[COMPOSITE] Composite used for pixmap population on redirect. (Bug #7447)

compNewPixmap copies bits from the parent window to the redirected child
pixmap to populate the pixmap with reasonable data. It cannot always use
CopyArea as that only works across matching depths. Use Composite when
the depths do not match.
(cherry picked from commit f98dfec79d)

composite/compalloc.c

@@ -461,7 +461,6 @@ compNewPixmap (WindowPtr pWin, int x, int y, int w, int h)
     ScreenPtr	    pScreen = pWin->drawable.pScreen;
     WindowPtr	    pParent = pWin->parent;
     PixmapPtr	    pPixmap;
-    GCPtr	    pGC;
 
     pPixmap = (*pScreen->CreatePixmap) (pScreen, w, h, pWin->drawable.depth);
 
@@ -471,25 +470,63 @@ compNewPixmap (WindowPtr pWin, int x, int y, int w, int h)
     pPixmap->screen_x = x;
     pPixmap->screen_y = y;
     
-    pGC = GetScratchGC (pWin->drawable.depth, pScreen);
-    
-    /*
-     * Copy bits from the parent into the new pixmap so that it will
-     * have "reasonable" contents in case for background None areas.
-     */
-    if (pGC)
+    if (pParent->drawable.depth == pWin->drawable.depth)
     {
-	XID val = IncludeInferiors;
+	GCPtr	pGC = GetScratchGC (pWin->drawable.depth, pScreen);
 	
-	ValidateGC(&pPixmap->drawable, pGC);
-	dixChangeGC (serverClient, pGC, GCSubwindowMode, &val, NULL);
-	(*pGC->ops->CopyArea) (&pParent->drawable,
-			       &pPixmap->drawable,
-			       pGC,
-			       x - pParent->drawable.x,
-			       y - pParent->drawable.y,
-			       w, h, 0, 0);
-	FreeScratchGC (pGC);
+	/*
+	 * Copy bits from the parent into the new pixmap so that it will
+	 * have "reasonable" contents in case for background None areas.
+	 */
+	if (pGC)
+	{
+	    XID val = IncludeInferiors;
+	    
+	    ValidateGC(&pPixmap->drawable, pGC);
+	    dixChangeGC (serverClient, pGC, GCSubwindowMode, &val, NULL);
+	    (*pGC->ops->CopyArea) (&pParent->drawable,
+				   &pPixmap->drawable,
+				   pGC,
+				   x - pParent->drawable.x,
+				   y - pParent->drawable.y,
+				   w, h, 0, 0);
+	    FreeScratchGC (pGC);
+	}
+    }
+    else
+    {
+	PictFormatPtr	pSrcFormat = compWindowFormat (pParent);
+	PictFormatPtr	pDstFormat = compWindowFormat (pWin);
+	XID		inferiors = IncludeInferiors;
+	int		error;
+
+	PicturePtr	pSrcPicture = CreatePicture (None,
+						     &pParent->drawable,
+						     pSrcFormat,
+						     CPSubwindowMode,
+						     &inferiors,
+						     serverClient, &error);
+						    
+	PicturePtr	pDstPicture = CreatePicture (None,
+						     &pPixmap->drawable,
+						     pDstFormat,
+						     0, 0,
+						     serverClient, &error);
+
+	if (pSrcPicture && pDstPicture)
+	{
+	    CompositePicture (PictOpSrc,
+			      pSrcPicture,
+			      NULL,
+			      pDstPicture,
+			      x - pParent->drawable.x,
+			      y - pParent->drawable.y,
+			      0, 0, 0, 0, w, h);
+	}
+	if (pSrcPicture)
+	    FreePicture (pSrcPicture, 0);
+	if (pDstPicture)
+	    FreePicture (pDstPicture, 0);
     }
     return pPixmap;
 }

composite/compint.h

@@ -232,6 +232,9 @@ compCheckTree (ScreenPtr pScreen);
 #define compCheckTree(s)
 #endif
 
+PictFormatPtr
+compWindowFormat (WindowPtr pWin);
+
 void
 compSetPixmap (WindowPtr pWin, PixmapPtr pPixmap);
 

composite/compwindow.c

@@ -685,7 +685,7 @@ compGetWindowVisual (WindowPtr pWin)
     return 0;
 }
 
-static PictFormatPtr
+PictFormatPtr
 compWindowFormat (WindowPtr pWin)
 {
     ScreenPtr	pScreen = pWin->drawable.pScreen;