Fix for https://freedesktop.org/bugzilla/show_bug.cgi?id=1664 - RFE: Add

    support for the DOUBLE-BUFFER extension to the Xprint server and DDX.
    Additionally a "pixmap-scrubber" optimisation is added to the
    PostScript DDX to remove all content from a vector pixmap when a
    |PolyFillRect()| call covers the whole pixmap surface with a solid fill
    (this avoids that a backbuffer vector pixmap gets constantly filled
    even when the content is not visible anymore after |XdbeSwapBuffers()|
    has cleared the hidden buffer with the background color).

3 files changed, 45 insertions, 3 deletions

diff --git a/Xprint/ps/Ps.h b/Xprint/ps/Ps.h
index 1b1f02a1a..726cf5aae 100644
--- a/Xprint/ps/Ps.h
+++ b/Xprint/ps/Ps.h
@@ -566,6 +566,7 @@ extern void PsSetFillColor(DrawablePtr pDrawable, GCPtr pGC, PsOutPtr psOut,
 
 extern PixmapPtr PsCreatePixmap(ScreenPtr pScreen, int width, int height,
                                 int depth);
+extern void PsScrubPixmap(PixmapPtr pPixmap);
 extern Bool PsDestroyPixmap(PixmapPtr pPixmap);
 extern DisplayListPtr PsGetFreeDisplayBlock(PsPixmapPrivPtr priv);
 extern void PsReplayPixmap(PixmapPtr pix, DrawablePtr pDrawable);
diff --git a/Xprint/ps/PsPixmap.c b/Xprint/ps/PsPixmap.c
index 6f4ca39d2..25a525b82 100644
--- a/Xprint/ps/PsPixmap.c
+++ b/Xprint/ps/PsPixmap.c
@@ -114,13 +114,15 @@ PsCreatePixmap(
   return pPixmap;
 }
 
-Bool
-PsDestroyPixmap(PixmapPtr pPixmap)
+/* PsScrubPixmap: Remove all content from a pixmap (used by
+ * |PsPolyFillRect()| when the "solid fill" operation covers
+ * the whole pixmap) */
+void
+PsScrubPixmap(PixmapPtr pPixmap)
 {
   PsPixmapPrivPtr priv = (PsPixmapPrivPtr)pPixmap->devPrivate.ptr;
   DisplayListPtr  disp = priv->dispList;
 
-  if( --pPixmap->refcnt ) return TRUE;
   while( disp )
   {
     int            i;
@@ -177,6 +179,20 @@ PsDestroyPixmap(PixmapPtr pPixmap)
     }
     xfree(oldDisp);
   }
+
+  priv->dispList = NULL;
+}
+
+Bool
+PsDestroyPixmap(PixmapPtr pPixmap)
+{
+  PsPixmapPrivPtr priv = (PsPixmapPrivPtr)pPixmap->devPrivate.ptr;
+  DisplayListPtr  disp = priv->dispList;
+
+  if( --pPixmap->refcnt ) return TRUE;
+
+  PsScrubPixmap(pPixmap);
+
   xfree(priv);
   xfree(pPixmap);
   return TRUE;
diff --git a/Xprint/ps/PsPolygon.c b/Xprint/ps/PsPolygon.c
index a5b373775..dca00fa21 100644
--- a/Xprint/ps/PsPolygon.c
+++ b/Xprint/ps/PsPolygon.c
@@ -203,6 +203,31 @@ PsPolyFillRect(
     DisplayListPtr  disp;
     GCPtr           gc;
 
+#ifdef DBE
+    /* Remove previous pixmap content if we render one single rect which
+     * covers the whole pixmap surface (this optimisation was added for
+     * the double-buffer extension ("DBE") which uses |PolyFillRect()|
+     * to clear the buffer - but it makes sense in other cases, too).
+     */    
+    if (nRects == 1)
+    {
+      extern Bool noDbeExtension;
+
+      if ( (pRects[0].x==0) && (pRects[0].y==0) &&
+           (pRects[0].width==pDrawable->width) && (pRects[0].height==pDrawable->height) &&
+           (pGC->fillStyle == FillSolid) &&
+           (noDbeExtension == False))
+      {
+#ifdef DEBUG_gismobile
+        ErrorF("PsPolyFillRect: scrubbing pixmap...\n");
+#endif /* DEBUG_gismobile */
+        /* Remove all content from the pixmap as it would be covered
+         * by the whole rect anyway */
+        PsScrubPixmap(pDrawable);
+      }
+    }
+#endif /* DBE */
+
     if ((gc = PsCreateAndCopyGC(pDrawable, pGC)) == NULL) return;
 
     disp = PsGetFreeDisplayBlock(priv);