1 files changed, 98 insertions, 0 deletions
diff --git a/include/cru/ui/render/render_object.hpp b/include/cru/ui/render/render_object.hpp
new file mode 100644
index 00000000..3cd14a6a
--- /dev/null
+++ b/include/cru/ui/render/render_object.hpp
@@ -0,0 +1,98 @@
+#pragma once
+#include "cru/common/base.hpp"
+
+#include "cru/common/ui_base.hpp"
+
+#include <vector>
+
+// forward declarations
+namespace cru::ui {
+class Control;
+}
+
+namespace cru::platform {
+struct Painter;
+}
+
+namespace cru::ui::render {
+class RenderObject : public Object {
+ protected:
+  RenderObject() = default;
+
+ 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; }
+
+  RenderObject* GetParent() const { return parent_; }
+
+  const std::vector<RenderObject*>& GetChildren() const { return children_; }
+  void AddChild(RenderObject* render_object, int position);
+  void RemoveChild(int position);
+
+  Point GetOffset() const { return offset_; }
+  void SetOffset(const Point& offset) { offset_ = offset; }
+  Size GetSize() const { return size_; }
+  void SetSize(const Size& size) {
+    const auto old_size = size_;
+    size_ = size;
+    OnSizeChanged(old_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::Painter* render_target) = 0;
+
+  virtual RenderObject* HitTest(const Point& point) = 0;
+
+ protected:
+  virtual void OnParentChanged(RenderObject* old_parent,
+                               RenderObject* new_parent);
+
+  virtual void OnAddChild(RenderObject* new_child, int position);
+  virtual void OnRemoveChild(RenderObject* removed_child, int position);
+
+  virtual void OnSizeChanged(const Size& old_size, const Size& new_size);
+
+  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;
+
+  Rect GetContentRect() const;
+
+ private:
+  void SetParent(RenderObject* new_parent);
+
+ private:
+  Control* control_ = nullptr;
+
+  RenderObject* parent_ = nullptr;
+  std::vector<RenderObject*> children_{};
+
+  Point offset_{};
+  Size size_{};
+
+  Thickness margin_{};
+  Thickness padding_{};
+
+  Size preferred_size_{};
+};
+}  // namespace cru::ui::render