...

10 files changed, 294 insertions, 237 deletions

diff --git a/CruUI/CruUI.vcxproj b/CruUI/CruUI.vcxproj
index ba46d963..62b23165 100644
--- a/CruUI/CruUI.vcxproj
+++ b/CruUI/CruUI.vcxproj
@@ -134,14 +134,16 @@
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
     <ClCompile>
-      <PrecompiledHeader>Use</PrecompiledHeader>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>MaxSpeed</Optimization>
       <FunctionLevelLinking>true</FunctionLevelLinking>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <SDLCheck>true</SDLCheck>
-      <PreprocessorDefinitions>NDEBUG;_WINDOWS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>_SILENCE_CXX17_OLD_ALLOCATOR_MEMBERS_DEPRECATION_WARNING;NDEBUG;_WINDOWS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <ConformanceMode>true</ConformanceMode>
+      <AdditionalIncludeDirectories>$(ProjectDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <LanguageStandard>stdcpplatest</LanguageStandard>
     </ClCompile>
     <Link>
       <SubSystem>Windows</SubSystem>
diff --git a/CruUI/main.cpp b/CruUI/main.cpp
index bd0d3247..99f9ded6 100644
--- a/CruUI/main.cpp
+++ b/CruUI/main.cpp
@@ -66,19 +66,13 @@ int APIENTRY wWinMain(
 
     //test 2
 
-    LinearLayout layout;
-    TextBlock text_block_1;
-    text_block_1.SetText(L"Hello World!!!");
-    TextBlock text_block_2;
-    text_block_2.SetText(L"This is a very very very very very long sentence!!!");
-    TextBlock text_block_3;
-    text_block_3.SetText(L"By crupest!!!");
-
-    layout.AddChild(&text_block_1);
-    layout.AddChild(&text_block_2);
-    layout.AddChild(&text_block_3);
-
-    window.AddChild(&layout);
+    const auto layout = LinearLayout::Create();
+
+    layout->AddChild(TextBlock::Create(L"Hello World!!!"));
+    layout->AddChild(TextBlock::Create(L"This is a very very very very very long sentence!!!"));
+    layout->AddChild(TextBlock::Create(L"By crupest!!!"));
+
+    window.AddChild(layout);
 
     window.Show();
 
diff --git a/CruUI/ui/control.cpp b/CruUI/ui/control.cpp
index ee6db284..507beee8 100644
--- a/CruUI/ui/control.cpp
+++ b/CruUI/ui/control.cpp
@@ -1,6 +1,8 @@
 #include "control.h"
 
+#include <string>
 #include <algorithm>
+#include <chrono>
 
 #include "window.h"
 #include "timer.h"
@@ -25,19 +27,29 @@ namespace cru {
 
         }
 
+        Control::~Control()
+        {
+            ForeachChild([](auto control)
+            {
+                delete control;
+            });
+        }
+
         void Control::ForeachChild(Action<Control*>&& predicate) const
         {
-            for (const auto child : children_)
-                predicate(child);
+            if (is_container_)
+                for (const auto child : children_)
+                    predicate(child);
         }
 
         void Control::ForeachChild(FlowControlAction<Control*>&& predicate) const
         {
-            for (const auto child : children_)
-            {
-                if (predicate(child) == FlowControl::Break)
-                    break;
-            }
+            if (is_container_)
+                for (const auto child : children_)
+                {
+                    if (predicate(child) == FlowControl::Break)
+                        break;
+                }
         }
 
         void AddChildCheck(Control* control)
@@ -128,7 +140,8 @@ namespace cru {
 
         void Control::TraverseDescendants(Action<Control*>&& predicate)
         {
-            TraverseDescendantsInternal(this, predicate);
+            if (is_container_)
+                TraverseDescendantsInternal(this, predicate);
         }
 
         Point Control::GetPositionRelative()
@@ -138,13 +151,16 @@ namespace cru {
 
         void Control::SetPositionRelative(const Point & position)
         {
-            if (old_position_ == position) // if cache has been refreshed and no pending notify
-                old_position_ = position_;
-            position_ = position;
-            if (auto window = GetWindow())
+            if (position != position_)
             {
-                window->GetLayoutManager()->InvalidateControlPositionCache(this);
-                window->Repaint();
+                if (old_position_ == position) // if cache has been refreshed and no pending notify
+                    old_position_ = position_;
+                position_ = position;
+                if (auto window = GetWindow())
+                {
+                    window->GetLayoutManager()->InvalidateControlPositionCache(this);
+                    window->Repaint();
+                }
             }
         }
 
@@ -241,9 +257,12 @@ namespace cru {
 
         void Control::Layout(const Rect& rect)
         {
+            auto before = std::chrono::steady_clock::now();
             SetPositionRelative(rect.GetLeftTop());
             SetSize(rect.GetSize());
             OnLayout(rect);
+            auto after = std::chrono::steady_clock::now();
+            OutputDebugStringW((L"Layout time duration:" + std::to_wstring(std::chrono::duration_cast<std::chrono::milliseconds>(after - before).count()) + L"\n").c_str());
         }
 
         Size Control::GetDesiredSize() const
diff --git a/CruUI/ui/control.h b/CruUI/ui/control.h
index f4302e80..41401008 100644
--- a/CruUI/ui/control.h
+++ b/CruUI/ui/control.h
@@ -36,7 +36,7 @@ namespace cru
             Control(Control&& other) = delete;
             Control& operator=(const Control& other) = delete;
             Control& operator=(Control&& other) = delete;
-            ~Control() override = default;
+            ~Control() override;
 
         public:
 
diff --git a/CruUI/ui/controls/linear_layout.cpp b/CruUI/ui/controls/linear_layout.cpp
index f639720d..1d88a4e1 100644
--- a/CruUI/ui/controls/linear_layout.cpp
+++ b/CruUI/ui/controls/linear_layout.cpp
@@ -44,9 +44,17 @@ namespace cru::ui::controls
         {
             control->Measure(rest_available_size_for_children);
             if (orientation_ == Orientation::Horizontal)
+            {
                 rest_available_size_for_children.width -= control->GetDesiredSize().width;
+                if (rest_available_size_for_children.width < 0)
+                    rest_available_size_for_children.width = 0;
+            }
             else
+            {
                 rest_available_size_for_children.height -= control->GetDesiredSize().height;
+                if (rest_available_size_for_children.height < 0)
+                    rest_available_size_for_children.height = 0;
+            }
         });
 
         auto actual_size_for_children = total_available_size_for_children - rest_available_size_for_children;
diff --git a/CruUI/ui/controls/linear_layout.h b/CruUI/ui/controls/linear_layout.h
index b8722b6f..74c504cb 100644
--- a/CruUI/ui/controls/linear_layout.h
+++ b/CruUI/ui/controls/linear_layout.h
@@ -13,6 +13,12 @@ namespace cru::ui::controls
             Vertical
         };
 
+        static LinearLayout* Create(const Orientation orientation = Orientation::Vertical)
+        {
+            return new LinearLayout(orientation);
+        }
+
+    private:
         explicit LinearLayout(Orientation orientation = Orientation::Vertical);
 
     protected:
diff --git a/CruUI/ui/controls/text_block.cpp b/CruUI/ui/controls/text_block.cpp
index 3649aea6..d15bd681 100644
--- a/CruUI/ui/controls/text_block.cpp
+++ b/CruUI/ui/controls/text_block.cpp
@@ -1,5 +1,7 @@
 #include "text_block.h"
 
+#include <chrono>
+
 #include "ui/window.h"
 #include "graph/graph.h"
 #include "exception.h"
@@ -27,9 +29,12 @@ namespace cru
 
             void TextBlock::SetText(const String& text)
             {
-                const auto old_text = text_;
-                text_ = text;
-                OnTextChangedCore(old_text, text);
+                if (text_ != text)
+                {
+                    const auto old_text = text_;
+                    text_ = text;
+                    OnTextChangedCore(old_text, text);
+                }
             }
 
             void TextBlock::SetBrush(const Microsoft::WRL::ComPtr<ID2D1Brush>& brush)
@@ -47,8 +52,12 @@ namespace cru
 
             void TextBlock::OnSizeChangedCore(events::SizeChangedEventArgs& args)
             {
+                auto before = std::chrono::steady_clock::now();
                 RecreateTextLayout();
                 Repaint();
+                auto after = std::chrono::steady_clock::now();
+                OutputDebugStringW((L"TextBlock OnSizeChangedCore time duration:" + std::to_wstring(std::chrono::duration_cast<std::chrono::milliseconds>(after - before).count()) + L"\n").c_str());
+
             }
 
             void TextBlock::OnDraw(ID2D1DeviceContext* device_context)
diff --git a/CruUI/ui/controls/text_block.h b/CruUI/ui/controls/text_block.h
index abf77112..04347a0c 100644
--- a/CruUI/ui/controls/text_block.h
+++ b/CruUI/ui/controls/text_block.h
@@ -15,11 +15,22 @@ namespace cru
             public:
                 using TextLayoutHandler = Action<Microsoft::WRL::ComPtr<IDWriteTextLayout>>;
 
+                static TextBlock* Create(
+                    const String& text = L"",
+                    const Microsoft::WRL::ComPtr<IDWriteTextFormat>& init_text_format = nullptr,
+                    const Microsoft::WRL::ComPtr<ID2D1Brush>& init_brush = nullptr)
+                {
+                    const auto text_block = new TextBlock(init_text_format, init_brush);
+                    text_block->SetText(text);
+                    return text_block;
+                }
 
+            private:
                 explicit TextBlock(
                     const Microsoft::WRL::ComPtr<IDWriteTextFormat>& init_text_format = nullptr,
                     const Microsoft::WRL::ComPtr<ID2D1Brush>& init_brush = nullptr
                 );
+            public:
                 TextBlock(const TextBlock& other) = delete;
                 TextBlock(TextBlock&& other) = delete;
                 TextBlock& operator=(const TextBlock& other) = delete;
diff --git a/CruUI/ui/window.cpp b/CruUI/ui/window.cpp
index 2c731a1e..392bca87 100644
--- a/CruUI/ui/window.cpp
+++ b/CruUI/ui/window.cpp
@@ -97,9 +97,9 @@ namespace cru
                     RefreshInvalidControlPositionCache(); // first refresh position cache.
                     for (const auto i : cache_invalid_controls_) // traverse all descendants of position-invalid controls and notify position change event
                         i->TraverseDescendants([](Control* control)
-                        {
-                            control->CheckAndNotifyPositionChanged();
-                        });
+                    {
+                        control->CheckAndNotifyPositionChanged();
+                    });
                     cache_invalid_controls_.clear(); // after update and notify, clear the set.
                 });
             }
@@ -401,6 +401,12 @@ namespace cru
             return rect;
         }
 
+        bool Window::IsMessageInQueue(UINT message)
+        {
+            MSG msg;
+            return ::PeekMessageW(&msg, hwnd_, message, message, PM_NOREMOVE) != 0;
+        }
+
         void Window::OnDestroyInternal() {
             Application::GetInstance()->GetWindowManager()->UnregisterWindow(hwnd_);
             hwnd_ = nullptr;
diff --git a/CruUI/ui/window.h b/CruUI/ui/window.h
index 7ecea456..9ffa4dc6 100644
--- a/CruUI/ui/window.h
+++ b/CruUI/ui/window.h
@@ -9,265 +9,267 @@
 #include "control.h"
 
 namespace cru {
-	namespace graph {
-		class WindowRenderTarget;
-	}
-
-	namespace ui {
-		class WindowClass : public Object
-		{
-		public:
-			WindowClass(const String& name, WNDPROC window_proc, HINSTANCE h_instance);
-		    WindowClass(const WindowClass& other) = delete;
-		    WindowClass(WindowClass&& other) = delete;
-		    WindowClass& operator=(const WindowClass& other) = delete;
-		    WindowClass& operator=(WindowClass&& other) = delete;
-		    ~WindowClass() override = default;
-
-
-			const wchar_t* GetName() const
-			{
-			    return name_.c_str();
-			}
-
-			ATOM GetAtom() const
-			{
-			    return atom_;
-			}
-
-		private:
-			String name_;
-			ATOM atom_;
-		};
-
-		class WindowManager : public Object
-		{
-		public:
-			WindowManager();
-		    WindowManager(const WindowManager& other) = delete;
-		    WindowManager(WindowManager&& other) = delete;
-		    WindowManager& operator=(const WindowManager& other) = delete;
-		    WindowManager& operator=(WindowManager&& other) = delete;
-			~WindowManager() override = default;
-
-
-			//Get the general window class for creating ordinary window.
-			WindowClass* GetGeneralWindowClass() const
-			{
+    namespace graph {
+        class WindowRenderTarget;
+    }
+
+    namespace ui {
+        class WindowClass : public Object
+        {
+        public:
+            WindowClass(const String& name, WNDPROC window_proc, HINSTANCE h_instance);
+            WindowClass(const WindowClass& other) = delete;
+            WindowClass(WindowClass&& other) = delete;
+            WindowClass& operator=(const WindowClass& other) = delete;
+            WindowClass& operator=(WindowClass&& other) = delete;
+            ~WindowClass() override = default;
+
+
+            const wchar_t* GetName() const
+            {
+                return name_.c_str();
+            }
+
+            ATOM GetAtom() const
+            {
+                return atom_;
+            }
+
+        private:
+            String name_;
+            ATOM atom_;
+        };
+
+        class WindowManager : public Object
+        {
+        public:
+            WindowManager();
+            WindowManager(const WindowManager& other) = delete;
+            WindowManager(WindowManager&& other) = delete;
+            WindowManager& operator=(const WindowManager& other) = delete;
+            WindowManager& operator=(WindowManager&& other) = delete;
+            ~WindowManager() override = default;
+
+
+            //Get the general window class for creating ordinary window.
+            WindowClass* GetGeneralWindowClass() const
+            {
                 return general_window_class_.get();
-			}
+            }
 
-			//Register a window newly created.
-			//This function adds the hwnd to hwnd-window map.
-			//It should be called immediately after a window was created.
-			void RegisterWindow(HWND hwnd, Window* window);
+            //Register a window newly created.
+            //This function adds the hwnd to hwnd-window map.
+            //It should be called immediately after a window was created.
+            void RegisterWindow(HWND hwnd, Window* window);
 
-			//Unregister a window that is going to be destroyed.
-			//This function removes the hwnd from the hwnd-window map.
-			//It should be called immediately before a window is going to be destroyed,
-			void UnregisterWindow(HWND hwnd);
+            //Unregister a window that is going to be destroyed.
+            //This function removes the hwnd from the hwnd-window map.
+            //It should be called immediately before a window is going to be destroyed,
+            void UnregisterWindow(HWND hwnd);
 
-			//Return a pointer to the Window object related to the HWND or nullptr if the hwnd is not in the map.
-			Window* FromHandle(HWND hwnd);
+            //Return a pointer to the Window object related to the HWND or nullptr if the hwnd is not in the map.
+            Window* FromHandle(HWND hwnd);
 
-		private:
-			std::unique_ptr<WindowClass> general_window_class_;
-			std::map<HWND, Window*> window_map_;
-		};
+        private:
+            std::unique_ptr<WindowClass> general_window_class_;
+            std::map<HWND, Window*> window_map_;
+        };
 
 
-		class WindowLayoutManager : public Object
-		{
-		public:
-			WindowLayoutManager() = default;
-		    WindowLayoutManager(const WindowLayoutManager& other) = delete;
-		    WindowLayoutManager(WindowLayoutManager&& other) = delete;
-		    WindowLayoutManager& operator=(const WindowLayoutManager& other) = delete;
-		    WindowLayoutManager& operator=(WindowLayoutManager&& other) = delete;
-			~WindowLayoutManager() override = default;
+        class WindowLayoutManager : public Object
+        {
+        public:
+            WindowLayoutManager() = default;
+            WindowLayoutManager(const WindowLayoutManager& other) = delete;
+            WindowLayoutManager(WindowLayoutManager&& other) = delete;
+            WindowLayoutManager& operator=(const WindowLayoutManager& other) = delete;
+            WindowLayoutManager& operator=(WindowLayoutManager&& other) = delete;
+            ~WindowLayoutManager() override = default;
 
-			//Mark position cache of the control and its descendants invalid,
-			//(which is saved as an auto-managed list internal)
-			//and send a message to refresh them.
-			void InvalidateControlPositionCache(Control* control);
+            //Mark position cache of the control and its descendants invalid,
+            //(which is saved as an auto-managed list internal)
+            //and send a message to refresh them.
+            void InvalidateControlPositionCache(Control* control);
 
-			//Refresh position cache of the control and its descendants whose cache
-			//has been marked as invalid.
-			void RefreshInvalidControlPositionCache();
+            //Refresh position cache of the control and its descendants whose cache
+            //has been marked as invalid.
+            void RefreshInvalidControlPositionCache();
 
-			//Refresh position cache of the control and its descendants immediately.
-			static void RefreshControlPositionCache(Control* control);
+            //Refresh position cache of the control and its descendants immediately.
+            static void RefreshControlPositionCache(Control* control);
 
-		private:
-			static void RefreshControlPositionCacheInternal(Control* control, const Point& parent_lefttop_absolute);
+        private:
+            static void RefreshControlPositionCacheInternal(Control* control, const Point& parent_lefttop_absolute);
 
-		private:
-			std::set<Control*> cache_invalid_controls_;
-		};
+        private:
+            std::set<Control*> cache_invalid_controls_;
+        };
 
-		class Window : public Control
-		{
-			friend class WindowManager;
-		public:
-			Window();
-		    Window(const Window& other) = delete;
-		    Window(Window&& other) = delete;
-		    Window& operator=(const Window& other) = delete;
-		    Window& operator=(Window&& other) = delete;
-			~Window() override;
+        class Window : public Control
+        {
+            friend class WindowManager;
+        public:
+            Window();
+            Window(const Window& other) = delete;
+            Window(Window&& other) = delete;
+            Window& operator=(const Window& other) = delete;
+            Window& operator=(Window&& other) = delete;
+            ~Window() override;
 
-		public:
-			//*************** region: managers ***************
-			WindowLayoutManager* GetLayoutManager() const
-			{
-			    return layout_manager_.get();
-			}
+        public:
+            //*************** region: managers ***************
+            WindowLayoutManager* GetLayoutManager() const
+            {
+                return layout_manager_.get();
+            }
 
 
-			//*************** region: handle ***************
+            //*************** region: handle ***************
 
-			//Get the handle of the window. Return null if window is invalid.
-			HWND GetWindowHandle() const
-			{
-			    return hwnd_;
-			}
+            //Get the handle of the window. Return null if window is invalid.
+            HWND GetWindowHandle() const
+            {
+                return hwnd_;
+            }
 
-			//Return if the window is still valid, that is, hasn't been closed or destroyed.
-			bool IsWindowValid() const
-			{
-			    return hwnd_ != nullptr;
-			}
+            //Return if the window is still valid, that is, hasn't been closed or destroyed.
+            bool IsWindowValid() const
+            {
+                return hwnd_ != nullptr;
+            }
 
 
-			//*************** region: window operations ***************
+            //*************** region: window operations ***************
 
-			//Close and destroy the window if the window is valid.
-			void Close();
+            //Close and destroy the window if the window is valid.
+            void Close();
 
-			//Send a repaint message to the window's message queue which may make the window repaint.
-			void Repaint() override;
+            //Send a repaint message to the window's message queue which may make the window repaint.
+            void Repaint() override;
 
-			//Show the window.
-			void Show();
+            //Show the window.
+            void Show();
 
-			//Hide thw window.
-			void Hide();
+            //Hide thw window.
+            void Hide();
 
-			//Get the client size.
-			Size GetClientSize();
+            //Get the client size.
+            Size GetClientSize();
 
-			//Set the client size and repaint.
-			void SetClientSize(const Size& size);
+            //Set the client size and repaint.
+            void SetClientSize(const Size& size);
 
-			//Get the rect of the window containing frame.
-			//The lefttop of the rect is relative to screen lefttop.
-			Rect GetWindowRect();
+            //Get the rect of the window containing frame.
+            //The lefttop of the rect is relative to screen lefttop.
+            Rect GetWindowRect();
 
-			//Set the rect of the window containing frame.
-			//The lefttop of the rect is relative to screen lefttop.
-			void SetWindowRect(const Rect& rect);
+            //Set the rect of the window containing frame.
+            //The lefttop of the rect is relative to screen lefttop.
+            void SetWindowRect(const Rect& rect);
 
-			//Handle the raw window message.
-			//Return true if the message is handled and get the result through "result" argument.
-			//Return false if the message is not handled.
-			bool HandleWindowMessage(HWND hwnd, int msg, WPARAM w_param, LPARAM l_param, LRESULT& result);
+            //Handle the raw window message.
+            //Return true if the message is handled and get the result through "result" argument.
+            //Return false if the message is not handled.
+            bool HandleWindowMessage(HWND hwnd, int msg, WPARAM w_param, LPARAM l_param, LRESULT& result);
 
 
-			//*************** region: position and size ***************
+            //*************** region: position and size ***************
 
-			//Always return (0, 0) for a window.
-			Point GetPositionRelative() override final;
+            //Always return (0, 0) for a window.
+            Point GetPositionRelative() override final;
 
-			//This method has no effect for a window.
-			void SetPositionRelative(const Point& position) override final;
+            //This method has no effect for a window.
+            void SetPositionRelative(const Point& position) override final;
 
-			//Get the size of client area for a window.
-			Size GetSize() override final;
+            //Get the size of client area for a window.
+            Size GetSize() override final;
 
-			//This method has no effect for a window. Use SetClientSize instead.
-			void SetSize(const Size& size) override final;
+            //This method has no effect for a window. Use SetClientSize instead.
+            void SetSize(const Size& size) override final;
 
 
-			//*************** region: features ***************
+            //*************** region: features ***************
 
-			//Refresh control list.
-			//It should be invoked every time a control is added or removed from the tree.
-			void RefreshControlList();
+            //Refresh control list.
+            //It should be invoked every time a control is added or removed from the tree.
+            void RefreshControlList();
 
-			//Get the most top control at "point".
-			Control* HitTest(const Point& point);
+            //Get the most top control at "point".
+            Control* HitTest(const Point& point);
 
-			
-			//*************** region: focus ***************
 
-			//Request focus for specified control.
-			bool RequestFocusFor(Control* control);
+            //*************** region: focus ***************
 
-			//Get the control that has focus.
-			Control* GetFocusControl();
+            //Request focus for specified control.
+            bool RequestFocusFor(Control* control);
 
+            //Get the control that has focus.
+            Control* GetFocusControl();
 
-		private:
-			//*************** region: native operations ***************
 
-			//Get the client rect in pixel.
-			RECT GetClientRectPixel();
+        private:
+            //*************** region: native operations ***************
 
+            //Get the client rect in pixel.
+            RECT GetClientRectPixel();
 
-			//*************** region: native messages ***************
+            bool IsMessageInQueue(UINT message);
 
-			void OnDestroyInternal();
-			void OnPaintInternal();
-			void OnResizeInternal(int new_width, int new_height);
 
-			void OnSetFocusInternal();
-			void OnKillFocusInternal();
+            //*************** region: native messages ***************
 
-			void OnMouseMoveInternal(POINT point);
-			void OnMouseLeaveInternal();
-			void OnMouseDownInternal(MouseButton button, POINT point);
-			void OnMouseUpInternal(MouseButton button, POINT point);
+            void OnDestroyInternal();
+            void OnPaintInternal();
+            void OnResizeInternal(int new_width, int new_height);
 
+            void OnSetFocusInternal();
+            void OnKillFocusInternal();
 
+            void OnMouseMoveInternal(POINT point);
+            void OnMouseLeaveInternal();
+            void OnMouseDownInternal(MouseButton button, POINT point);
+            void OnMouseUpInternal(MouseButton button, POINT point);
 
-			//*************** region: event dispatcher helper ***************
 
-			template<typename EventArgs>
-			using EventMethod = void (Control::*)(EventArgs&);
 
-			// Dispatch the event.
-			// 
-			// This will invoke the "event_method" of the control and its parent and parent's
-			// parent ... (until "last_receiver" if it's not nullptr) with appropriate args.
-			//
-			// Args is of type "EventArgs". The first init argument is "sender", which is
-			// automatically bound to each receiving control. The second init argument is
-			// "original_sender", which is unchanged. And "args" will be perfectly forwarded
-			// as the rest arguments.
-			template<typename EventArgs, typename... Args>
-			void DispatchEvent(Control* original_sender, EventMethod<EventArgs> event_method, Control* last_receiver, Args&&... args)
-			{
-				auto control = original_sender;
-				while (control != nullptr && control != last_receiver)
-				{
-					EventArgs event_args(control, original_sender, std::forward<Args>(args)...);
-					(control->*event_method)(event_args);
-					control = control->GetParent();
-				}
-			}
+            //*************** region: event dispatcher helper ***************
 
-		private:
-			std::unique_ptr<WindowLayoutManager> layout_manager_;
+            template<typename EventArgs>
+            using EventMethod = void (Control::*)(EventArgs&);
 
-			HWND hwnd_ = nullptr;
-			std::shared_ptr<graph::WindowRenderTarget> render_target_{};
+            // Dispatch the event.
+            // 
+            // This will invoke the "event_method" of the control and its parent and parent's
+            // parent ... (until "last_receiver" if it's not nullptr) with appropriate args.
+            //
+            // Args is of type "EventArgs". The first init argument is "sender", which is
+            // automatically bound to each receiving control. The second init argument is
+            // "original_sender", which is unchanged. And "args" will be perfectly forwarded
+            // as the rest arguments.
+            template<typename EventArgs, typename... Args>
+            void DispatchEvent(Control* original_sender, EventMethod<EventArgs> event_method, Control* last_receiver, Args&&... args)
+            {
+                auto control = original_sender;
+                while (control != nullptr && control != last_receiver)
+                {
+                    EventArgs event_args(control, original_sender, std::forward<Args>(args)...);
+                    (control->*event_method)(event_args);
+                    control = control->GetParent();
+                }
+            }
 
-			std::list<Control*> control_list_{};
+        private:
+            std::unique_ptr<WindowLayoutManager> layout_manager_;
 
-			Control* mouse_hover_control_ = nullptr;
+            HWND hwnd_ = nullptr;
+            std::shared_ptr<graph::WindowRenderTarget> render_target_{};
 
-			bool window_focus_ = false;
-			Control* focus_control_ = this; // "focus_control_" can't be nullptr
-		};
-	}
+            std::list<Control*> control_list_{};
+
+            Control* mouse_hover_control_ = nullptr;
+
+            bool window_focus_ = false;
+            Control* focus_control_ = this; // "focus_control_" can't be nullptr
+        };
+    }
 }