Imported nx-X11-3.1.0-1.tar.gznx-X11/3.1.0-1

Summary: Imported nx-X11-3.1.0-1.tar.gz
Keywords:

Imported nx-X11-3.1.0-1.tar.gz
into Git repository

1 files changed, 1030 insertions, 0 deletions

diff --git a/nx-X11/programs/Xserver/Xext/mbufbf.c b/nx-X11/programs/Xserver/Xext/mbufbf.c
new file mode 100644
index 000000000..8585c52d2
--- /dev/null
+++ b/nx-X11/programs/Xserver/Xext/mbufbf.c
@@ -0,0 +1,1030 @@
+/* $XFree86: xc/programs/Xserver/Xext/mbufbf.c,v 3.5tsi Exp $ */
+/*
+
+Copyright 1989, 1998  The Open Group
+
+Permission to use, copy, modify, distribute, and sell this software and its
+documentation for any purpose is hereby granted without fee, provided that
+the above copyright notice appear in all copies and that both that
+copyright notice and this permission notice appear in supporting
+documentation.
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+Except as contained in this notice, the name of The Open Group shall not be
+used in advertising or otherwise to promote the sale, use or other dealings
+in this Software without prior written authorization from The Open Group.
+
+*/
+
+/* $Xorg: mbufbf.c,v 1.4 2001/02/09 02:04:32 xorgcvs Exp $ */
+
+#define NEED_REPLIES
+#define NEED_EVENTS
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#include <stdio.h>
+#include <X11/X.h>
+#include <X11/Xproto.h>
+#include "misc.h"
+#include "os.h"
+#include "windowstr.h"
+#include "scrnintstr.h"
+#include "pixmapstr.h"
+#include "extnsionst.h"
+#include "dixstruct.h"
+#include "resource.h"
+#include "opaque.h"
+#include "regionstr.h"
+#include "gcstruct.h"
+#include "inputstr.h"
+#include "validate.h"
+#include <sys/time.h>
+
+#define _MULTIBUF_SERVER_	/* don't want Xlib structures */
+#define _MULTIBUF_BUFFER_
+#include <X11/extensions/multibufst.h>
+
+/* 
+Support for doublebuffer hardare
+
+This code is designed to support doublebuffer hardware where the
+displayed buffer is selected on a per-pixel basis by an additional bit
+plane, called the select plane. It could probably be easily modified
+to work with systems that use window-id planes.
+
+This is done by creating a new drawable type, DRAWABLE_BUFFER. The
+type has the same exact layout as a window drawable. Your code should
+treat a DRAWABLE_BUFFER the same as it would tread a DRAWABLE_WINDOW
+when handling the gc drawing functions. In addition, PaintWindowBackground,
+CopyWindow, and all of the gc drawing functions to be able to draw into both
+framebuffers. Which framebuffer to draw into is selected by the contents of
+	pWin->devPrivates[frameWindowPrivateIndex].
+The content of the devPrivate is either from frameBuffer[0] or
+frameBuffer[1], depending on which buffer is being drawn into. When
+	pWin->devPrivates[frameWindowPrivateIndex] == frameBuffer[0],
+the functions should draw into the front framebuffer. When
+	pWin->devPrivates[frameWindowPrivateIndex] == frameBuffer[1],
+the functions should draw into the back framebuffer.
+
+In addition, you need to provide a function that allows you to copy
+bits between the buffers (optional since CopyArea can be used) and a
+function that draws into the select plane. Then, you need to register
+your functions and other information, by calling:
+
+void
+RegisterDoubleBufferHardware(pScreen, nInfo, pInfo, frameBuffer, selectPlane,
+			     CopyBufferBitsFunc, DrawSelectPlaneFunc)
+    int			nInfo;
+    xMbufBufferInfo	*pInfo;
+    DevUnion		*frameBuffer;
+    DevUnion		selectPlane;
+
+"pInfo" is an array indicating which visuals and depths that double
+buffering is supported on. "nInfo" is the length of the array.
+
+"frameBuffer" is array of length 2. The contents of the array element
+is ddx-specific. The content of frameBuffer[0] should, when placed in
+the window private, indicate that framebuffer 0 should be drawn into.
+The contents of frameBuffer[1], when placed into the window private,
+should indicate that framebuffer 1 should be drawn into.
+
+"selectPlane" is ddx-specific. It should contain information
+neccessary for your displayProc to access the select plane.
+It is passed to DrawSelectPlaneFunc.
+
+"CopyBufferBitsFunc" is a ddx-specific function that copies from one
+buffer of a multibuffered window to another buffer. If the CopyBufferBitsFunc
+is NULL, a default function will be used that calls pScreen->CopyArea.
+
+    void CopyBufferBitsFunc(pMBWindow, srcBufferNum, dstBufferNum)
+        mbufWindowPtr pMBWindow;
+        int srcBufferNum, dstBufferNum;
+
+"DrawSelectPlaneFunc" is a ddx-specific function that fills the
+regions "prgn" of select plane with the value "bufferNum". If 
+selectPlane is a DrawablePtr (such as a PixmapPtr), you can pass
+NULL for DrawSelectPlaneFunc, a default function will be used that
+calls FillRectangle on the selectPlane.
+
+    void DrawSelectPlaneFunc(pScreen, selectPlane, prgn, bufferNum)
+        ScreenPtr	pScreen;
+        DevUnion	selectPlane;
+        RegionPtr	prgn;
+        long		bufferNum;
+
+...
+...
+...
+
+*/
+
+#define MAX_BUFFERS  2	/* Only supports 2 buffers */
+#define FRONT_BUFFER 0
+#define BACK_BUFFER  1
+
+
+/* Buffer drawables have the same structure as window drawables */
+typedef WindowRec BufferRec;
+typedef WindowPtr BufferPtr;
+
+
+/*
+ * Call RegisterHdwrBuffer for every screen that has doublebuffer hardware. 
+ */
+
+static int		bufNumInfo[MAXSCREENS];
+static xMbufBufferInfo	*bufInfo[MAXSCREENS];
+static DevUnion		*bufFrameBuffer[MAXSCREENS];
+static DevUnion		bufselectPlane[MAXSCREENS];
+static void		(* bufCopyBufferBitsFunc[MAXSCREENS])();
+static void		(* bufDrawSelectPlaneFunc[MAXSCREENS])();
+
+static Bool bufMultibufferInit();
+
+
+void
+RegisterDoubleBufferHardware(pScreen, nInfo, pInfo, frameBuffer, selectPlane,
+			     CopyBufferBitsFunc, DrawSelectPlaneFunc)
+    ScreenPtr		pScreen;
+    int			nInfo;
+    xMbufBufferInfo	*pInfo;
+    DevUnion		*frameBuffer;
+    DevUnion		selectPlane;
+    void		(* CopyBufferBitsFunc)();
+    void		(* DrawSelectPlaneFunc)();
+{
+    bufNumInfo[pScreen->myNum]     = nInfo;
+    bufInfo[pScreen->myNum]        = pInfo;
+    bufFrameBuffer[pScreen->myNum] = frameBuffer;
+    bufselectPlane[pScreen->myNum] = selectPlane;
+
+    bufCopyBufferBitsFunc[pScreen->myNum]  = CopyBufferBitsFunc;
+    bufDrawSelectPlaneFunc[pScreen->myNum] = DrawSelectPlaneFunc;
+
+    /* Register ourselves with device-independent multibuffers code */
+    RegisterMultibufferInit(pScreen, bufMultibufferInit);
+}
+
+
+/*
+ * Called by Multibuffer extension initialization.
+ * Initializes mbufScreenRec and its devPrivate.
+ */
+    
+static Bool NoopDDA_True() { return TRUE; }
+static Bool bufPositionWindow();
+static int  bufCreateImageBuffers();
+static void bufDestroyImageBuffers();
+static void bufDisplayImageBuffers();
+static void bufClearImageBufferArea();
+static void bufDestroyBuffer();
+static void bufCopyBufferBits();
+static void bufDrawSelectPlane();
+static void bufWrapScreenFuncs();
+static void bufResetProc();
+
+static void bufPostValidateTree();
+static void bufClipNotify();
+static void bufWindowExposures();
+static Bool bufChangeWindowAttributes();
+static void bufClearToBackground();
+static void bufCopyWindow();
+
+extern WindowPtr *WindowTable;
+
+static Bool
+bufMultibufferInit(pScreen, pMBScreen)
+    ScreenPtr pScreen;
+    mbufScreenPtr pMBScreen;
+{
+    mbufBufferPrivPtr	pMBPriv;
+    BoxRec		box;
+
+    /* Multibuffer info */
+    pMBScreen->nInfo = bufNumInfo[pScreen->myNum];
+    pMBScreen->pInfo = bufInfo[pScreen->myNum];
+
+    /* Hooks */
+    pMBScreen->CreateImageBuffers = bufCreateImageBuffers;
+    pMBScreen->DestroyImageBuffers = bufDestroyImageBuffers;
+    pMBScreen->DisplayImageBuffers = bufDisplayImageBuffers;
+    pMBScreen->ClearImageBufferArea = bufClearImageBufferArea;
+    pMBScreen->ChangeMBufferAttributes = NoopDDA_True;
+    pMBScreen->ChangeBufferAttributes = NoopDDA_True;
+    pMBScreen->DeleteBufferDrawable = bufDestroyBuffer;
+    pMBScreen->WrapScreenFuncs = bufWrapScreenFuncs;
+    pMBScreen->ResetProc = bufResetProc;
+    /* Create devPrivate part */
+    pMBPriv = (mbufBufferPrivPtr) xalloc(sizeof *pMBPriv);
+    if (!pMBPriv)
+	return (FALSE);
+
+    pMBScreen->devPrivate.ptr = (pointer) pMBPriv;
+    pMBPriv->frameBuffer  = bufFrameBuffer[pScreen->myNum];
+    pMBPriv->selectPlane = bufselectPlane[pScreen->myNum];
+
+    /*
+     * Initializing the subtractRgn to the screen area will ensure that
+     * the selectPlane will get cleared on the first PostValidateTree.
+     */
+
+    box.x1 = 0;
+    box.y1 = 0;
+    box.x2 = pScreen->width;
+    box.y2 = pScreen->height;
+
+    pMBPriv->rgnChanged = TRUE;
+    REGION_INIT(pScreen, &pMBPriv->backBuffer, &box, 1);
+    REGION_INIT(pScreen, &pMBPriv->subtractRgn, &box, 1);
+    REGION_NULL(pScreen, &pMBPriv->unionRgn);
+
+    /* Misc functions */
+    pMBPriv->CopyBufferBits  = bufCopyBufferBitsFunc[pScreen->myNum];
+    pMBPriv->DrawSelectPlane = bufDrawSelectPlaneFunc[pScreen->myNum];
+
+    if (!pMBPriv->CopyBufferBits)
+	pMBPriv->CopyBufferBits = bufCopyBufferBits;
+
+    if (!pMBPriv->DrawSelectPlane)
+	pMBPriv->DrawSelectPlane = bufDrawSelectPlane;
+
+    /* screen functions */
+    pMBPriv->funcsWrapped = 0;
+    pMBPriv->inClearToBackground = FALSE;
+    pMBPriv->WindowExposures = NULL;
+    pMBPriv->CopyWindow = NULL;
+    pMBPriv->ClearToBackground = NULL;
+    pMBPriv->ClipNotify = NULL;
+    pMBPriv->ChangeWindowAttributes = NULL;
+
+    /* Start out wrapped to clear select plane */
+    WRAP_SCREEN_FUNC(pScreen,pMBPriv,PostValidateTree, bufPostValidateTree);
+    return TRUE;
+}
+
+static void
+UpdateBufferFromWindow(pBuffer, pWin)
+    BufferPtr	pBuffer;
+    WindowPtr	pWin;
+{
+    pBuffer->drawable.x      = pWin->drawable.x;
+    pBuffer->drawable.y      = pWin->drawable.y;
+    pBuffer->drawable.width  = pWin->drawable.width;
+    pBuffer->drawable.height = pWin->drawable.height;
+
+    pBuffer->drawable.serialNumber = NEXT_SERIAL_NUMBER;
+
+    /* Update for PaintWindowBackground */
+    pBuffer->parent = pWin->parent;
+
+    /*
+     * Make the borderClip the same as the clipList so
+     * NotClippedByChildren comes out with just clipList.
+     */
+
+    pBuffer->clipList   = pWin->clipList;
+    pBuffer->borderClip = pWin->clipList;
+    pBuffer->winSize    = pWin->winSize;
+    pBuffer->borderSize = pWin->borderSize;
+
+    pBuffer->origin = pWin->origin;
+}
+
+static BufferPtr
+bufCreateBuffer(pScreen, pWin, bufferNum)
+    ScreenPtr	pScreen;
+    WindowPtr	pWin;
+    int		bufferNum;
+{
+    mbufBufferPrivPtr	pMBPriv;
+    DevUnion	*devPrivates;
+    BufferPtr	pBuffer;
+    int		i;
+
+    pMBPriv = MB_SCREEN_PRIV_BUFFER(pScreen);
+
+    pBuffer = AllocateWindow(pWin->drawable.pScreen);
+    if (!pBuffer)
+	return (NULL);
+
+    /* XXX- Until we know what is needed, copy everything. */
+    devPrivates = pBuffer->devPrivates;
+    *pBuffer = *pWin;
+    pBuffer->devPrivates   = devPrivates;
+
+    pBuffer->drawable.type = DRAWABLE_BUFFER;
+    pBuffer->drawable.serialNumber = NEXT_SERIAL_NUMBER;
+
+    pBuffer->nextSib    = NULL;
+    pBuffer->prevSib    = NULL;
+    pBuffer->firstChild = NULL;
+    pBuffer->lastChild  = NULL;
+
+    /* XXX - Worry about backingstore later */
+    pBuffer->backStorage   = NULL;
+    pBuffer->backingStore  = NotUseful;
+
+    /* XXX - Need to call pScreen->CreateWindow for tile/stipples
+     *       or should I just copy the devPrivates?
+     */
+    
+    for (i=0; i < pScreen->WindowPrivateLen; i++)
+	pBuffer->devPrivates[i] = pWin->devPrivates[i];
+
+    pBuffer->devPrivates[frameWindowPrivateIndex] =
+	pMBPriv->frameBuffer[bufferNum];
+
+    return pBuffer;
+}
+
+static void
+bufDestroyBuffer(pDrawable)
+    DrawablePtr	pDrawable;
+{
+    xfree(pDrawable);
+}
+
+/*ARGSUSED*/
+static int
+bufCreateImageBuffers (pWin, nbuf, ids, action, hint)
+    WindowPtr	pWin;
+    int		nbuf;
+    XID		*ids;
+    int		action;
+    int		hint;
+{
+    ScreenPtr		pScreen;
+    mbufScreenPtr	pMBScreen;
+    mbufWindowPtr	pMBWindow;
+    mbufBufferPtr	pMBBuffer;
+    int			i;
+
+    pScreen   = pWin->drawable.pScreen;
+    pMBScreen = MB_SCREEN_PRIV(pScreen);
+    pMBWindow = MB_WINDOW_PRIV(pWin);
+
+    pMBWindow->devPrivate.ptr = (pointer) REGION_CREATE(pScreen, 0,0);
+    if (!pMBWindow->devPrivate.ptr)
+	return(0);
+    REGION_COPY(pScreen, (RegionPtr) pMBWindow->devPrivate.ptr,
+			    &pWin->clipList);
+
+    for (i = 0; i < nbuf; i++)
+    {
+	pMBBuffer = pMBWindow->buffers + i;
+	pMBBuffer->pDrawable = (DrawablePtr) bufCreateBuffer(pScreen,pWin,i);
+
+	if (!pMBBuffer->pDrawable)
+	    break;
+
+	if (!AddResource (ids[i], MultibufferDrawableResType,
+			  (pointer) pMBBuffer->pDrawable))
+	{
+	    bufDestroyBuffer((BufferPtr) pMBBuffer->pDrawable);
+	    break;
+	}
+	pMBBuffer->pDrawable->id = ids[i];
+
+	/*
+	 * If window is already mapped, generate exposures and
+	 * clear the area of the newly buffers.
+	 */
+
+	if ((pWin->realized) && (i != pMBWindow->displayedMultibuffer))
+	    (* pMBScreen->ClearImageBufferArea)(pMBBuffer, 0,0, 0,0, TRUE);
+    }
+
+    return i;
+}
+
+static void
+bufDestroyImageBuffers(pWin)
+    WindowPtr	pWin;
+{
+    ScreenPtr		pScreen;
+    mbufWindowPtr	pMBWindow;
+
+    pScreen   = pWin->drawable.pScreen;
+
+    if (pMBWindow = MB_WINDOW_PRIV(pWin))
+    {
+	mbufBufferPrivPtr pMBPriv = MB_SCREEN_PRIV_BUFFER(pScreen);
+
+	/*
+	 * if the backbuffer is currently being displayed, move the bits
+	 * to the frontbuffer and display it instead.
+	 */
+
+	if (pWin->realized && (pMBWindow->displayedMultibuffer == BACK_BUFFER))
+	{
+	    (* pMBPriv->CopyBufferBits)(pMBWindow, BACK_BUFFER, FRONT_BUFFER);
+	    REGION_SUBTRACT(pScreen, &pMBPriv->backBuffer,
+				  &pMBPriv->backBuffer, &pWin->clipList);
+	    (* pMBPriv->DrawSelectPlane)(pScreen, pMBPriv->selectPlane,
+			    &pWin->clipList, FRONT_BUFFER);
+	}
+
+	/* Switch window rendering to front buffer */
+	pWin->devPrivates[frameWindowPrivateIndex] =
+	    pMBPriv->frameBuffer[FRONT_BUFFER];
+
+	REGION_DESTROY(pScreen, (RegionPtr) pMBWindow->devPrivate.ptr);
+	pMBWindow->devPrivate.ptr = NULL;
+    }
+}
+
+/*
+ * Can be replaced by pScreen->ClearToBackground if pBuffer->eventMask
+ * and wOtherEventsMasks(pBuffer) were setup.
+ */
+
+static void
+bufClearImageBufferArea(pMBBuffer, x,y, w,h, generateExposures)
+    mbufBufferPtr	pMBBuffer;
+    short		x,y;
+    unsigned short	w,h;
+    Bool		generateExposures;
+{
+    BoxRec box;
+    RegionRec	reg;
+    RegionPtr pBSReg = NullRegion;
+    ScreenPtr	pScreen;
+    BoxPtr  extents;
+    int	    x1, y1, x2, y2;
+    BufferPtr pBuffer;
+
+    pBuffer = (BufferPtr) pMBBuffer->pDrawable;
+    /* compute everything using ints to avoid overflow */
+
+    x1 = pBuffer->drawable.x + x;
+    y1 = pBuffer->drawable.y + y;
+    if (w)
+        x2 = x1 + (int) w;
+    else
+        x2 = x1 + (int) pBuffer->drawable.width - (int) x;
+    if (h)
+        y2 = y1 + h;	
+    else
+        y2 = y1 + (int) pBuffer->drawable.height - (int) y;
+
+    extents = &pBuffer->clipList.extents;
+    
+    /* clip the resulting rectangle to the window clipList extents.  This
+     * makes sure that the result will fit in a box, given that the
+     * screen is < 32768 on a side.
+     */
+
+    if (x1 < extents->x1)
+	x1 = extents->x1;
+    if (x2 > extents->x2)
+	x2 = extents->x2;
+    if (y1 < extents->y1)
+	y1 = extents->y1;
+    if (y2 > extents->y2)
+	y2 = extents->y2;
+
+    if (x2 <= x1 || y2 <= y1)
+    {
+	x2 = x1 = 0;
+	y2 = y1 = 0;
+    }
+
+    box.x1 = x1;
+    box.x2 = x2;
+    box.y1 = y1;
+    box.y2 = y2;
+
+    pScreen = pBuffer->drawable.pScreen;
+    REGION_INIT(pScreen, &reg, &box, 1);
+    if (pBuffer->backStorage)
+    {
+	/*
+	 * If the window has backing-store on, call through the
+	 * ClearToBackground vector to handle the special semantics
+	 * (i.e. things backing store is to be cleared out and
+	 * an Expose event is to be generated for those areas in backing
+	 * store if generateExposures is TRUE).
+	 */
+	pBSReg = (* pScreen->ClearBackingStore)(pBuffer, x, y, w, h,
+						 generateExposures);
+    }
+
+    REGION_INTERSECT(pScreen, &reg, &reg, &pBuffer->clipList);
+    if (pBuffer->backgroundState != None)
+	(*pScreen->PaintWindowBackground)(pBuffer, &reg, PW_BACKGROUND);
+    if (generateExposures)
+	MultibufferExpose(pMBBuffer, &reg);
+#ifdef _notdef
+    /* XXBS - This is the original miClearToBackground code.
+     * WindowExposures needs to be called (or the functionality emulated)
+     * in order for backingStore to work, but first, pBuffer->eventMask
+     * and wOtherEventsMasks(pBuffer) need to be setup correctly.
+     */
+
+    if (generateExposures)
+	(*pScreen->WindowExposures)(pBuffer, &reg, pBSReg);
+    else if (pBuffer->backgroundState != None)
+        (*pScreen->PaintWindowBackground)(pBuffer, &reg, PW_BACKGROUND);
+#endif
+    REGION_UNINIT(pScreen, &reg);
+    if (pBSReg)
+	REGION_DESTROY(pScreen, pBSReg);
+}
+
+static void
+bufWrapScreenFuncs(pScreen)
+    ScreenPtr pScreen;
+{
+    mbufBufferPrivPtr pMBPriv = MB_SCREEN_PRIV_BUFFER(pScreen);
+
+    WRAP_SCREEN_FUNC(pScreen,pMBPriv,PostValidateTree, bufPostValidateTree);
+    WRAP_SCREEN_FUNC(pScreen,pMBPriv,ClipNotify, bufClipNotify);
+    WRAP_SCREEN_FUNC(pScreen,pMBPriv,WindowExposures,bufWindowExposures);
+    WRAP_SCREEN_FUNC(pScreen,pMBPriv,ChangeWindowAttributes, bufChangeWindowAttributes);
+    WRAP_SCREEN_FUNC(pScreen,pMBPriv,ClearToBackground,bufClearToBackground);
+    WRAP_SCREEN_FUNC(pScreen,pMBPriv,CopyWindow,bufCopyWindow);
+}
+
+static void
+bufResetProc(pScreen)
+    ScreenPtr pScreen;
+{
+    mbufBufferPrivPtr pMBPriv = MB_SCREEN_PRIV_BUFFER(pScreen);
+
+    /*
+     * frameBuffer, selectPlane, and pInfo should be freed by
+     * whoever called RegisterDoubleBufferHardware
+     */
+
+    REGION_UNINIT(pScreen, &pMBPriv->backBuffer);
+    REGION_UNINIT(pScreen, &pMBPriv->subtractRgn);
+    REGION_UNINIT(pScreen, &pMBPriv->unionRgn);
+    xfree(pMBPriv);
+}
+
+/*---------------------------------------------------------------------------*/
+
+/* 
+ * Used if CopyBufferBitsFunc is not provided when registering.
+ * This should work for everybody since CopyArea needs to support
+ * copying between buffers anyway.
+ */
+
+static void
+bufCopyBufferBits(pMBWindow, srcBufferNum, dstBufferNum)
+    mbufWindowPtr pMBWindow;
+    int srcBufferNum, dstBufferNum;
+{
+    DrawablePtr pSrcBuffer, pDstBuffer;
+    GCPtr pGC;
+
+    pSrcBuffer = pMBWindow->buffers[srcBufferNum].pDrawable;
+    pDstBuffer = pMBWindow->buffers[dstBufferNum].pDrawable;
+
+    pGC = GetScratchGC (pDstBuffer->depth, pDstBuffer->pScreen);
+    if (!pGC)
+	return;
+
+    ValidateGC (pDstBuffer, pGC);
+    (* pGC->ops->CopyArea) (pSrcBuffer, pDstBuffer, pGC,
+		    0,0, pDstBuffer->width, pDstBuffer->height, 0,0);
+    FreeScratchGC (pGC);
+}
+
+/*
+ * Used if DrawSelectPlanFunc is not provided for when registering.
+ * However, it only works if selectPlane.ptr is a drawable. Also
+ * assumes that painting with color 0 selects the front buffer,
+ * while color 1 selects the back buffer.
+ */
+
+static void
+bufDrawSelectPlane(pScreen, selectPlane, prgn, bufferNum)
+    ScreenPtr	pScreen;
+    DevUnion	selectPlane;
+    RegionPtr	prgn;
+    long	bufferNum;
+{
+    DrawablePtr pDrawable;
+    GCPtr pGC;
+    register int i;
+    register BoxPtr pbox;
+    register xRectangle *prect;
+    int numRects;
+    XID	value;
+
+    if (REGION_NUM_RECTS(prgn) == 0)
+	return;
+
+    pDrawable = (DrawablePtr) selectPlane.ptr;
+    pGC = GetScratchGC (pDrawable->depth, pScreen);
+    if (!pGC)
+	return;
+
+    prect = (xRectangle *)ALLOCATE_LOCAL(REGION_NUM_RECTS(prgn) *
+					 sizeof(xRectangle));
+    if (!prect)
+    {
+	FreeScratchGC(pGC);
+	return;
+    }
+
+    value = (XID) bufferNum;
+    DoChangeGC(pGC, GCForeground, &value, 0);
+    ValidateGC(pDrawable, pGC);
+
+    numRects = REGION_NUM_RECTS(prgn);
+    pbox = REGION_RECTS(prgn);
+    for (i= numRects; --i >= 0; pbox++, prect++)
+    {
+	prect->x = pbox->x1;
+	prect->y = pbox->y1;
+	prect->width = pbox->x2 - pbox->x1;
+	prect->height = pbox->y2 - pbox->y1;
+    }
+    prect -= numRects;
+    (* pGC->ops->PolyFillRect)(pDrawable, pGC, numRects, prect);
+
+    DEALLOCATE_LOCAL(prect);
+    FreeScratchGC (pGC);
+}
+
+
+static void
+bufDisplayImageBuffers(pScreen, ppMBWindow, ppMBBuffer, nbuf)
+    ScreenPtr		pScreen;
+    mbufBufferPtr	*ppMBBuffer;
+    mbufWindowPtr	*ppMBWindow;
+    int			nbuf;
+{
+    WindowPtr       pWin;
+    BufferPtr	    pPrevBuffer, pNewBuffer;
+    int		    i, number;
+    mbufBufferPrivPtr pMBPriv;
+    mbufBufferPtr   pPrevMBBuffer;
+
+    pMBPriv   = MB_SCREEN_PRIV_BUFFER(pScreen);
+
+    for (i = 0; i < nbuf; i++)
+    {
+	number = ppMBBuffer[i]->number; /* 0=frontbuffer, 1=backbuffer */
+	pWin = ppMBWindow[i]->pWindow;
+	pPrevMBBuffer = MB_DISPLAYED_BUFFER(ppMBWindow[i]);
+
+	pPrevBuffer = (BufferPtr) pPrevMBBuffer->pDrawable;
+	pNewBuffer  = (BufferPtr) ppMBBuffer[i]->pDrawable;
+
+	if (pPrevBuffer != pNewBuffer)
+	{
+	    RegionPtr backBuffer = &pMBPriv->backBuffer;
+
+	    /*
+	     * Update the select plane and the backBuffer region.
+	     */
+
+	    (* pMBPriv->DrawSelectPlane)(pScreen, pMBPriv->selectPlane,
+			    &pWin->clipList, number);
+
+	    if (number == BACK_BUFFER)
+		REGION_UNION(pScreen, backBuffer, backBuffer,
+				   &pWin->clipList);
+	    else
+		REGION_SUBTRACT(pScreen, backBuffer, backBuffer,
+				   &pWin->clipList);
+
+	    /* Switch which framebuffer the window draws into */
+	    pWin->devPrivates[frameWindowPrivateIndex] =
+		pMBPriv->frameBuffer[number];
+	}
+
+	switch (ppMBWindow[i]->updateAction)
+	{
+	case MultibufferUpdateActionUndefined:
+	    break;
+	case MultibufferUpdateActionBackground:
+	    (* MB_SCREEN_PRIV(pScreen)->ClearImageBufferArea)
+		(pPrevMBBuffer, 0,0, 0,0, FALSE);
+	    break;
+	case MultibufferUpdateActionUntouched:
+	    break;
+	case MultibufferUpdateActionCopied:
+	    if (pPrevBuffer != pNewBuffer)
+	    {
+		(* pMBPriv->CopyBufferBits) (ppMBWindow[i],
+			ppMBBuffer[i]->number, pPrevMBBuffer->number);
+	    }
+	    break;
+	}
+    }
+}
+
+/* Updates the backBuffer region and paints the selectPlane. */
+
+static void
+bufPostValidateTree(pParent, pChild, kind)
+    WindowPtr	pParent, pChild;
+    VTKind	kind;
+{
+    ScreenPtr pScreen;
+    mbufBufferPrivPtr pMBPriv;
+
+    if (pParent)
+	pScreen = pParent->drawable.pScreen;
+    else if (pChild)
+	pScreen = pChild->drawable.pScreen;
+    else
+	return; /* Hopeless */
+
+    pMBPriv = MB_SCREEN_PRIV_BUFFER(pScreen);
+
+    UNWRAP_SCREEN_FUNC(pScreen, pMBPriv, void, PostValidateTree);
+    if (pScreen->PostValidateTree)
+	(* pScreen->PostValidateTree)(pParent, pChild, kind);
+    REWRAP_SCREEN_FUNC(pScreen, pMBPriv, void, PostValidateTree);
+
+    /* Does backBuffer need to change? */
+    if (pMBPriv->rgnChanged)
+    {
+	RegionRec exposed;
+	RegionPtr pSubtractRgn, pUnionRgn;
+	Bool overlap;
+
+	pMBPriv->rgnChanged = FALSE;
+
+	pSubtractRgn = &pMBPriv->subtractRgn;
+	pUnionRgn    = &pMBPriv->unionRgn;
+	REGION_VALIDATE(pScreen, pSubtractRgn, &overlap);
+#ifdef DEBUG
+	if (overlap)
+	    FatalError("bufPostValidateTree: subtractRgn overlaps");
+#endif
+	REGION_VALIDATE(pScreen, pUnionRgn, &overlap);
+#ifdef DEBUG
+	if (overlap)
+	    FatalError("bufPostValidateTree: unionRgn overlaps");
+#endif
+
+	/* Update backBuffer: subtract must come before union */
+	REGION_SUBTRACT(pScreen, &pMBPriv->backBuffer, &pMBPriv->backBuffer,
+			      pSubtractRgn);
+	REGION_UNION(pScreen, &pMBPriv->backBuffer, &pMBPriv->backBuffer,
+			      pUnionRgn);
+
+	/* Paint gained and lost backbuffer areas in select plane */
+	REGION_NULL(pScreen, &exposed);
+	REGION_SUBTRACT(pScreen, &exposed, pSubtractRgn, pUnionRgn);
+	(* pMBPriv->DrawSelectPlane)(pScreen, pMBPriv->selectPlane,
+				     &exposed, FRONT_BUFFER);
+
+	REGION_SUBTRACT(pScreen, &exposed, pUnionRgn, pSubtractRgn);
+	(* pMBPriv->DrawSelectPlane)(pScreen, pMBPriv->selectPlane,
+				    &exposed, BACK_BUFFER);
+	
+	REGION_UNINIT(pScreen, &exposed);
+	REGION_EMPTY(pScreen, pSubtractRgn);
+	REGION_EMPTY(pScreen, pUnionRgn);
+    }
+}
+
+/*
+ * If the window is multibuffered and displaying the backbuffer,
+ * add the old clipList to the subtractRgn and add the new clipList
+ * to the unionRgn. PostValidateTree will use subtractRgn and unionRgn
+ * to update the backBuffer region and the selectPlane.
+ *
+ * Copy changes to the window structure into the buffers.
+ * Send ClobberNotify events.
+ */
+
+static void
+bufClipNotify(pWin, dx,dy)
+    WindowPtr pWin;
+    int       dx,dy;
+{
+    ScreenPtr pScreen = pWin->drawable.pScreen;
+    mbufBufferPrivPtr pMBPriv = MB_SCREEN_PRIV_BUFFER(pScreen);
+    mbufWindowPtr	pMBWindow;
+    int i;
+
+    UNWRAP_SCREEN_FUNC(pScreen, pMBPriv, void, ClipNotify);
+    if (pScreen->ClipNotify)
+	(* pScreen->ClipNotify)(pWin, dx,dy);
+    REWRAP_SCREEN_FUNC(pScreen, pMBPriv, void, ClipNotify);
+
+    if (pMBWindow = MB_WINDOW_PRIV(pWin))
+    {
+	RegionPtr pOldClipList = (RegionPtr) pMBWindow->devPrivate.ptr;
+
+	if (! REGION_EQUAL(pScreen, pOldClipList, &pWin->clipList))
+	{
+	    if (pMBWindow->displayedMultibuffer == BACK_BUFFER)
+	    {
+		pMBPriv->rgnChanged = TRUE;
+		REGION_APPEND(pScreen, &pMBPriv->subtractRgn, pOldClipList);
+		REGION_APPEND(pScreen, &pMBPriv->unionRgn, &pWin->clipList);
+	    }
+
+	    REGION_COPY(pScreen, pOldClipList,&pWin->clipList);
+	}
+
+	/* Update buffer x,y,w,h, and clipList */
+	for (i=0; i<pMBWindow->numMultibuffer; i++)
+	{
+	    mbufBufferPtr pMBBuffer = pMBWindow->buffers + i;
+	    if (pMBBuffer->clobber != pWin->visibility)
+	    {
+		pMBBuffer->clobber = pWin->visibility;
+		MultibufferClobber(pMBBuffer);
+	    }
+	    UpdateBufferFromWindow(pMBBuffer->pDrawable, pWin);
+	}
+    }
+}
+
+/*
+ * Updates buffer's background fields when the window's changes.
+ * This is necessary because pScreen->PaintWindowBackground
+ * is used to paint the buffer.
+ *
+ * XXBS - Backingstore state will have be tracked too if it is supported.
+ */
+
+static Bool
+bufChangeWindowAttributes(pWin, mask)
+    WindowPtr pWin;
+    unsigned long mask;
+{
+    ScreenPtr pScreen = pWin->drawable.pScreen;
+    mbufBufferPrivPtr pMBPriv = MB_SCREEN_PRIV_BUFFER(pScreen);
+    mbufWindowPtr pMBWindow;
+    Bool ret;
+
+    UNWRAP_SCREEN_FUNC(pScreen, pMBPriv, Bool, ChangeWindowAttributes);
+    ret = (* pScreen->ChangeWindowAttributes)(pWin, mask);
+    REWRAP_SCREEN_FUNC(pScreen, pMBPriv, Bool, ChangeWindowAttributes);
+
+    if (pMBWindow = MB_WINDOW_PRIV(pWin))
+    {
+	if (mask & (CWBackPixmap | CWBackPixel))
+	{
+	    BufferPtr pBuffer;
+	    int i;
+
+	    for (i=0; i<pMBWindow->displayedMultibuffer; i++)
+	    {
+		pBuffer = (BufferPtr) pMBWindow->buffers[i].pDrawable;
+		pBuffer->backgroundState = pWin->backgroundState;
+		pBuffer->background = pWin->background;
+	    }
+	}
+    }
+    return ret;
+}
+
+/*
+ * Send exposures and clear the background for a buffer whenever
+ * its corresponding window is exposed, except when called by
+ * ClearToBackground.
+ */
+
+static void 
+bufWindowExposures(pWin, prgn, other_exposed)
+    WindowPtr pWin;
+    register RegionPtr prgn, other_exposed;
+{
+    ScreenPtr pScreen = pWin->drawable.pScreen;
+    mbufWindowPtr pMBWindow = MB_WINDOW_PRIV(pWin);
+    mbufBufferPrivPtr pMBPriv = MB_SCREEN_PRIV_BUFFER(pScreen);
+    RegionRec tmp_rgn;
+    int i;
+    Bool handleBuffers;
+
+    handleBuffers = (!pMBPriv->inClearToBackground) &&
+	(pWin->drawable.type == DRAWABLE_WINDOW) &&
+	pMBWindow && (prgn && !REGION_NIL(prgn));
+
+    /* miWindowExposures munges prgn and other_exposed. */
+    if (handleBuffers)
+    {
+	REGION_NULL(pScreen, &tmp_rgn);
+	REGION_COPY(pScreen, &tmp_rgn, prgn);
+    }
+
+    UNWRAP_SCREEN_FUNC(pScreen, pMBPriv, void, WindowExposures);
+    (* pScreen->WindowExposures) (pWin, prgn, other_exposed);
+    REWRAP_SCREEN_FUNC(pScreen, pMBPriv, void, WindowExposures);
+
+    if (!handleBuffers)
+	return;
+
+    /*
+     * Send expose events to all clients. Paint the exposed region for all
+     * buffers except the displayed buffer since it is handled when the
+     * window is painted.
+     *
+     * XXBS - Will have to be re-written to handle BackingStore on buffers.
+     */
+
+    for (i=0; i<pMBWindow->numMultibuffer; i++)
+    {
+	mbufBufferPtr pMBBuffer;
+	BufferPtr pBuffer;
+
+	pMBBuffer = pMBWindow->buffers + i;
+	pBuffer = (BufferPtr) pMBBuffer->pDrawable;
+
+	if (i != pMBWindow->displayedMultibuffer)
+	    (* pScreen->PaintWindowBackground)(pBuffer,&tmp_rgn,PW_BACKGROUND);
+	if ((pMBBuffer->otherEventMask | pMBBuffer->eventMask) & ExposureMask)
+	    MultibufferExpose(pMBBuffer, &tmp_rgn);
+    }
+
+    REGION_UNINIT(pScreen, &tmp_rgn);
+}
+
+/*
+ * Set ``inClearToBackground'' so that WindowExposures does not attempt
+ * to send expose events or clear the background on the buffers.
+ */
+
+static void
+bufClearToBackground(pWin, x,y,w,h, sendExpose)
+    WindowPtr pWin;
+    int x,y, w,h;
+    Bool sendExpose;
+{
+    ScreenPtr pScreen = pWin->drawable.pScreen;
+    mbufBufferPrivPtr pMBPriv = MB_SCREEN_PRIV_BUFFER(pScreen);
+
+    pMBPriv->inClearToBackground = TRUE;
+
+    UNWRAP_SCREEN_FUNC(pScreen, pMBPriv, void, ClearToBackground);
+    (* pScreen->ClearToBackground)(pWin, x,y,w,h, sendExpose);
+    REWRAP_SCREEN_FUNC(pScreen, pMBPriv, void, ClearToBackground);
+
+    pMBPriv->inClearToBackground = FALSE;
+}
+
+/*
+ * Move bits in both buffers. It does this by calling pScreen->CopyWindow
+ * twice, once with the root window's devPrivate[frameWindowPrivateIndex]
+ * pointing to the frontbuffer pixmap and once with it pointed to the
+ * backbuffer pixmap. It does this if there are *any* existing multibuffered
+ * window... a possible optimization is to copy the backbuffer only if this
+ * window or its inferiors are multibuffered. May be faster, maybe not.
+ *
+ * XXX - Only works if your CopyWindow checks the root window's devPrivate
+ *       to see which buffer to draw into. Works for cfbPaintWindow.
+ */
+
+/*ARGSUSED*/
+static void 
+bufCopyWindow(pWin, ptOldOrg, prgnSrc)
+    WindowPtr pWin;
+    DDXPointRec ptOldOrg;
+    RegionPtr prgnSrc;
+{
+    ScreenPtr pScreen = pWin->drawable.pScreen;
+    mbufBufferPrivPtr pMBPriv = MB_SCREEN_PRIV_BUFFER(pScreen);
+    WindowPtr pwinroot;
+    DevUnion save;
+
+    UNWRAP_SCREEN_FUNC(pScreen, pMBPriv, void, CopyWindow);
+
+    pwinroot = WindowTable[pScreen->myNum];
+    save = pwinroot->devPrivates[frameWindowPrivateIndex];
+
+    /*
+     * Copy front buffer
+     */
+
+    pwinroot->devPrivates[frameWindowPrivateIndex] =
+	pMBPriv->frameBuffer[FRONT_BUFFER];
+    (* pScreen->CopyWindow)(pWin, ptOldOrg, prgnSrc);
+
+    /*
+     * Copy back buffer
+     */
+
+    /* CopyWindow translates prgnSrc... translate it back for 2nd call. */
+    REGION_TRANSLATE(pScreen, prgnSrc,
+				  ptOldOrg.x - pWin->drawable.x,
+				  ptOldOrg.y - pWin->drawable.y);
+    pwinroot->devPrivates[frameWindowPrivateIndex] =
+	pMBPriv->frameBuffer[BACK_BUFFER];
+    (* pScreen->CopyWindow)(pWin, ptOldOrg, prgnSrc);
+
+    pwinroot->devPrivates[frameWindowPrivateIndex] = save;
+    REWRAP_SCREEN_FUNC(pScreen, pMBPriv, void, CopyWindow);
+}