Merge branch 'nxagent'

1 files changed, 3267 insertions, 0 deletions

diff --git a/nx-X11/programs/Xserver/hw/nxagent/Drawable.c b/nx-X11/programs/Xserver/hw/nxagent/Drawable.c
new file mode 100644
index 000000000..9c167743f
--- /dev/null
+++ b/nx-X11/programs/Xserver/hw/nxagent/Drawable.c
@@ -0,0 +1,3267 @@
+/**************************************************************************/
+/*                                                                        */
+/* Copyright (c) 2001, 2011 NoMachine, http://www.nomachine.com/.         */
+/*                                                                        */
+/* NXAGENT, NX protocol compression and NX extensions to this software    */
+/* are copyright of NoMachine. Redistribution and use of the present      */
+/* software is allowed according to terms specified in the file LICENSE   */
+/* which comes in the source distribution.                                */
+/*                                                                        */
+/* Check http://www.nomachine.com/licensing.html for applicability.       */
+/*                                                                        */
+/* NX and NoMachine are trademarks of Medialogic S.p.A.                   */
+/*                                                                        */
+/* All rights reserved.                                                   */
+/*                                                                        */
+/**************************************************************************/
+
+#include "dixstruct.h"
+#include "../../fb/fb.h"
+
+#include "Agent.h"
+#include "Display.h"
+#include "Screen.h"
+#include "Trap.h"
+#include "Image.h"
+#include "Drawable.h"
+#include "Client.h"
+#include "Visual.h"
+#include "Events.h"
+#include "GCs.h"
+#include "Utils.h"
+#include "Handlers.h"
+#include "Pixels.h"
+#include "Reconnect.h"
+#include "GCOps.h"
+
+#include "NXlib.h"
+
+#include "mibstorest.h"
+
+#define PANIC
+#define WARNING
+#undef  TEST
+#undef  DEBUG
+#undef  DUMP
+
+/*
+ * The list of rectangles composing a region
+ * s returned by nxagentGetOptimizedRegion-
+ * Boxes() instead of REGION_RECTS().
+ */
+
+#define USE_OPTIMIZED_BOXES
+
+/*
+ * The rectangles composing a region are de-
+ * fragmented to reduce the number of synch-
+ * ronizing PutImage's.
+ */
+
+#define ADVANCED_BOXES_DEFRAG
+
+/*
+ * If defined, send the XClearArea at the end
+ * of the loop synchronizing the shadow pixmap.
+ * In this way, large images can be splitted but
+ * the user will see more updates togheter.
+ */
+
+#undef  COLLECTED_UPDATES
+
+#ifdef ADVANCED_BOXES_DEFRAG
+#define INCLUDE_MARGIN 10
+#endif
+
+struct nxagentExposeBackground
+{
+  PixmapPtr pBackground;
+  RegionPtr pExpose;
+};
+
+RESTYPE RT_NX_CORR_BACKGROUND;
+RESTYPE RT_NX_CORR_WINDOW;
+RESTYPE RT_NX_CORR_PIXMAP;
+
+int nxagentCorruptedPixmaps     = 0;
+int nxagentCorruptedWindows     = 0;
+int nxagentCorruptedBackgrounds = 0;
+
+int nxagentForceSynchronization = 0;
+
+_nxagentSynchronizationRec nxagentSynchronization = { (DrawablePtr) NULL, 0, 0, 0, 0, 0 };
+
+RegionPtr nxagentDeferredBackgroundExposures = NullRegion;
+
+/*
+ * Predicate functions used to synchronize the
+ * content of the remote drawable with the data
+ * stored in the virtual frame-buffer.
+ */
+
+void nxagentSynchronizeDrawablePredicate(void *p0, XID x1, void *p2);
+void nxagentExposeBackgroundPredicate(void *p0, XID x1, void *p2);
+
+/*
+ * Imported from NXresource.c
+ */
+
+extern int nxagentFindClientResource(int, RESTYPE, pointer);
+
+unsigned long nxagentGetColor(DrawablePtr pDrawable, int xPixel, int yPixel);
+unsigned long nxagentGetDrawableColor(DrawablePtr pDrawable);
+unsigned long nxagentGetRegionColor(DrawablePtr pDrawable, RegionPtr pRegion);
+
+int nxagentSynchronizeDrawable(DrawablePtr pDrawable, int wait, unsigned int breakMask, WindowPtr owner)
+{
+  int result;
+
+  pDrawable = nxagentSplitDrawable(pDrawable);
+
+  if (nxagentLosslessTrap == 0)
+  {
+    if (nxagentDrawableStatus(pDrawable) == Synchronized)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentSynchronizeDrawable: Drawable [%s][%p] with id [%ld] already "
+                  "synchronized.\n", nxagentDrawableType(pDrawable),
+                      (void *) pDrawable, pDrawable -> id);
+      #endif
+
+      return 0;
+    }
+  }
+
+  /*
+   * What we want here is to avoid drawing on the
+   * framebuffer and just perform the operation
+   * on the real X server. This is the purpose of
+   * the FB trap. At the same time we also want
+   * to avoid a split, so that the image will be
+   * transferred in a single operation.
+   */
+
+  nxagentFBTrap = 1;
+
+  nxagentSplitTrap = 1;
+
+  result = nxagentSynchronizeDrawableData(pDrawable, breakMask, owner);
+
+  nxagentSplitTrap = 0;
+
+  nxagentFBTrap = 0;
+
+  if (wait == DO_WAIT && nxagentSplitResource(pDrawable) != NULL)
+  {
+    nxagentWaitDrawable(pDrawable);
+  }
+
+  #ifdef TEST
+
+  if (nxagentDrawableStatus(pDrawable) == Synchronized)
+  {
+    fprintf(stderr, "nxagentSynchronizeDrawable: Drawable %s [%p] with id [%ld] now synchronized.\n",
+                nxagentDrawableType(pDrawable), (void *) pDrawable, pDrawable -> id);
+  }
+  else
+  {
+    fprintf(stderr, "nxagentSynchronizeDrawable: Drawable %s [%p] with id [%ld] not fully synchronized.\n",
+                nxagentDrawableType(pDrawable), (void *) pDrawable, pDrawable -> id);
+  }
+
+  #endif
+
+  return result;
+}
+
+int nxagentSynchronizeDrawableData(DrawablePtr pDrawable, unsigned int breakMask, WindowPtr owner)
+{
+  int width, height, depth, length;
+  unsigned int leftPad, format;
+
+  char *data = NULL;
+  DrawablePtr pSrcDrawable;
+  GCPtr pGC;
+
+  int success;
+
+  if (pDrawable -> type == DRAWABLE_PIXMAP)
+  {
+    leftPad = 0;
+
+    width  = pDrawable -> width;
+    height = pDrawable -> height;
+    depth  = pDrawable -> depth;
+
+    #ifdef TEST
+    fprintf(stderr, "nxagentSynchronizeDrawableData: Synchronizing drawable (%s) with geometry [%d][%d][%d].\n",
+                nxagentDrawableType(pDrawable), width, height, depth);
+    #endif
+
+    format = (depth == 1) ? XYPixmap : ZPixmap;
+
+    length = nxagentImageLength(width, height, format, leftPad, depth);
+
+    if ((data = xalloc(length)) == NULL)
+    {
+      #ifdef WARNING
+      fprintf(stderr, "nxagentSynchronizeDrawableData: WARNING! Failed to allocate memory for the operation.\n");
+      #endif
+
+      success = 0;
+
+      goto nxagentSynchronizeDrawableDataEnd;
+    }
+
+    pSrcDrawable = (pDrawable -> type == DRAWABLE_PIXMAP ?
+                        ((DrawablePtr) nxagentVirtualPixmap((PixmapPtr) pDrawable)) :
+                            pDrawable);
+
+    /*
+     * Synchronize the whole pixmap if we need
+     * to download a fresh copy with lossless
+     * compression turned off.
+     */
+
+    if (nxagentLosslessTrap == 1)
+    {
+      pGC = nxagentGetGraphicContext(pDrawable);
+
+      if (pGC == NULL)
+      {
+        #ifdef WARNING
+        fprintf(stderr, "nxagentSynchronizeDrawableData: WARNING! Failed to get the temporary GC.\n");
+        #endif
+
+        success = 0;
+
+        goto nxagentSynchronizeDrawableDataFree;
+      }
+
+      ValidateGC(pDrawable, pGC);
+
+      fbGetImage(pSrcDrawable, 0, 0,
+                     width, height, format, AllPlanes, data);
+
+      #ifdef TEST
+      fprintf(stderr, "nxagentSynchronizeDrawableData: Forcing synchronization of "
+                  "pixmap at [%p] with lossless compression.\n", (void *) pDrawable);
+      #endif
+
+      nxagentPutImage(pDrawable, pGC, depth, 0, 0,
+                          width, height, leftPad, format, data);
+
+      success = 1;
+
+      goto nxagentSynchronizeDrawableDataFree;
+    }
+    else if (nxagentReconnectTrap == 1)
+    {
+      /*
+       * The pixmap data is not synchronized unless
+       * we need it. We noticed we have to reconnect
+       * the pixmaps used by the GC's clip mask.
+       * The other data will be synchronized on demand.
+       */
+
+      if (pDrawable -> depth == 1)
+      {
+        #ifdef TEST
+
+        if (nxagentReconnectTrap == 1)
+        {
+          static int totalLength;
+          static int totalReconnectedPixmaps;
+
+          totalLength += length;
+          totalReconnectedPixmaps++;
+
+          fprintf(stderr, "nxagentSynchronizeDrawableData: Reconnecting pixmap at [%p] [%dx%d] "
+                      "Depth [%d] Size [%d]. Total size [%d]. Total reconnected pixmaps [%d].\n", 
+                          (void *) pDrawable, width, height, depth, length,
+                              totalLength, totalReconnectedPixmaps);
+        }
+
+        #endif
+
+        pGC = nxagentGetGraphicContext(pDrawable);
+
+        if (pGC == NULL)
+        {
+          #ifdef WARNING
+          fprintf(stderr, "nxagentSynchronizeDrawableData: WARNING! Failed to create the temporary GC.\n");
+          #endif
+
+          success = 0;
+
+          goto nxagentSynchronizeDrawableDataFree;
+        }
+
+        ValidateGC(pDrawable, pGC);
+
+        fbGetImage(pSrcDrawable, 0, 0,
+                       width, height, format, AllPlanes, data);
+
+        nxagentPutImage(pDrawable, pGC, depth, 0, 0,
+                            width, height, leftPad, format, data);
+
+        success = 1;
+
+        goto nxagentSynchronizeDrawableDataFree;
+      }
+      else
+      {
+        #ifdef TEST
+        fprintf(stderr, "nxagentSynchronizeDrawableData: Skipping synchronization of "
+                    "pixmap at [%p][%p] during reconnection.\n", (void *) pDrawable, (void*) nxagentVirtualPixmap((PixmapPtr)pDrawable));
+        #endif
+
+        nxagentMarkCorruptedRegion(pDrawable, NullRegion);
+
+        success = 1;
+
+        goto nxagentSynchronizeDrawableDataFree;
+      }
+    }
+  }
+
+  /*
+   * By calling this function with the NullRegion
+   * as parameter we are requesting to synchro-
+   * nize the full visible corrupted region of
+   * the drawable.
+   */
+
+  success = nxagentSynchronizeRegion(pDrawable, NullRegion, breakMask, owner);
+
+nxagentSynchronizeDrawableDataFree:
+
+  if (data != NULL)
+  {
+    xfree(data);
+  }
+
+nxagentSynchronizeDrawableDataEnd:
+
+  return success;
+}
+
+/*
+ * If pRegion is NullRegion, all the viewable
+ * corrupted region will be synchronized.
+ */
+
+int nxagentSynchronizeRegion(DrawablePtr pDrawable, RegionPtr pRegion, unsigned int breakMask, WindowPtr owner)
+{
+  GCPtr pGC;
+  DrawablePtr pSrcDrawable;
+  BoxPtr pBox;
+  RegionPtr clipRegion;
+
+  RegionRec tileRegion;
+  RegionRec exposeRegion;
+  BoxRec box;
+  BoxRec tileBox;
+
+  #ifdef COLLECTED_UPDATES
+  RegionRec collectedUpdates;
+  #endif
+
+  char *data;
+
+  int nBox;
+  int x, y;
+  int w, h;
+  int extentWidth, extentHeight;
+  int tileWidth, tileHeight;
+  int length, format, leftPad;
+  int i;
+  int saveTrap;
+  int success;
+  int useStoredBitmap;
+
+  unsigned long now;
+  unsigned long elapsedTime;
+
+
+  leftPad    = 0;
+  success    = 0;
+  data       = NULL;
+  pGC        = NULL;
+  clipRegion = NullRegion;
+
+  #ifdef COLLECTED_UPDATES
+  REGION_INIT(pDrawable -> pScreen, &collectedUpdates, NullBox, 1);
+  #endif
+
+  REGION_INIT(pDrawable -> pScreen, &exposeRegion, NullBox, 1);
+
+  if (nxagentDrawableBitmap(pDrawable) != NullPixmap &&
+          nxagentDrawableStatus((DrawablePtr) nxagentDrawableBitmap(pDrawable)) == Synchronized)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentSynchronizeRegion: WARNING! Drawable [%s] at [%p] has an already synchronized "
+                "bitmap at [%p].\n", nxagentDrawableType(pDrawable),
+                    (void *) pDrawable, (void *) nxagentDrawableBitmap(pDrawable));
+    #endif
+
+    nxagentDestroyDrawableBitmap(pDrawable);
+  }
+
+  /*
+   * The stored bitmap may be used if we
+   * are going to synchronize the full
+   * drawable.
+   */
+
+  useStoredBitmap = (nxagentDrawableBitmap(pDrawable) != NullPixmap && pRegion == NullRegion);
+
+  if (useStoredBitmap != 0)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentSynchronizeRegion: Drawable [%s] at [%p] has a synchronization bitmap at [%p] "
+                "[%d,%d,%d,%d] with [%ld] rects.\n", nxagentDrawableType(pDrawable),
+                    (void *) pDrawable, (void *) nxagentDrawableBitmap(pDrawable),
+                        nxagentCorruptedRegion((DrawablePtr) nxagentDrawableBitmap(pDrawable)) -> extents.x1,
+                            nxagentCorruptedRegion((DrawablePtr) nxagentDrawableBitmap(pDrawable)) -> extents.y1,
+                                nxagentCorruptedRegion((DrawablePtr) nxagentDrawableBitmap(pDrawable)) -> extents.x2,
+                                    nxagentCorruptedRegion((DrawablePtr) nxagentDrawableBitmap(pDrawable)) -> extents.y2,
+                                        REGION_NUM_RECTS(nxagentCorruptedRegion((DrawablePtr) nxagentDrawableBitmap(pDrawable))));
+    #endif
+
+    clipRegion = nxagentCreateRegion(pDrawable, NULL, 0, 0, pDrawable -> width, pDrawable -> height);
+
+    /*
+     * Intersecting the viewable region of the
+     * drawable with the region remaining from
+     * a previous loop.
+     */
+
+    REGION_INTERSECT(pDrawable -> pScreen, clipRegion, clipRegion,
+                         nxagentCorruptedRegion((DrawablePtr) nxagentDrawableBitmap(pDrawable)));
+
+    /*
+     * The bitmap regions used in the synchro-
+     * nizations are only those corrupted also
+     * on the drawable. In this way, if we put
+     * a tile in a bad position (e.g. if the
+     * corrupted region moves), the next synch-
+     * ronization will fix the error.
+     */
+
+    REGION_INTERSECT(pDrawable -> pScreen, clipRegion, clipRegion,
+                         nxagentCorruptedRegion(pDrawable));
+
+    /*
+     * The bitmap to synchronize is clipped.
+     */
+
+    if (REGION_NIL(clipRegion) == 1)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentSynchronizeRegion: The bitmap region [%d,%d,%d,%d] is not viewable. "
+                  "Destroying it.\n", clipRegion -> extents.x1, clipRegion -> extents.y1,
+                      clipRegion -> extents.x2, clipRegion -> extents.y2);
+      #endif
+
+      nxagentDestroyDrawableBitmap(pDrawable);
+
+      goto nxagentSynchronizeRegionFree;
+    }
+
+    /*
+     * Using the saved bitmap as source, instead
+     * of the drawable itself.
+     */
+
+    pSrcDrawable = ((DrawablePtr) nxagentVirtualPixmap(nxagentDrawableBitmap(pDrawable)));
+  }
+  else
+  {
+    if (pRegion != NullRegion && REGION_NIL(pRegion) == 1)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentSynchronizeRegion: Region [%d,%d,%d,%d] is nil. Skipping synchronization.\n",
+                  pRegion -> extents.x1, pRegion -> extents.y1, pRegion -> extents.x2, pRegion -> extents.y2);
+      #endif
+
+      goto nxagentSynchronizeRegionFree;
+    }
+
+    if (nxagentDrawableStatus(pDrawable) == Synchronized)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentSynchronizeRegion: The [%s] at [%p] is already synchronized.\n",
+                  nxagentDrawableType(pDrawable), (void *) pDrawable);
+      #endif
+
+      goto nxagentSynchronizeRegionFree;
+    }
+
+    /*
+     * Creating a region containing the viewable
+     * area of drawable.
+     */
+
+    clipRegion = nxagentCreateRegion(pDrawable, NULL, 0, 0, pDrawable -> width, pDrawable -> height);
+
+    /*
+     * If the corrupted region is not viewable, we
+     * can skip the synchronization.
+     */
+
+    REGION_INTERSECT(pDrawable -> pScreen, clipRegion, clipRegion, nxagentCorruptedRegion(pDrawable));
+
+    if (REGION_NIL(clipRegion) == 1)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentSynchronizeRegion: The corrupted region [%d,%d,%d,%d] is not viewable "
+                  "on [%s] at [%p]. Skipping the synchronization.\n", clipRegion -> extents.x1,
+                      clipRegion -> extents.y1, clipRegion -> extents.x2, clipRegion -> extents.y2,
+                          nxagentDrawableType(pDrawable), (void *) pDrawable);
+      #endif
+
+     goto nxagentSynchronizeRegionFree; 
+    }
+
+    /*
+     * We can skip the synchronization if the re-
+     * quested region is not corrupted. Specifying
+     * a NullRegion as parameter, all the viewable
+     * corrupted region will be synchronized.
+     */
+
+    if (pRegion != NullRegion)
+    {
+      REGION_INTERSECT(pDrawable -> pScreen, clipRegion, clipRegion, pRegion);
+
+      if (REGION_NIL(clipRegion) == 1)
+      {
+        #ifdef TEST
+        fprintf(stderr, "nxagentSynchronizeRegion: Region requested [%d,%d,%d,%d] already "
+                    "synchronized on [%s] at [%p].\n", pRegion -> extents.x1,
+                        pRegion -> extents.y1, pRegion -> extents.x2, pRegion -> extents.y2,
+                            nxagentDrawableType(pDrawable), (void *) pDrawable);
+        #endif
+
+        goto nxagentSynchronizeRegionFree;
+      }
+    }
+
+    pSrcDrawable = (pDrawable -> type == DRAWABLE_PIXMAP ?
+                      ((DrawablePtr) nxagentVirtualPixmap((PixmapPtr) pDrawable)) :
+                          pDrawable);
+  }
+
+  #ifdef TEST
+  fprintf(stderr, "nxagentSynchronizeRegion: Synchronizing region with coordinates [%d,%d,%d,%d] "
+              "on [%s] at [%p].\n", clipRegion -> extents.x1, clipRegion -> extents.y1,
+                  clipRegion -> extents.x2, clipRegion -> extents.y2,
+                      nxagentDrawableType(pDrawable), (void *) pDrawable);
+  #endif
+
+  saveTrap = nxagentGCTrap;
+
+  nxagentGCTrap = 0;
+
+  nxagentFBTrap = 1;
+
+  nxagentSplitTrap = 1;
+
+  pGC = nxagentGetGraphicContext(pDrawable);
+
+  if (pGC == NULL)
+  {
+    #ifdef WARNING
+    fprintf(stderr, "nxagentSynchronizeRegion: WARNING! Failed to create the temporary GC.\n");
+    #endif
+
+    goto nxagentSynchronizeRegionFree;
+  }
+
+  ValidateGC(pDrawable, pGC);
+
+  #ifdef TEST
+  fprintf(stderr, "nxagentSynchronizeRegion: Going to synchronize [%ld] rects of [%s] at [%p].\n",
+              REGION_NUM_RECTS(clipRegion), nxagentDrawableType(pDrawable), (void *) pDrawable);
+
+  fprintf(stderr, "nxagentSynchronizeRegion: Extents geometry [%d,%d,%d,%d].\n",
+          clipRegion -> extents.x1, clipRegion -> extents.y1, clipRegion -> extents.x2, clipRegion -> extents.y2);
+
+  fprintf(stderr, "nxagentSynchronizeRegion: Drawable geometry [%d,%d,%d,%d].\n",
+              pDrawable -> x, pDrawable -> y, pDrawable -> width, pDrawable -> height);
+  #endif
+
+  /*
+   * We are going to synchronize the corrupted
+   * area, so we use the corrupted extents as
+   * maximum size of the image data. It's im-
+   * portant to avoid using the drawable size,
+   * because in case of a huge window it had to
+   * result in a failed data memory allocation.
+   */
+
+  extentWidth  = clipRegion -> extents.x2 - clipRegion -> extents.x1;
+  extentHeight = clipRegion -> extents.y2 - clipRegion -> extents.y1;
+
+  w = tileWidth  = (nxagentOption(TileWidth)  > extentWidth  ? extentWidth  : nxagentOption(TileWidth));
+  h = tileHeight = (nxagentOption(TileHeight) > extentHeight ? extentHeight : nxagentOption(TileHeight));
+
+  #ifdef DEBUG
+  fprintf(stderr, "nxagentSynchronizeRegion: Using tiles of size [%dx%d].\n", tileWidth, tileHeight);
+  #endif
+
+  data = nxagentAllocateImageData(w, h, pDrawable -> depth, &length, &format);
+
+  if (data == NULL)
+  {
+    #ifdef WARNING
+
+    fprintf(stderr, "nxagentSynchronizeRegion: WARNING! Failed to allocate memory for synchronization.\n");
+
+    /*
+     * Print detailed informations if the
+     * image length is zero.
+     */
+
+    if (length == 0)
+    {
+      fprintf(stderr, "nxagentSynchronizeRegion: Drawable [%s] at [%p] with region geometry [%ld][%d,%d,%d,%d].\n",
+                  nxagentDrawableType(pDrawable), (void *) pDrawable, REGION_NUM_RECTS(clipRegion),
+                      clipRegion -> extents.x1, clipRegion -> extents.y1,
+                          clipRegion -> extents.x2, clipRegion -> extents.y2);
+    }
+
+    #endif
+
+    goto nxagentSynchronizeRegionFree;
+  }
+
+  #ifndef USE_OPTIMIZED_BOXES
+
+  pBox = REGION_RECTS(clipRegion);
+
+  #else
+
+  pBox = nxagentGetOptimizedRegionBoxes(clipRegion);
+
+  #endif /* USE_OPTIMIZED_BOXES */
+
+  nBox = REGION_NUM_RECTS(clipRegion);
+
+  now = GetTimeInMillis();
+
+  nxagentSynchronization.abort = 0;
+
+  /*
+   * Going to split the updated region into small blocks.
+   */
+
+  for (i = 0; i < nBox; i++)
+  {
+    #ifdef USE_OPTIMIZED_BOXES
+
+    if (pBox[i].x1 == 0 && pBox[i].y1 == 0 &&
+            pBox[i].x2 == 0 && pBox[i].y2 == 0)
+    {
+      continue;
+    }
+
+    #endif
+
+    box = pBox[i];
+
+    for (y = box.y1; y < box.y2; y += h)
+    {
+      h = MIN(box.y2 - y, tileHeight);
+
+      for (x = box.x1; x < box.x2; x += w)
+      {
+        w = MIN(box.x2 - x, tileWidth);
+
+        /*
+         * FIXME: This should not occur.
+         */
+
+        if (nxagentDrawableStatus(pDrawable) == Synchronized)
+        {
+          #ifdef WARNING
+
+          if (pDrawable -> type == DRAWABLE_WINDOW && pSrcDrawable != pDrawable)
+          {
+            fprintf(stderr, "nxagentSynchronizeRegion: WARNING! Trying to synchronize "
+                        "the clean drawable type [%d] at [%p] with source at [%p].\n",
+                            pDrawable -> type, (void *) pDrawable, (void *) pSrcDrawable);
+          }
+
+          #endif
+
+          goto nxagentSynchronizeRegionStop;
+        }
+
+        if (canBreakOnTimeout(breakMask))
+        {
+          /*
+           * Abort the synchronization loop if it
+           * lasts for more than DeferTimeout
+           * milliseconds.
+           */
+
+          elapsedTime = GetTimeInMillis() - now;
+
+          if (elapsedTime > nxagentOption(DeferTimeout))
+          {
+            #ifdef TEST
+            fprintf(stderr, "nxagentSynchronizeRegion: Synchronization break with "
+                        "[%lu] ms elapsed.\n", elapsedTime);
+            #endif
+
+            nxagentSynchronization.abort = 1;
+
+            goto nxagentSynchronizeRegionStop;
+          }
+        }
+
+        /*
+         * Abort the loop if we go out of bandwidth.
+         */
+
+        if (breakOnCongestionDrawable(breakMask, pDrawable) == 1)
+        {
+          #ifdef TEST
+          fprintf(stderr, "nxagentSynchronizeRegion: Synchronization break with "
+                      "congestion [%d] blocking [%d].\n", nxagentCongestion,
+                          nxagentBlocking);
+          #endif
+
+          nxagentSynchronization.abort = 1;
+
+          goto nxagentSynchronizeRegionStop;
+        }
+
+        /*
+         * Abort the loop if the display blocks.
+         */
+
+        if (breakOnBlocking(breakMask) == 1)
+        {
+          #ifdef TEST
+          fprintf(stderr, "nxagentSynchronizeRegion: Synchronization break with "
+                      "blocking [%d] congestion [%d].\n", nxagentBlocking,
+                          nxagentCongestion);
+          #endif
+
+          nxagentSynchronization.abort = 1;
+
+          goto nxagentSynchronizeRegionStop;
+        }
+
+        tileBox.x1 = x;
+        tileBox.y1 = y;
+        tileBox.x2 = x + w;
+        tileBox.y2 = y + h;
+
+        #ifdef DEBUG
+        fprintf(stderr, "nxagentSynchronizeRegion: Going to synchronize tile [%d,%d,%d,%d].\n",
+                    tileBox.x1, tileBox.y1, tileBox.x2, tileBox.y2);
+        #endif
+
+        nxagentGetImage(pSrcDrawable, x, y, w, h, format, AllPlanes, data);
+
+        /*
+         * Going to unmark the synchronized
+         * region.
+         */
+
+        REGION_INIT(pDrawable -> pScreen, &tileRegion, &tileBox, 1);
+
+        REGION_UNION(pDrawable -> pScreen, &exposeRegion, &exposeRegion, &tileRegion);
+
+        #ifdef COLLECTED_UPDATES
+        REGION_APPEND(pDrawable -> pScreen, &collectedUpdates, &tileRegion);
+        #endif
+
+        if (useStoredBitmap != 0)
+        {
+          /*
+           * When a bitmap's tile is synchronized,
+           * we can clear the corresponding region.
+           * We can't use the nxagentUnmarkCorrupted-
+           * Region because we have not a resource
+           * associated to this pixmap.
+           */
+
+          REGION_SUBTRACT(pDrawable -> pScreen, nxagentPixmapCorruptedRegion(nxagentDrawableBitmap(pDrawable)),
+                              nxagentPixmapCorruptedRegion(nxagentDrawableBitmap(pDrawable)), &tileRegion); 
+
+          /*
+           * The drawable's corrupted region can
+           * be cleared if the bitmap's tile data
+           * matches the drawable's content at the
+           * same position.
+           */
+
+          if (nxagentDrawableStatus(pDrawable) == NotSynchronized)
+          {
+            char *cmpData;
+
+            int cmpLength, cmpFormat;
+
+            cmpData = nxagentAllocateImageData(w, h, pDrawable -> depth, &cmpLength, &cmpFormat);
+
+            if (cmpData != NULL)
+            {
+              nxagentGetImage(pDrawable, x, y, w, h, format, AllPlanes, cmpData);
+
+              if (memcmp(data, cmpData, cmpLength) == 0)
+              {
+                #ifdef TEST
+                fprintf(stderr, "nxagentSynchronizeRegion: Tile [%d,%d,%d,%d] matches drawable's data at same position.\n",
+                            x, y, x + w, y + h);
+                #endif
+
+                nxagentUnmarkCorruptedRegion(pDrawable, &tileRegion);
+              }
+              #ifdef TEST
+              else
+              {
+                fprintf(stderr, "nxagentSynchronizeRegion: Tile [%d,%d,%d,%d] on drawable [%p] doesn't match.\n",
+                            x, y, x + w, y + h, (void *) pDrawable);
+              }
+              #endif
+            }
+            else
+            {
+              #ifdef WARNING
+              fprintf(stderr, "nxagentSynchronizeRegion: WARNING! Failed to allocate memory to compare tiles.\n");
+              #endif
+            }
+
+            if (cmpData != NULL)
+            {
+              xfree(cmpData);
+            }
+          }
+        }
+        else
+        {
+          nxagentUnmarkCorruptedRegion(pDrawable, &tileRegion);
+
+          if (nxagentDrawableBitmap(pDrawable) != NullPixmap)
+          {
+            #ifdef TEST
+            fprintf(stderr, "nxagentSynchronizeRegion: Going to clean bitmap at [%p] with newer data.\n",
+                        (void *) nxagentDrawableBitmap(pDrawable));
+            #endif
+
+            REGION_SUBTRACT(pDrawable -> pScreen, nxagentPixmapCorruptedRegion(nxagentDrawableBitmap(pDrawable)),
+                                nxagentPixmapCorruptedRegion(nxagentDrawableBitmap(pDrawable)), &tileRegion);
+          }
+        }
+
+        /*
+         * Realize the image after comparing the
+         * source data with the bitmap data.
+         */
+
+        nxagentRealizeImage(pDrawable, pGC, pDrawable -> depth,
+                                x, y, w, h, leftPad, format, data);
+
+        REGION_UNINIT(pDrawable -> pScreen, &tileRegion);
+
+        #if !defined(COLLECTED_UPDATES)
+
+        if (owner != NULL)
+        {
+          if (nxagentOption(Shadow) == 1 &&
+                  (nxagentOption(XRatio) != DONT_SCALE ||
+                      nxagentOption(YRatio) != DONT_SCALE))
+          {
+            int scaledx;
+            int scaledy;
+            int scaledw;
+            int scaledh;
+
+            scaledx = nxagentScale(x, nxagentOption(XRatio));
+            scaledy = nxagentScale(y, nxagentOption(YRatio));
+
+            scaledw = nxagentScale(x + w, nxagentOption(XRatio)) - scaledx;
+            scaledh = nxagentScale(y + h, nxagentOption(YRatio)) - scaledy;
+
+            XClearArea(nxagentDisplay, nxagentWindow(owner), scaledx, scaledy, scaledw, scaledh, 0);
+          }
+          else
+          {
+            XClearArea(nxagentDisplay, nxagentWindow(owner), x, y, w, h, 0);
+          }
+        }
+
+        #endif /* #if !defined(COLLECTED_UPDATES) */
+
+        /*
+         * Abort the loop on the user's input.
+         * This is done here to check for events
+         * read after the flush caused by the
+         * PutImage.
+         */
+
+        nxagentDispatchHandler((ClientPtr) 0, 0, 0);
+
+        if (breakOnEvent(breakMask) == 1)
+        {
+          #ifdef TEST
+          fprintf(stderr, "nxagentSynchronizeRegion: Synchronization break with "
+                      "new input events.\n");
+          #endif
+
+          nxagentSynchronization.abort = 1;
+
+          goto nxagentSynchronizeRegionStop;
+        }
+      }
+    }
+  }
+
+nxagentSynchronizeRegionStop:
+
+  nxagentSplitTrap = 0;
+
+  nxagentFBTrap = 0;
+
+  nxagentGCTrap = saveTrap;
+
+  success = 1;
+
+  if (nxagentOption(Shadow) == 0)
+  {
+    if (nxagentSynchronization.abort == 1)
+    {
+      /*
+       * Storing the pointer to the drawable we
+       * were synchronizing when the loop aborted.
+       * It is used in nxagentSynchronizeDrawable-
+       * Predicate.
+       */
+
+      nxagentSynchronization.pDrawable = pDrawable;
+      nxagentSynchronization.drawableType = pDrawable -> type;
+
+      if (nxagentDrawableBitmap(pDrawable) == NullPixmap)
+      {
+        #ifdef TEST
+        fprintf(stderr, "nxagentSynchronizeRegion: Going to create the synchronization bitmap.\n");
+        #endif
+
+        nxagentCreateDrawableBitmap(pDrawable);
+      }
+    }
+    else
+    {
+      if (nxagentDrawableBitmap(pDrawable) != NullPixmap)
+      {
+        #ifdef TEST
+        fprintf(stderr, "nxagentSynchronizeRegion: Synchronization loop finished. Going to destroy synchronization bitmap.\n");
+        #endif
+
+        nxagentDestroyDrawableBitmap(pDrawable);
+      }
+    }
+
+    if (pDrawable -> type == DRAWABLE_PIXMAP &&
+            nxagentIsCorruptedBackground((PixmapPtr) pDrawable) == 1 &&
+                REGION_NIL(&exposeRegion) == 0)
+    {
+      struct nxagentExposeBackground eb;
+
+      int i;
+
+      eb.pBackground = (PixmapPtr) pDrawable;
+      eb.pExpose = &exposeRegion;
+
+      for (i = 0; i < MAXCLIENTS; i++)
+      {
+        if (clients[i] != NULL)
+        {
+          FindClientResourcesByType(clients[i], RT_WINDOW,
+                                        nxagentExposeBackgroundPredicate, &eb);
+        }
+      }
+    }
+  }
+  #ifdef COLLECTED_UPDATES
+  else
+  {
+    if (owner != NULL)
+    {
+      int overlap = 0;
+
+      REGION_VALIDATE(pDrawable -> pScreen, &collectedUpdates, &overlap);
+
+      for (i = 0; i < REGION_NUM_RECTS(&collectedUpdates); i++)
+      {
+        x = REGION_RECTS(&collectedUpdates)[i].x1;
+        y = REGION_RECTS(&collectedUpdates)[i].y1;
+        w = REGION_RECTS(&collectedUpdates)[i].x2 - REGION_RECTS(&collectedUpdates)[i].x1;
+        h = REGION_RECTS(&collectedUpdates)[i].y2 - REGION_RECTS(&collectedUpdates)[i].y1;
+       
+        if (nxagentOption(Shadow) == 1 &&
+                (nxagentOption(XRatio) != DONT_SCALE ||
+                    nxagentOption(YRatio) != DONT_SCALE))
+        {
+          int scaledx;
+          int scaledy;
+          int scaledw;
+          int scaledh;
+
+          scaledx = nxagentScale(x, nxagentOption(XRatio));
+          scaledy = nxagentScale(y, nxagentOption(YRatio));
+
+          scaledw = nxagentScale(x + w, nxagentOption(XRatio)) - scaledx;
+          scaledh = nxagentScale(y + h, nxagentOption(YRatio)) - scaledy;
+
+          XClearArea(nxagentDisplay, nxagentWindow(owner), scaledx, scaledy, scaledw, scaledh, 0);
+        }
+        else
+        {
+          XClearArea(nxagentDisplay, nxagentWindow(owner), x, y, w, h, 0);
+        }
+      }
+    }
+  }
+  #endif /* #ifdef COLLECTED_UPDATES */
+
+nxagentSynchronizeRegionFree:
+
+  if (clipRegion != NullRegion)
+  {
+    nxagentFreeRegion(pDrawable, clipRegion);
+  }
+
+  if (data != NULL)
+  {
+    xfree(data);
+  }
+
+  REGION_UNINIT(pDrawable -> pScreen, &exposeRegion);
+
+  #ifdef COLLECTED_UPDATES
+
+  REGION_UNINIT(pDrawable -> pScreen, &collectedUpdates);
+
+  #endif /* #ifdef COLLECTED_UPDATES */
+
+  return success;
+}
+
+void nxagentSynchronizeBox(DrawablePtr pDrawable, BoxPtr pBox, unsigned int breakMask)
+{
+  RegionPtr pRegion;
+
+  if (nxagentDrawableStatus(pDrawable) == Synchronized)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentSynchronizeBox: The [%s] at [%p] is already synchronized.\n",
+                nxagentDrawableType(pDrawable), (void *) pDrawable);
+    #endif
+
+    return;
+  }
+
+  if (pBox == NullBox)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentSynchronizeBox: Going to synchronize the whole [%s] at [%p].\n",
+                nxagentDrawableType(pDrawable), (void *) pDrawable);
+    #endif
+
+    nxagentSynchronizeRegion(pDrawable, NullRegion, breakMask, NULL);
+  }
+  else
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentSynchronizeBox: Going to create a region from box [%d,%d,%d,%d].\n",
+                pBox -> x1, pBox -> y1, pBox -> x2, pBox -> y2);
+    #endif
+
+    pRegion = nxagentCreateRegion(pDrawable, NULL, pBox -> x1, pBox -> y1,
+                                      pBox -> x2 - pBox -> x1, pBox -> y2 - pBox -> y1);
+
+
+    if (REGION_NIL(pRegion) == 1)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentSynchronizeBox: Resulting region [%d,%d,%d,%d] is nil. Skipping synchronization.\n",
+                  pRegion -> extents.x1, pRegion -> extents.y1, pRegion -> extents.x2, pRegion -> extents.y2);
+      #endif
+
+      nxagentFreeRegion(pDrawable, pRegion);
+
+      return;
+    }
+
+    #ifdef TEST
+    fprintf(stderr, "nxagentSynchronizeBox: Going to synchronize the region [%d,%d,%d,%d] of "
+                "[%s] at [%p].\n", pRegion -> extents.x1, pRegion -> extents.y1, pRegion -> extents.x2,
+                    pRegion -> extents.y2, nxagentDrawableType(pDrawable), (void *) pDrawable);
+    #endif
+
+    nxagentSynchronizeRegion(pDrawable, pRegion, breakMask, NULL);
+
+    nxagentFreeRegion(pDrawable, pRegion);
+  }
+}
+
+void nxagentSynchronizeDrawablePredicate(void *p0, XID x1, void *p2)
+{
+  DrawablePtr pDrawable = (DrawablePtr) p0;
+  unsigned int *breakMask = (unsigned int *) p2;
+
+  int shouldClearHiddenRegion = 1;
+
+  /*
+   * The nxagentSynchronization.abort propa-
+   * gates a break condition across the resour-
+   * ces loop, in order to block also the sub-
+   * sequent synchronizations.
+   */
+
+  if (nxagentSynchronization.abort == 1 ||
+          nxagentDrawableStatus(pDrawable) == Synchronized)
+  {
+    return;
+  }
+
+  /*
+   * In order to implement a kind of round-robin
+   * synchronization, the previous incomplete
+   * drawable synchronization is saved to jump
+   * to the next resource available of same type.
+   */
+
+  if (nxagentSynchronization.pDrawable != NULL &&
+          pDrawable -> type == nxagentSynchronization.drawableType)
+  {
+    if (nxagentSynchronization.pDrawable != pDrawable)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentSynchronizeDrawablePredicate: Skipping drawable [%s][%p] while looking "
+                  "for last synchronized drawable [%p].\n", nxagentDrawableType(pDrawable),
+                      (void *) pDrawable, (void *) nxagentSynchronization.pDrawable);
+      #endif
+
+      return;
+    }
+    else
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentSynchronizeDrawablePredicate: Last synchronized drawable [%p] found. "
+                  "Skipping to the next resource.\n", (void *) nxagentSynchronization.pDrawable);
+      #endif
+
+      nxagentSynchronization.pDrawable = NULL;
+
+      return;
+    }
+  }
+
+  if (pDrawable -> type == DRAWABLE_PIXMAP)
+  {
+    /*
+     * The pixmaps to be synchronized are those
+     * used as background or used as source of
+     * any deferred operations for at least 2
+     * times.
+     */
+
+    if (NXAGENT_SHOULD_SYNCHRONIZE_PIXMAP(pDrawable) == 0)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentSynchronizeDrawablePredicate: Skipping pixmap at [%p] "
+                  "with usage [%d] background [%d].\n", (void *) pDrawable,
+                      nxagentPixmapUsageCounter((PixmapPtr) pDrawable),
+                          nxagentIsCorruptedBackground((PixmapPtr) pDrawable));
+      #endif
+
+      return;
+    }
+    #ifdef TEST
+    else
+    {
+      fprintf(stderr, "nxagentSynchronizeDrawablePredicate: Synchronizing pixmap at [%p] "
+                  "with usage [%d] background [%d].\n", (void *) pDrawable,
+                      nxagentPixmapUsageCounter((PixmapPtr) pDrawable),
+                          nxagentIsCorruptedBackground((PixmapPtr) pDrawable));
+    }
+    #endif
+  }
+  else if (NXAGENT_SHOULD_SYNCHRONIZE_WINDOW(pDrawable) == 0)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentSynchronizeDrawablePredicate: Skipping not visible window at [%p].\n",
+                (void *) pDrawable);
+    #endif
+
+    if (shouldClearHiddenRegion == 1)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentSynchronizeDrawablePredicate: Clearing out the not visible window "
+                  "at [%p].\n", (void *) pDrawable);
+      #endif
+
+      nxagentCleanCorruptedDrawable(pDrawable);
+    }
+
+    return;
+  }
+
+  /*
+   * Postpone the synchronization if we went
+   * out of bandwidth or if the display blocks.
+   * The pixmap synchronization is more careful
+   * with bandwidth usage.
+   */
+
+/*
+FIXME: This condition sounds only as a
+       complication, as the break parameters
+       are already checked while synchroni-
+       zing the drawable.
+
+  if (breakOnCongestion(*breakMask) == 1 ||
+          (pDrawable -> type == DRAWABLE_PIXMAP &&
+               *breakMask != NEVER_BREAK && nxagentCongestion > 0))
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentSynchronizeDrawablePredicate: WARNING! Breaking the "
+                "synchronization with congestion [%d] blocking [%d].\n",
+                    nxagentCongestion, nxagentBlocking);
+    #endif
+
+    nxagentSynchronization.abort = 1;
+
+    return;
+  }
+*/
+
+  #ifdef TEST
+  fprintf(stderr, "nxagentSynchronizeDrawablePredicate: Synchronizing drawable [%s][%p] "
+              "with geometry (%dx%d).\n", nxagentDrawableType(pDrawable),
+                  (void *) pDrawable, pDrawable -> width, pDrawable -> height);
+
+  fprintf(stderr, "nxagentSynchronizeDrawablePredicate: Corrupted extents [%d,%d,%d,%d] "
+              "with [%ld] rects.\n", nxagentCorruptedRegion(pDrawable) -> extents.x1,
+                  nxagentCorruptedRegion(pDrawable) -> extents.y1, nxagentCorruptedRegion(pDrawable) ->
+                      extents.x2, nxagentCorruptedRegion(pDrawable) -> extents.y2,
+                          REGION_NUM_RECTS(nxagentCorruptedRegion(pDrawable)));
+  #endif
+
+  /*
+   * The stored bitmap is destroyed inside
+   * the synchronization loop, so we have
+   * to check here its presence to know if
+   * we can clear the dirty windows.
+   */
+
+  shouldClearHiddenRegion = (nxagentDrawableBitmap(pDrawable) == NullPixmap);
+
+  nxagentSynchronizeDrawable(pDrawable, DONT_WAIT, *breakMask, NULL);
+
+  if (nxagentDrawableStatus(pDrawable) == NotSynchronized)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentSynchronizeDrawablePredicate: Drawable [%s][%p] not fully synchronized.\n",
+                nxagentDrawableType(pDrawable), (void *) pDrawable);
+    #endif
+
+    /*
+     * If the remaining corrupted region is on
+     * an hidden section (not viewable or outside
+     * of the pixmap's area) of a drawable,
+     * we can clear it.
+     */
+
+    if (nxagentSynchronization.abort == 0 &&
+            shouldClearHiddenRegion == 1)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentSynchronizeDrawablePredicate: Clearing out the remaining corrupted "
+                  "[%s] at [%p].\n", nxagentDrawableType(pDrawable), (void *) pDrawable);
+      #endif
+
+      nxagentCleanCorruptedDrawable(pDrawable);
+    }
+  }
+}
+
+void nxagentSynchronizationLoop(unsigned int mask)
+{
+  unsigned int breakMask;
+
+  int doRoundRobin;
+
+/*
+FIXME: All drawables should be set as synchronized and
+       never marked as corrupted while the display is
+       down.
+*/
+  if (NXDisplayError(nxagentDisplay) == 1)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentSynchronizationLoop: WARNING! Not synchronizing the drawables "
+                "with the display down.\n");
+    #endif
+
+    return;
+  }
+
+  #ifdef TEST
+  fprintf(stderr, "nxagentSynchronizationLoop: Synchronizing [%d] windows [%d] pixmaps "
+              "and [%d] backgrounds with mask [%u].\n", nxagentCorruptedWindows, nxagentCorruptedPixmaps,
+                  nxagentCorruptedBackgrounds, mask);
+
+  fprintf(stderr, "nxagentSynchronizationLoop: Stored bitmaps [%d] windows [%d] pixmaps "
+              "and [%d] backgrounds.\n", nxagentSynchronization.windowBitmaps,
+                  nxagentSynchronization.pixmapBitmaps, nxagentSynchronization.backgroundBitmaps);
+
+  fprintf(stderr, "nxagentSynchronizationLoop: Starting loops with congestion [%d] "
+              "blocking [%d].\n", nxagentCongestion, nxagentBlocking);
+  #endif
+
+  breakMask = mask;
+
+  /*
+   * The resource counter can be reset if we
+   * have not aborted the synchronization loop,
+   * if we are not skipping resources to do
+   * round-robin and if the bitmaps are all
+   * synchronized.
+   */
+
+  doRoundRobin = (nxagentSynchronization.pDrawable != NULL);
+
+  nxagentSynchronization.abort = 0;
+
+  /*
+   * Synchronize the windows.
+   */
+
+  if (NXAGENT_SHOULD_SYNCHRONIZE_CORRUPTED_WINDOWS(mask))
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentSynchronizationLoop: Going to loop through corrupted window resources.\n");
+    #endif
+
+    FindClientResourcesByType(clients[serverClient -> index], RT_NX_CORR_WINDOW,
+                                  nxagentSynchronizeDrawablePredicate, &breakMask);
+
+    #ifdef TEST
+
+    if (nxagentSynchronization.abort == 0 &&
+            nxagentSynchronization.windowBitmaps == 0 &&
+                doRoundRobin == 0)
+    {
+      if (nxagentCorruptedWindows > 0)
+      {
+        fprintf(stderr, "nxagentSynchronizationLoop: Closing the loop with [%d] "
+                    "corrupted windows.\n", nxagentCorruptedWindows);
+      }
+
+      nxagentCorruptedWindows = 0;
+    }
+
+    #endif
+  }
+
+  /*
+   * Synchronize the backgrounds.
+   */
+
+  if (nxagentSynchronization.abort == 0 &&
+          NXAGENT_SHOULD_SYNCHRONIZE_CORRUPTED_BACKGROUNDS(mask))
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentSynchronizationLoop: Going to loop through corrupted background resources.\n");
+    #endif
+
+    FindClientResourcesByType(clients[serverClient -> index], RT_NX_CORR_BACKGROUND,
+                                  nxagentSynchronizeDrawablePredicate, &breakMask);
+
+    #ifdef TEST
+
+    if (nxagentSynchronization.abort == 0 &&
+            nxagentSynchronization.backgroundBitmaps == 0 &&
+                doRoundRobin == 0)
+    {
+      if (nxagentCorruptedBackgrounds > 0)
+      {
+        fprintf(stderr, "nxagentSynchronizationLoop: Closing the loop with [%d] "
+                    "corrupted backgrounds.\n", nxagentCorruptedBackgrounds);
+      }
+
+      nxagentCorruptedBackgrounds = 0;
+    }
+
+    #endif
+  }
+
+  /*
+   * If there is bandwidth remaining, synchronize
+   * the pixmaps. Synchronizing a pixmap doesn't
+   * produce any visible results. Better is to
+   * synchronize them on demand, before using the
+   * pixmap in a copy or in a composite operation.
+   */
+
+  if (nxagentSynchronization.abort == 0 &&
+          NXAGENT_SHOULD_SYNCHRONIZE_CORRUPTED_PIXMAPS(mask))
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentSynchronizationLoop: Going to loop through corrupted pixmap resources.\n");
+    #endif
+
+    FindClientResourcesByType(clients[serverClient -> index], RT_NX_CORR_PIXMAP,
+                                  nxagentSynchronizeDrawablePredicate, &breakMask);
+
+
+    if (nxagentSynchronization.abort == 0 &&
+            nxagentSynchronization.pixmapBitmaps == 0 &&
+                doRoundRobin == 0)
+    {
+      #ifdef TEST
+
+      if (nxagentCorruptedPixmaps > 0)
+      {
+        fprintf(stderr, "nxagentSynchronizationLoop: Closing the loop with [%d] "
+                    "corrupted pixmaps.\n", nxagentCorruptedPixmaps);
+      }
+
+      #endif
+
+      nxagentCorruptedPixmaps = 0;
+    }
+
+  }
+
+  /*
+   * If the last synchronized drawable has been
+   * removed, we have to reset the variable sto-
+   * ring its pointer.
+   */
+
+  if (nxagentSynchronization.pDrawable != NULL &&
+          nxagentFindClientResource(serverClient -> index, RT_NX_CORR_WINDOW,
+              nxagentSynchronization.pDrawable) == 0 &&
+                  nxagentFindClientResource(serverClient -> index, RT_NX_CORR_BACKGROUND,
+                      nxagentSynchronization.pDrawable) == 0 &&
+                          nxagentFindClientResource(serverClient -> index, RT_NX_CORR_PIXMAP,
+                              nxagentSynchronization.pDrawable) == 0)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentSynchronizationLoop: Synchronization drawable [%p] removed from resources.\n",
+                (void *) nxagentSynchronization.pDrawable);
+    #endif
+
+    nxagentSynchronization.pDrawable = NULL;
+  }
+
+  #ifdef TEST
+  fprintf(stderr, "nxagentSynchronizationLoop: Closing loops with congestion [%d] "
+              "blocking [%d].\n", nxagentCongestion, nxagentBlocking);
+
+  fprintf(stderr, "nxagentSynchronizationLoop: There are now [%d] windows [%d] pixmaps "
+              "and [%d] backgrounds to synchronize.\n", nxagentCorruptedWindows,
+                  nxagentCorruptedPixmaps, nxagentCorruptedBackgrounds);
+  #endif
+}
+
+RegionPtr nxagentCreateRegion(DrawablePtr pDrawable, GCPtr pGC, int x, int y,
+                                  int width, int height)
+{
+  RegionPtr pRegion;
+  BoxRec box;
+
+  box.x1 = x;
+  box.y1 = y;
+  box.x2 = x + width;
+  box.y2 = y + height;
+
+  pRegion = REGION_CREATE(pDrawable -> pScreen, &box, 1);
+
+  /*
+   * Clipping the region.
+   */
+
+  if (pDrawable -> type == DRAWABLE_PIXMAP)
+  {
+    BoxRec tmpBox;
+    RegionRec tmpRegion;
+
+    /*
+     * The region created doesn't need to be clipped
+     * if it has the pixmap dimensions.
+     */
+
+    if (x != 0 || y != 0 ||
+            width != pDrawable -> width ||
+                height != pDrawable -> height)
+    {
+      tmpBox.x1 = 0;
+      tmpBox.y1 = 0;
+      tmpBox.x2 = pDrawable -> width;
+      tmpBox.y2 = pDrawable -> height;
+
+      REGION_INIT(pDrawable -> pScreen, &tmpRegion, &tmpBox, 1);
+
+      REGION_INTERSECT(pDrawable -> pScreen, pRegion, &tmpRegion, pRegion);
+
+      REGION_UNINIT(pDrawable -> pScreen, &tmpRegion);
+    }
+  }
+  else
+  {
+    /*
+     * We use the clipList because the borderClip
+     * contains also parts of the window covered
+     * by its children.
+     */
+
+    REGION_TRANSLATE(pDrawable -> pScreen, pRegion,
+                         pDrawable -> x, pDrawable -> y);
+
+    if (nxagentWindowPriv((WindowPtr) pDrawable) -> hasTransparentChildren == 1)
+    {
+      REGION_INTERSECT(pDrawable -> pScreen, pRegion, pRegion, &((WindowPtr) pDrawable) -> borderClip);
+    }
+    else
+    {
+      REGION_INTERSECT(pDrawable -> pScreen, pRegion, pRegion, &((WindowPtr) pDrawable) -> clipList);
+    }
+
+    REGION_TRANSLATE(pDrawable -> pScreen, pRegion,
+                         -pDrawable -> x, -pDrawable -> y);
+  }
+
+  #ifdef TEST
+  fprintf(stderr, "nxagentCreateRegion: New region created with coordinates [%d,%d,%d,%d].\n",
+              pRegion -> extents.x1, pRegion -> extents.y1,
+                  pRegion -> extents.x2, pRegion -> extents.y2);
+  #endif
+
+  /*
+   * If the pRegion is NIL we don't need
+   * to intersect it with the GC's clipmask.
+   */
+
+  if (REGION_NIL(pRegion) == 0 &&
+          pGC != NULL && pGC -> clientClip != NULL &&
+              pGC -> clientClipType == CT_REGION)
+  {
+    RegionRec clipRegion;
+
+    REGION_INIT(pDrawable -> pScreen, &clipRegion, NullBox, 1);
+
+    REGION_COPY(pDrawable -> pScreen, &clipRegion, (RegionPtr) pGC -> clientClip);
+
+    /*
+     * The clip origin is relative to the origin of
+     * the destination drawable. The clip mask coor-
+     * dinates are relative to the clip origin.
+     */
+
+    if (pGC -> clipOrg.x != 0 || pGC -> clipOrg.y != 0)
+    {
+      REGION_TRANSLATE(pDrawable -> pScreen, &clipRegion, pGC -> clipOrg.x, pGC -> clipOrg.y);
+    }
+
+    #ifdef TEST
+    fprintf(stderr, "nxagentCreateRegion: Clipping region to the clip mask with coordinates [%d,%d,%d,%d].\n",
+                clipRegion.extents.x1, clipRegion.extents.y1,
+                    clipRegion.extents.x2, clipRegion.extents.y2);
+    #endif
+
+    REGION_INTERSECT(pDrawable -> pScreen, pRegion, pRegion, &clipRegion);
+
+    REGION_UNINIT(pDrawable -> pScreen, &clipRegion);
+  }
+
+  return pRegion;
+}
+
+void nxagentMarkCorruptedRegion(DrawablePtr pDrawable, RegionPtr pRegion)
+{
+  int x;
+  int y;
+  int width;
+  int height;
+
+  if (pRegion != NullRegion && REGION_NIL(pRegion) == 1)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentMarkCorruptedRegion: Region [%d,%d,%d,%d] is nil. Skipping operation.\n",
+                pRegion -> extents.x1, pRegion -> extents.y1, pRegion -> extents.x2, pRegion -> extents.y2);
+    #endif
+
+    return;
+  }
+
+  /*
+   * If the drawable was synchronized, the counter
+   * reporting the number of corrupted drawables
+   * must be increased. Moreover the corrupted ti-
+   * mestamp must be set.
+   */
+
+  if (nxagentDrawableStatus(pDrawable) == Synchronized)
+  {
+    if (pDrawable -> type == DRAWABLE_WINDOW)
+    {
+      nxagentAllocateCorruptedResource(pDrawable, RT_NX_CORR_WINDOW);
+    }
+
+    nxagentSetCorruptedTimestamp(pDrawable);
+  }
+
+  if (pRegion == NullRegion)
+  {
+    x = 0;
+    y = 0;
+
+    width  = pDrawable -> width;
+    height = pDrawable -> height;
+
+    #ifdef TEST
+    fprintf(stderr, "nxagentMarkCorruptedRegion: Fully invalidating %s [%p] with "
+                "coordinates [%d,%d][%d,%d].\n", nxagentDrawableType(pDrawable),
+                    (void *) pDrawable, x, y, width, height);
+    #endif
+
+    pRegion = nxagentCreateRegion(pDrawable, NULL, x, y, width, height);
+
+    nxagentValidateSplit(pDrawable, pRegion);
+
+    REGION_UNION(pDrawable -> pScreen, nxagentCorruptedRegion(pDrawable),
+                     nxagentCorruptedRegion(pDrawable), pRegion);
+
+    nxagentFreeRegion(pDrawable, pRegion);
+  }
+  else
+  {
+    #ifdef TEST
+
+    x = pRegion -> extents.x1;
+    y = pRegion -> extents.y1;
+
+    width = pRegion -> extents.x2 - pRegion -> extents.x1;
+    height = pRegion -> extents.y2 - pRegion -> extents.y1;
+
+    fprintf(stderr, "nxagentMarkCorruptedRegion: Partly invalidating %s [%p] with "
+                "coordinates [%d,%d][%d,%d].\n", nxagentDrawableType(pDrawable),
+                    (void *) pDrawable, x, y, width, height);
+
+    #endif
+
+    nxagentValidateSplit(pDrawable, pRegion);
+
+    REGION_UNION(pDrawable -> pScreen, nxagentCorruptedRegion(pDrawable),
+                     nxagentCorruptedRegion(pDrawable), pRegion);
+  }
+}
+
+void nxagentUnmarkCorruptedRegion(DrawablePtr pDrawable, RegionPtr pRegion)
+{
+  int oldStatus;
+
+  if (pRegion != NullRegion && REGION_NIL(pRegion) == 1)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentUnmarkCorruptedRegion: Region [%d,%d,%d,%d] is nil. Skipping operation.\n",
+                pRegion -> extents.x1, pRegion -> extents.y1, pRegion -> extents.x2, pRegion -> extents.y2);
+    #endif
+
+    return;
+  }
+
+  oldStatus = nxagentDrawableStatus(pDrawable);
+
+  if (oldStatus == Synchronized)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentUnmarkCorruptedRegion: Drawable %s [%p] already synchronized.\n",
+                nxagentDrawableType(pDrawable), (void *) pDrawable);
+    #endif
+
+    return;
+  }
+
+  if (pRegion == NullRegion)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentUnmarkCorruptedRegion: Fully validating %s [%p].\n",
+                nxagentDrawableType(pDrawable), (void *) pDrawable);
+    #endif
+
+    nxagentValidateSplit(pDrawable, NULL);
+
+    REGION_EMPTY(pDrawable -> pScreen, nxagentCorruptedRegion(pDrawable));
+  }
+  else
+  {
+    #ifdef TEST
+
+    fprintf(stderr, "nxagentUnmarkCorruptedRegion: Validating %s [%p] with region [%d,%d,%d,%d].\n",
+                nxagentDrawableType(pDrawable), (void *) pDrawable,
+                    pRegion -> extents.x1, pRegion -> extents.y1, pRegion -> extents.x2, pRegion -> extents.y2);
+
+    #endif
+
+    nxagentValidateSplit(pDrawable, pRegion);
+
+    REGION_SUBTRACT(pDrawable -> pScreen, nxagentCorruptedRegion(pDrawable),
+                        nxagentCorruptedRegion(pDrawable), pRegion);
+  }
+
+  /*
+   * If the drawable becomes synchronized, the
+   * counter reporting the number of corrupted
+   * drawables must be decreased. Moreover the
+   * corrupted timestamp must be reset.
+   */
+
+  if (oldStatus == NotSynchronized &&
+          nxagentDrawableStatus(pDrawable) == Synchronized)
+  {
+    if (pDrawable -> type == DRAWABLE_PIXMAP)
+    {
+      nxagentDestroyCorruptedResource(pDrawable, RT_NX_CORR_BACKGROUND);
+
+      nxagentDestroyCorruptedResource(pDrawable, RT_NX_CORR_PIXMAP);
+
+      nxagentPixmapPriv(nxagentRealPixmap((PixmapPtr) pDrawable)) -> containTrapezoids = 0;
+    }
+    else
+    {
+      nxagentDestroyCorruptedResource(pDrawable, RT_NX_CORR_WINDOW);
+    }
+
+    nxagentResetCorruptedTimestamp(pDrawable);
+
+    /*
+     * If the resource is no longer dirty,
+     * the associated bitmap is destroyed.
+     */
+
+    if (nxagentDrawableBitmap(pDrawable) != NullPixmap)
+    {
+       nxagentDestroyDrawableBitmap(pDrawable);
+    }
+  }
+}
+
+void nxagentMoveCorruptedRegion(WindowPtr pWin, unsigned int mask)
+{
+  /*
+   * If a window is resized, its corrupted
+   * region is moved according to the bit
+   * gravity.
+   */
+
+  if (nxagentDrawableStatus((DrawablePtr) pWin) == NotSynchronized)
+  {
+    if (((mask & CWHeight) && nxagentWindowPriv(pWin) -> height != pWin -> drawable.height) ||
+            ((mask & CWWidth) && nxagentWindowPriv(pWin) -> width != pWin -> drawable.width))
+    {
+      int nx, ny;
+
+      GravityTranslate(0, 0,
+                       nxagentWindowPriv(pWin) -> x - pWin -> origin.x + wBorderWidth(pWin),
+                       nxagentWindowPriv(pWin) -> y - pWin -> origin.y + wBorderWidth(pWin),
+                       pWin -> drawable.width - nxagentWindowPriv(pWin) -> width,
+                       pWin -> drawable.height - nxagentWindowPriv(pWin) -> height,
+                       pWin -> bitGravity, &nx, &ny);
+
+      #ifdef TEST
+      fprintf(stderr, "nxagentMoveCorruptedRegion: Moving the corrupted region to [%d,%d] for window [%p].\n",
+                  nx, ny, (void *) pWin);
+      #endif
+
+      REGION_TRANSLATE(pWin -> pScreen, nxagentCorruptedRegion((DrawablePtr) pWin),
+                           nx, ny);
+
+      /*
+       * Having moved the corrupted region, we
+       * need to invalidate the pending commits
+       * or otherwise the image will fall in
+       * the wrong area.
+       */
+
+      nxagentValidateSplit((DrawablePtr) pWin, NULL);
+
+
+      /*
+       * The window reconfiguration invalidates
+       * the synchronization bitmap.
+       */
+
+      nxagentDestroyDrawableBitmap((DrawablePtr) pWin);
+    }
+  }
+}
+
+/*
+ * The DDX layer uses an 'Y-X banding' representation of
+ * regions: it sorts all rectangles composing a region
+ * using first the y-dimension, than the x-dimension; mo-
+ * reover it organizes the rectangles in 'bands' sharing
+ * the same y-dimension. This representation does not mi-
+ * nimize the number of rectangles. For example, the fol-
+ * lowing region has 4 rectangles:
+ *
+ *    +-----------+
+ *    |           |   +---+
+ *    |     A     |   | B |
+ *    |           |   +---+
+ *    +-----------+
+ *
+ * The rectangle 'B' creates a band which splits the rec-
+ * tangle A in 3 parts, for a total of 3 bands. The num-
+ * ber of rectangles composing the region is 4.
+ *
+ * This kind of representation is not advisable for the
+ * lazy synchronization because, in the example above,
+ * the nxagent had to send 4 put images instead of 2.
+ *
+ * To minimize the problem we use the following function:
+ * by traversing the list of rectangles we merge all bo-
+ * xes with same x coordinates and coincident y, in order
+ * to create an X-Y banding.
+ *
+ * Be careful: all the coordinates of boxes merged are
+ * set to 0, so take care of this when looping through
+ * the box list returned by this function.
+ */
+
+BoxPtr nxagentGetOptimizedRegionBoxes(RegionPtr pRegion)
+{
+  BoxPtr pBox;
+
+  BoxRec boxExtents;
+
+  int nBox;
+  int i, j;
+
+  #ifdef DEBUG
+  int nBoxOptim;
+  #endif
+
+  pBox = REGION_RECTS(pRegion);
+
+  nBox = REGION_NUM_RECTS(pRegion);
+
+  #ifdef TEST
+  fprintf(stderr, "nxagentGetOptimizedRegionBoxes: Going to optimize region at [%p] with [%d] rects.\n",
+              (void *) pRegion, nBox);
+  #endif
+
+  if (nBox <= 1)
+  {
+    return pBox;
+  }
+
+  #ifdef DEBUG
+  nBoxOptim = nBox;
+  #endif
+
+  /*
+   * The boxes are now grouped to grown as much
+   * as possible, using their overlapping vertex
+   * as rule.
+   */
+
+  for (i = 0; i < nBox; i++)
+  {
+    /*
+     * If the coordinates are (0,0) the box
+     * has been already merged, so we can skip
+     * it.
+     */
+
+    if (pBox[i].x1 == 0 && pBox[i].y1 == 0 &&
+            pBox[i].x2 == 0 && pBox[i].y2 == 0)
+    {
+      continue;
+    }
+
+    #ifdef DEBUG
+    fprintf(stderr, "nxagentGetOptimizedRegionBoxes: Referential box [%d] has coordinates [%d,%d,%d,%d].\n",
+                i, pBox[i].x1, pBox[i].y1, pBox[i].x2, pBox[i].y2);
+    #endif
+
+    #ifdef ADVANCED_BOXES_DEFRAG
+
+    boxExtents.x1 = pBox[i].x1;
+    boxExtents.y1 = pBox[i].y1;
+    boxExtents.x2 = pBox[i].x2;
+
+    #endif
+
+    boxExtents.y2 = pBox[i].y2;
+
+    for (j = i+1; j < nBox; j++)
+    {
+      if (pBox[j].x1 == 0 && pBox[j].y1 == 0 &&
+              pBox[j].x2 == 0 && pBox[j].y2 == 0)
+      {
+        continue;
+      }
+
+      #ifdef DEBUG
+      fprintf(stderr, "nxagentGetOptimizedRegionBoxes: Mergeable box [%d] has coordinates [%d,%d,%d,%d].\n",
+                  j, pBox[j].x1, pBox[j].y1, pBox[j].x2, pBox[j].y2);
+      #endif
+
+      /*
+       * Each consequent box is merged if its
+       * higher side overlaps the lower side
+       * of current box.
+       * In case of ADVANCED_BOXES_DEFRAG the higher
+       * side must be included within a range
+       * defined by INCLUDE_MARGIN.
+       */
+
+      #ifndef ADVANCED_BOXES_DEFRAG
+
+      if (pBox[j].y1 == boxExtents.y2 &&
+          pBox[j].x1 == pBox[i].x1 &&
+          pBox[j].x2 == pBox[i].x2)
+
+      #else
+
+      if (pBox[j].x1 > boxExtents.x1 - INCLUDE_MARGIN &&
+          pBox[j].x1 < boxExtents.x1 + INCLUDE_MARGIN &&
+          pBox[j].y1 > boxExtents.y2 - INCLUDE_MARGIN &&
+          pBox[j].y1 < boxExtents.y2 + INCLUDE_MARGIN &&
+          pBox[j].x2 > boxExtents.x2 - INCLUDE_MARGIN &&
+          pBox[j].x2 < boxExtents.x2 + INCLUDE_MARGIN)
+
+      #endif
+      {
+        #ifdef DEBUG
+        fprintf(stderr, "nxagentGetOptimizedRegionBoxes: Going to merge box at [%d] with box at [%d].\n",
+                    j, i);
+        #endif
+
+        #ifdef ADVANCED_BOXES_DEFRAG
+
+        if (pBox[j].x1 < boxExtents.x1)
+        {
+          boxExtents.x1 = pBox[j].x1;
+        }
+
+        if (pBox[j].x2 > boxExtents.x2)
+        {
+          boxExtents.x2 = pBox[j].x2;
+        }
+
+        if (pBox[j].y1 < boxExtents.y1)
+        {
+          boxExtents.y1 = pBox[j].y1;
+        }
+
+        #endif
+
+        if (pBox[j].y2 > boxExtents.y2)
+        {
+          boxExtents.y2 = pBox[j].y2;
+        }
+
+        /*
+         * By appending a box to another, we have
+         * to remove it from the box list. We do
+         * this by setting its coordinates to (0,0)
+         * and by checking their value in the main
+         * loop.
+         */
+
+        pBox[j].x1 = pBox[j].y1 = pBox[j].x2 = pBox[j].y2 = 0;
+
+        #ifdef DEBUG
+        nBoxOptim--;
+        #endif
+      }
+    }
+
+    /*
+     * Extend the box height.
+     */
+
+    #ifdef ADVANCED_BOXES_DEFRAG
+
+    pBox[i].x1 = boxExtents.x1;
+    pBox[i].y1 = boxExtents.y1;
+    pBox[i].x2 = boxExtents.x2;
+
+    #endif
+
+    pBox[i].y2 = boxExtents.y2;
+  }
+
+  #ifdef ADVANCED_BOXES_DEFRAG
+
+  /*
+   * The new list need to be validated to
+   * avoid boxes overlapping. This code may
+   * be improved to remove also the partial-
+   * ly overlapping boxes.
+   */
+
+  for (i = 0; i < nBox; i++)
+  {
+    if (pBox[i].x1 == 0 && pBox[i].y1 == 0 &&
+            pBox[i].x2 == 0 && pBox[i].y2 == 0)
+    {
+      continue;
+    }
+
+    #ifdef DEBUG
+    fprintf(stderr, "nxagentGetOptimizedRegionBoxes: Referential box [%d] has coordinates [%d,%d,%d,%d].\n",
+                i, pBox[i].x1, pBox[i].y1, pBox[i].x2, pBox[i].y2);
+    #endif
+
+    boxExtents.x1 = pBox[i].x1;
+    boxExtents.y1 = pBox[i].y1;
+    boxExtents.x2 = pBox[i].x2;
+    boxExtents.y2 = pBox[i].y2;
+
+    for (j = i+1; j < nBox; j++)
+    {
+      if (pBox[j].x1 == 0 && pBox[j].y1 == 0 &&
+              pBox[j].x2 == 0 && pBox[j].y2 == 0)
+      {
+        continue;
+      }
+
+      #ifdef DEBUG
+      fprintf(stderr, "nxagentGetOptimizedRegionBoxes: Mergeable box [%d] has coordinates [%d,%d,%d,%d].\n",
+                  j, pBox[j].x1, pBox[j].y1, pBox[j].x2, pBox[j].y2);
+      #endif
+
+      if ((boxExtents.x1 <= pBox[j].x1 &&
+           boxExtents.x2 >= pBox[j].x2 &&
+           boxExtents.y1 <= pBox[j].y1 &&
+           boxExtents.y2 >= pBox[j].y2))
+      {
+        /*
+         * If a box is completely inside
+         * another, we set its coordinates
+         * to 0 to consider it as merged.
+         */
+
+        #ifdef DEBUG
+        fprintf(stderr, "nxagentGetOptimizedRegionBoxes: Going to merge box [%d,%d,%d,%d] "
+                    "with its box container [%d,%d,%d,%d].\n", pBox[j].x1, pBox[j].y1,
+                        pBox[j].x2, pBox[j].y2, boxExtents.x1, boxExtents.y1, boxExtents.y1,
+                            boxExtents.y2);
+        #endif
+
+        pBox[j].x1 = pBox[j].y1 = pBox[j].x2 = pBox[j].y2 = 0;
+
+        #ifdef DEBUG
+        nBoxOptim--;
+        #endif
+      }
+    }
+  }
+
+  #endif
+
+  #ifdef DEBUG
+  fprintf(stderr, "nxagentGetOptimizedRegionBoxes: Original boxes number [%d] Optimized boxes number [%d].\n",
+              nBox, nBoxOptim);
+  #endif
+
+  return pBox;
+}
+
+unsigned long nxagentGetColor(DrawablePtr pDrawable, int xPixel, int yPixel)
+{
+  XImage *ximage;
+  Visual *pVisual;
+  char *data;
+
+  int depth, format, length;
+  int leftPad = 0;
+  unsigned long pixel;
+
+  depth = pDrawable -> depth;
+  format = (depth == 1) ? XYPixmap : ZPixmap;
+  length = nxagentImageLength(1, 1, format, leftPad, depth);
+
+  if ((data = xalloc(length)) == NULL)
+  {
+    #ifdef WARNING
+    fprintf(stderr, "nxagentGetColor: WARNING! Failed to allocate memory for the operation.\n");
+    #endif
+
+    return -1;
+  }
+
+  pVisual = nxagentImageVisual(pDrawable, depth);
+
+  if (pVisual == NULL)
+  {
+    #ifdef WARNING
+    fprintf(stderr, "nxagentGetColor: WARNING! Visual not found. Using default visual.\n");
+    #endif
+
+    pVisual = nxagentVisuals[nxagentDefaultVisualIndex].visual;
+  }
+
+  fbGetImage(pDrawable, xPixel, yPixel, 1, 1, format, AllPlanes, data);
+
+  ximage = XCreateImage(nxagentDisplay, pVisual, depth, format, leftPad, (char *) data,
+                            1, 1, BitmapPad(nxagentDisplay),
+                                nxagentImagePad(1, format, leftPad, 1));
+
+  if (ximage == NULL)
+  {
+    #ifdef WARNING
+    fprintf(stderr, "nxagentGetColor: WARNING! Failed to create the XImage.\n");
+    #endif
+
+    xfree(data);
+
+    return -1;
+  }
+
+  pixel = XGetPixel(ximage, 0, 0);
+
+  XDestroyImage(ximage);
+
+  return pixel;
+}
+
+/*
+ * This function could be used to determine
+ * the ClearArea color of corrupted regions
+ * on screen.
+ */
+
+unsigned long nxagentGetRegionColor(DrawablePtr pDrawable, RegionPtr pRegion)
+{
+  int xPicker, yPicker;
+
+  if (REGION_NIL(pRegion) == 1)
+  {
+    return nxagentGetDrawableColor(pDrawable);
+  }
+
+  /*
+   * The pixel used as reference is the first
+   * outer pixel at the bottom right corner
+   * of corrupted region extents.
+   */
+
+  xPicker = pRegion -> extents.x2 + 1;
+
+  if (xPicker > pDrawable -> width)
+  {
+    xPicker = pDrawable -> width;
+  }
+
+  yPicker = pRegion -> extents.y2 + 1;
+
+  if (yPicker > pDrawable -> height)
+  {
+    yPicker = pDrawable -> height;
+  }
+
+  return nxagentGetColor(pDrawable, xPicker, yPicker);
+}
+
+unsigned long nxagentGetDrawableColor(DrawablePtr pDrawable)
+{
+  int xPicker, yPicker;
+
+  /*
+   * The pixel used to determine the co-
+   * lor of a drawable is at coordinates
+   * (x + width - 4, y + 4).
+   */
+
+  xPicker = pDrawable -> width - 4;
+
+  yPicker = 4;
+
+  return nxagentGetColor(pDrawable, xPicker, yPicker);
+}
+
+void nxagentClearRegion(DrawablePtr pDrawable, RegionPtr pRegion)
+{
+  WindowPtr pWin;
+  BoxPtr pBox;
+
+  unsigned long color;
+  unsigned long backupPixel = 0;
+  int nBox, i;
+  int restore;
+
+  #ifdef DEBUG
+  static int nBoxCleared;
+  #endif
+
+  if (pDrawable -> type != DRAWABLE_WINDOW)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentClearRegion: Cannot clear a pixmap. Exiting.\n");
+    #endif
+
+    return;
+  }
+
+  if (pRegion == NullRegion || REGION_NIL(pRegion) == 1)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentClearRegion: The region is empty. Exiting.\n");
+    #endif
+
+    return;
+  }
+
+  pWin = (WindowPtr) pDrawable;
+
+  restore = 0;
+
+  /*
+   * If the window has already a background, we
+   * can hope it will be nice.
+   */
+
+  if (pWin -> backgroundState != None)
+  {
+    #ifdef DEBUG
+    fprintf(stderr, "nxagentClearRegion: Window at [%p] has background state [%u].\n",
+                (void *) pWin, pWin -> backgroundState);
+    #endif
+  }
+  else
+  {
+    /*
+     * Save the original state.
+     */
+
+    backupPixel = pWin -> background.pixel;
+
+    color = nxagentGetDrawableColor((DrawablePtr) pWin);
+
+    if (color == -1)
+    {
+      color = 0xffffff;
+    }
+
+    pWin -> backgroundState = BackgroundPixel;
+    pWin -> background.pixel = color;
+
+    nxagentChangeWindowAttributes(pWin, CWBackPixel);
+
+    #ifdef DEBUG
+    fprintf(stderr, "nxagentClearRegion: Window at [%p] now has pixel background [%ld].\n",
+                (void *) pWin, color);
+    #endif
+
+    restore = 1;
+  }
+
+  pBox = nxagentGetOptimizedRegionBoxes(pRegion);
+
+  nBox = REGION_NUM_RECTS(pRegion);
+
+  for (i = 0; i < nBox; i++)
+  {
+    if (pBox[i].x1 == 0 && pBox[i].y1 == 0 &&
+            pBox[i].x2 == 0 && pBox[i].y2 == 0)
+    {
+      continue;
+    }
+
+    XClearArea(nxagentDisplay, nxagentWindow(pWin), pBox[i].x1, pBox[i].y1,
+                   pBox[i].x2 - pBox[i].x1, pBox[i].y2 - pBox[i].y1, False);
+
+    #ifdef DEBUG
+    nBoxCleared++;
+    #endif
+  }
+
+  /*
+   * Restore the old state.
+   */
+
+  if (restore == 1)
+  {
+    pWin -> backgroundState = None;
+    pWin -> background.pixel = backupPixel;
+  }
+
+  #ifdef DEBUG
+  fprintf(stderr, "nxagentClearRegion: Number of cleared boxes is [%d].\n", nBoxCleared);
+  #endif
+}
+
+void nxagentFillRemoteRegion(DrawablePtr pDrawable, RegionPtr pRegion)
+{
+  GCPtr      pGC;
+  BoxPtr     pBox;
+  XRectangle *pRects;
+
+  int        nrects;
+  int        i;
+
+  if (REGION_NIL(pRegion) == 1)
+  {
+    return;
+  }
+
+  pGC = nxagentGetGraphicContext(pDrawable);
+
+  nrects = REGION_NUM_RECTS(pRegion);
+
+  #ifdef TEST
+  fprintf(stderr, "nxagentFillRemoteRegion: Going to fill remote region [%d,%d,%d,%d] rects [%d] with color [%lu].\n",
+              pRegion -> extents.x1, pRegion -> extents.y1, pRegion -> extents.x2, pRegion -> extents.y2,
+                  nrects, pGC -> fgPixel);
+  #endif
+
+  if (nrects == 1)
+  {
+    XFillRectangle(nxagentDisplay, nxagentDrawable(pDrawable), nxagentGC(pGC),
+                      pRegion -> extents.x1, pRegion -> extents.y1,
+                          pRegion -> extents.x2 - pRegion -> extents.x1,
+                              pRegion -> extents.y2 - pRegion -> extents.y1);
+  }
+  else
+  {
+    pBox = REGION_RECTS(pRegion);
+
+    pRects = xalloc(nrects * sizeof(XRectangle));
+
+    for (i = 0; i < nrects; i++)
+    {
+      pRects[i].x      = pBox[i].x1;
+      pRects[i].y      = pBox[i].y1;
+      pRects[i].width  = pBox[i].x2 - pBox[i].x1;
+      pRects[i].height = pBox[i].y2 - pBox[i].y1;
+    }
+
+    XFillRectangles(nxagentDisplay, nxagentDrawable(pDrawable), nxagentGC(pGC),
+                        pRects, nrects);
+
+    xfree(pRects);
+  }
+}
+
+int nxagentDestroyCorruptedWindowResource(pointer p, XID id)
+{
+  #ifdef TEST
+  fprintf(stderr, "nxagentDestroyCorruptedWindowResource: Removing corrupted window [%p] from resources.\n",
+              (void *) p);
+  #endif
+
+  nxagentWindowPriv((WindowPtr) p) -> corruptedId = None;
+
+  return 1;
+}
+
+int nxagentDestroyCorruptedPixmapResource(pointer p, XID id)
+{
+  #ifdef TEST
+  fprintf(stderr, "nxagentDestroyCorruptedPixmapResource: Removing corrupted pixmap [%p] from resources.\n",
+              (void *) p);
+  #endif
+
+  nxagentPixmapPriv((PixmapPtr) p) -> corruptedId = None;
+
+  return 1;
+}
+
+int nxagentDestroyCorruptedBackgroundResource(pointer p, XID id)
+{
+  #ifdef TEST
+  fprintf(stderr, "nxagentDestroyCorruptedBackgroundResource: Removing corrupted pixmap background [%p] from resources.\n",
+              (void *) p);
+  #endif
+
+  nxagentPixmapPriv((PixmapPtr) p) -> corruptedBackgroundId = None;
+
+  return 1;
+}
+
+void nxagentPointsToDirtyRegion(DrawablePtr pDrawable, int mode,
+                                    int nPoints, xPoint *pPoints)
+{
+  RegionPtr pRegion;
+  RegionRec tmpRegion;
+  BoxRec box, extents;
+
+  xPoint *xp;
+  int np;
+
+  np = nPoints;
+  xp = pPoints;
+
+  pRegion = REGION_CREATE(pDrawable -> pScreen, NullBox, 1);
+
+  while (np--)
+  {
+    if (CoordModePrevious)
+    {
+      box.x1 = box.x2 = (xp-1) -> x + xp -> x;
+      box.y1 = box.y2 = (xp-1) -> y + xp -> y;
+    }
+    else
+    {
+      box.x1 = box.x2 = xp -> x;
+      box.y1 = box.y2 = xp -> y;
+    }
+
+    #ifdef TEST
+    fprintf(stderr, "nxagentPointsToDirtyRegion: Adding the point (%d,%d) to the dirty region.\n",
+                box.x1, box.y1);
+    #endif
+
+    /*
+     * By using REGION_APPEND() and REGION_VALIDATE()
+     * this loop could become less expensive.
+     */
+
+    REGION_INIT(pDrawable -> pScreen, &tmpRegion, &box, 1);
+
+    REGION_UNION(pDrawable -> pScreen, pRegion, pRegion, &tmpRegion);
+
+    REGION_UNINIT(pDrawable -> pScreen, &tmpRegion);
+
+    xp++;
+  }
+
+  extents = *REGION_EXTENTS(pDrawable -> pScreen, pRegion);
+
+  REGION_RESET(pDrawable -> pScreen, pRegion, &extents);
+
+  #ifdef TEST
+  fprintf(stderr, "nxagentPointsToDirtyRegion: The resulting dirty region has [%ld] rects and"
+              " extents (%d,%d,%d,%d).\n", REGION_NUM_RECTS(pRegion), extents.x1,
+                  extents.y1, extents.x2, extents.y2);
+  #endif
+
+  nxagentMarkCorruptedRegion(pDrawable, pRegion);
+
+  REGION_DESTROY(pDrawable -> pScreen, pRegion);
+}
+
+#ifdef DUMP
+
+#define USE_MULTIPLE_COLORS
+
+void nxagentCorruptedRegionOnWindow(void *p0, XID x, void *p2)
+{
+  WindowPtr pWin = (WindowPtr) p0;
+  RegionPtr clipRegion;
+  RegionRec visRegion;
+  BoxPtr pBox;
+
+  XlibGC gc;
+  XGCValues value;
+
+  static unsigned long color = 0xff000000;
+  int nrectangles;
+  int i;
+
+  /*
+   * There are no regions to draw.
+   */
+
+  if (nxagentDrawableStatus((DrawablePtr) pWin) == Synchronized)
+  {
+    return;
+  }
+
+  /*
+   * The window is not visible.
+   */
+
+  if (nxagentWindowIsVisible(pWin) == 0)
+  {
+    return;
+  }
+
+  #ifdef TEST
+  fprintf(stderr, "nxagentCorruptedRegionOnWindow: Going to draw on window at [%p].\n",
+              (void *) pWin);
+  #endif
+
+  clipRegion = nxagentCreateRegion((DrawablePtr) pWin, NULL, 0, 0,
+                                      pWin -> drawable.width, pWin -> drawable.height);
+
+  REGION_INIT(pWin -> drawable.pScreen, &visRegion, NullBox, 1);
+
+  REGION_INTERSECT(pWin -> drawable.pScreen, &visRegion, clipRegion, nxagentCorruptedRegion((DrawablePtr) pWin));
+
+  nxagentFreeRegion(pWin -> drawable.pScreen, clipRegion);
+
+  if (REGION_NIL(&visRegion) == 1)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentCorruptedRegionOnWindow: The corrupted region of window at [%p] is hidden.\n",
+                (void *) pWin);
+    #endif
+
+    REGION_UNINIT(pWin -> drawable.pScreen, &visRegion);
+
+    return;
+  }
+
+  nxagentClearRegion((DrawablePtr) pWin, &visRegion);
+
+  #ifdef USE_MULTIPLE_COLORS
+
+  color += nxagentWindow(pWin) * 5;
+
+  if (color == 0 || color == 0xffffffff)
+  {
+    color = 0xff000000;
+  }
+
+  #endif
+
+  value.foreground = color;
+  value.subwindow_mode = IncludeInferiors;
+
+  gc = XCreateGC(nxagentDisplay, nxagentWindow(pWin), GCForeground | GCSubwindowMode, &value);
+
+  nrectangles = REGION_NUM_RECTS(&visRegion);
+
+  #ifdef TEST
+  fprintf(stderr, "nxagentCorruptedRegionOnWindow: Going to draw the region with extents [%d,%d,%d,%d] and [%d] rects.\n",
+              visRegion.extents.x1, visRegion.extents.y1, visRegion.extents.x2, visRegion.extents.y2,
+                  nrectangles);
+  #endif
+
+  pBox = nxagentGetOptimizedRegionBoxes(&visRegion);
+
+  for (i = 0; i < nrectangles; i++)
+  {
+    if (pBox[i].x1 == 0 && pBox[i].y1 == 0 &&
+            pBox[i].x2 == 0 && pBox[i].y2 == 0)
+    {
+      continue;
+    }
+
+    XDrawRectangle(nxagentDisplay, nxagentWindow(pWin), gc,
+                       pBox[i].x1, pBox[i].y1, pBox[i].x2 - pBox[i].x1 - 1,
+                           pBox[i].y2 - pBox[i].y1 - 1);
+  }
+
+  XFreeGC(nxagentDisplay, gc);
+
+  REGION_UNINIT(pWin -> drawable.pScreen, &visRegion);
+}
+
+void nxagentRegionsOnScreen()
+{
+  FindClientResourcesByType(clients[serverClient -> index], RT_NX_CORR_WINDOW,
+                                nxagentCorruptedRegionOnWindow, NULL);
+}
+
+#endif
+
+/*
+ * If the synchronization loop breaks and the
+ * drawable synchronization cannot be completed,
+ * the remaining data is stored in a bitmap.
+ * The synchronization loop is then restarted
+ * using the bitmap as source instead of the
+ * drawable.
+ */
+
+void nxagentCreateDrawableBitmap(DrawablePtr pDrawable)
+{
+  PixmapPtr pBitmap;
+  GCPtr pGC = NULL;
+  RegionPtr pClipRegion = NullRegion;
+
+  int x, y;
+  int w, h;
+  int saveTrap;
+
+  #ifdef TEST
+  fprintf(stderr, "nxagentCreateDrawableBitmap: Creating synchronization bitmap for [%s] at [%p].\n",
+              nxagentDrawableType(pDrawable), (void *) pDrawable);
+  #endif
+
+  /*
+   * The bitmap is created only in the
+   * nxagent.
+   */
+
+  saveTrap = nxagentGCTrap;
+
+  nxagentGCTrap = 1;
+
+  if (nxagentDrawableStatus(pDrawable) == Synchronized)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentCreateDrawableBitmap: The drawable is already synchronized. Skipping bitmap creation.\n");
+    #endif
+
+    goto nxagentCreateDrawableBitmapEnd;
+  }
+
+  /*
+   * Should create a function to append
+   * a bitmap to another, instead of de-
+   * stroy the old one.
+   */
+
+  if (nxagentDrawableBitmap(pDrawable) != NullPixmap)
+  {
+    #ifdef WARNING
+    fprintf(stderr, "nxagentCreateDrawableBitmap: WARNING! Going to replace the bitmap at [%p] with corrupted [%d,%d,%d,%d].\n",
+                  (void *) nxagentDrawableBitmap(pDrawable),
+                      nxagentCorruptedRegion((DrawablePtr) nxagentDrawableBitmap(pDrawable)) -> extents.x1,
+                          nxagentCorruptedRegion((DrawablePtr) nxagentDrawableBitmap(pDrawable)) -> extents.y1,
+                              nxagentCorruptedRegion((DrawablePtr) nxagentDrawableBitmap(pDrawable)) -> extents.x2,
+                                  nxagentCorruptedRegion((DrawablePtr) nxagentDrawableBitmap(pDrawable)) -> extents.y2);
+    #endif
+
+    nxagentDestroyDrawableBitmap(pDrawable);
+  }
+
+  /*
+   * Clipping to the visible area.
+   */
+
+  pClipRegion = nxagentCreateRegion(pDrawable, NULL, 0, 0, pDrawable -> width, pDrawable -> height);
+
+  REGION_INTERSECT(pDrawable -> pScreen, pClipRegion, pClipRegion, nxagentCorruptedRegion(pDrawable));
+
+  if (REGION_NIL(pClipRegion) == 1)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentCreateDrawableBitmap: The corrupted region is not visible. Skipping bitmap creation.\n");
+    #endif
+
+    goto nxagentCreateDrawableBitmapEnd;
+  }
+
+  /*
+   * FIXME: A better way it would be create the bitmap
+   * with the same extents of the clipRegion. This
+   * requires to save the offset with respect to the
+   * drawable origin like in the backing store. This
+   * becomes particularly important when the drawable
+   * is a huge window, because the pixmap creation
+   * would fail.
+   */
+
+  pBitmap = nxagentCreatePixmap(pDrawable -> pScreen, pDrawable -> width, pDrawable -> height, pDrawable -> depth);
+
+  if (pBitmap == NULL)
+  {
+    #ifdef WARNING
+    fprintf(stderr, "nxagentCreateDrawableBitmap: Cannot create pixmap for the bitmap data.\n");
+    #endif
+
+    goto nxagentCreateDrawableBitmapEnd;
+  }
+
+  pGC = GetScratchGC(pBitmap -> drawable.depth, pBitmap -> drawable.pScreen);
+
+  ValidateGC((DrawablePtr) pBitmap, pGC);
+
+  x = pClipRegion -> extents.x1;
+  y = pClipRegion -> extents.y1;
+  w = pClipRegion -> extents.x2 - pClipRegion -> extents.x1;
+  h = pClipRegion -> extents.y2 - pClipRegion -> extents.y1;
+
+  nxagentCopyArea(pDrawable, (DrawablePtr) pBitmap, pGC, x, y, w, h, x, y);
+
+  REGION_UNION(pDrawable -> pScreen, nxagentCorruptedRegion((DrawablePtr) pBitmap),
+                   nxagentCorruptedRegion((DrawablePtr) pBitmap), pClipRegion);
+
+  if (pDrawable -> type == DRAWABLE_PIXMAP)
+  {
+    nxagentPixmapPriv(nxagentRealPixmap((PixmapPtr) pDrawable)) -> synchronizationBitmap = pBitmap;
+
+    if (nxagentIsCorruptedBackground((PixmapPtr) pDrawable) == 1)
+    {
+      nxagentSynchronization.backgroundBitmaps++;
+    }
+    else
+    {
+      nxagentSynchronization.pixmapBitmaps++;
+    }
+  }
+  else
+  {
+    nxagentWindowPriv((WindowPtr) pDrawable) -> synchronizationBitmap = pBitmap;
+
+    nxagentSynchronization.windowBitmaps++;
+  }
+
+  #ifdef TEST
+  fprintf(stderr, "nxagentCreateDrawableBitmap: Drawable [%p] has bitmap at [%p] with corrupted [%d,%d,%d,%d].\n",
+                (void *) pDrawable, (void *) nxagentDrawableBitmap(pDrawable),
+                    nxagentCorruptedRegion((DrawablePtr) nxagentDrawableBitmap(pDrawable)) -> extents.x1,
+                        nxagentCorruptedRegion((DrawablePtr) nxagentDrawableBitmap(pDrawable)) -> extents.y1,
+                            nxagentCorruptedRegion((DrawablePtr) nxagentDrawableBitmap(pDrawable)) -> extents.x2,
+                                nxagentCorruptedRegion((DrawablePtr) nxagentDrawableBitmap(pDrawable)) -> extents.y2);
+  #endif
+
+nxagentCreateDrawableBitmapEnd:
+
+  nxagentGCTrap = saveTrap;
+
+  if (pClipRegion != NullRegion)
+  {
+    nxagentFreeRegion(pDrawable, pClipRegion);
+  }
+
+  if (pGC != NULL)
+  {
+    FreeScratchGC(pGC);
+  }
+}
+
+void nxagentDestroyDrawableBitmap(DrawablePtr pDrawable)
+{
+  if (nxagentDrawableBitmap(pDrawable) != NullPixmap)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentDestroyDrawableBitmap: Destroying bitmap for drawable at [%p].\n",
+                (void *) pDrawable);
+    #endif
+
+    nxagentDestroyPixmap(nxagentDrawableBitmap(pDrawable));
+
+    if (pDrawable -> type == DRAWABLE_PIXMAP)
+    {
+      nxagentPixmapPriv(nxagentRealPixmap((PixmapPtr) pDrawable)) -> synchronizationBitmap = NullPixmap;
+
+      if (nxagentIsCorruptedBackground((PixmapPtr) pDrawable) == 1)
+      {
+        nxagentSynchronization.backgroundBitmaps--;
+      }
+      else
+      {
+        nxagentSynchronization.pixmapBitmaps--;
+      }
+    }
+    else
+    {
+      nxagentWindowPriv((WindowPtr) pDrawable) -> synchronizationBitmap = NullPixmap;
+
+      nxagentSynchronization.windowBitmaps--;
+    }
+  }
+}
+
+void nxagentIncreasePixmapUsageCounter(PixmapPtr pPixmap)
+{
+  if (nxagentDrawableStatus((DrawablePtr) pPixmap) == Synchronized)
+  {
+    return;
+  }
+
+  #ifdef TEST
+  fprintf(stderr, "nxagentIncreasePixmapUsageCounter: Pixmap usage counter was [%d].\n",
+              nxagentPixmapUsageCounter(pPixmap));
+  #endif
+
+  nxagentPixmapUsageCounter(pPixmap) += 1;
+
+  nxagentAllocateCorruptedResource((DrawablePtr) pPixmap, RT_NX_CORR_PIXMAP);
+}
+
+void nxagentAllocateCorruptedResource(DrawablePtr pDrawable, RESTYPE type)
+{
+  PixmapPtr pRealPixmap;
+
+  if (nxagentSessionState == SESSION_DOWN)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentAllocateCorruptedResource: WARNING! Not allocated corrupted resource "
+                "[%s][%p] with the display down.\n", nxagentDrawableType(pDrawable),
+                    (void *) pDrawable);
+    #endif
+
+    return;
+  }
+
+  if (type == RT_NX_CORR_WINDOW)
+  {
+    if (nxagentWindowPriv((WindowPtr) pDrawable) -> corruptedId == 0)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentAllocateCorruptedResource: New resource at [%p]. Corrupted "
+                  "windows counter was [%d].\n", (void *) pDrawable, nxagentCorruptedWindows);
+      #endif
+
+      nxagentCorruptedWindows++;
+
+      nxagentWindowPriv((WindowPtr) pDrawable) -> corruptedId = FakeClientID(serverClient -> index);
+
+      AddResource(nxagentWindowPriv((WindowPtr) pDrawable) -> corruptedId, RT_NX_CORR_WINDOW,
+                      (pointer) pDrawable);
+    }
+  }
+  else if (type == RT_NX_CORR_BACKGROUND)
+  {
+    pRealPixmap = nxagentRealPixmap((PixmapPtr) pDrawable);
+
+    if (nxagentPixmapPriv(pRealPixmap) -> corruptedBackgroundId == 0)
+    {
+      /*
+       * When a pixmap is added to the background
+       * corrupted resources, it must be removed
+       * from the pixmap corrupted resources.
+       */
+
+      nxagentDestroyCorruptedResource(pDrawable, RT_NX_CORR_PIXMAP);
+
+      #ifdef TEST
+      fprintf(stderr, "nxagentAllocateCorruptedResource: New resource at [%p]. Corrupted "
+                  "backgrounds counter was [%d].\n", (void *) pDrawable, nxagentCorruptedBackgrounds);
+      #endif
+
+      nxagentCorruptedBackgrounds++;
+
+      nxagentPixmapPriv(pRealPixmap) -> corruptedBackgroundId = FakeClientID(serverClient -> index);
+
+      AddResource(nxagentPixmapPriv(pRealPixmap) -> corruptedBackgroundId, RT_NX_CORR_BACKGROUND,
+                      (pointer) pRealPixmap);
+    }
+  }
+  else if (type == RT_NX_CORR_PIXMAP)
+  {
+    /*
+     * The shared memory pixmaps are always dirty
+     * and shouldn't be synchronized.
+     */
+
+    if (nxagentPixmapUsageCounter((PixmapPtr) pDrawable) >= MINIMUM_PIXMAP_USAGE_COUNTER &&
+            nxagentIsShmPixmap((PixmapPtr) pDrawable) == 0)
+    {
+      pRealPixmap = nxagentRealPixmap((PixmapPtr) pDrawable);
+
+      if (nxagentPixmapPriv(pRealPixmap) -> corruptedId == 0)
+      {
+        #ifdef TEST
+        fprintf(stderr, "nxagentAllocateCorruptedResource: New resource at [%p]. Corrupted "
+                    "pixmaps counter was [%d].\n", (void *) pDrawable, nxagentCorruptedPixmaps);
+        #endif
+
+        nxagentCorruptedPixmaps++;
+
+        nxagentPixmapPriv(pRealPixmap) -> corruptedId = FakeClientID(serverClient -> index);
+
+        AddResource(nxagentPixmapPriv(pRealPixmap) -> corruptedId, RT_NX_CORR_PIXMAP,
+                        (pointer) pRealPixmap);
+      }
+    }
+  }
+}
+
+void nxagentDestroyCorruptedResource(DrawablePtr pDrawable, RESTYPE type)
+{
+  PixmapPtr pRealPixmap;
+
+  if (type == RT_NX_CORR_WINDOW)
+  {
+    if (nxagentWindowPriv((WindowPtr) pDrawable) -> corruptedId != 0)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentDestroyCorruptedResource: Removing resource at [%p]. Corrupted "
+                  "windows counter was [%d].\n", (void *) pDrawable, nxagentCorruptedWindows);
+      #endif
+
+      if (nxagentCorruptedWindows > 0)
+      {
+        nxagentCorruptedWindows--;
+      }
+
+      FreeResource(nxagentWindowPriv((WindowPtr) pDrawable) -> corruptedId, RT_NONE);
+
+      if (nxagentSynchronization.pDrawable == pDrawable)
+      {
+        nxagentSynchronization.pDrawable = NULL;
+      }
+    }
+  }
+  else if (type == RT_NX_CORR_BACKGROUND)
+  {
+    pRealPixmap = nxagentRealPixmap((PixmapPtr) pDrawable);
+
+    if (nxagentPixmapPriv(pRealPixmap) -> corruptedBackgroundId != 0)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentDestroyCorruptedResource:  Removing resource at [%p]. Corrupted "
+                  "backgrounds counter was [%d].\n", (void *) pDrawable, nxagentCorruptedBackgrounds);
+      #endif
+
+      if (nxagentCorruptedBackgrounds > 0)
+      {
+        nxagentCorruptedBackgrounds--;
+      }
+
+      FreeResource(nxagentPixmapPriv(pRealPixmap) -> corruptedBackgroundId, RT_NONE);
+
+      if (nxagentSynchronization.pDrawable == pDrawable)
+      {
+        nxagentSynchronization.pDrawable = NULL;
+      }
+    }
+  }
+  else if (type == RT_NX_CORR_PIXMAP)
+  {
+    pRealPixmap = nxagentRealPixmap((PixmapPtr) pDrawable);
+
+    if (nxagentPixmapPriv(pRealPixmap) -> corruptedId != 0)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentDestroyCorruptedResource:  Removing resource at [%p]. Corrupted "
+                  "pixmaps counter was [%d].\n", (void *) pDrawable, nxagentCorruptedPixmaps);
+      #endif
+
+      if (nxagentCorruptedPixmaps > 0)
+      {
+        nxagentCorruptedPixmaps--;
+      }
+
+      FreeResource(nxagentPixmapPriv(pRealPixmap) -> corruptedId, RT_NONE);
+
+      if (nxagentSynchronization.pDrawable == pDrawable)
+      {
+        nxagentSynchronization.pDrawable = NULL;
+      }
+    }
+  }
+}
+
+void nxagentCleanCorruptedDrawable(DrawablePtr pDrawable)
+{
+  if (nxagentDrawableStatus(pDrawable) == Synchronized)
+  {
+    return;
+  }
+
+  #ifdef TEST
+  fprintf(stderr, "nxagentCleanCorruptedDrawable: Clearing out the corrupted drawable [%s][%p].\n",
+              nxagentDrawableType(pDrawable), (void *) pDrawable);
+  #endif
+
+  nxagentUnmarkCorruptedRegion(pDrawable, NullRegion);
+
+  if (nxagentDrawableBitmap(pDrawable) != NullPixmap)
+  {
+    nxagentDestroyDrawableBitmap(pDrawable);
+  }
+}
+
+void nxagentUnmarkExposedRegion(WindowPtr pWin, RegionPtr pRegion, RegionPtr pOther)
+{
+  RegionRec clipRegion;
+
+  if (pRegion != NullRegion && REGION_NIL(pRegion) == 0 &&
+          nxagentDrawableStatus((DrawablePtr) pWin) == NotSynchronized)
+  {
+    REGION_INIT(pWin -> drawable.pScreen, &clipRegion, NullBox, 1);
+
+    REGION_COPY(pWin -> drawable.pScreen, &clipRegion, pRegion);
+    
+    if (pOther != NullRegion && REGION_NIL(pOther) == 0)
+    {
+      REGION_UNION(pWin -> drawable.pScreen, &clipRegion, &clipRegion, pOther);
+    }
+
+    REGION_TRANSLATE(pWin -> drawable.pScreen, &clipRegion, -pWin -> drawable.x, -pWin -> drawable.y);
+
+    #ifdef TEST
+    fprintf(stderr, "nxagentUnmarkExposedRegion: Validating expose region [%d,%d,%d,%d] "
+                "on window [%p].\n", clipRegion.extents.x1, clipRegion.extents.y1,
+                    clipRegion.extents.x2, clipRegion.extents.y2, (void *) pWin);
+    #endif
+
+    nxagentUnmarkCorruptedRegion((DrawablePtr) pWin, &clipRegion);
+
+    REGION_UNINIT(pWin -> drawable.pScreen, &clipRegion);
+  }
+}
+
+int nxagentSynchronizationPredicate()
+{
+  if (nxagentCorruptedWindows == 0 &&
+          nxagentCorruptedBackgrounds == 0 &&
+              nxagentCorruptedPixmaps == 0)
+  {
+    return NotNeeded;
+  }
+
+  if (nxagentBlocking == 0 &&
+          nxagentCongestion <= 4 &&
+              nxagentReady == 0 &&
+                  nxagentUserInput(NULL) == 0)
+  {
+    return Needed;
+  }
+
+  /*
+   * If there are resources to synchronize
+   * but the conditions to start the loop
+   * are not satisfied, a little delay is
+   * requested to check for a new loop as
+   * soon as possible.
+   */
+
+  return Delayed;
+}
+
+void nxagentSendBackgroundExpose(WindowPtr pWin, PixmapPtr pBackground, RegionPtr pExpose)
+{
+  RegionRec expose;
+  miBSWindowPtr pBackingStore;
+
+  REGION_INIT(pWin -> pScreen, &expose, NullBox, 1);
+
+  #ifdef DEBUG
+  fprintf(stderr, "nxagentSendBackgroundExpose: Original expose region is [%d,%d,%d,%d].\n",
+              pExpose -> extents.x1, pExpose -> extents.y1,
+                  pExpose -> extents.x2, pExpose -> extents.y2);
+
+  fprintf(stderr, "nxagentSendBackgroundExpose: Window clipList is [%d,%d,%d,%d].\n",
+              pWin -> clipList.extents.x1, pWin -> clipList.extents.y1,
+                  pWin -> clipList.extents.x2, pWin -> clipList.extents.y2);
+  #endif
+
+  if (nxagentDrawableStatus((DrawablePtr) pBackground) == Synchronized &&
+          (pBackground -> drawable.width < pWin -> drawable.width ||
+              pBackground -> drawable.height < pWin -> drawable.height))
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentSendBackgroundExpose: Pixmap background [%dx%d] is "
+                "smaller than window [%dx%d]. Going to expose the winSize.\n",
+                    pBackground -> drawable.width, pBackground -> drawable.height, 
+                        pWin -> drawable.width, pWin -> drawable.height);
+    #endif
+
+    REGION_COPY(pWin -> pScreen, &expose, &pWin -> winSize);
+  }
+  else
+  {
+    REGION_COPY(pWin -> pScreen, &expose, pExpose);
+
+    REGION_TRANSLATE(pWin -> pScreen, &expose, pWin -> drawable.x, pWin -> drawable.y);
+  }
+
+  REGION_SUBTRACT(pWin -> pScreen, &expose, &expose, nxagentCorruptedRegion((DrawablePtr) pWin));
+
+  if (REGION_NIL(&pWin -> clipList) != 0)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentSendBackgroundExpose: Exposures deferred because the window "
+                "is hidden.\n");
+    #endif
+
+    REGION_UNION(pWin -> pScreen, nxagentDeferredBackgroundExposures,
+                     nxagentDeferredBackgroundExposures, &expose);
+
+    nxagentWindowPriv(pWin) -> deferredBackgroundExpose = 1;
+
+    goto nxagentSendBackgroundExposeEnd;
+  }
+
+  #ifdef TEST
+  fprintf(stderr, "nxagentSendBackgroundExpose: Sending expose [%d,%d,%d,%d].\n",
+              expose.extents.x1, expose.extents.y1, expose.extents.x2, expose.extents.y2);
+  #endif
+
+  /*
+   * This prevents hidden region to be exposed.
+   */
+
+  pBackingStore = (miBSWindowPtr)pWin->backStorage;
+
+  if ((pBackingStore != NULL) && (REGION_NIL(&pBackingStore->SavedRegion) == 0))
+  {
+    REGION_TRANSLATE(pWin -> pScreen, &expose, -pWin -> drawable.x, -pWin -> drawable.y);
+
+    REGION_SUBTRACT(pWin -> pScreen, &expose, &expose, &pBackingStore -> SavedRegion);
+
+    REGION_TRANSLATE(pWin -> pScreen, &expose, pWin -> drawable.x, pWin -> drawable.y);
+  }
+
+  REGION_INTERSECT(pWin -> pScreen, &expose, &expose, &pWin -> clipList);
+
+  /*
+   * Reduce the overall region to expose.
+   */
+  
+  REGION_TRANSLATE(pWin -> pScreen, &expose, -pWin -> drawable.x, -pWin -> drawable.y);
+  
+  REGION_SUBTRACT(pWin -> pScreen, pExpose, pExpose, &expose);
+  
+  REGION_TRANSLATE(pWin -> pScreen, &expose, pWin -> drawable.x, pWin -> drawable.y);
+
+  miWindowExposures(pWin, &expose, &expose);
+
+nxagentSendBackgroundExposeEnd:
+
+  REGION_UNINIT(pWin -> pScreen, &expose);
+}
+
+void nxagentExposeBackgroundPredicate(void *p0, XID x1, void *p2)
+{
+  WindowPtr pWin = (WindowPtr) p0;
+  WindowPtr pParent;
+
+  struct nxagentExposeBackground *pPair = p2;
+
+  if (REGION_NIL(pPair -> pExpose) != 0)
+  {
+    return;
+  }
+
+  if (pWin -> backgroundState == BackgroundPixmap &&
+          pWin -> background.pixmap == pPair -> pBackground)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentExposeBackgroundPredicate: Window at [%p] uses pixmap [%p] "
+                "as background.\n", (void *) pWin, (void *) pPair -> pBackground);
+    #endif
+
+    nxagentSendBackgroundExpose(pWin, pPair -> pBackground, pPair -> pExpose);
+  }
+  else if (pWin -> backgroundState == ParentRelative)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentExposeBackgroundPredicate: Window [%p] uses parent's background.\n",
+                (void *) pWin);
+    #endif
+
+    pParent = pWin -> parent;
+
+    while (pParent != NULL)
+    {
+      if (pParent -> backgroundState == BackgroundPixmap &&
+              pParent -> background.pixmap == pPair -> pBackground)
+      {
+        #ifdef TEST
+        fprintf(stderr, "nxagentExposeBackgroundPredicate: Parent window at [%p] uses pixmap [%p] "
+                    "as background.\n", (void *) pParent, (void *) pPair -> pBackground);
+        #endif
+
+        nxagentSendBackgroundExpose(pWin, pPair -> pBackground, pPair -> pExpose);
+
+        break;
+      }
+
+      pParent = pParent -> parent;
+    }
+  }
+}
+
+/*
+ * This function is similar to nxagentClipAndSendExpose().
+ */
+
+int nxagentClipAndSendClearExpose(WindowPtr pWin, pointer ptr)
+{
+  RegionPtr exposeRgn;
+  RegionPtr remoteExposeRgn;
+
+  #ifdef DEBUG
+  BoxRec box;
+  #endif
+
+  remoteExposeRgn = (RegionRec *) ptr;
+
+  if (nxagentWindowPriv(pWin) -> deferredBackgroundExpose == 1)
+  {
+    exposeRgn = REGION_CREATE(pWin -> drawable.pScreen, NULL, 1);
+
+    #ifdef DEBUG
+    box = *REGION_EXTENTS(pWin->drawable.pScreen, remoteExposeRgn);
+
+    fprintf(stderr, "nxagentClipAndSendClearExpose: Background expose extents: [%d,%d,%d,%d].\n",
+                box.x1, box.y1, box.x2, box.y2);
+
+    box = *REGION_EXTENTS(pWin->drawable.pScreen, &pWin -> clipList);
+
+    fprintf(stderr, "nxagentClipAndSendClearExpose: Clip list extents for window at [%p]: [%d,%d,%d,%d].\n",
+                (void *) pWin, box.x1, box.y1, box.x2, box.y2);
+    #endif
+
+    REGION_INTERSECT(pWin -> drawable.pScreen, exposeRgn, remoteExposeRgn, &pWin -> clipList);
+
+    /*
+     * If the region will be synchronized,
+     * the expose on corrupted regions can
+     * be ignored.
+     */
+
+    REGION_SUBTRACT(pWin -> drawable.pScreen, exposeRgn, exposeRgn, nxagentCorruptedRegion((DrawablePtr) pWin));
+
+    if (REGION_NOTEMPTY(pWin -> drawable.pScreen, exposeRgn))
+    {
+      #ifdef DEBUG
+      box = *REGION_EXTENTS(pWin->drawable.pScreen, exposeRgn);
+
+      fprintf(stderr, "nxagentClipAndSendClearExpose: Forwarding expose [%d,%d,%d,%d] to window at [%p] pWin.\n",
+                  box.x1, box.y1, box.x2, box.y2, (void *) pWin);
+      #endif
+
+      REGION_SUBTRACT(pWin -> drawable.pScreen, remoteExposeRgn, remoteExposeRgn, exposeRgn);
+
+      miWindowExposures(pWin, exposeRgn, exposeRgn);
+    }
+
+    REGION_DESTROY(pWin -> drawable.pScreen, exposeRgn);
+
+    nxagentWindowPriv(pWin) -> deferredBackgroundExpose = 0;
+  }
+
+  if (REGION_NOTEMPTY(pWin -> drawable.pScreen, remoteExposeRgn))
+  {
+    #ifdef DEBUG
+    fprintf(stderr, "nxagentClipAndSendClearExpose: Region not empty. Walk children.\n");
+    #endif
+
+
+    return WT_WALKCHILDREN;
+  }
+  else
+  {
+    #ifdef DEBUG
+    fprintf(stderr, "nxagentClipAndSendClearExpose: Region empty. Stop walking.\n");
+    #endif
+
+    return WT_STOPWALKING;
+  }
+}
+
+void nxagentSendDeferredBackgroundExposures(void)
+{
+  if (nxagentDeferredBackgroundExposures == NullRegion)
+  {
+    nxagentDeferredBackgroundExposures = REGION_CREATE(WindowTable[0] -> drawable.pScreen, NullBox, 1);
+  }
+
+  if (REGION_NOTEMPTY(WindowTable[0] -> drawable.pScreen, nxagentDeferredBackgroundExposures) != 0)
+  {
+    #ifdef TEST
+    fprintf(stderr, "nxagentSendDeferredBackgroundExposures: Going to send deferred exposures to the root window.\n");
+    #endif
+
+    TraverseTree(WindowTable[0], nxagentClipAndSendClearExpose, (void *) nxagentDeferredBackgroundExposures);
+
+    REGION_EMPTY(WindowTable[0] -> drawable.pScreen, nxagentDeferredBackgroundExposures);
+  }
+}
+