[PATCH] Enable X11DRV_DIB_GetImageBits_8 in all cases and optimize X11DRV_DIB_GetNearestIndex to fix bug 2666 and other strange behavior

[Alex Henrie]

---
 dlls/winex11.drv/dib.c |   39 +++++++++++++++++----------------------
 1 files changed, 17 insertions(+), 22 deletions(-)

diff --git a/dlls/winex11.drv/dib.c b/dlls/winex11.drv/dib.c
index 4593d9a..6535ea8 100644
--- a/dlls/winex11.drv/dib.c
+++ b/dlls/winex11.drv/dib.c
@@ -32,6 +32,7 @@
 # endif
 #endif /* defined(HAVE_LIBXXSHM) */
 
+#include <limits.h>
 #include <stdarg.h>
 #include <stdlib.h>
 #include <string.h>
@@ -341,19 +342,25 @@ static int X11DRV_DIB_MapColor( int *physMap, int nPhysMap, int phys, int oldcol
  */
 static INT X11DRV_DIB_GetNearestIndex(RGBQUAD *colormap, int numColors, BYTE r, BYTE g, BYTE b)
 {
-    INT i, best = -1, diff, bestdiff = -1;
+    INT i, best, diff, bestdiff;
     RGBQUAD *color;
 
+    /* most likely, one of the colors in the color map is an exact match of the color we're looking for */
+    for(color = colormap, i = 0; i < numColors; color++, i++)
+        if(r == color->rgbRed && g == color->rgbGreen && b == color->rgbBlue)
+            return i;
+
+    /* but if it's not, sum the squares to find the color with the smallest difference */
+    best = 0;
+    bestdiff = INT_MAX;
     for(color = colormap, i = 0; i < numColors; color++, i++) {
         diff = (r - color->rgbRed) * (r - color->rgbRed) +
-	       (g - color->rgbGreen) * (g - color->rgbGreen) +
-	       (b - color->rgbBlue) * (b - color->rgbBlue);
-	if(diff == 0)
-	    return i;
-	if(best == -1 || diff < bestdiff) {
-	    best = i;
-	    bestdiff = diff;
-	}
+               (g - color->rgbGreen) * (g - color->rgbGreen) +
+               (b - color->rgbBlue) * (b - color->rgbBlue);
+        if(diff < bestdiff) {
+            best = i;
+            bestdiff = diff;
+        }
     }
     return best;
 }
@@ -1344,15 +1351,6 @@ static void X11DRV_DIB_GetImageBits_8( int lines, BYTE *dstbits,
        linebytes = -linebytes;
     }
 
-    /*
-     * Hack for now
-     * This condition is true when GetImageBits has been called by
-     * UpdateDIBSection. For now, GetNearestIndex is too slow to support
-     * 256 colormaps, so we'll just use it for GetDIBits calls.
-     * (In some cases, in an updateDIBSection, the returned colors are bad too)
-     */
-    if (!srccolors) goto updatesection;
-
     switch (bmpImage->depth) {
     case 1:
     case 4:
@@ -1563,7 +1561,6 @@ static void X11DRV_DIB_GetImageBits_8( int lines, BYTE *dstbits,
         WARN("from unknown %d bit bitmap (%lx,%lx,%lx) to 8 bit DIB\n",
               bmpImage->depth, bmpImage->red_mask,
               bmpImage->green_mask, bmpImage->blue_mask );
-    updatesection:
         /* ==== any bmp format -> pal 8 dib ==== */
         for (h=lines-1; h>=0; h--) {
             dstbyte=dstbits;
@@ -3456,12 +3453,10 @@ static void X11DRV_DIB_DoCopyDIBSection(X_PHYSBITMAP *physBitmap, BOOL toDIB,
   descr.compression = dibSection.dsBmih.biCompression;
   descr.physBitmap  = physBitmap;
 
-  if(descr.infoBpp == 1)
-      descr.colorMap = (void*)identity;
-
   switch (descr.infoBpp)
   {
     case 1:
+      descr.colorMap = (void*)identity;
     case 4:
     case 8:
       descr.rMask = descr.gMask = descr.bMask = 0;
-- 
1.7.4.1