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eed47acb1f
Until now, every paint phase of every PaintableBox injected its own
clipping sequence into the display list:
```
before_paint: Save
AddClipRect (1)
...clip rectangles for each containing block with clip...
AddClipRect (N)
paint: ...paint phase items...
after_paint: Restore
```
Because we ran that sequence for every phase of every box, Skia had to
rebuild clip stack `paint_phases * paintable_boxes` times. Worse,
usually most paint phases contribute no visible drawing at all, yet we
still had to emit clipping items because `before_paint()` has no way to
know that in advance.
This change takes a different approach:
- Clip information is now attached as metadata `ClipFrame` to each
DisplayList item.
- `DisplayListPlayer` groups consecutive commands that share a
`ClipFrame`, applying the clip once at the start of the group and
restoring it once at the end.
Going from 10 ms to 5 ms in rasterization on Discord might not sound
like much, but keep in mind that for 60fps we have 16 ms per frame and
there is a lot more work besides display list rasterization we do in
each frame.
* https://discord.com/channels/1247070541085671459/1247090064480014443
- DisplayList items: 81844 -> 3671
- rasterize time: 10 ms -> 5 ms
- record time: 5 ms -> 3 ms
* https://github.com/LadybirdBrowser/ladybird
- DisplayList items: 7902 -> 1176
- rasterize time: 4 ms -> 4 ms
- record time: 3 ms -> 2 ms
31 lines
810 B
C++
31 lines
810 B
C++
/*
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* Copyright (c) 2024, Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <LibWeb/Painting/BorderRadiiData.h>
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#include <LibWeb/Painting/ScrollFrame.h>
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#include <LibWeb/PixelUnits.h>
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namespace Web::Painting {
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struct ClipRectWithScrollFrame {
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CSSPixelRect rect;
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BorderRadiiData corner_radii;
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RefPtr<ScrollFrame const> enclosing_scroll_frame;
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};
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struct ClipFrame : public AtomicRefCounted<ClipFrame> {
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Vector<ClipRectWithScrollFrame> const& clip_rects() const { return m_clip_rects; }
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void add_clip_rect(CSSPixelRect rect, BorderRadiiData radii, RefPtr<ScrollFrame const> enclosing_scroll_frame);
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CSSPixelRect clip_rect_for_hit_testing() const;
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private:
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Vector<ClipRectWithScrollFrame> m_clip_rects;
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};
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}
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