2020: paint background-color

components/layout_2020/display_list.rs

@@ -0,0 +1,106 @@
+/* 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 https://mozilla.org/MPL/2.0/. */
+
+use crate::fragments::{BoxFragment, Fragment};
+use crate::geom::physical::{Rect, Vec2};
+use crate::style_ext::ComputedValuesExt;
+use app_units::Au;
+use style::values::computed::Length;
+use webrender_api::CommonItemProperties;
+
+pub struct DisplayListBuilder {
+    pipeline_id: webrender_api::PipelineId,
+    pub wr: webrender_api::DisplayListBuilder,
+    pub is_contentful: bool,
+}
+
+impl DisplayListBuilder {
+    pub fn new(
+        pipeline_id: webrender_api::PipelineId,
+        viewport_size: webrender_api::units::LayoutSize,
+    ) -> Self {
+        Self {
+            pipeline_id,
+            is_contentful: false,
+            wr: webrender_api::DisplayListBuilder::new(pipeline_id, viewport_size),
+        }
+    }
+}
+
+/// Contentful paint, for the purpose of
+/// https://w3c.github.io/paint-timing/#first-contentful-paint
+/// (i.e. the display list contains items of type text,
+/// image, non-white canvas or SVG). Used by metrics.
+pub struct IsContentful(pub bool);
+
+impl Fragment {
+    pub(crate) fn build_display_list(
+        &self,
+        builder: &mut DisplayListBuilder,
+        is_contentful: &mut IsContentful,
+        containing_block: &Rect<Length>,
+    ) {
+        match self {
+            Fragment::Box(b) => b.build_display_list(builder, is_contentful, containing_block),
+            Fragment::Anonymous(a) => {
+                let rect = a
+                    .rect
+                    .to_physical(a.mode, containing_block)
+                    .translate(&containing_block.top_left);
+                for child in &a.children {
+                    child.build_display_list(builder, is_contentful, &rect)
+                }
+            },
+            Fragment::Text(_) => {
+                is_contentful.0 = true;
+                // FIXME
+            },
+        }
+    }
+}
+
+impl BoxFragment {
+    fn build_display_list(
+        &self,
+        builder: &mut DisplayListBuilder,
+        is_contentful: &mut IsContentful,
+        containing_block: &Rect<Length>,
+    ) {
+        let background_color = self
+            .style
+            .resolve_color(self.style.clone_background_color());
+        if background_color.alpha > 0 {
+            let clip_rect = self
+                .border_rect()
+                .to_physical(self.style.writing_mode(), containing_block)
+                .translate(&containing_block.top_left)
+                .into();
+            let common = CommonItemProperties {
+                clip_rect,
+                clip_id: webrender_api::ClipId::root(builder.pipeline_id),
+                spatial_id: webrender_api::SpatialId::root_scroll_node(builder.pipeline_id),
+                hit_info: None,
+                // TODO(gw): Make use of the WR backface visibility functionality.
+                is_backface_visible: true,
+            };
+            builder.wr.push_rect(&common, rgba(background_color))
+        }
+        let content_rect = self
+            .content_rect
+            .to_physical(self.style.writing_mode(), containing_block)
+            .translate(&containing_block.top_left);
+        for child in &self.children {
+            child.build_display_list(builder, is_contentful, &content_rect)
+        }
+    }
+}
+
+fn rgba(rgba: cssparser::RGBA) -> webrender_api::ColorF {
+    webrender_api::ColorF::new(
+        rgba.red_f32(),
+        rgba.green_f32(),
+        rgba.blue_f32(),
+        rgba.alpha_f32(),
+    )
+}