1 files changed, 92 insertions, 0 deletions
diff --git a/src/components/servo/layout/display_list_builder.rs b/src/components/servo/layout/display_list_builder.rs
new file mode 100644
index 00000000000..1d0ea27b7e5
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+++ b/src/components/servo/layout/display_list_builder.rs
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+/* 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/. */
+
+///
+/// Constructs display lists from render boxes.
+///
+
+use core::cell::Cell;
+
+use layout::context::LayoutContext;
+use layout::flow::FlowContext;
+
+use geom::point::Point2D;
+use geom::rect::Rect;
+use gfx::display_list::DisplayList;
+use gfx::geometry::Au;
+use gfx;
+use newcss;
+use servo_util::tree::TreeNodeRef;
+
+/// A builder object that manages display list builder should mainly hold information about the
+/// initial request and desired result--for example, whether the `DisplayList` is to be used for
+/// painting or hit testing. This can affect which boxes are created.
+///
+/// Right now, the builder isn't used for much, but it establishes the pattern we'll need once we
+/// support display-list-based hit testing and so forth.
+pub struct DisplayListBuilder<'self> {
+    ctx:  &'self LayoutContext,
+}
+
+pub trait FlowDisplayListBuilderMethods {
+    fn build_display_list(&self, a: &DisplayListBuilder, b: &Rect<Au>, c: &Cell<DisplayList>);
+    fn build_display_list_for_child(&self,
+                                    a: &DisplayListBuilder,
+                                    b: FlowContext,
+                                    c: &Rect<Au>,
+                                    d: &Point2D<Au>,
+                                    e: &Cell<DisplayList>);
+}
+
+impl FlowDisplayListBuilderMethods for FlowContext {
+    fn build_display_list(&self,
+                          builder: &DisplayListBuilder,
+                          dirty: &Rect<Au>,
+                          list: &Cell<DisplayList>) {
+        let zero = gfx::geometry::zero_point();
+        self.build_display_list_recurse(builder, dirty, &zero, list);
+    }
+
+    fn build_display_list_for_child(&self,
+                                    builder: &DisplayListBuilder,
+                                    child_flow: FlowContext,
+                                    dirty: &Rect<Au>,
+                                    offset: &Point2D<Au>,
+                                    list: &Cell<DisplayList>) {
+        // Adjust the dirty rect to child flow context coordinates.
+        do child_flow.with_base |child_node| {
+            let abs_flow_bounds = child_node.position.translate(offset);
+            let adj_offset = offset.add(&child_node.position.origin);
+
+            debug!("build_display_list_for_child: rel=%?, abs=%?",
+                   child_node.position,
+                   abs_flow_bounds);
+            debug!("build_display_list_for_child: dirty=%?, offset=%?", dirty, offset);
+
+            if dirty.intersects(&abs_flow_bounds) {
+                debug!("build_display_list_for_child: intersected. recursing into child flow...");
+                child_flow.build_display_list_recurse(builder, dirty, &adj_offset, list);
+            } else {
+                debug!("build_display_list_for_child: Did not intersect...");
+            }
+        }
+    }
+}
+
+//
+// Miscellaneous useful routines
+//
+
+/// Allows a CSS color to be converted into a graphics color.
+pub trait ToGfxColor {
+    /// Converts a CSS color to a graphics color.
+    fn to_gfx_color(&self) -> gfx::color::Color;
+}
+
+impl ToGfxColor for newcss::color::Color {
+    fn to_gfx_color(&self) -> gfx::color::Color {
+        gfx::color::rgba(self.red, self.green, self.blue, self.alpha)
+    }
+}
+