winex11.drv: Support GdiAlphaBlend with blendfn.AlphaFormat == 0 (3rd try, fixes bug #9262)

[Mikolaj Zalewski]

The 'if' is now put outside of the inner loop and we use memcpy for
the AC_SRC_ALPHA case
-------------- next part --------------
From e3c7cb189a81a66417d585216afedd01d2a699f0 Mon Sep 17 00:00:00 2001
From: Mikolaj Zalewski <mikolaj at zalewski.pl>
Date: Thu, 30 Aug 2007 10:43:20 -0700
Subject: [PATCH] winex11.drv: Support GdiAlphaBlend with blendfn.AlphaFormat == 0 (fixes bug #9262)
---
 dlls/winex11.drv/xrender.c |   34 +++++++++++++++++++++++++++++-----
 1 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/dlls/winex11.drv/xrender.c b/dlls/winex11.drv/xrender.c
index 449c671..5f41a0d 100644
--- a/dlls/winex11.drv/xrender.c
+++ b/dlls/winex11.drv/xrender.c
@@ -1572,14 +1572,17 @@ #endif
         return FALSE;
     }
 
-    if (xSrc < 0 || ySrc < 0 || widthSrc < 0 || heightSrc < 0 || xSrc + widthSrc > dib.dsBmih.biWidth
-        || ySrc + heightSrc > abs(dib.dsBmih.biHeight))
+    if (xSrc < 0 || ySrc < 0 || widthSrc < 0 || heightSrc < 0 || (LONGLONG)xSrc + widthSrc > dib.dsBmih.biWidth
+        || (LONGLONG)ySrc + heightSrc > abs(dib.dsBmih.biHeight))
     {
         WARN("Invalid src coords: (%d,%d), size %dx%d\n", xSrc, ySrc, widthSrc, heightSrc);
         SetLastError(ERROR_INVALID_PARAMETER);
         return FALSE;
     }
 
+    if ((blendfn.AlphaFormat & AC_SRC_ALPHA) && blendfn.SourceConstantAlpha != 0xff)
+        FIXME("Ignoring SourceConstantAlpha %d for AC_SRC_ALPHA\n", blendfn.SourceConstantAlpha);
+
     if(dib.dsBm.bmBitsPixel != 32) {
         FIXME("not a 32 bpp dibsection\n");
         return FALSE;
@@ -1598,9 +1601,30 @@ #endif
         y2 = y - heightSrc + 1;
     }
     for(; y >= y2; y--) {
-        memcpy(dstbits, (char *)dib.dsBm.bmBits + y * dib.dsBm.bmWidthBytes + xSrc * 4,
-               widthSrc * 4);
-        dstbits += (top_down ? -1 : 1) * widthSrc * 4;
+        char *srcbits = (char *)dib.dsBm.bmBits + y * dib.dsBm.bmWidthBytes + xSrc * 4;
+
+        if (blendfn.AlphaFormat & AC_SRC_ALPHA)
+        {
+            memcpy(dstbits, srcbits, widthSrc * 4);
+            dstbits += (top_down ? -1 : 1) * widthSrc * 4;
+        }
+        else
+        {
+            int source_alpha = ((DWORD)blendfn.SourceConstantAlpha) << 24;
+            int x;
+
+            for (x = 0; x < widthSrc; x++)
+            {
+                DWORD argb = *(DWORD *)srcbits;
+                argb = (argb & 0xffffff) | source_alpha;
+                *(DWORD *)dstbits = argb;
+                srcbits += 4;
+                dstbits += 4;
+            }
+            if (top_down)  /* we traversed the row forward so we should go back by two rows */
+                dstbits -= 2 * widthSrc * 4;
+        }
+
     }
 
     wine_tsx11_lock();
-- 
1.4.1