From f63f322ecba08914a171fd20b0382837164963ea Mon Sep 17 00:00:00 2001
From: Christoph von Wittich <christoph_vw@reactos.org>
Date: Mon, 26 Nov 2007 20:45:05 +0000
Subject: [PATCH] fix TAG_BITMAP redzone overwrite for colordepths != 32 bit

svn path=/trunk/; revision=30790
---
 .../win32/win32k/ntuser/cursoricon.c          | 21 +++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/reactos/subsystems/win32/win32k/ntuser/cursoricon.c b/reactos/subsystems/win32/win32k/ntuser/cursoricon.c
index 1460c0d85b2..5a77bce453f 100644
--- a/reactos/subsystems/win32/win32k/ntuser/cursoricon.c
+++ b/reactos/subsystems/win32/win32k/ntuser/cursoricon.c
@@ -1401,8 +1401,7 @@ UserDrawIconEx(
    }
 
    /* NtGdiCreateCompatibleBitmap will create a monochrome bitmap
-      when cxWidth or cyHeight is 0
-   */
+      when cxWidth or cyHeight is 0 */
    if ((bmpColor.bmBitsPixel == 32) && (cxWidth != 0) && (cyHeight != 0))
    {
       bAlpha = TRUE;
@@ -1425,6 +1424,9 @@ UserDrawIconEx(
    if (DoFlickerFree || bAlpha)
    {
       RECT r;
+      BITMAP bm;
+      BITMAPOBJ *BitmapObj = NULL;
+
       r.right = cxWidth;
       r.bottom = cyHeight;
 
@@ -1442,6 +1444,21 @@ UserDrawIconEx(
          goto cleanup;
       }
 
+      /* make sure we have a 32 bit offscreen bitmap
+        otherwise we can't do alpha blending */
+      BitmapObj = BITMAPOBJ_LockBitmap(hbmOff);
+      if (BitmapObj == NULL)
+      {
+          DPRINT1("GDIOBJ_LockObj() failed!\n");
+          goto cleanup;
+      }
+      BITMAP_GetObject(BitmapObj, sizeof(BITMAP), &bm);
+
+      if (bm.bmBitsPixel != 32)
+        bAlpha = FALSE;
+
+      BITMAPOBJ_UnlockBitmap(BitmapObj);
+
       hOldOffBmp = NtGdiSelectObject(hdcOff, hbmOff);
       if (!hOldOffBmp)
       {