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LibWeb: Add some basic paint tree traversal helpers

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Give the Paintable class some basic helpers for traversing the paint
tree. Note that they actually piggy-back on the layout tree for links
between nodes.
This commit is contained in:
Andreas Kling 2022-04-08 15:19:02 +02:00
parent 40f090c7e8
commit dcbb83a33e
2 changed files with 49 additions and 0 deletions
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16
Userland/Libraries/LibWeb/Painting/Paintable.cpp
View file

@ -46,4 +46,20 @@ Optional<HitTestResult> Paintable::hit_test(Gfx::FloatPoint const&, HitTestType)
return {};
}
Paintable const* Paintable::first_child() const
{
auto* layout_child = m_layout_node.first_child();
for (; layout_child && !layout_child->paintable(); layout_child = layout_child->next_sibling())
;
return layout_child ? layout_child->paintable() : nullptr;
}
Paintable const* Paintable::next_sibling() const
{
auto* layout_node = m_layout_node.next_sibling();
for (; layout_node && !layout_node->paintable(); layout_node = layout_node->next_sibling())
;
return layout_node ? layout_node->paintable() : nullptr;
}
}

33
Userland/Libraries/LibWeb/Painting/Paintable.h
View file

@ -49,6 +49,33 @@ class Paintable : public RefCounted<Paintable> {
public:
virtual ~Paintable() = default;
Paintable const* first_child() const;
Paintable const* next_sibling() const;
template<typename U, typename Callback>
IterationDecision for_each_in_inclusive_subtree_of_type(Callback callback) const
{
if (is<U>(*this)) {
if (callback(static_cast<const U&>(*this)) == IterationDecision::Break)
return IterationDecision::Break;
}
for (auto* child = first_child(); child; child = child->next_sibling()) {
if (child->template for_each_in_inclusive_subtree_of_type<U>(callback) == IterationDecision::Break)
return IterationDecision::Break;
}
return IterationDecision::Continue;
}
template<typename U, typename Callback>
IterationDecision for_each_in_subtree_of_type(Callback callback) const
{
for (auto* child = first_child(); child; child = child->next_sibling()) {
if (child->template for_each_in_inclusive_subtree_of_type<U>(callback) == IterationDecision::Break)
return IterationDecision::Break;
}
return IterationDecision::Continue;
}
virtual void paint(PaintContext&, PaintPhase) const { }
virtual void before_children_paint(PaintContext&, PaintPhase) const { }
virtual void after_children_paint(PaintContext&, PaintPhase) const { }
@ -91,6 +118,9 @@ public:
return *m_containing_block;
}
template<typename T>
bool fast_is() const = delete;
protected:
explicit Paintable(Layout::Node const& layout_node)
: m_layout_node(layout_node)
@ -112,4 +142,7 @@ inline DOM::Node const* HitTestResult::dom_node() const
return paintable->dom_node();
}
template<>
inline bool Paintable::fast_is<PaintableBox>() const { return m_layout_node.is_box(); }
}