1 files changed, 118 insertions, 0 deletions
diff --git a/include/cru/ui/render/RenderObject.hpp b/include/cru/ui/render/RenderObject.hpp
new file mode 100644
index 00000000..7cfa3883
--- /dev/null
+++ b/include/cru/ui/render/RenderObject.hpp
@@ -0,0 +1,118 @@
+#pragma once
+#include "Base.hpp"
+
+#include "cru/common/Event.hpp"
+
+namespace cru::ui::render {
+// Render object will not destroy its children when destroyed. Control must
+// manage lifecycle of its render objects. Since control will destroy its
+// children when destroyed, render objects will be destroyed along with it.
+class RenderObject : public Object {
+  friend WindowRenderObject;
+
+ protected:
+  enum class ChildMode {
+    None,
+    Single,
+    Multiple,
+  };
+
+  RenderObject() = default;
+  RenderObject(ChildMode child_mode) : RenderObject() {
+    SetChildMode(child_mode);
+  }
+
+ public:
+  RenderObject(const RenderObject& other) = delete;
+  RenderObject(RenderObject&& other) = delete;
+  RenderObject& operator=(const RenderObject& other) = delete;
+  RenderObject& operator=(RenderObject&& other) = delete;
+  ~RenderObject() override = default;
+
+  Control* GetAttachedControl() const { return control_; }
+  void SetAttachedControl(Control* new_control) { control_ = new_control; }
+
+  UiHost* GetUiHost() const { return ui_host_; }
+
+  RenderObject* GetParent() const { return parent_; }
+
+  const std::vector<RenderObject*>& GetChildren() const { return children_; }
+  Index GetChildCount() const { return static_cast<Index>(children_.size()); }
+  void AddChild(RenderObject* render_object, Index position);
+  void RemoveChild(Index position);
+
+  Point GetOffset() const { return offset_; }
+  void SetOffset(const Point& offset) { offset_ = offset; }
+  Point GetTotalOffset() const;
+  Point FromRootToContent(const Point& point) const;
+  Size GetSize() const { return size_; }
+  void SetSize(const Size& size) { size_ = size; }
+
+  Thickness GetMargin() const { return margin_; }
+  void SetMargin(const Thickness& margin) { margin_ = margin; }
+
+  Thickness GetPadding() const { return padding_; }
+  void SetPadding(const Thickness& padding) { padding_ = padding; }
+
+  Size GetPreferredSize() const { return preferred_size_; }
+  void SetPreferredSize(const Size& preferred_size) {
+    preferred_size_ = preferred_size;
+  }
+
+  void Measure(const Size& available_size);
+  void Layout(const Rect& rect);
+
+  virtual void Draw(platform::graph::IPainter* painter) = 0;
+
+  virtual RenderObject* HitTest(const Point& point) = 0;
+
+ public:
+  void InvalidateLayout();
+  void InvalidatePaint();
+
+ protected:
+  void SetChildMode(ChildMode mode) { child_mode_ = mode; }
+
+ protected:
+  virtual void OnParentChanged(RenderObject* old_parent,
+                               RenderObject* new_parent);
+
+  // default is to invalidate both layout and paint
+  virtual void OnAddChild(RenderObject* new_child, Index position);
+  // default is to invalidate both layout and paint
+  virtual void OnRemoveChild(RenderObject* removed_child, Index position);
+
+  virtual void OnMeasureCore(const Size& available_size);
+  virtual void OnLayoutCore(const Rect& rect);
+  virtual Size OnMeasureContent(const Size& available_size) = 0;
+  virtual void OnLayoutContent(const Rect& content_rect) = 0;
+
+  virtual void OnAfterLayout();
+  static void NotifyAfterLayoutRecursive(RenderObject* render_object);
+
+  Rect GetPaddingRect() const;
+  Rect GetContentRect() const;
+
+ private:
+  void SetParent(RenderObject* new_parent);
+
+  void SetRenderHostRecursive(UiHost* host);
+
+ private:
+  Control* control_ = nullptr;
+  UiHost* ui_host_ = nullptr;
+
+  RenderObject* parent_ = nullptr;
+  std::vector<RenderObject*> children_{};
+
+  ChildMode child_mode_ = ChildMode::None;
+
+  Point offset_{};
+  Size size_{};
+
+  Thickness margin_{};
+  Thickness padding_{};
+
+  Size preferred_size_{};
+};
+}  // namespace cru::ui::render