LibWeb: Split Paintable into Paintable and PaintableBox

To prepare for paintable inline content, we take the basic painting
functionality and hoist it into a base class.

Author: awesomekling

Userland/Libraries/LibWeb/DOM/Node.cpp

@@ -1010,7 +1010,7 @@ size_t Node::length() const
     return child_count();
 }
 
-Painting::Paintable const* Node::paint_box() const
+Painting::PaintableBox const* Node::paint_box() const
 {
     if (!layout_node())
         return nullptr;

Userland/Libraries/LibWeb/DOM/Node.h

@@ -158,7 +158,7 @@ class Node
     const Layout::Node* layout_node() const { return m_layout_node; }
     Layout::Node* layout_node() { return m_layout_node; }
 
-    Painting::Paintable const* paint_box() const;
+    Painting::PaintableBox const* paint_box() const;
 
     void set_layout_node(Badge<Layout::Node>, Layout::Node*) const;
 

Userland/Libraries/LibWeb/Forward.h

@@ -266,6 +266,7 @@ class PerformanceTiming;
 namespace Web::Painting {
 enum class PaintPhase;
 class Paintable;
+class PaintableBox;
 class PaintableWithLines;
 }
 

Userland/Libraries/LibWeb/Layout/Box.cpp

@@ -34,11 +34,6 @@ Box::~Box()
 {
 }
 
-void Box::set_paint_box(OwnPtr<Painting::Paintable> paint_box)
-{
-    m_paint_box = move(paint_box);
-}
-
 // https://www.w3.org/TR/css-display-3/#out-of-flow
 bool Box::is_out_of_flow(FormattingContext const& formatting_context) const
 {
@@ -93,7 +88,12 @@ bool Box::is_body() const
 
 OwnPtr<Painting::Paintable> Box::create_paintable() const
 {
-    return Painting::Paintable::create(*this);
+    return Painting::PaintableBox::create(*this);
+}
+
+Painting::PaintableBox const* Box::paint_box() const
+{
+    return static_cast<Painting::PaintableBox const*>(Node::paintable());
 }
 
 }

Userland/Libraries/LibWeb/Layout/Box.h

@@ -20,10 +20,7 @@ struct LineBoxFragmentCoordinate {
 
 class Box : public NodeWithStyleAndBoxModelMetrics {
 public:
-    Painting::Paintable const* paint_box() const { return m_paint_box.ptr(); }
-    void set_paint_box(OwnPtr<Painting::Paintable>);
-
-    OwnPtr<Painting::Paintable> m_paint_box;
+    Painting::PaintableBox const* paint_box() const;
 
     bool is_out_of_flow(FormattingContext const&) const;
 
@@ -44,7 +41,7 @@ class Box : public NodeWithStyleAndBoxModelMetrics {
 
     virtual void did_set_rect() { }
 
-    virtual OwnPtr<Painting::Paintable> create_paintable() const;
+    virtual OwnPtr<Painting::Paintable> create_paintable() const override;
 
 protected:
     Box(DOM::Document&, DOM::Node*, NonnullRefPtr<CSS::StyleProperties>);

Userland/Libraries/LibWeb/Layout/FormattingState.cpp

@@ -38,17 +38,19 @@ void FormattingState::commit()
         node.box_model().border = { node_state.border_top, node_state.border_right, node_state.border_bottom, node_state.border_left };
         node.box_model().margin = { node_state.margin_top, node_state.margin_right, node_state.margin_bottom, node_state.margin_left };
 
+        node.set_paintable(node.create_paintable());
+
         // For boxes, transfer all the state needed for painting.
         if (is<Layout::Box>(node)) {
             auto& box = static_cast<Layout::Box&>(node);
-            box.set_paint_box(box.create_paintable());
-            box.m_paint_box->set_offset(node_state.offset);
-            box.m_paint_box->set_content_size(node_state.content_width, node_state.content_height);
-            box.m_paint_box->set_overflow_data(move(node_state.overflow_data));
-            box.m_paint_box->set_containing_line_box_fragment(node_state.containing_line_box_fragment);
+            auto& paint_box = const_cast<Painting::PaintableBox&>(*box.paint_box());
+            paint_box.set_offset(node_state.offset);
+            paint_box.set_content_size(node_state.content_width, node_state.content_height);
+            paint_box.set_overflow_data(move(node_state.overflow_data));
+            paint_box.set_containing_line_box_fragment(node_state.containing_line_box_fragment);
 
             if (is<Layout::BlockContainer>(box))
-                static_cast<Painting::PaintableWithLines&>(*box.m_paint_box).set_line_boxes(move(node_state.line_boxes));
+                static_cast<Painting::PaintableWithLines&>(paint_box).set_line_boxes(move(node_state.line_boxes));
         }
     }
 }

Userland/Libraries/LibWeb/Layout/FormattingState.h

@@ -55,12 +55,12 @@ struct FormattingState {
         float border_box_width() const { return border_box_left() + content_width + border_box_right(); }
         float border_box_height() const { return border_box_top() + content_height + border_box_bottom(); }
 
-        Optional<Painting::Paintable::OverflowData> overflow_data;
+        Optional<Painting::PaintableBox::OverflowData> overflow_data;
 
-        Painting::Paintable::OverflowData& ensure_overflow_data()
+        Painting::PaintableBox::OverflowData& ensure_overflow_data()
         {
             if (!overflow_data.has_value())
-                overflow_data = Painting::Paintable::OverflowData {};
+                overflow_data = Painting::PaintableBox::OverflowData {};
             return *overflow_data;
         }
 

Userland/Libraries/LibWeb/Layout/InitialContainingBlock.cpp

@@ -33,9 +33,9 @@ void InitialContainingBlock::build_stacking_context_tree()
             VERIFY(!box.paint_box()->stacking_context());
             return IterationDecision::Continue;
         }
-        auto* parent_context = const_cast<Painting::Paintable*>(box.paint_box())->enclosing_stacking_context();
+        auto* parent_context = const_cast<Painting::PaintableBox*>(box.paint_box())->enclosing_stacking_context();
         VERIFY(parent_context);
-        const_cast<Painting::Paintable*>(box.paint_box())->set_stacking_context(make<Painting::StackingContext>(box, parent_context));
+        const_cast<Painting::PaintableBox*>(box.paint_box())->set_stacking_context(make<Painting::StackingContext>(box, parent_context));
         return IterationDecision::Continue;
     });
 }

Userland/Libraries/LibWeb/Layout/Node.cpp

@@ -584,4 +584,14 @@ NonnullRefPtr<NodeWithStyle> NodeWithStyle::create_anonymous_wrapper() const
     return wrapper;
 }
 
+void Node::set_paintable(OwnPtr<Painting::Paintable> paintable)
+{
+    m_paintable = move(paintable);
+}
+
+OwnPtr<Painting::Paintable> Node::create_paintable() const
+{
+    return nullptr;
+}
+
 }

Userland/Libraries/LibWeb/Layout/Node.h

@@ -54,6 +54,11 @@ class Node : public TreeNode<Node> {
     const DOM::Node* dom_node() const { return m_dom_node; }
     DOM::Node* dom_node() { return m_dom_node; }
 
+    Painting::Paintable const* paintable() const { return m_paintable; }
+    void set_paintable(OwnPtr<Painting::Paintable>);
+
+    virtual OwnPtr<Painting::Paintable> create_paintable() const;
+
     DOM::Document& document() { return m_document; }
     const DOM::Document& document() const { return m_document; }
 
@@ -219,6 +224,7 @@ class Node : public TreeNode<Node> {
 
     NonnullRefPtr<DOM::Document> m_document;
     RefPtr<DOM::Node> m_dom_node;
+    OwnPtr<Painting::Paintable> m_paintable;
 
     bool m_inline { false };
     bool m_has_style { false };