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https://github.com/servo/servo.git
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68 lines
3.3 KiB
Rust
68 lines
3.3 KiB
Rust
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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//! Transforms a display list to produce a visually-equivalent, but cheaper-to-paint, one.
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use display_list::{DisplayItem, DisplayList, StackingContext};
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use collections::linked_list::LinkedList;
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use geom::rect::Rect;
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use util::geometry::{self, Au};
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use std::sync::Arc;
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/// Transforms a display list to produce a visually-equivalent, but cheaper-to-paint, one.
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pub struct DisplayListOptimizer {
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/// The visible rect in page coordinates.
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visible_rect: Rect<Au>,
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}
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impl DisplayListOptimizer {
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/// Creates a new display list optimizer object. `visible_rect` specifies the visible rect in
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/// page coordinates.
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pub fn new(visible_rect: &Rect<f32>) -> DisplayListOptimizer {
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DisplayListOptimizer {
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visible_rect: geometry::f32_rect_to_au_rect(*visible_rect),
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}
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}
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/// Optimizes the given display list, returning an equivalent, but cheaper-to-paint, one.
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pub fn optimize(self, display_list: &DisplayList) -> DisplayList {
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let mut result = DisplayList::new();
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self.add_in_bounds_display_items(&mut result.background_and_borders,
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display_list.background_and_borders.iter());
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self.add_in_bounds_display_items(&mut result.block_backgrounds_and_borders,
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display_list.block_backgrounds_and_borders.iter());
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self.add_in_bounds_display_items(&mut result.floats, display_list.floats.iter());
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self.add_in_bounds_display_items(&mut result.content, display_list.content.iter());
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self.add_in_bounds_display_items(&mut result.outlines, display_list.outlines.iter());
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self.add_in_bounds_stacking_contexts(&mut result.children, display_list.children.iter());
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result
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}
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/// Adds display items that intersect the visible rect to `result_list`.
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fn add_in_bounds_display_items<'a,I>(&self,
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result_list: &mut LinkedList<DisplayItem>,
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display_items: I)
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where I: Iterator<Item=&'a DisplayItem> {
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for display_item in display_items {
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if self.visible_rect.intersects(&display_item.base().bounds) &&
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display_item.base().clip.might_intersect_rect(&self.visible_rect) {
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result_list.push_back((*display_item).clone())
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}
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}
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}
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/// Adds child stacking contexts whose boundaries intersect the visible rect to `result_list`.
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fn add_in_bounds_stacking_contexts<'a,I>(&self,
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result_list: &mut LinkedList<Arc<StackingContext>>,
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stacking_contexts: I)
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where I: Iterator<Item=&'a Arc<StackingContext>> {
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for stacking_context in stacking_contexts {
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let overflow = stacking_context.overflow.translate(&stacking_context.bounds.origin);
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if self.visible_rect.intersects(&overflow) {
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result_list.push_back((*stacking_context).clone())
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}
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}
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}
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}
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