Clip destination instead of source. Should be the same, but it looks nicer

to me.
Clean up transition between cheap and expensive GC wrappers by using the
    prologue and epilogue macros. Before, the GC would be left unvalidated
    sometimes which would cause all kinds of entertaining bugs against a
    DDX which cares (XAA).

composite/compwindow.c

@@ -702,15 +702,15 @@ compWindowUpdateAutomatic (WindowPtr pWin)
     REGION_INTERSECT (pScreen, pRegion, pRegion, &cw->borderClip);
 
     /*
-     * Now translate from screen to pixmap coordinates
+     * Now translate from screen to dest coordinates
      */
     REGION_TRANSLATE (pScreen, pRegion, 
-		      -pSrcPixmap->screen_x, -pSrcPixmap->screen_y);
+		      -pParent->drawable.x, -pParent->drawable.y);
     
     /*
      * Clip the picture
      */
-    SetPictureClipRegion (pSrcPicture, 0, 0, pRegion);
+    SetPictureClipRegion (pDstPicture, 0, 0, pRegion);
     
     /*
      * And paint
@@ -719,9 +719,8 @@ compWindowUpdateAutomatic (WindowPtr pWin)
 		      pSrcPicture,
 		      0,
 		      pDstPicture,
-		      0,
-		      0,
-		      0, 0,
+		      0, 0, /* src_x, src_y */
+		      0, 0, /* msk_x, msk_y */
 		      pSrcPixmap->screen_x - pParent->drawable.x,
 		      pSrcPixmap->screen_y - pParent->drawable.y,
 		      pSrcPixmap->drawable.width,