific_item, glyphs) => {
                         push_vec(&mut temp, glyphs);
-                        SpecificDisplayItem::Text(v)
+                        SpecificDisplayItem::Text(specific_item)
                     },
-                    Image(v) => SpecificDisplayItem::Image(v),
-                    YuvImage(v) => SpecificDisplayItem::YuvImage(v),
-                    Border(v) => SpecificDisplayItem::Border(v),
-                    BoxShadow(v) => SpecificDisplayItem::BoxShadow(v),
-                    Gradient(v) => SpecificDisplayItem::Gradient(v),
-                    RadialGradient(v) => SpecificDisplayItem::RadialGradient(v),
-                    Iframe(v) => SpecificDisplayItem::Iframe(v),
-                    PushStackingContext(v, filters) => {
+                    Image(specific_item) => SpecificDisplayItem::Image(specific_item),
+                    YuvImage(specific_item) => SpecificDisplayItem::YuvImage(specific_item),
+                    Border(specific_item) => SpecificDisplayItem::Border(specific_item),
+                    BoxShadow(specific_item) => SpecificDisplayItem::BoxShadow(specific_item),
+                    Gradient(specific_item) => SpecificDisplayItem::Gradient(specific_item),
+                    RadialGradient(specific_item) =>
+                        SpecificDisplayItem::RadialGradient(specific_item),
+                    Iframe(specific_item) => SpecificDisplayItem::Iframe(specific_item),
+                    PushStackingContext(specific_item, filters) => {
                         push_vec(&mut temp, filters);
-                        SpecificDisplayItem::PushStackingContext(v)
+                        SpecificDisplayItem::PushStackingContext(specific_item)
                     },
                     PopStackingContext => SpecificDisplayItem::PopStackingContext,
                     SetGradientStops(stops) => {
                         push_vec(&mut temp, stops);
                         SpecificDisplayItem::SetGradientStops
                     },
-                    PushShadow(v) => SpecificDisplayItem::PushShadow(v),
+                    PushShadow(specific_item) => SpecificDisplayItem::PushShadow(specific_item),
                     PopAllShadows => SpecificDisplayItem::PopAllShadows,
                 },
                 clip_and_scroll: complete.clip_and_scroll,
@@ -766,6 +789,7 @@ pub struct SaveState {
     dl_len: usize,
     clip_stack_len: usize,
     next_clip_id: u64,
+    next_clip_chain_id: u64,
 }
 
 #[derive(Clone)]
@@ -774,6 +798,7 @@ pub struct DisplayListBuilder {
     pub pipeline_id: PipelineId,
     clip_stack: Vec<ClipAndScrollInfo>,
     next_clip_id: u64,
+    next_clip_chain_id: u64,
     builder_start_time: u64,
 
     /// The size of the content of this display list. This is used to allow scrolling
@@ -804,6 +829,7 @@ impl DisplayListBuilder {
                 ClipAndScrollInfo::simple(ClipId::root_scroll_node(pipeline_id)),
             ],
             next_clip_id: FIRST_CLIP_ID,
+            next_clip_chain_id: 0,
             builder_start_time: start_time,
             content_size,
             save_state: None,
@@ -829,6 +855,7 @@ impl DisplayListBuilder {
             clip_stack_len: self.clip_stack.len(),
             dl_len: self.data.len(),
             next_clip_id: self.next_clip_id,
+            next_clip_chain_id: self.next_clip_chain_id,
         });
     }
 
@@ -839,6 +866,7 @@ impl DisplayListBuilder {
         self.clip_stack.truncate(state.clip_stack_len);
         self.data.truncate(state.dl_len);
         self.next_clip_id = state.next_clip_id;
+        self.next_clip_chain_id = state.next_clip_chain_id;
     }
 
     /// Discards the builder's save (indicating the attempted operation was sucessful).
@@ -964,6 +992,7 @@ impl DisplayListBuilder {
         stretch_size: LayoutSize,
         tile_spacing: LayoutSize,
         image_rendering: ImageRendering,
+        alpha_type: AlphaType,
         key: ImageKey,
     ) {
         let item = SpecificDisplayItem::Image(ImageDisplayItem {
@@ -971,6 +1000,7 @@ impl DisplayListBuilder {
             stretch_size,
             tile_spacing,
             image_rendering,
+            alpha_type,
         });
 
         self.push_item(item, info);
@@ -1315,6 +1345,11 @@ impl DisplayListBuilder {
         })
     }
 
+    fn generate_clip_chain_id(&mut self) -> ClipChainId {
+        self.next_clip_chain_id += 1;
+        ClipChainId(self.next_clip_chain_id - 1, self.pipeline_id)
+    }
+
     pub fn define_scroll_frame<I>(
         &mut self,
         id: Option<ClipId>,
@@ -1355,8 +1390,8 @@ impl DisplayListBuilder {
     {
         let id = self.generate_clip_id(id);
         let item = SpecificDisplayItem::ScrollFrame(ScrollFrameDisplayItem {
-            id: id,
-            image_mask: image_mask,
+            id,
+            image_mask,
             scroll_sensitivity,
         });
         let info = LayoutPrimitiveInfo::with_clip_rect(content_rect, clip_rect);
@@ -1367,6 +1402,21 @@ impl DisplayListBuilder {
         id
     }
 
+    pub fn define_clip_chain<I>(
+        &mut self,
+        parent: Option<ClipChainId>,
+        clips: I,
+    ) -> ClipChainId
+    where
+        I: IntoIterator<Item = ClipId>,
+        I::IntoIter: ExactSizeIterator + Clone,
+    {
+        let id = self.generate_clip_chain_id();
+        self.push_new_empty_item(SpecificDisplayItem::ClipChain(ClipChainItem { id, parent}));
+        self.push_iter(clips);
+        id
+    }
+
     pub fn define_clip<I>(
         &mut self,
         id: Option<ClipId>,

gfx/webrender_api/src/font.rs

@@ -199,6 +199,16 @@ impl Hash for FontVariation {
 #[derive(Clone, Copy, Debug, Deserialize, Hash, Eq, PartialEq, PartialOrd, Ord, Serialize)]
 pub struct GlyphOptions {
     pub render_mode: FontRenderMode,
+    pub flags: FontInstanceFlags,
+}
+
+impl Default for GlyphOptions {
+    fn default() -> GlyphOptions {
+        GlyphOptions {
+            render_mode: FontRenderMode::Subpixel,
+            flags: FontInstanceFlags::empty(),
+        }
+    }
 }
 
 bitflags! {
@@ -210,6 +220,9 @@ bitflags! {
         const SYNTHETIC_BOLD    = 1 << 1;
         const EMBEDDED_BITMAPS  = 1 << 2;
         const SUBPIXEL_BGR      = 1 << 3;
+        const TRANSPOSE         = 1 << 4;
+        const FLIP_X            = 1 << 5;
+        const FLIP_Y            = 1 << 6;
 
         // Windows flags
         const FORCE_GDI         = 1 << 16;

gfx/webrender_api/src/image.rs

@@ -51,7 +51,7 @@ pub struct ExternalImageData {
 #[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, PartialEq, Serialize)]
 pub enum ImageFormat {
     Invalid = 0,
-    A8 = 1,
+    R8 = 1,
     BGRA8 = 3,
     RGBAF32 = 4,
     RG8 = 5,
@@ -60,7 +60,7 @@ pub enum ImageFormat {
 impl ImageFormat {
     pub fn bytes_per_pixel(self) -> u32 {
         match self {
-            ImageFormat::A8 => 1,
+            ImageFormat::R8 => 1,
             ImageFormat::BGRA8 => 4,
             ImageFormat::RGBAF32 => 16,
             ImageFormat::RG8 => 2,