fix/implement alphablend for 8-to-32 bpp blits

diff --git a/lib/gdi/gpixmap.cpp b/lib/gdi/gpixmap.cpp
index 855cb8b25518b8aa011df534d6568aafec2d9133..e2960ad71f2257dc70f4ae0af0cf637969e728ce 100644 (file)
--- a/lib/gdi/gpixmap.cpp
+++ b/lib/gdi/gpixmap.cpp
@@ -207,6 +207,54 @@ void gPixmap::fill(const gRegion &region, const gRGB &color)
        }
 }
 
+static void blit_8i_to_32(__u32 *dst, __u8 *src, __u32 *pal, int width)
+{
+       while (width--)
+               *dst++=pal[*src++];
+}
+
+static void blit_8i_to_32_at(__u32 *dst, __u8 *src, __u32 *pal, int width)
+{
+       while (width--)
+       {
+               if (!(pal[*src]&0x80000000))
+               {
+                       src++;
+                       dst++;
+               } else
+                       *dst++=pal[*src++];
+       }
+}
+
+               /* WARNING, this function is not endian safe! */
+static void blit_8i_to_32_ab(__u32 *dst, __u8 *src, __u32 *pal, int width)
+{
+       while (width--)
+       {
+#define BLEND(x, y, a) (y + (((x-y) * a)>>8))
+               __u32 srccol = pal[*src++];
+               __u32 dstcol = *dst;
+               unsigned char sb = srccol & 0xFF;
+               unsigned char sg = (srccol >> 8) & 0xFF;
+               unsigned char sr = (srccol >> 16) & 0xFF;
+               unsigned char sa = (srccol >> 24) & 0xFF;
+
+               unsigned char db = dstcol & 0xFF;
+               unsigned char dg = (dstcol >> 8) & 0xFF;
+               unsigned char dr = (dstcol >> 16) & 0xFF;
+               unsigned char da = (dstcol >> 24) & 0xFF;
+
+               da = BLEND(0xFF, da, sa) & 0xFF;
+               dr = BLEND(sr, dr, sa) & 0xFF;
+               dg = BLEND(sg, dg, sa) & 0xFF;
+               db = BLEND(sb, db, sa) & 0xFF;
+
+#undef BLEND
+               *dst++ = db | (dg << 8) | (dr << 16) | (da << 24);
+       }
+}
+
+
 void gPixmap::blit(const gPixmap &src, ePoint pos, const gRegion &clip, int flag)
 {
        for (unsigned int i=0; i<clip.rects.size(); ++i)
@@ -305,6 +353,7 @@ void gPixmap::blit(const gPixmap &src, ePoint pos, const gRegion &clip, int flag
                                                dst[2] = BLEND(sr, dr, sa);
                                                dst[1] = BLEND(sg, dg, sa);
                                                dst[0] = BLEND(sb, db, sa);
+#undef BLEND
 
                                                src += 4; dst += 4;
                                        }
@@ -332,30 +381,15 @@ void gPixmap::blit(const gPixmap &src, ePoint pos, const gRegion &clip, int flag
                        dstptr+=area.left()*surface->bypp+area.top()*surface->stride;
                        for (int y=0; y<area.height(); y++)
                        {
+                               int width=area.width();
+                               unsigned char *psrc=(unsigned char*)srcptr;
+                               __u32 *dst=(__u32*)dstptr;
                                if (flag & blitAlphaTest)
-                               {
-                     // no real alphatest yet
-                                       int width=area.width();
-                                       unsigned char *src=(unsigned char*)srcptr;
-                                       __u32 *dst=(__u32*)dstptr;
-                                               // use duff's device here!
-                                       while (width--)
-                                       {
-                                               if (!(pal[*src]&0x80000000))
-                                               {
-                                                       src++;
-                                                       dst++;
-                                               } else
-                                                       *dst++=pal[*src++];
-                                       }
-                               } else
-                               {
-                                       int width=area.width();
-                                       unsigned char *src=(unsigned char*)srcptr;
-                                       __u32 *dst=(__u32*)dstptr;
-                                       while (width--)
-                                               *dst++=pal[*src++];
-                               }
+                                       blit_8i_to_32_at(dst, psrc, pal, width);
+                               else if (flag & blitAlphaBlend)
+                                       blit_8i_to_32_ab(dst, psrc, pal, width);
+                               else
+                                       blit_8i_to_32(dst, psrc, pal, width);
                                srcptr+=src.surface->stride;
                                dstptr+=surface->stride;
                        }