os: add texture_rgb888.h and texture_rgb565.h

The headers 'texture_rgb565.h' and 'texture_rgb888' contain
template specializations needed for using the 'Texture::rgba' function
for the respective pixel formats. The specializations were formerly
contained in application-local code.

repos/demo/include/scout/canvas.h

@@ -70,42 +70,10 @@ struct Scout::Canvas_base : Texture_allocator
 };
 
 
-#include <os/pixel_rgb565.h>
+#include <os/texture_rgb565.h>
 #include <base/env.h>
 
 
-namespace Genode {
-
-	template <>
-	inline void
-	Texture<Pixel_rgb565>::rgba(unsigned char const *rgba, unsigned len, int y)
-	{
-		if (len > size().w()) len = size().w();
-		if (y < 0 || y >= (int)size().h()) return;
-
-		Genode::Pixel_rgb565 *dst_pixel = pixel() + y*size().w();
-		unsigned char        *dst_alpha = alpha() ? alpha() + y*size().w() : 0;
-
-		Genode::Dither_matrix::Row dither_row = Dither_matrix::row(y);
-
-		for (unsigned i = 0; i < len; i++) {
-
-			int v = dither_row.value(i) >> 5;
-			int r = *rgba++ + v;
-			int g = *rgba++ + v;
-			int b = *rgba++ + v;
-			int a = *rgba++ + v;
-
-			using Genode::min;
-			dst_pixel[i].rgba(min(r, 255), min(g, 255), min(b, 255));
-
-			if (dst_alpha)
-				dst_alpha[i] = min(a, 255);
-		}
-	}
-}
-
-
 template <typename PT>
 class Scout::Canvas : public Canvas_base
 {

repos/gems/src/app/backdrop/main.cc

@@ -21,14 +21,14 @@
 #include <nitpicker_gfx/texture_painter.h>
 #include <os/attached_dataspace.h>
 #include <util/volatile_object.h>
+#include <os/texture_rgb565.h>
+#include <os/texture_rgb888.h>
 
 /* gems includes */
 #include <gems/png_image.h>
 #include <gems/file.h>
 #include <gems/xml_anchor.h>
 #include <gems/texture_utils.h>
-#include <gems/texture_rgb565.h>
-#include <gems/texture_rgb888.h>
 
 using namespace Genode;
 

repos/os/include/os/pixel_rgb888.h

@@ -21,6 +21,25 @@ namespace Genode {
 	typedef Pixel_rgba<unsigned long, Surface_base::RGB888,
 	                  0xff0000, 16, 0xff00, 8, 0xff, 0, 0, 0>
 	        Pixel_rgb888;
+
+	template <>
+	inline Pixel_rgb888 Pixel_rgb888::blend(Pixel_rgb888 src, int alpha)
+	{
+		Pixel_rgb888 res;
+		res.pixel = (alpha * ((src.pixel & 0xff00) >> 8) & 0xff00)
+		          | (((alpha * (src.pixel & 0xff00ff)) >> 8) & 0xff00ff);
+		return res;
+	}
+
+
+	template <>
+	inline Pixel_rgb888 Pixel_rgb888::mix(Pixel_rgb888 p1, Pixel_rgb888 p2, int alpha)
+	{
+		Pixel_rgb888 res;
+
+		res.pixel = blend(p1, 255 - alpha).pixel + blend(p2, alpha).pixel;
+		return res;
+	}
 }
 
 #endif /* _INCLUDE__OS__PIXEL_RGB888_H_ */

repos/os/include/os/texture.h

@@ -57,7 +57,7 @@ class Genode::Texture : public Texture_base
 		/**
 		 * Import rgba data line into texture
 		 */
-		void rgba(unsigned char const *rgba, unsigned len, int y);
+		inline void rgba(unsigned char const *rgba, unsigned len, int y);
 };
 
 #endif /* _INCLUDE__OS__TEXTURE_H_ */

repos/os/include/os/texture_rgb565.h

@@ -22,7 +22,7 @@
 namespace Genode {
 
 	template <>
-	void
+	inline void
 	Texture<Pixel_rgb565>::rgba(unsigned char const *rgba, unsigned len, int y)
 	{
 		if (len > size().w()) len = size().w();

repos/os/include/os/texture_rgb888.h

@@ -21,7 +21,7 @@
 namespace Genode {
 
 	template <>
-	void
+	inline void
 	Texture<Pixel_rgb888>::rgba(unsigned char const *rgba, unsigned len, int y)
 	{
 		if (len > size().w()) len = size().w();