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LibWeb: Move hit testing to the painting tree

This commit is contained in:
Andreas Kling 2022-03-11 00:03:28 +01:00
parent ba606d9057
commit 5779a910e5
18 changed files with 196 additions and 172 deletions

View file

@ -10,6 +10,7 @@
#include <LibWeb/Painting/BackgroundPainting.h>
#include <LibWeb/Painting/PaintableBox.h>
#include <LibWeb/Painting/ShadowPainting.h>
#include <LibWeb/Painting/StackingContext.h>
namespace Web::Painting {
@ -307,4 +308,116 @@ Layout::BlockContainer& PaintableWithLines::layout_box()
return static_cast<Layout::BlockContainer&>(PaintableBox::layout_box());
}
void PaintableBox::set_stacking_context(NonnullOwnPtr<StackingContext> stacking_context)
{
m_stacking_context = move(stacking_context);
}
template<typename Callback>
void PaintableBox::for_each_child_in_paint_order(Callback callback) const
{
// Element traversal using the order defined in https://www.w3.org/TR/CSS2/zindex.html#painting-order.
// Note: Some steps are skipped because they are not relevant to node traversal.
// 3. Stacking contexts formed by positioned descendants with negative z-indices (excluding 0) in z-index order
// (most negative first) then tree order.
// FIXME: This does not retrieve elements in the z-index order.
layout_box().for_each_child([&](auto& child) {
if (!child.is_positioned() || !is<Layout::Box>(child))
return;
auto& box_child = verify_cast<Layout::Box>(child);
auto* stacking_context = box_child.paint_box()->stacking_context();
if (stacking_context && box_child.computed_values().z_index().has_value() && box_child.computed_values().z_index().value() < 0)
callback(child);
});
// 4. For all its in-flow, non-positioned, block-level descendants in tree order: If the element is a block, list-item,
// or other block equivalent:
layout_box().for_each_child([&](auto& child) {
if (is<Layout::Box>(child) && verify_cast<Layout::Box>(child).paint_box()->stacking_context())
return;
if (!child.is_positioned())
callback(child);
});
// 5. All non-positioned floating descendants, in tree order. For each one of these, treat the element as if it created
// a new stacking context, but any positioned descendants and descendants which actually create a new stacking context
// should be considered part of the parent stacking context, not this new one.
layout_box().for_each_child([&](auto& child) {
if (is<Layout::Box>(child) && verify_cast<Layout::Box>(child).paint_box()->stacking_context())
return;
if (child.is_positioned())
callback(child);
});
// 8. All positioned descendants with 'z-index: auto' or 'z-index: 0', in tree order. For those with 'z-index: auto', treat
// the element as if it created a new stacking context, but any positioned descendants and descendants which actually
// create a new stacking context should be considered part of the parent stacking context, not this new one. For those
// with 'z-index: 0', treat the stacking context generated atomically.
layout_box().for_each_child([&](auto& child) {
if (!child.is_positioned() || !is<Layout::Box>(child))
return;
auto& box_child = verify_cast<Layout::Box>(child);
auto* stacking_context = box_child.paint_box()->stacking_context();
if (stacking_context && box_child.computed_values().z_index().has_value() && box_child.computed_values().z_index().value() == 0)
callback(child);
});
// 9. Stacking contexts formed by positioned descendants with z-indices greater than or equal to 1 in z-index order
// (smallest first) then tree order.
// FIXME: This does not retrieve elements in the z-index order.
layout_box().for_each_child([&](auto& child) {
if (!child.is_positioned() || !is<Layout::Box>(child))
return;
auto& box_child = verify_cast<Layout::Box>(child);
auto* stacking_context = box_child.paint_box()->stacking_context();
if (stacking_context && box_child.computed_values().z_index().has_value() && box_child.computed_values().z_index().value() > 0)
callback(child);
});
}
HitTestResult PaintableBox::hit_test(Gfx::IntPoint const& position, HitTestType type) const
{
if (layout_box().is_initial_containing_block_box())
return stacking_context()->hit_test(position, type);
HitTestResult result { absolute_border_box_rect().contains(position.x(), position.y()) ? this : nullptr };
for_each_child_in_paint_order([&](auto& child) {
if (child.paintable()) {
auto child_result = child.paintable()->hit_test(position, type);
if (child_result.paintable)
result = child_result;
}
});
return result;
}
HitTestResult PaintableWithLines::hit_test(const Gfx::IntPoint& position, HitTestType type) const
{
if (!layout_box().children_are_inline())
return PaintableBox::hit_test(position, type);
HitTestResult last_good_candidate;
for (auto& line_box : m_line_boxes) {
for (auto& fragment : line_box.fragments()) {
if (is<Layout::Box>(fragment.layout_node()) && static_cast<Layout::Box const&>(fragment.layout_node()).paint_box()->stacking_context())
continue;
if (enclosing_int_rect(fragment.absolute_rect()).contains(position)) {
if (is<Layout::BlockContainer>(fragment.layout_node()) && fragment.layout_node().paintable())
return fragment.layout_node().paintable()->hit_test(position, type);
return { fragment.layout_node().paintable(), fragment.text_index_at(position.x()) };
}
if (fragment.absolute_rect().top() <= position.y())
last_good_candidate = { fragment.layout_node().paintable(), fragment.text_index_at(position.x()) };
}
}
if (type == HitTestType::TextCursor && last_good_candidate.paintable)
return last_good_candidate;
return { absolute_border_box_rect().contains(position.x(), position.y()) ? this : nullptr };
}
}