[jgardou] 64179: [WIN32K] - Return empty region in DceGetVisRgn if there is nothing to return.

Author: jgardou
Date: Wed Sep 17 12:01:34 2014
New Revision: 64179

URL: http://svn.reactos.org/svn/reactos?rev=64179&view=rev
Log:
[WIN32K]
 - Return empty region in DceGetVisRgn if there is nothing to return.

Modified:
    trunk/reactos/win32ss/user/ntuser/windc.c

Modified: trunk/reactos/win32ss/user/ntuser/windc.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/win32ss/user/ntuser/windc.…
==============================================================================
--- trunk/reactos/win32ss/user/ntuser/windc.c	[iso-8859-1] (original)
+++ trunk/reactos/win32ss/user/ntuser/windc.c	[iso-8859-1] Wed Sep 17 12:01:34 2014
@@ -69,10 +69,15 @@
 PREGION FASTCALL
 DceGetVisRgn(PWND Window, ULONG Flags, HWND hWndChild, ULONG CFlags)
 {
-  return VIS_ComputeVisibleRegion( Window,
-                                   0 == (Flags & DCX_WINDOW),
-                                   0 != (Flags & DCX_CLIPCHILDREN),
-                                   0 != (Flags & DCX_CLIPSIBLINGS));
+    PREGION Rgn;
+    Rgn = VIS_ComputeVisibleRegion( Window,
+                                    0 == (Flags & DCX_WINDOW),
+                                    0 != (Flags & DCX_CLIPCHILDREN),
+                                    0 != (Flags & DCX_CLIPSIBLINGS));
+    /* Caller expects a non-null region */
+    if (!Rgn)
+        Rgn = IntSysCreateRectpRgn(0, 0, 0, 0);
+    return Rgn;
 }
 
 PDCE FASTCALL