diff --git a/include/nana/basic_types.hpp b/include/nana/basic_types.hpp
index e1607fd7..b07f5da0 100644
--- a/include/nana/basic_types.hpp
+++ b/include/nana/basic_types.hpp
@@ -147,16 +147,10 @@ namespace nana
 		highlight = 0x1CC4F7
 	};
 
-#pragma pack(1)
-	struct rgb_color
-	{
-		unsigned char blue;
-		unsigned char green;
-		unsigned char red;
-
-		rgb_color(unsigned clr);
-	};
-#pragma pack()
+	//Some helper types to identify an integer as color.
+	enum class color_rgb :	unsigned{};
+	enum class color_argb:	unsigned{};
+	enum class color_rgba : unsigned{};
 
 	class expr_color
 	{
@@ -164,7 +158,9 @@ namespace nana
 		expr_color() = default;
 		expr_color(colors);
 		expr_color(colors, double alpha);
-		expr_color(const rgb_color&);
+		expr_color(color_rgb);
+		expr_color(color_argb);
+		expr_color(color_rgba);
 		expr_color(unsigned red, unsigned green, unsigned blue);
 		expr_color(unsigned red, unsigned green, unsigned blue, double alpha);
 
@@ -193,7 +189,7 @@ namespace nana
 		double r_;
 		double g_;
 		double b_;
-		double a_{ 0.0 };
+		double a_{ 0.0 };	//invisible
 	};
 
 
diff --git a/source/basic_types.cpp b/source/basic_types.cpp
index 531c3824..91f113e7 100644
--- a/source/basic_types.cpp
+++ b/source/basic_types.cpp
@@ -13,10 +13,6 @@
 
 namespace nana
 {
-	rgb_color::rgb_color(unsigned clr)
-		: blue((0xFF00 & clr) >> 8), green(0xFF & clr), red((0xFF0000 & clr) >> 16)
-	{}
-
 	//class color
 	expr_color::expr_color(colors clr)
 		: expr_color((static_cast<unsigned>(clr)& 0xFF0000) >> 16, (static_cast<unsigned>(clr)& 0xFF00) >> 8, static_cast<unsigned>(clr)& 0xFF)
@@ -26,10 +22,26 @@ namespace nana
 		: expr_color((static_cast<unsigned>(clr)& 0xFF0000) >> 16, (static_cast<unsigned>(clr)& 0xFF00) >> 8, static_cast<unsigned>(clr)& 0xFF, alpha)
 	{}
 
-	expr_color::expr_color(const rgb_color& rgb)
-		: a_(1.0), r_(rgb.red), g_(rgb.green), b_(rgb.blue)
-	{
-	}
+	expr_color::expr_color(color_rgb rgb)
+		:	r_((static_cast<int>(rgb) >> 16) & 0xFF),
+			g_((static_cast<int>(rgb) >> 8) & 0xFF),
+			b_(static_cast<int>(rgb) & 0xFF),
+			a_(1.0)
+	{}
+
+	expr_color::expr_color(color_argb argb)
+		:	r_((static_cast<int>(argb) >> 16) & 0xFF),
+			g_((static_cast<int>(argb) >> 8) & 0xFF),
+			b_(static_cast<int>(argb) & 0xFF),
+			a_(((static_cast<int>(argb) >> 24) & 0xFF) / 255.0)
+	{}
+
+	expr_color::expr_color(color_rgba rgba)
+		:	r_((static_cast<int>(rgba) >> 24) & 0xFF),
+			g_((static_cast<int>(rgba) >> 16) & 0xFF),
+			b_((static_cast<int>(rgba) >> 8) & 0xFF),
+			a_((static_cast<int>(rgba) & 0xFF) / 255.0)
+	{}
 
 	expr_color::expr_color(unsigned red, unsigned green, unsigned blue)
 		: a_(1.0), r_(red), g_(green), b_(blue)