[PATCH] winex11: Make MapColor fall back to GetNearestIndex

[Alex Henrie]

Fixes bug 2666. Also improves performance of GetNearestIndex and DoCopyDIBSection. Supersedes previously submitted patch.
---
 dlls/winex11.drv/dib.c |   54 ++++++++++++++++++++++++++---------------------
 1 files changed, 30 insertions(+), 24 deletions(-)

diff --git a/dlls/winex11.drv/dib.c b/dlls/winex11.drv/dib.c
index 4593d9a..b5c8923 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>
@@ -313,25 +314,6 @@ static int *X11DRV_DIB_BuildColorMap( X11DRV_PDEVICE *physDev, WORD coloruse, WO
                                    colorPtr, 0, *nColors);
 }
 
-/***********************************************************************
- *           X11DRV_DIB_MapColor
- */
-static int X11DRV_DIB_MapColor( int *physMap, int nPhysMap, int phys, int oldcol )
-{
-    int color;
-
-    if ((oldcol < nPhysMap) && (physMap[oldcol] == phys))
-        return oldcol;
-
-    for (color = 0; color < nPhysMap; color++)
-        if (physMap[color] == phys)
-            return color;
-
-    WARN("Strange color %08x\n", phys);
-    return 0;
-}
-
-
 /*********************************************************************
  *         X11DRV_DIB_GetNearestIndex
  *
@@ -341,7 +323,7 @@ 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 = -1, diff, bestdiff = INT_MAX;
     RGBQUAD *color;
 
     for(color = colormap, i = 0; i < numColors; color++, i++) {
@@ -350,13 +332,39 @@ static INT X11DRV_DIB_GetNearestIndex(RGBQUAD *colormap, int numColors, BYTE r,
 	       (b - color->rgbBlue) * (b - color->rgbBlue);
 	if(diff == 0)
 	    return i;
-	if(best == -1 || diff < bestdiff) {
+	if(diff < bestdiff) {
 	    best = i;
 	    bestdiff = diff;
 	}
     }
     return best;
 }
+
+/***********************************************************************
+ *           X11DRV_DIB_MapColor
+ *
+ * Helper similar to X11DRV_DIB_GetNearestIndex, but optimized for exact matches
+ */
+static int X11DRV_DIB_MapColor( int *physMap, int nPhysMap, int phys, int oldcol )
+{
+    int color;
+
+    /* check if the color is an exact match of the previous color searched for */
+    if ((oldcol < nPhysMap) && (physMap[oldcol] == phys))
+        return oldcol;
+
+    /* check if the color is an exact match of any color in the list */
+    for (color = 0; color < nPhysMap; color++)
+        if (physMap[color] == phys)
+            return color;
+
+    /* find a color that's at least close */
+    return X11DRV_DIB_GetNearestIndex((RGBQUAD*)physMap, nPhysMap,
+                                      ((RGBQUAD*)&phys)->rgbRed,
+                                      ((RGBQUAD*)&phys)->rgbGreen,
+                                      ((RGBQUAD*)&phys)->rgbBlue);
+}
+
 /*********************************************************************
  *         X11DRV_DIB_MaskToShift
  *
@@ -3456,12 +3464,10 @@ 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