11 files changed, 137 insertions, 13 deletions
diff --git a/include/cru/common/event.hpp b/include/cru/common/event.hpp
index 763f8378..6228d867 100644
--- a/include/cru/common/event.hpp
+++ b/include/cru/common/event.hpp
@@ -22,7 +22,7 @@ class Event {
         : resolver_(resolver), token_(token) {}
     EventHandlerRevokerImpl(const EventHandlerRevokerImpl& other) = default;
     EventHandlerRevokerImpl(EventHandlerRevokerImpl&& other) = default;
-    EventHandlerRevokerImpl& operator=(EventHandlerRevokerImpl&& other) =
+    EventHandlerRevokerImpl& operator=(const EventHandlerRevokerImpl& other) =
         default;
     EventHandlerRevokerImpl& operator=(EventHandlerRevokerImpl&& other) =
         default;
@@ -31,7 +31,7 @@ class Event {
     void operator()() {
       const auto true_resolver = resolver_.lock();
       if (true_resolver) {
-        true_resolver()->RemoveHandler(token_);
+        (*true_resolver)()->RemoveHandler(token_);
       }
     }
 
@@ -63,10 +63,11 @@ class Event {
     return EventHandlerRevoker(EventHandlerRevokerImpl(event_resolver_, token));
   }
 
-  template <typename... Args>
-  EventHandlerRevoker AddHandler(Args&& args...) {
+  template <typename Arg>
+  EventHandlerRevoker AddHandler(Arg&& handler) {
+    static_assert(std::is_invocable_v<Arg, TArgs...>, "Handler not invocable.");
     const auto token = current_token_++;
-    handlers_.emplace(token, EventHandler(std::forward<Args>(args)...));
+    handlers_.emplace(token, EventHandler(std::forward<Arg>(handler)));
     return EventHandlerRevoker(EventHandlerRevokerImpl(event_resolver_, token));
   }
 
diff --git a/include/cru/common/format.hpp b/include/cru/common/format.hpp
index 1fb6863a..f085635a 100644
--- a/include/cru/common/format.hpp
+++ b/include/cru/common/format.hpp
@@ -83,7 +83,7 @@ inline std::string_view FormatToString(const std::string& string,
 }
 
 inline std::wstring_view FormatToString(const std::wstring_view& string,
-                                        details::TypeTag<String>) {
+                                        details::TypeTag<std::wstring>) {
   return string;
 }
 
@@ -93,7 +93,7 @@ inline std::string_view FormatToString(const std::string_view& string,
 }
 
 inline std::wstring_view FormatToString(const wchar_t* string,
-                                        details::TypeTag<String>) {
+                                        details::TypeTag<std::wstring>) {
   return std::wstring_view(string);
 }
 
diff --git a/include/cru/platform/basic_types.hpp b/include/cru/platform/basic_types.hpp
index 81ee3e34..e6ab4b59 100644
--- a/include/cru/platform/basic_types.hpp
+++ b/include/cru/platform/basic_types.hpp
@@ -1,3 +1,4 @@
+#pragma once
 #include "cru/common/pre_config.hpp"
 
 namespace cru::platform {
diff --git a/include/cru/platform/matrix.hpp b/include/cru/platform/matrix.hpp
index e5e5cf42..37e4725e 100644
--- a/include/cru/platform/matrix.hpp
+++ b/include/cru/platform/matrix.hpp
@@ -1,3 +1,4 @@
+#pragma once
 #include "cru/common/pre_config.hpp"
 
 #include "cru/common/ui_base.hpp"
@@ -29,12 +30,14 @@ struct Matrix {
            m31 == 0.0f && m32 == 0.0f;
   }
 
-  Matrix& operator*=(const Matrix& matrix) const {
+  Matrix& operator*=(const Matrix& matrix) {
     *this = Product(*this, matrix);
     return *this;
   }
 
-  Matrix operator*(const Matrix& matrix) const { return Product(this, matrix); }
+  Matrix operator*(const Matrix& matrix) const {
+    return Product(*this, matrix);
+  }
 
   ui::Point TransformPoint(const ui::Point& point) const {
     return ui::Point{point.x * m11 + point.y * m21 + m31,
diff --git a/include/cru/platform/painter.hpp b/include/cru/platform/painter.hpp
index eaaf61f9..b7b89fc9 100644
--- a/include/cru/platform/painter.hpp
+++ b/include/cru/platform/painter.hpp
@@ -19,7 +19,7 @@ struct Painter : virtual Interface {
   virtual void StrokeGeometry(Geometry* geometry, Brush* brush,
                               float width) = 0;
   virtual void FillGeometry(Geometry* geometry, Brush* brush) = 0;
-  virtual void DrawText(const ui::Point& offset, TextLayout* text_layout, Brush* brush);
+  virtual void DrawText(const ui::Point& offset, TextLayout* text_layout, Brush* brush) = 0;
   virtual void EndDraw() = 0;
   virtual bool IsDisposed() = 0;
 };
diff --git a/include/cru/platform/win/win_text_layout.hpp b/include/cru/platform/win/win_text_layout.hpp
index 9c93aa8c..dfb54264 100644
--- a/include/cru/platform/win/win_text_layout.hpp
+++ b/include/cru/platform/win/win_text_layout.hpp
@@ -17,7 +17,7 @@ class WinTextLayout : public Object, public virtual TextLayout {
   WinTextLayout(WinTextLayout&& other) = delete;
   WinTextLayout& operator=(const WinTextLayout& other) = delete;
   WinTextLayout& operator=(WinTextLayout&& other) = delete;
-  ~WinTextLayout() override;
+  ~WinTextLayout() override = default;
 
   std::wstring GetText() override;
   void SetText(std::wstring new_text) override;
diff --git a/include/cru/ui/controls/button.hpp b/include/cru/ui/controls/button.hpp
new file mode 100644
index 00000000..348416c5
--- /dev/null
+++ b/include/cru/ui/controls/button.hpp
@@ -0,0 +1,39 @@
+#pragma once
+#include "../content_control.hpp"
+
+#include <memory>
+
+namespace cru::ui::render {
+class BorderRenderObject;
+}
+
+namespace cru::ui::controls {
+class Button : public ContentControl {
+ public:
+  static constexpr auto control_type = L"Button";
+
+  static Button* Create() { return new Button(); }
+
+ protected:
+  Button();
+
+ public:
+  Button(const Button& other) = delete;
+  Button(Button&& other) = delete;
+  Button& operator=(const Button& other) = delete;
+  Button& operator=(Button&& other) = delete;
+  ~Button() override = default;
+
+  std::wstring_view GetControlType() const override final {
+    return control_type;
+  }
+
+  render::RenderObject* GetRenderObject() const override;
+
+ protected:
+  void OnChildChanged(Control* old_child, Control* new_child) override;
+
+ private:
+  std::shared_ptr<render::BorderRenderObject> render_object_{};
+};
+}  // namespace cru::ui::controls
diff --git a/include/cru/ui/controls/flex_layout.hpp b/include/cru/ui/controls/flex_layout.hpp
new file mode 100644
index 00000000..7422bc05
--- /dev/null
+++ b/include/cru/ui/controls/flex_layout.hpp
@@ -0,0 +1,41 @@
+#pragma once
+#include "../layout_control.hpp"
+
+#include <memory>
+
+namespace cru::ui::render {
+class FlexLayoutRenderObject;
+}
+
+namespace cru::ui::controls {
+
+class FlexLayout : public LayoutControl {
+ public:
+  static constexpr auto control_type = L"FlexLayout";
+
+  static FlexLayout* Create() { return new FlexLayout(); }
+
+ protected:
+  FlexLayout();
+
+ public:
+  FlexLayout(const FlexLayout& other) = delete;
+  FlexLayout(FlexLayout&& other) = delete;
+  FlexLayout& operator=(const FlexLayout& other) = delete;
+  FlexLayout& operator=(FlexLayout&& other) = delete;
+  ~FlexLayout() override = default;
+
+  std::wstring_view GetControlType() const override final {
+    return control_type;
+  }
+
+  render::RenderObject* GetRenderObject() const override;
+
+ protected:
+  void OnAddChild(Control* child, int position) override;
+  void OnRemoveChild(Control* child, int position) override;
+
+ private:
+  std::shared_ptr<render::FlexLayoutRenderObject> render_object_;
+};
+}  // namespace cru::ui::controls
diff --git a/include/cru/ui/controls/text_block.hpp b/include/cru/ui/controls/text_block.hpp
new file mode 100644
index 00000000..45cd12b9
--- /dev/null
+++ b/include/cru/ui/controls/text_block.hpp
@@ -0,0 +1,39 @@
+#pragma once
+#include "../no_child_control.hpp"
+
+#include <memory>
+
+namespace cru::ui::render {
+class TextRenderObject;
+}
+
+namespace cru::ui::controls {
+class TextBlock : public NoChildControl {
+ public:
+  static constexpr auto control_type = L"TextBlock";
+
+  static TextBlock* Create() { return new TextBlock(); }
+
+ protected:
+  TextBlock();
+
+ public:
+  TextBlock(const TextBlock& other) = delete;
+  TextBlock(TextBlock&& other) = delete;
+  TextBlock& operator=(const TextBlock& other) = delete;
+  TextBlock& operator=(TextBlock&& other) = delete;
+  ~TextBlock() override = default;
+
+  std::wstring_view GetControlType() const override final {
+    return control_type;
+  }
+
+  render::RenderObject* GetRenderObject() const override;
+
+  std::wstring GetText() const;
+  void SetText(std::wstring text);
+
+ private:
+  std::shared_ptr<render::TextRenderObject> render_object_;
+};
+}  // namespace cru::ui::controls
diff --git a/include/cru/ui/render/text_render_object.hpp b/include/cru/ui/render/text_render_object.hpp
index 329af18a..527fcd71 100644
--- a/include/cru/ui/render/text_render_object.hpp
+++ b/include/cru/ui/render/text_render_object.hpp
@@ -21,7 +21,7 @@ class TextRenderObject : public RenderObject {
   TextRenderObject(TextRenderObject&& other) = delete;
   TextRenderObject& operator=(const TextRenderObject& other) = delete;
   TextRenderObject& operator=(TextRenderObject&& other) = delete;
-  ~TextRenderObject() override;
+  ~TextRenderObject() override = default;
 
   std::wstring GetText() const;
   void SetText(std::wstring new_text);
diff --git a/include/cru/ui/window.hpp b/include/cru/ui/window.hpp
index 94deb4c5..991ebf70 100644
--- a/include/cru/ui/window.hpp
+++ b/include/cru/ui/window.hpp
@@ -38,7 +38,7 @@ class Window final : public ContentControl {
 
   render::RenderObject* GetRenderObject() const override;
 
-  platform::NativeWindow* GetNativeWindow() const;
+  platform::NativeWindow* GetNativeWindow() const { return native_window_; }
 
   Control* GetMouseHoverControl() const { return mouse_hover_control_; }