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bffaad118e
a separate `ClipDisplayItem`. We push down clipping areas during absolute position calculation. This makes display items into a flat list, improving cache locality. It dramatically simplifies the code all around. Because we need to push down clip rects even for absolutely-positioned children of non-absolutely-positioned flows, this patch alters the parallel traversal to compute absolute positions for absolutely-positioned children at the same time it computes absolute positions for other children. This doesn't seem to break anything either in theory (since the overall order remains correct) or in practice. It simplifies the parallel traversal code quite a bit. See the relevant Gecko bug: https://bugzilla.mozilla.org/show_bug.cgi?id=615734
54 lines
1.7 KiB
Rust
54 lines
1.7 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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use display_list::{DisplayItem, DisplayList};
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use collections::dlist::DList;
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use geom::rect::Rect;
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use servo_util::geometry::Au;
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use sync::Arc;
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pub struct DisplayListOptimizer {
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display_list: Arc<DisplayList>,
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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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/// `visible_rect` specifies the visible rect in page coordinates.
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pub fn new(display_list: Arc<DisplayList>, visible_rect: Rect<Au>) -> DisplayListOptimizer {
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DisplayListOptimizer {
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display_list: display_list,
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visible_rect: visible_rect,
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}
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}
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pub fn optimize(self) -> DisplayList {
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self.process_display_list(&*self.display_list)
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}
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fn process_display_list(&self, display_list: &DisplayList) -> DisplayList {
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let mut result = DList::new();
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for item in display_list.iter() {
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match self.process_display_item(item) {
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None => {}
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Some(display_item) => result.push(display_item),
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}
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}
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DisplayList {
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list: result,
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}
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}
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fn process_display_item(&self, display_item: &DisplayItem) -> Option<DisplayItem> {
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// Eliminate display items outside the visible region.
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if !self.visible_rect.intersects(&display_item.base().bounds) ||
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!self.visible_rect.intersects(&display_item.base().clip_rect) {
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None
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} else {
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Some((*display_item).clone())
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}
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}
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}
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