diff --git a/include/nana/basic_types.hpp b/include/nana/basic_types.hpp
index 4d13b6ec..adbf55da 100644
--- a/include/nana/basic_types.hpp
+++ b/include/nana/basic_types.hpp
@@ -84,7 +84,7 @@ namespace nana
 
 	enum class mouse_action
 	{
-		begin, normal = begin, over, pressed, end
+		begin, normal = begin, hovered, pressed, end
 	};
 
 	enum class element_state
@@ -337,6 +337,8 @@ namespace nana
 
 		bool operator==(const color& other) const;
 		bool operator!=(const color& other) const;
+
+		friend color operator+(const color&, const color&);
 	private:
 		double r_{ 0.0 };
 		double g_{ 0.0 };
@@ -344,60 +346,91 @@ namespace nana
 		double a_{ 0.0 };	//invisible
 	};
 
-
-	struct rectangle;
-
-	struct point
+	template<typename T>
+	struct basic_point
 	{
-		point();
-		point(int x, int y);
-		point(const rectangle&);
+		//typedef-names
+		using value_type = T;
 
-		point& operator=(const rectangle&);
-		bool operator==(const point&) const;
-		bool operator!=(const point&) const;
-		bool operator<(const point&) const;
-		bool operator<=(const point&) const;
-		bool operator>(const point&) const;
-		bool operator>=(const point&) const;
+		//data member
+		value_type x{};
+		value_type y{};
 
-		point operator-(const point&) const;
-		point operator+(const point&) const;
-		point& operator-=(const point&);
-		point& operator+=(const point&);
+		//member functions
+		basic_point() = default;
 
-		int x;
-		int y;
+		basic_point(value_type x, value_type y)
+			: x{ x }, y{y}
+		{}
+
+		bool operator==(const basic_point& other) const noexcept
+		{
+			return (x == other.x && y == other.y);
+		}
+
+		bool operator!=(const basic_point& other) const noexcept
+		{
+			return (x != other.x || y != other.y);
+		}
+
+		bool operator<(const basic_point& other) const noexcept
+		{
+			return ((y < other.y) || (y == other.y && x < other.x));
+		}
+
+		bool operator<=(const basic_point& other) const noexcept
+		{
+			return ((y < other.y) || (y == other.y && x <= other.x));
+		}
+
+		bool operator>(const basic_point& other) const noexcept
+		{
+			return ((y > other.y) || (y == other.y && x > other.x));
+		}
+
+		bool operator>=(const basic_point& other) const noexcept
+		{
+			return ((y > other.y) || (y == other.y && x >= other.x));
+		}
+
+		basic_point operator-(const basic_point& other) const noexcept
+		{
+			return{ x - other.x, y - other.y };
+		}
+
+		basic_point operator+(const basic_point& other) const noexcept
+		{
+			return{ x + other.x, y + other.y };
+		}
+
+		basic_point& operator-=(const basic_point& other) noexcept
+		{
+			x -= other.x;
+			y -= other.y;
+			return *this;
+		}
+
+		basic_point& operator+=(const basic_point& other) noexcept
+		{
+			x += other.x;
+			y += other.y;
+			return *this;
+		}
 	};
 
-	struct upoint
-	{
-		typedef unsigned value_type;
-
-		upoint();
-		upoint(value_type x, value_type y);
-		bool operator==(const upoint&) const;
-		bool operator!=(const upoint&) const;
-		bool operator<(const upoint&) const;
-		bool operator<=(const upoint&) const;
-		bool operator>(const upoint&) const;
-		bool operator>=(const upoint&) const;
-
-		value_type x;
-		value_type y;
-	};
+	using point = basic_point<int>;
+	using upoint = basic_point<unsigned>;
 
 	struct size
 	{
 		using value_type = unsigned;
 		size();
 		size(value_type width, value_type height);
-		size(const rectangle&);
-
-		size& operator=(const rectangle&);
 
 		bool empty() const;		///< true if width * height == 0
 		bool is_hit(const point&) const;	///< Assume it is a rectangle at (0,0), and check whether a specified position is in the rectange.
+		size& shift();
+
 		bool operator==(const size& rhs) const;
 		bool operator!=(const size& rhs) const;
 		size operator+(const size&) const;
@@ -419,8 +452,11 @@ namespace nana
 		rectangle& operator=(const point&);
 		rectangle& operator=(const size&);
 
-		rectangle& set_pos(const point&);
-		rectangle& set_size(const size&);
+		point position() const noexcept;
+		rectangle& position(const point&) noexcept;
+
+		size dimension() const noexcept;
+		rectangle& dimension(const size&) noexcept;
 
 		rectangle& pare_off(int pixels);	 ///<Pares the specified pixels off the rectangle. It's equal to x += pixels; y + pixels; width -= (pixels << 1); height -= (pixels << 1);
 
@@ -428,7 +464,8 @@ namespace nana
 		int bottom() const;
 		bool is_hit(int x, int y) const;
 		bool is_hit(const point& pos) const;
-		bool empty() const;		///< true if width * height == 0
+		bool empty() const;		///< true if width * height == 0.
+		rectangle& shift();	///< Swap position x and y, size width and height.
 
 		int x;
 		int y;
diff --git a/include/nana/gui/detail/effects_renderer.hpp b/include/nana/gui/detail/effects_renderer.hpp
index 1a55e2ab..f7bd7d03 100644
--- a/include/nana/gui/detail/effects_renderer.hpp
+++ b/include/nana/gui/detail/effects_renderer.hpp
@@ -144,7 +144,7 @@ namespace nana{
 			{
 				if((focused_wd == wd) && (static_cast<unsigned>(wd->effect.edge_nimbus) & static_cast<unsigned>(effects::edge_nimbus::active)))
 					return true;
-				else if((static_cast<unsigned>(wd->effect.edge_nimbus) & static_cast<unsigned>(effects::edge_nimbus::over)) && (wd->flags.action == mouse_action::over))
+				else if((static_cast<unsigned>(wd->effect.edge_nimbus) & static_cast<unsigned>(effects::edge_nimbus::over)) && (wd->flags.action == mouse_action::hovered))
 					return true;
 				return false;
 			}
diff --git a/source/basic_types.cpp b/source/basic_types.cpp
index c8bd2c34..5820c3cf 100644
--- a/source/basic_types.cpp
+++ b/source/basic_types.cpp
@@ -528,124 +528,25 @@ namespace nana
 		return (px_color().value != other.px_color().value);
 	}
 
+	color operator+(const color& x, const color& y)
+	{
+		double a = x.a_ + y.a_;
+		auto r = static_cast<unsigned>(x.r_ + y.r_);
+		auto g = static_cast<unsigned>(x.g_ + y.g_);
+		auto b = static_cast<unsigned>(x.b_ + y.b_);
+
+		return color{
+			r > 255 ? 255 : r,
+			g > 255 ? 255 : g,
+			b > 255 ? 255 : b,
+			a > 1.0 ? 1.0 : a };
+	}
 	//end class color
-	//struct point
-		point::point():x(0), y(0){}
-		point::point(int x, int y):x(x), y(y){}
-		point::point(const rectangle& r)
-			: x(r.x), y(r.y)
-		{}
 
-		point& point::operator=(const rectangle& r)
-		{
-			x = r.x;
-			y = r.y;
-			return *this;
-		}
-
-		bool point::operator==(const point& rhs) const
-		{
-			return ((x == rhs.x) && (y == rhs.y));
-		}
-
-		bool point::operator!=(const point& rhs) const
-		{
-			return ((x != rhs.x) || (y != rhs.y));
-		}
-
-		bool point::operator<(const point& rhs) const
-		{
-			return ((y < rhs.y) || (y == rhs.y && x < rhs.x));
-		}
-
-		bool point::operator<=(const point& rhs) const
-		{
-			return ((y < rhs.y) || (y == rhs.y && x <= rhs.x));
-		}
-
-		bool point::operator>(const point& rhs) const
-		{
-			return ((y > rhs.y) || (y == rhs.y && x > rhs.x));
-		}
-
-		bool point::operator>=(const point& rhs) const
-		{
-			return ((y > rhs.y) || (y == rhs.y && x >= rhs.x));
-		}
-
-		point point::operator-(const point& rhs) const
-		{
-			return{x - rhs.x, y - rhs.y};
-		}
-
-		point point::operator+(const point& rhs) const
-		{
-			return{ x + rhs.x, y + rhs.y };
-		}
-
-		point& point::operator-=(const point& rhs)
-		{
-			x -= rhs.x;
-			y -= rhs.y;
-			return *this;
-		}
-
-		point& point::operator+=(const point& rhs)
-		{
-			x += rhs.x;
-			y += rhs.y;
-			return *this;
-		}
-	//end struct point
-
-	//struct upoint
-		upoint::upoint():x(0), y(0){}
-		upoint::upoint(unsigned x, unsigned y):x(x), y(y){}
-
-		bool upoint::operator==(const upoint& rhs) const
-		{
-			return ((x == rhs.x) && (y == rhs.y));
-		}
-
-		bool upoint::operator!=(const upoint& rhs) const
-		{
-			return ((x != rhs.x) || (y != rhs.y));
-		}
-
-		bool upoint::operator<(const upoint& rhs) const
-		{
-			return ((y < rhs.y) || (y == rhs.y && x < rhs.x));
-		}
-
-		bool upoint::operator<=(const upoint& rhs) const
-		{
-			return ((y < rhs.y) || (y == rhs.y && x <= rhs.x));
-		}
-
-		bool upoint::operator>(const upoint& rhs) const
-		{
-			return ((y > rhs.y) || (y == rhs.y && x > rhs.x));
-		}
-
-		bool upoint::operator>=(const upoint& rhs) const
-		{
-			return ((y > rhs.y) || (y == rhs.y && x >= rhs.x));
-		}
-	//end struct upoint
 
 	//struct size
 		size::size():width(0), height(0){}
 		size::size(value_type width, value_type height) : width(width), height(height){}
-		size::size(const rectangle& r)
-			: width(r.width), height(r.height)
-		{}
-
-		size& size::operator=(const rectangle& r)
-		{
-			width = r.width;
-			height = r.height;
-			return *this;
-		}
 
 		bool size::empty() const
 		{
@@ -657,6 +558,12 @@ namespace nana
 			return (0 <= pos.x && pos.x < static_cast<int>(width) && 0 <= pos.y && pos.y < static_cast<int>(height));
 		}
 
+		size& size::shift()
+		{
+			std::swap(width, height);
+			return *this;
+		}
+
 		bool size::operator==(const size& rhs) const
 		{
 			return (width == rhs.width) && (height == rhs.height);
@@ -714,19 +621,38 @@ namespace nana
 			return *this;
 		}
 
-		rectangle& rectangle::set_pos(const point& pos)
+		point rectangle::position() const
 		{
-			x = pos.x;
-			y = pos.y;
+			return{ x, y };
+		}
+
+		rectangle& rectangle::position(const point& p)
+		{
+			x = p.x;
+			y = p.y;
 			return *this;
 		}
 
+		size rectangle::dimension() const
+		{
+			return{width, height};
+		}
+
+		rectangle& rectangle::dimension(const size& sz)
+		{
+			width = sz.width;
+			height = sz.height;
+			return *this;
+		}
+
+		/*
 		rectangle& rectangle::set_size(const size& sz)
 		{
 			width = sz.width;
 			height = sz.height;
 			return *this;
 		}
+		*/
 
 		rectangle& rectangle::pare_off(int pixels)
 		{
@@ -763,6 +689,13 @@ namespace nana
 		{
 			return (0 == width) || (0 == height);
 		}
+
+		rectangle& rectangle::shift()
+		{
+			std::swap(x, y);
+			std::swap(width, height);
+			return *this;
+		}
 	//end struct rectangle
 
 	//class rectangle_rotator
diff --git a/source/gui/detail/basic_window.cpp b/source/gui/detail/basic_window.cpp
index 6e592a0e..5c149ec3 100644
--- a/source/gui/detail/basic_window.cpp
+++ b/source/gui/detail/basic_window.cpp
@@ -354,8 +354,8 @@ namespace nana
 
 			void basic_window::_m_init_pos_and_size(basic_window* parent, const rectangle& r)
 			{
-				pos_owner = pos_root = r;
-				dimension = r;
+				pos_owner = pos_root = r.position();
+				dimension = r.dimension();
 
 				if (parent)
 					pos_root += parent->pos_root;
diff --git a/source/gui/detail/bedrock_windows.cpp b/source/gui/detail/bedrock_windows.cpp
index 098f7556..b84549bd 100644
--- a/source/gui/detail/bedrock_windows.cpp
+++ b/source/gui/detail/bedrock_windows.cpp
@@ -999,7 +999,7 @@ namespace detail
 
 					if (msgwnd->dimension.is_hit(arg.pos))
 					{
-						msgwnd->set_action(mouse_action::over);
+						msgwnd->set_action(mouse_action::hovered);
 						if ((::nana::mouse::left_button == arg.button) && (pressed_wd == msgwnd))
 						{
 							click_arg.window_handle = reinterpret_cast<window>(msgwnd);
@@ -1065,7 +1065,7 @@ namespace detail
 							if (pressed_wd == msgwnd)
 								msgwnd->set_action(mouse_action::pressed);
 							else if (mouse_action::pressed != msgwnd->flags.action)
-								msgwnd->set_action(mouse_action::over);
+								msgwnd->set_action(mouse_action::hovered);
 						}
 						arg_mouse arg;
 						assign_arg(arg, msgwnd, message, pmdec);
@@ -1084,7 +1084,7 @@ namespace detail
 						if (pressed_wd == msgwnd)
 							msgwnd->set_action(mouse_action::pressed);
 						else if (mouse_action::pressed != msgwnd->flags.action)
-							msgwnd->set_action(mouse_action::over);
+							msgwnd->set_action(mouse_action::hovered);
 
 						hovered_wd = msgwnd;
 						arg.evt_code = event_code::mouse_enter;
diff --git a/source/gui/element.cpp b/source/gui/element.cpp
index e1f4b649..48adbbfc 100644
--- a/source/gui/element.cpp
+++ b/source/gui/element.cpp
@@ -1300,7 +1300,7 @@ namespace nana
 			if (stretch_all_)
 			{
 				if (from_r.width == to_r.width && from_r.height == to_r.height)
-					method_->paste(from_r, dst, to_r);
+					method_->paste(from_r, dst, to_r.position());
 				else
 					method_->stretch(from_r, dst, to_r);
 
@@ -1392,7 +1392,7 @@ namespace nana
 				if (top_)
 				{
 					src_r.height = top_;
-					method_->paste(src_r, dst, to_r);
+					method_->paste(src_r, dst, to_r.position());
 				}
 				if (bottom_)
 				{
diff --git a/source/gui/place_parts.hpp b/source/gui/place_parts.hpp
index 1c969884..5f777e3b 100644
--- a/source/gui/place_parts.hpp
+++ b/source/gui/place_parts.hpp
@@ -135,7 +135,7 @@ namespace nana
 				if (!x_pointed_)
 					return;
 
-				x_state_ = ::nana::mouse_action::over;
+				x_state_ = ::nana::mouse_action::hovered;
 				refresh(graph);
 				API::dev::lazy_refresh();
 
@@ -387,7 +387,7 @@ namespace nana
 					}
 
 					panels_.emplace_back();
-					widget * w=wdg.get();
+					auto wdg = wdg.get();
 					panels_.back().widget_ptr.swap(wdg);
 
 					for (auto & pn : panels_)
@@ -395,7 +395,7 @@ namespace nana
 						if (pn.widget_ptr)
 							pn.widget_ptr->move(r);
 					}
-					return w;
+					return wdg;
 				}
 				return nullptr;
 			}
diff --git a/source/gui/programming_interface.cpp b/source/gui/programming_interface.cpp
index 6dcfc63a..133b8326 100644
--- a/source/gui/programming_interface.cpp
+++ b/source/gui/programming_interface.cpp
@@ -1358,7 +1358,7 @@ namespace API
 			{
 			case nana::mouse_action::normal:
 				return (is_focused ? nana::element_state::focus_normal : nana::element_state::normal);
-			case nana::mouse_action::over:
+			case nana::mouse_action::hovered:
 				return (is_focused ? nana::element_state::focus_hovered : nana::element_state::hovered);
 			case nana::mouse_action::pressed:
 				return nana::element_state::pressed;
diff --git a/source/gui/widgets/categorize.cpp b/source/gui/widgets/categorize.cpp
index a79073d4..cf29e267 100644
--- a/source/gui/widgets/categorize.cpp
+++ b/source/gui/widgets/categorize.cpp
@@ -89,7 +89,7 @@ namespace nana
 
 					if(ui_el_.what == ui_el_.item_root)
 					{
-						_m_item_bground(graph, r.x + 1, r.y, r.width - 2, r.height, (state == mouse_action::pressed ? mouse_action::pressed : mouse_action::over));
+						_m_item_bground(graph, r.x + 1, r.y, r.width - 2, r.height, (state == mouse_action::pressed ? mouse_action::pressed : mouse_action::hovered));
 						graph.rectangle(r, false, static_cast<color_rgb>(0x3C7FB1));
 						if(state == mouse_action::pressed)
 						{
@@ -114,8 +114,8 @@ namespace nana
 						mouse_action state_arrow, state_name;
 						if(mouse_action::pressed != state)
 						{
-							state_arrow = (ui_el_.what == ui_el_.item_arrow ? mouse_action::over : mouse_action::normal);
-							state_name = (ui_el_.what == ui_el_.item_name ? mouse_action::over : mouse_action::normal);
+							state_arrow = (ui_el_.what == ui_el_.item_arrow ? mouse_action::hovered : mouse_action::normal);
+							state_name = (ui_el_.what == ui_el_.item_name ? mouse_action::hovered : mouse_action::normal);
 						}
 						else
 						{
@@ -170,7 +170,7 @@ namespace nana
 					nana::color clr_top(static_cast<color_rgb>(0xEAEAEA)), clr_bottom(static_cast<color_rgb>(0xDCDCDC));
 					switch(state)
 					{
-					case mouse_action::over:
+					case mouse_action::hovered:
 						clr_top.from_rgb(0xdf, 0xf2, 0xfc);
 						clr_bottom.from_rgb(0xa9, 0xda, 0xf5);
 						break;
diff --git a/source/gui/widgets/treebox.cpp b/source/gui/widgets/treebox.cpp
index 11b4508f..e319b54f 100644
--- a/source/gui/widgets/treebox.cpp
+++ b/source/gui/widgets/treebox.cpp
@@ -1270,7 +1270,7 @@ namespace nana
 							if(size.width > attr.area.width || size.height > attr.area.height)
 							{
 								nana::size fit_size;
-								nana::fit_zoom(size, attr.area, fit_size);
+								nana::fit_zoom(size, attr.area.dimension(), fit_size);
 
 								attr.area.x += (attr.area.width - fit_size.width) / 2;
 								attr.area.y += (attr.area.height - fit_size.height) / 2;
@@ -1442,8 +1442,9 @@ namespace nana
 				virtual bool comp_attribute(component_t comp, comp_attribute_t& attr) const override
 				{
 					attr.area = node_r_;
-					if(impl_->data.comp_placer->locate(comp, node_attr_, &attr.area))
+					if (impl_->data.comp_placer->locate(comp, node_attr_, &attr.area))
 					{
+						attr.mouse_pointed = node_attr_.mouse_pointed;
 						attr.area.x += pos_.x;
 						attr.area.y += pos_.y;
 						return true;