ladybird/Userland/Libraries/LibWeb/Painting/StackingContext.h
Andreas Kling d6c3cbd958 LibWeb: Make StackingContext sorting a lot faster
Stacking contexts are sorted after building a tree of them. They are
sorted by z-index first, DOM tree order second.

Sorting was previously *very* slow on pages with many stacking contexts.
That was because the sort() function used Node::is_before() in the
quick_sort comparator to see if one StackingContext was before another.
is_before() does tree traversal and can take quite a long time per call.

This patch avoids all that by letting StackingContext know its index
among all StackingContexts within the same document in tree order.
There's a noticeable snappiness increase on the CSS-FLEXBOX-1 spec page,
for instance. :^)
2023-06-02 15:00:38 +02:00

60 lines
1.8 KiB
C++

/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Vector.h>
#include <LibGfx/Matrix4x4.h>
#include <LibWeb/Layout/Node.h>
#include <LibWeb/Painting/Paintable.h>
namespace Web::Painting {
class StackingContext {
public:
StackingContext(Layout::Box&, StackingContext* parent, size_t index_in_tree_order);
StackingContext* parent() { return m_parent; }
StackingContext const* parent() const { return m_parent; }
PaintableBox const& paintable_box() const { return *m_box->paintable_box(); }
enum class StackingContextPaintPhase {
BackgroundAndBorders,
Floats,
BackgroundAndBordersForInlineLevelAndReplaced,
Foreground,
FocusAndOverlay,
};
void paint_descendants(PaintContext&, Layout::Node const&, StackingContextPaintPhase) const;
void paint(PaintContext&) const;
Optional<HitTestResult> hit_test(CSSPixelPoint, HitTestType) const;
Gfx::FloatMatrix4x4 const& transform_matrix() const { return m_transform; }
Gfx::AffineTransform affine_transform_matrix() const;
void dump(int indent = 0) const;
void sort();
private:
JS::NonnullGCPtr<Layout::Box> m_box;
Gfx::FloatMatrix4x4 m_transform;
Gfx::FloatPoint m_transform_origin;
StackingContext* const m_parent { nullptr };
Vector<StackingContext*> m_children;
size_t m_index_in_tree_order { 0 };
void paint_internal(PaintContext&) const;
Gfx::FloatMatrix4x4 get_transformation_matrix(CSS::Transformation const& transformation) const;
Gfx::FloatMatrix4x4 combine_transformations(Vector<CSS::Transformation> const& transformations) const;
Gfx::FloatPoint transform_origin() const { return m_transform_origin; }
Gfx::FloatPoint compute_transform_origin() const;
};
}