port cairo ARGB/BGRA -> pixbuf RGBA patch from recent 2.X commit (restores text on...

git-svn-id: svn://localhost/ardour2/branches/3.0@7842 d708f5d6-7413-0410-9779-e7cbd77b26cf

diff --git a/gtk2_ardour/utils.cc b/gtk2_ardour/utils.cc
index 5e0497460be834d24900038f01580fb29692c950..b94a6f8260da97a65197e42b5fa947a16e0bb912 100644 (file)
--- a/gtk2_ardour/utils.cc
+++ b/gtk2_ardour/utils.cc
@@ -933,18 +933,39 @@ convert_bgra_to_rgba (guint8 const* src,
 {
        guint8 const* src_pixel = src;
        guint8*       dst_pixel = dst;
-
+       
        for (int y = 0; y < height; y++)
                for (int x = 0; x < width; x++)
                {
+#if G_BYTE_ORDER == G_LITTLE_ENDIAN
+                        /* [ B G R A ] is actually [ B G R A ] in memory SOURCE
+                                                     0 1 2 3
+                           [ R G B A ] is actually [ R G B A ] in memory DEST
+                        */
                        dst_pixel[0] = convert_color_channel (src_pixel[2],
-                                                             src_pixel[3]);
+                                                             src_pixel[3]); // R [0] <= [ 2 ]
                        dst_pixel[1] = convert_color_channel (src_pixel[1],
-                                                             src_pixel[3]);
-                       dst_pixel[2] = convert_color_channel (src_pixel[0],
-                                                             src_pixel[3]);
-                       dst_pixel[3] = src_pixel[3];
-
+                                                             src_pixel[3]); // G [1] <= [ 1 ]
+                       dst_pixel[2] = convert_color_channel (src_pixel[0],  
+                                                             src_pixel[3]); // B [2] <= [ 0 ]
+                       dst_pixel[3] = src_pixel[3]; // alpha
+
+#elif G_BYTE_ORDER == G_BIG_ENDIAN
+                        /* [ B G R A ] is actually [ A R G B ] in memory SOURCE
+                                                     0 1 2 3
+                           [ R G B A ] is actually [ A B G R ] in memory DEST
+                        */
+                       dst_pixel[3] = convert_color_channel (src_pixel[1],
+                                                             src_pixel[0]); // R [3] <= [ 1 ]
+                       dst_pixel[2] = convert_color_channel (src_pixel[2],
+                                                             src_pixel[0]); // G [2] <= [ 2 ]
+                       dst_pixel[1] = convert_color_channel (src_pixel[3],
+                                                             src_pixel[0]); // B [1] <= [ 3 ]
+                       dst_pixel[0] = src_pixel[0]; // alpha
+
+#else
+#error ardour does not currently support PDP-endianess
+#endif                 
                        dst_pixel += 4;
                        src_pixel += 4;
                }