EngLineTo: if pco == NULL use a private clip object, initialized with bounds rect

svn path=/trunk/; revision=33743

reactos/subsystems/win32/win32k/eng/lineto.c

@@ -348,6 +348,7 @@ EngLineTo(SURFOBJ *DestObj,
     INTENG_ENTER_LEAVE EnterLeave;
     RECT_ENUM RectEnum;
     BOOL EnumMore;
+    CLIPOBJ *pcoPriv = NULL;
 
     if (x1 < x2)
     {
@@ -375,6 +376,15 @@ EngLineTo(SURFOBJ *DestObj,
         return FALSE;
     }
 
+    if (!Clip)
+    {
+        Clip = pcoPriv = IntEngCreateClipRegion(0, 0, RectBounds);
+        if (!Clip)
+        {
+            return FALSE;
+        }
+    }
+
     x1 += Translate.x;
     x2 += Translate.x;
     y1 += Translate.y;
@@ -487,6 +497,11 @@ EngLineTo(SURFOBJ *DestObj,
         }
     }
 
+    if (pcoPriv)
+    {
+        IntEngDeleteClipRegion(pcoPriv);
+    }
+
     return IntEngLeave(&EnterLeave);
 }