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/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/QuickSort.h>
#include <AK/StringBuilder.h>
#include <LibWeb/DOM/Node.h>
#include <LibWeb/Layout/Box.h>
#include <LibWeb/Layout/InitialContainingBlockBox.h>
#include <LibWeb/Painting/StackingContext.h>
namespace Web::Layout {
StackingContext::StackingContext(Box& box, StackingContext* parent)
: m_box(box)
, m_parent(parent)
{
VERIFY(m_parent != this);
if (m_parent) {
m_parent->m_children.append(this);
// FIXME: Don't sort on every append..
// FIXME: Apparently this also breaks tree order inside layers
quick_sort(m_parent->m_children, [](auto& a, auto& b) {
return a->m_box.computed_values().z_index().value_or(0) < b->m_box.computed_values().z_index().value_or(0);
});
}
}
void StackingContext::paint_descendants(PaintContext& context, Node& box, StackingContextPaintPhase phase)
{
box.for_each_child([&](auto& child) {
switch (phase) {
case StackingContextPaintPhase::BackgroundAndBorders:
if (!child.is_floating() && !child.is_positioned()) {
child.paint(context, PaintPhase::Background);
child.paint(context, PaintPhase::Border);
paint_descendants(context, child, phase);
}
break;
case StackingContextPaintPhase::Floats:
if (!child.is_positioned()) {
if (child.is_floating()) {
child.paint(context, PaintPhase::Background);
child.paint(context, PaintPhase::Border);
paint_descendants(context, child, StackingContextPaintPhase::BackgroundAndBorders);
}
paint_descendants(context, child, phase);
}
break;
case StackingContextPaintPhase::Foreground:
if (!child.is_positioned()) {
child.paint(context, PaintPhase::Foreground);
child.before_children_paint(context, PaintPhase::Foreground);
paint_descendants(context, child, phase);
child.after_children_paint(context, PaintPhase::Foreground);
}
break;
case StackingContextPaintPhase::FocusAndOverlay:
if (context.has_focus()) {
child.paint(context, PaintPhase::FocusOutline);
}
child.paint(context, PaintPhase::Overlay);
paint_descendants(context, child, phase);
break;
}
});
}
void StackingContext::paint(PaintContext& context)
{
// For a more elaborate description of the algorithm, see CSS 2.1 Appendix E
// Draw the background and borders for the context root (steps 1, 2)
m_box.paint(context, PaintPhase::Background);
m_box.paint(context, PaintPhase::Border);
// Draw positioned descendants with negative z-indices (step 3)
for (auto* child : m_children) {
if (child->m_box.computed_values().z_index().has_value() && child->m_box.computed_values().z_index().value() < 0)
child->paint(context);
}
// Draw the background and borders for block-level children (step 4)
paint_descendants(context, m_box, StackingContextPaintPhase::BackgroundAndBorders);
// Draw the non-positioned floats (step 5)
paint_descendants(context, m_box, StackingContextPaintPhase::Floats);
// Draw inline content, replaced content, etc. (steps 6, 7)
m_box.paint(context, PaintPhase::Foreground);
paint_descendants(context, m_box, StackingContextPaintPhase::Foreground);
// Draw other positioned descendants (steps 8, 9)
for (auto* child : m_children) {
if (child->m_box.computed_values().z_index().has_value() && child->m_box.computed_values().z_index().value() < 0)
continue;
child->paint(context);
}
m_box.paint(context, PaintPhase::FocusOutline);
m_box.paint(context, PaintPhase::Overlay);
paint_descendants(context, m_box, StackingContextPaintPhase::FocusAndOverlay);
}
HitTestResult StackingContext::hit_test(const Gfx::IntPoint& position, HitTestType type) const
{
HitTestResult result;
if (!is<InitialContainingBlockBox>(m_box)) {
result = m_box.hit_test(position, type);
} else {
// NOTE: InitialContainingBlockBox::hit_test() merely calls StackingContext::hit_test()
// so we call its base class instead.
result = downcast<InitialContainingBlockBox>(m_box).BlockBox::hit_test(position, type);
}
int z_index = m_box.computed_values().z_index().value_or(0);
for (auto* child : m_children) {
int child_z_index = child->m_box.computed_values().z_index().value_or(0);
if (result.layout_node && (child_z_index < z_index))
continue;
auto result_here = child->hit_test(position, type);
if (result_here.layout_node)
result = result_here;
}
return result;
}
void StackingContext::dump(int indent) const
{
StringBuilder builder;
for (int i = 0; i < indent; ++i)
builder.append(' ');
builder.appendff("SC for {}({}) {} [children: {}]", m_box.class_name(), m_box.dom_node() ? m_box.dom_node()->node_name().characters() : "(anonymous)", m_box.absolute_rect().to_string().characters(), m_children.size());
dbgln("{}", builder.string_view());
for (auto& child : m_children)
child->dump(indent + 1);
}
}
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