dmxextension.c

/* $XFree86$ */
/*
 * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
 *
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation on the rights to use, copy, modify, merge,
 * publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) 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
 * NON-INFRINGEMENT.  IN NO EVENT SHALL RED HAT AND/OR THEIR SUPPLIERS
 * 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.
 */

/*
 * Author:
 *   Rickard E. (Rik) Faith <faith@redhat.com>
 *   Kevin E. Martin <kem@redhat.com>
 *
 */

/** \file
 * This file provides the only interface to the X server extension support
 * in programs/Xserver/Xext.  Those programs should only include dmxext.h
 */

#ifdef HAVE_DMX_CONFIG_H
#include <dmx-config.h>
#endif

#include "dmx.h"
#include "dmxinit.h"
#include "dmxextension.h"
#include "dmxwindow.h"
#include "dmxcb.h"
#include "dmxcursor.h"
#include "dmxpixmap.h"
#include "dmxgc.h"
#include "dmxfont.h"
#include "dmxcmap.h"
#ifdef RENDER
#include "dmxpict.h"
#endif
#include "dmxinput.h"
#include "dmxsync.h"
#include "dmxscrinit.h"
#include "input/dmxinputinit.h"

#include "windowstr.h"
#include "inputstr.h"                 /* For DeviceIntRec */
#include <X11/extensions/dmxproto.h>  /* For DMX_BAD_* */
#include "cursorstr.h"

/* The default font is declared in dix/globals.c, but is not included in
 * _any_ header files. */
extern FontPtr  defaultFont;
    
/** This routine provides information to the DMX protocol extension
 * about a particular screen. */
Bool dmxGetScreenAttributes(int physical, DMXScreenAttributesPtr attr)
{
    DMXScreenInfo *dmxScreen;

    if (physical < 0 || physical >= dmxNumScreens) return FALSE;

    dmxScreen = &dmxScreens[physical];
    attr->displayName         = dmxScreen->name;
#ifdef PANORAMIX
    attr->logicalScreen       = noPanoramiXExtension ? dmxScreen->index : 0;
#else
    attr->logicalScreen       = dmxScreen->index;
#endif

    attr->screenWindowWidth   = dmxScreen->scrnWidth;
    attr->screenWindowHeight  = dmxScreen->scrnHeight;
    attr->screenWindowXoffset = dmxScreen->scrnX;
    attr->screenWindowYoffset = dmxScreen->scrnY;

    attr->rootWindowWidth     = dmxScreen->rootWidth;
    attr->rootWindowHeight    = dmxScreen->rootHeight;
    attr->rootWindowXoffset   = dmxScreen->rootX;
    attr->rootWindowYoffset   = dmxScreen->rootY;

    attr->rootWindowXorigin   = dmxScreen->rootXOrigin;
    attr->rootWindowYorigin   = dmxScreen->rootYOrigin;

    return TRUE;
}

/** This routine provides information to the DMX protocol extension
 * about a particular window. */
Bool dmxGetWindowAttributes(WindowPtr pWindow, DMXWindowAttributesPtr attr)
{
    dmxWinPrivPtr pWinPriv = DMX_GET_WINDOW_PRIV(pWindow);

    attr->screen         = pWindow->drawable.pScreen->myNum;
    attr->window         = pWinPriv->window;

    attr->pos.x          = pWindow->drawable.x;
    attr->pos.y          = pWindow->drawable.y;
    attr->pos.width      = pWindow->drawable.width;
    attr->pos.height     = pWindow->drawable.height;

    if (!pWinPriv->window || pWinPriv->offscreen) {
        attr->vis.x      = 0;
        attr->vis.y      = 0;
        attr->vis.height = 0;
        attr->vis.width  = 0;
        return pWinPriv->window ? TRUE : FALSE;
    }

                                /* Compute display-relative coordinates */
    attr->vis.x          = pWindow->drawable.x;
    attr->vis.y          = pWindow->drawable.y;
    attr->vis.width      = pWindow->drawable.width;
    attr->vis.height     = pWindow->drawable.height;

    if (attr->pos.x < 0) {
        attr->vis.x     -= attr->pos.x;
        attr->vis.width  = attr->pos.x + attr->pos.width - attr->vis.x;
    }
    if (attr->pos.x + attr->pos.width > pWindow->drawable.pScreen->width) {
        if (attr->pos.x < 0)
            attr->vis.width  = pWindow->drawable.pScreen->width;
        else
            attr->vis.width  = pWindow->drawable.pScreen->width - attr->pos.x;
    }
    if (attr->pos.y < 0) {
        attr->vis.y     -= attr->pos.y;
        attr->vis.height = attr->pos.y + attr->pos.height - attr->vis.y;
    }
    if (attr->pos.y + attr->pos.height > pWindow->drawable.pScreen->height) {
        if (attr->pos.y < 0)
            attr->vis.height = pWindow->drawable.pScreen->height;
        else
            attr->vis.height = pWindow->drawable.pScreen->height - attr->pos.y;
    }

                                /* Convert to window-relative coordinates */
    attr->vis.x -= attr->pos.x;
    attr->vis.y -= attr->pos.y;

    return TRUE;
}

void dmxGetDesktopAttributes(DMXDesktopAttributesPtr attr)
{
    attr->width  = dmxGlobalWidth;
    attr->height = dmxGlobalHeight;
    attr->shiftX = 0;            /* NOTE: The upper left hand corner of */
    attr->shiftY = 0;            /*       the desktop is always <0,0>. */
}

/** Return the total number of devices, not just #dmxNumInputs.  The
 * number returned should be the same as that returned by
 * XListInputDevices. */
int dmxGetInputCount(void)
{
    int i, total;
    
    for (total = i = 0; i < dmxNumInputs; i++) total += dmxInputs[i].numDevs;
    return total;
}

/** Return information about the device with id = \a deviceId.  This
 * information is primarily for the #ProcDMXGetInputAttributes()
 * function, which does not have access to the appropriate data
 * structure. */
int dmxGetInputAttributes(int deviceId, DMXInputAttributesPtr attr)
{
    int          i, j;
    DMXInputInfo *dmxInput;

    if (deviceId < 0) return -1;
    for (i = 0; i < dmxNumInputs; i++) {
        dmxInput = &dmxInputs[i];
        for (j = 0; j < dmxInput->numDevs; j++) {
            DMXLocalInputInfoPtr dmxLocal = dmxInput->devs[j];
            if (deviceId != dmxLocal->pDevice->id) continue;
            attr->isCore             = !!dmxLocal->isCore;
            attr->sendsCore          = !!dmxLocal->sendsCore;
            attr->detached           = !!dmxInput->detached;
            attr->physicalScreen     = -1;
            attr->physicalId         = -1;
            attr->name               = NULL;
            switch (dmxLocal->extType) {
            case DMX_LOCAL_TYPE_LOCAL:
                attr->inputType      = 0;
                break;
            case DMX_LOCAL_TYPE_CONSOLE:
                attr->inputType      = 1;
                attr->name           = dmxInput->name;
                attr->physicalId     = dmxLocal->deviceId;
                break;
            case DMX_LOCAL_TYPE_BACKEND:
            case DMX_LOCAL_TYPE_COMMON:
                attr->inputType      = 2;
                attr->physicalScreen = dmxInput->scrnIdx;
                attr->name           = dmxInput->name;
                attr->physicalId     = dmxLocal->deviceId;
                break;
            }
            return 0;           /* Success */
        }
    }
    return -1;                  /* Failure */
}

/** Reinitialized the cursor boundaries. */
static void dmxAdjustCursorBoundaries(void)
{
    int           i;

    dmxReInitOrigins();
    dmxInitOverlap();
    dmxComputeWidthHeight(DMX_NO_RECOMPUTE_BOUNDING_BOX);
    dmxConnectionBlockCallback();
    for (i = 0; i < dmxNumInputs; i++) {
        DMXInputInfo *dmxInput = &dmxInputs[i];
	if (!dmxInput->detached) dmxInputReInit(dmxInput);
    }

    dmxCheckCursor();

    for (i = 0; i < dmxNumInputs; i++) {
        DMXInputInfo *dmxInput = &dmxInputs[i];
	if (!dmxInput->detached) dmxInputLateReInit(dmxInput);
    }
}

/** Add an input with the specified attributes.  If the input is added,
 * the physical id is returned in \a deviceId. */
int dmxAddInput(DMXInputAttributesPtr attr, int *id)
{
    int retcode = BadValue;

    if (attr->inputType == 1)   /* console */
        retcode = dmxInputAttachConsole(attr->name, attr->sendsCore, id);
    else if (attr->inputType == 2)   /* backend */
        retcode = dmxInputAttachBackend(attr->physicalScreen,
                                        attr->sendsCore,id);

    if (retcode == Success) {
        /* Adjust the cursor boundaries */
        dmxAdjustCursorBoundaries();

        /* Force completion of the changes */
        dmxSync(NULL, TRUE);
    }

    return retcode;
}

/** Remove the input with physical id \a id. */
int dmxRemoveInput(int id)
{
    return dmxInputDetachId(id);
}

/** Return the value of #dmxNumScreens -- the total number of backend
 * screens in use (these are logical screens and may be larger than the
 * number of backend displays). */
unsigned long dmxGetNumScreens(void)
{
    return dmxNumScreens;
}

/** Make sure that #dmxCreateAndRealizeWindow has been called for \a
 * pWindow. */
void dmxForceWindowCreation(WindowPtr pWindow)
{
    dmxWinPrivPtr pWinPriv = DMX_GET_WINDOW_PRIV(pWindow);
    if (!pWinPriv->window) dmxCreateAndRealizeWindow(pWindow, TRUE);
}

/** Flush pending syncs for all screens. */
void dmxFlushPendingSyncs(void)
{
    dmxSync(NULL, TRUE);
}

/** Update DMX's screen resources to match those of the newly moved
 *  and/or resized "root" window. */
void dmxUpdateScreenResources(ScreenPtr pScreen, int x, int y, int w, int h)
{
    DMXScreenInfo *dmxScreen = &dmxScreens[pScreen->myNum];
    WindowPtr      pRoot     = WindowTable[pScreen->myNum];
    WindowPtr      pChild;
    Bool           anyMarked = FALSE;

    /* Handle special case where width and/or height are zero */
    if (w == 0 || h == 0) {
	w = 1;
	h = 1;
    }

    /* Change screen size */
    pScreen->width  = w;
    pScreen->height = h;

    /* Reset the root window's drawable's size */
    pRoot->drawable.width  = w;
    pRoot->drawable.height = h;

    /* Set the root window's new winSize and borderSize */
    pRoot->winSize.extents.x1 = 0;
    pRoot->winSize.extents.y1 = 0;
    pRoot->winSize.extents.x2 = w;
    pRoot->winSize.extents.y2 = h;

    pRoot->borderSize.extents.x1 = 0;
    pRoot->borderSize.extents.y1 = 0;
    pRoot->borderSize.extents.x2 = w;
    pRoot->borderSize.extents.y2 = h;

    /* Recompute this screen's mmWidth & mmHeight */
    pScreen->mmWidth =
	(w * 254 + dmxScreen->beXDPI * 5) / (dmxScreen->beXDPI * 10);
    pScreen->mmHeight =
	(h * 254 + dmxScreen->beYDPI * 5) / (dmxScreen->beYDPI * 10);

    /* Recompute this screen's window's clip rects as follows: */
    /*   1. Mark all of root's children's windows */
    for (pChild = pRoot->firstChild; pChild; pChild = pChild->nextSib)
	anyMarked |= pScreen->MarkOverlappedWindows(pChild, pChild,
						    (WindowPtr *)NULL);

    /*   2. Set the root window's borderClip */
    pRoot->borderClip.extents.x1 = 0;
    pRoot->borderClip.extents.y1 = 0;
    pRoot->borderClip.extents.x2 = w;
    pRoot->borderClip.extents.y2 = h;

    /*   3. Set the root window's clipList */
    if (anyMarked) {
	/* If any windows have been marked, set the root window's
	 * clipList to be broken since it will be recalculated in
	 * ValidateTree()
	 */
	REGION_BREAK(pScreen, &pRoot->clipList);
    } else {
	/* Otherwise, we just set it directly since there are no
	 * windows visible on this screen
	 */
	pRoot->clipList.extents.x1 = 0;
	pRoot->clipList.extents.y1 = 0;
	pRoot->clipList.extents.x2 = w;
	pRoot->clipList.extents.y2 = h;
    }

    /*   4. Revalidate all clip rects and generate expose events */
    if (anyMarked) {
	pScreen->ValidateTree(pRoot, NULL, VTBroken);
	pScreen->HandleExposures(pRoot);
	if (pScreen->PostValidateTree)
	    pScreen->PostValidateTree(pRoot, NULL, VTBroken);
    }
}

#ifdef PANORAMIX
#include "panoramiXsrv.h"

/* Defined in dix/events.c */
extern void ReinitializeRootWindow(WindowPtr win, int xoff, int yoff);

/** Change the "screen" window attributes by resizing the actual window
 *  on the back-end display (if necessary). */
static void dmxConfigureScreenWindow(int idx,
				     int x, int y, int w, int h)
{
    DMXScreenInfo *dmxScreen = &dmxScreens[idx];
    ScreenPtr      pScreen   = screenInfo.screens[idx];

    /* Resize "screen" window */
    if (dmxScreen->scrnX      != x ||
	dmxScreen->scrnY      != y ||
	dmxScreen->scrnWidth  != w ||
	dmxScreen->scrnHeight != h) {
	dmxResizeScreenWindow(pScreen, x, y, w, h);
    }

    /* Change "screen" window values */
    dmxScreen->scrnX      = x;
    dmxScreen->scrnY      = y;
    dmxScreen->scrnWidth  = w;
    dmxScreen->scrnHeight = h;
}
				     
/** Change the "root" window position and size by resizing the actual
 *  window on the back-end display (if necessary) and updating all of
 *  DMX's resources by calling #dmxUpdateScreenResources. */
static void dmxConfigureRootWindow(int idx, int x, int y, int w, int h)
{
    DMXScreenInfo *dmxScreen = &dmxScreens[idx];
    WindowPtr      pRoot     = WindowTable[idx];

    /* NOTE: Either this function or the ones that it calls must handle
     * the case where w == 0 || h == 0.  Currently, the functions that
     * this one calls handle that case. */

    /* 1. Resize "root" window */
    if (dmxScreen->rootX      != x ||
	dmxScreen->rootY      != y ||
	dmxScreen->rootWidth  != w ||
	dmxScreen->rootHeight != h) {
	dmxResizeRootWindow(pRoot, x, y, w, h);
    }

    /* 2. Update all of the screen's resources associated with this root
     *    window */
    if (dmxScreen->rootWidth  != w ||
	dmxScreen->rootHeight != h) {
	dmxUpdateScreenResources(screenInfo.screens[idx], x, y, w, h);
    }

    /* Change "root" window values */
    dmxScreen->rootX      = x;
    dmxScreen->rootY      = y;
    dmxScreen->rootWidth  = w;
    dmxScreen->rootHeight = h;
}

/** Change the "root" window's origin by updating DMX's internal data
 *  structures (dix and Xinerama) to use the new origin and adjust the
 *  positions of windows that overlap this "root" window. */
static void dmxSetRootWindowOrigin(int idx, int x, int y)
{
    DMXScreenInfo *dmxScreen = &dmxScreens[idx];
    ScreenPtr      pScreen   = screenInfo.screens[idx];
    WindowPtr      pRoot     = WindowTable[idx];
    WindowPtr      pChild;
    int            xoff;
    int            yoff;

    /* Change "root" window's origin */
    dmxScreen->rootXOrigin = x;
    dmxScreen->rootYOrigin = y;

    /* Compute offsets here in case <x,y> has been changed above */
    xoff = x - dixScreenOrigins[idx].x;
    yoff = y - dixScreenOrigins[idx].y;

    /* Adjust the root window's position in dixScreenOrigins */
    dixScreenOrigins[idx].x = dmxScreen->rootXOrigin;
    dixScreenOrigins[idx].y = dmxScreen->rootYOrigin;

    /* Recalculate the Xinerama regions and data structs */
    XineramaReinitData(pScreen);

    /* Adjust each of the root window's children */
    if (!idx) ReinitializeRootWindow(WindowTable[0], xoff, yoff);
    pChild = pRoot->firstChild;
    while (pChild) {
	/* Adjust child window's position */
	pScreen->MoveWindow(pChild,
			    pChild->origin.x - wBorderWidth(pChild) - xoff,
			    pChild->origin.y - wBorderWidth(pChild) - yoff,
			    pChild->nextSib,
			    VTMove);

	/* Note that the call to MoveWindow will eventually call
	 * dmxPositionWindow which will automatically create a
	 * window if it is now exposed on screen (for lazy window
	 * creation optimization) and it will properly set the
	 * offscreen flag.
	 */

	pChild = pChild->nextSib;
    }
}

/** Configure the attributes of each "screen" and "root" window. */
int dmxConfigureScreenWindows(int nscreens,
			      CARD32 *screens,
			      DMXScreenAttributesPtr attribs,
			      int *errorScreen)
{
    int           i;

    for (i = 0; i < nscreens; i++) {
	DMXScreenAttributesPtr  attr      = &attribs[i];
	int                     idx       = screens[i];
	DMXScreenInfo          *dmxScreen = &dmxScreens[idx];

	if (errorScreen) *errorScreen = i;

	if (!dmxScreen->beDisplay) return DMX_BAD_VALUE;

	/* Check for illegal values */
	if (idx < 0 || idx >= dmxNumScreens) return BadValue;

	/* The "screen" and "root" windows must have valid sizes */
	if (attr->screenWindowWidth <= 0 || attr->screenWindowHeight <= 0 ||
	    attr->rootWindowWidth   <  0 || attr->rootWindowHeight   <  0)
	    return DMX_BAD_VALUE;

	/* The "screen" window must fit entirely within the BE display */
	if (attr->screenWindowXoffset < 0 ||
	    attr->screenWindowYoffset < 0 ||
	    attr->screenWindowXoffset
	    + attr->screenWindowWidth  > (unsigned)dmxScreen->beWidth ||
	    attr->screenWindowYoffset
	    + attr->screenWindowHeight > (unsigned)dmxScreen->beHeight)
	    return DMX_BAD_VALUE;

	/* The "root" window must fit entirely within the "screen" window */
	if (attr->rootWindowXoffset < 0 ||
	    attr->rootWindowYoffset < 0 ||
	    attr->rootWindowXoffset
	    + attr->rootWindowWidth  > attr->screenWindowWidth ||
	    attr->rootWindowYoffset
	    + attr->rootWindowHeight > attr->screenWindowHeight)
	    return DMX_BAD_VALUE;

	/* The "root" window must not expose unaddressable coordinates */
	if (attr->rootWindowXorigin < 0 ||
	    attr->rootWindowYorigin < 0 ||
	    attr->rootWindowXorigin + attr->rootWindowWidth  > 32767 ||
	    attr->rootWindowYorigin + attr->rootWindowHeight > 32767)
	    return DMX_BAD_VALUE;

	/* The "root" window must fit within the global bounding box */
	if (attr->rootWindowXorigin
	    + attr->rootWindowWidth > (unsigned)dmxGlobalWidth ||
	    attr->rootWindowYorigin
	    + attr->rootWindowHeight > (unsigned)dmxGlobalHeight)
	    return DMX_BAD_VALUE;

	/* FIXME: Handle the rest of the illegal value checking */
    }

    /* No illegal values found */
    if (errorScreen) *errorScreen = 0;

    for (i = 0; i < nscreens; i++) {
	DMXScreenAttributesPtr  attr      = &attribs[i];
	int                     idx       = screens[i];
	DMXScreenInfo          *dmxScreen = &dmxScreens[idx];

	dmxLog(dmxInfo, "Changing screen #%d attributes "
	       "from %dx%d+%d+%d %dx%d+%d+%d +%d+%d "
	       "to %dx%d+%d+%d %dx%d+%d+%d +%d+%d\n",
	       idx,
	       dmxScreen->scrnWidth,      dmxScreen->scrnHeight,
	       dmxScreen->scrnX,          dmxScreen->scrnY,
	       dmxScreen->rootWidth,      dmxScreen->rootHeight,
	       dmxScreen->rootX,          dmxScreen->rootY,
	       dmxScreen->rootXOrigin,    dmxScreen->rootYOrigin,
	       attr->screenWindowWidth,   attr->screenWindowHeight,
	       attr->screenWindowXoffset, attr->screenWindowYoffset,
	       attr->rootWindowWidth,     attr->rootWindowHeight,
	       attr->rootWindowXoffset,   attr->rootWindowYoffset,
	       attr->rootWindowXorigin,   attr->rootWindowYorigin);

	/* Configure "screen" window */
	dmxConfigureScreenWindow(idx,
				 attr->screenWindowXoffset,
				 attr->screenWindowYoffset,
				 attr->screenWindowWidth,
				 attr->screenWindowHeight);

	/* Configure "root" window */
	dmxConfigureRootWindow(idx,
			       attr->rootWindowXoffset,
			       attr->rootWindowYoffset,
			       attr->rootWindowWidth,
			       attr->rootWindowHeight);


	/* Set "root" window's origin */
	dmxSetRootWindowOrigin(idx,
			       attr->rootWindowXorigin,
			       attr->rootWindowYorigin);
    }

    /* Adjust the cursor boundaries */
    dmxAdjustCursorBoundaries();

    /* Force completion of the changes */
    dmxSync(NULL, TRUE);

    return Success;
}

/** Configure the attributes of the global desktop. */
int dmxConfigureDesktop(DMXDesktopAttributesPtr attribs)
{
    if (attribs->width  <= 0 || attribs->width  >= 32767 ||
	attribs->height <= 0 || attribs->height >= 32767)
	return DMX_BAD_VALUE;

    /* If the desktop is shrinking, adjust the "root" windows on each
     * "screen" window to only show the visible desktop.  Also, handle
     * the special case where the desktop shrinks such that the it no
     * longer overlaps an portion of a "screen" window. */
    if (attribs->width < dmxGlobalWidth || attribs->height < dmxGlobalHeight) {
	int   i;
	for (i = 0; i < dmxNumScreens; i++) {
	    DMXScreenInfo *dmxScreen = &dmxScreens[i];
	    if (dmxScreen->rootXOrigin
		+ dmxScreen->rootWidth  > attribs->width ||
		dmxScreen->rootYOrigin
		+ dmxScreen->rootHeight > attribs->height) {
		int  w, h;
		if ((w = attribs->width  - dmxScreen->rootXOrigin) < 0) w = 0;
		if ((h = attribs->height - dmxScreen->rootYOrigin) < 0) h = 0;
		if (w > dmxScreen->scrnWidth)  w = dmxScreen->scrnWidth;
		if (h > dmxScreen->scrnHeight) h = dmxScreen->scrnHeight;
		if (w > dmxScreen->rootWidth)  w = dmxScreen->rootWidth;
		if (h > dmxScreen->rootHeight) h = dmxScreen->rootHeight;
		dmxConfigureRootWindow(i,
				       dmxScreen->rootX,
				       dmxScreen->rootY,
				       w, h);
	    }
	}
    }

    /* Set the global width/height */
    dmxSetWidthHeight(attribs->width, attribs->height);

    /* Handle shift[XY] changes */
    if (attribs->shiftX || attribs->shiftY) {
	int   i;
	for (i = 0; i < dmxNumScreens; i++) {
	    ScreenPtr  pScreen = screenInfo.screens[i];
	    WindowPtr  pChild  = WindowTable[i]->firstChild;
	    while (pChild) {
		/* Adjust child window's position */
		pScreen->MoveWindow(pChild,
				    pChild->origin.x - wBorderWidth(pChild)
				    - attribs->shiftX,
				    pChild->origin.y - wBorderWidth(pChild)
				    - attribs->shiftY,
				    pChild->nextSib,
				    VTMove);

		/* Note that the call to MoveWindow will eventually call
		 * dmxPositionWindow which will automatically create a
		 * window if it is now exposed on screen (for lazy
		 * window creation optimization) and it will properly
		 * set the offscreen flag.
		 */

		pChild = pChild->nextSib;
	    }
	}
    }

    /* Update connection block, Xinerama, etc. -- these appears to
     * already be handled in dmxConnectionBlockCallback(), which is
     * called from dmxAdjustCursorBoundaries() [below]. */

    /* Adjust the cursor boundaries */
    dmxAdjustCursorBoundaries();

    /* Force completion of the changes */
    dmxSync(NULL, TRUE);

    return Success;
}
#endif

/** Create the scratch GCs per depth. */
static void dmxBECreateScratchGCs(int scrnNum)
{
    ScreenPtr  pScreen = screenInfo.screens[scrnNum];
    GCPtr     *ppGC    = pScreen->GCperDepth;
    int        i;

    for (i = 0; i <= pScreen->numDepths; i++)
	dmxBECreateGC(pScreen, ppGC[i]);
}

#ifdef PANORAMIX
static Bool FoundPixImage;

/** Search the Xinerama XRT_PIXMAP resources for the pixmap that needs
 *  to have its image restored.  When it is found, see if there is
 *  another screen with the same image.  If so, copy the pixmap image
 *  from the existing screen to the newly created pixmap. */
static void dmxBERestorePixmapImage(pointer value, XID id, RESTYPE type,
				    pointer p)
{
    if ((type & TypeMask) == (XRT_PIXMAP & TypeMask)) {
	PixmapPtr      pDst     = (PixmapPtr)p;
	int            idx      = pDst->drawable.pScreen->myNum;
	PanoramiXRes  *pXinPix  = (PanoramiXRes *)value;
	PixmapPtr      pPix;
	int            i;

	pPix = (PixmapPtr)LookupIDByType(pXinPix->info[idx].id, RT_PIXMAP);
	if (pPix != pDst) return; /* Not a match.... Next! */

	for (i = 0; i < PanoramiXNumScreens; i++) {
	    PixmapPtr      pSrc;
	    dmxPixPrivPtr  pSrcPriv = NULL;

	    if (i == idx) continue; /* Self replication is bad */

	    pSrc =
		(PixmapPtr)LookupIDByType(pXinPix->info[i].id, RT_PIXMAP);
	    pSrcPriv = DMX_GET_PIXMAP_PRIV(pSrc);
	    if (pSrcPriv->pixmap) {
		DMXScreenInfo *dmxSrcScreen = &dmxScreens[i];
		DMXScreenInfo *dmxDstScreen = &dmxScreens[idx];
		dmxPixPrivPtr  pDstPriv = DMX_GET_PIXMAP_PRIV(pDst);
		XImage        *img;
		int            j;
		XlibGC         gc = NULL;

		/* This should never happen, but just in case.... */
		if (pSrc->drawable.width  != pDst->drawable.width ||
		    pSrc->drawable.height != pDst->drawable.height)
		    return;

		/* Copy from src pixmap to dst pixmap */
		img = XGetImage(dmxSrcScreen->beDisplay,
				pSrcPriv->pixmap,
				0, 0,
				pSrc->drawable.width, pSrc->drawable.height,
				-1,
				ZPixmap);

		for (j = 0; j < dmxDstScreen->beNumPixmapFormats; j++) {
		    if (dmxDstScreen->bePixmapFormats[j].depth == img->depth) {
			unsigned long  m;
			XGCValues      v;

			m = GCFunction | GCPlaneMask | GCClipMask;
			v.function = GXcopy;
			v.plane_mask = AllPlanes;
			v.clip_mask = None;

			gc = XCreateGC(dmxDstScreen->beDisplay,
				       dmxDstScreen->scrnDefDrawables[j],
				       m, &v);
			break;
		    }
		}

		if (gc) {
		    XPutImage(dmxDstScreen->beDisplay,
			      pDstPriv->pixmap,
			      gc, img, 0, 0, 0, 0,
			      pDst->drawable.width, pDst->drawable.height);
		    XFreeGC(dmxDstScreen->beDisplay, gc);
		    FoundPixImage = True;
		} else {
		    dmxLog(dmxWarning, "Could not create GC\n");
		}

		XDestroyImage(img);
		return;
	    }
	}
    }
}
#endif

/** Restore the pixmap image either from another screen or from an image
 *  that was saved when the screen was previously detached. */
static void dmxBERestorePixmap(PixmapPtr pPixmap)
{
#ifdef PANORAMIX
    int i;

    /* If Xinerama is not active, there's nothing we can do (see comment
     * in #else below for more info). */
    if (noPanoramiXExtension) {
	dmxLog(dmxWarning, "Cannot restore pixmap image\n");
	return;
    }

    FoundPixImage = False;
    for (i = currentMaxClients; --i >= 0; )
	if (clients[i])
	    FindAllClientResources(clients[i], dmxBERestorePixmapImage,
				   (pointer)pPixmap);

    /* No corresponding pixmap image was found on other screens, so we
     * need to copy it from the saved image when the screen was detached
     * (if available). */
    if (!FoundPixImage) {
	dmxPixPrivPtr  pPixPriv = DMX_GET_PIXMAP_PRIV(pPixmap);

	if (pPixPriv->detachedImage) {
	    ScreenPtr      pScreen   = pPixmap->drawable.pScreen;
	    DMXScreenInfo *dmxScreen = &dmxScreens[pScreen->myNum];
	    XlibGC         gc        = NULL;

	    for (i = 0; i < dmxScreen->beNumPixmapFormats; i++) {
		if (dmxScreen->bePixmapFormats[i].depth ==
		    pPixPriv->detachedImage->depth) {
		    unsigned long  m;
		    XGCValues      v;

		    m = GCFunction | GCPlaneMask | GCClipMask;
		    v.function = GXcopy;
		    v.plane_mask = AllPlanes;
		    v.clip_mask = None;

		    gc = XCreateGC(dmxScreen->beDisplay,
				   dmxScreen->scrnDefDrawables[i],
				   m, &v);
		    break;
		}
	    }

	    if (gc) {
		XPutImage(dmxScreen->beDisplay,
			  pPixPriv->pixmap,
			  gc,
			  pPixPriv->detachedImage,
			  0, 0, 0, 0,
		      pPixmap->drawable.width, pPixmap->drawable.height);
		XFreeGC(dmxScreen->beDisplay, gc);
	    } else {
		dmxLog(dmxWarning, "Cannot restore pixmap image\n");
	    }

	    XDestroyImage(pPixPriv->detachedImage);
	    pPixPriv->detachedImage = NULL;
	} else {
	    dmxLog(dmxWarning, "Cannot restore pixmap image\n");
	}
    }
#else
    /* If Xinerama is not enabled, then there is no other copy of the
     * pixmap image that we can restore.  Saving all pixmap data is not
     * a feasible option since there is no mechanism for updating pixmap
     * data when a screen is detached, which means that the data that
     * was previously saved would most likely be out of date. */
    dmxLog(dmxWarning, "Cannot restore pixmap image\n");
    return;
#endif
}

/** Create resources on the back-end server.  This function is called
 *  from #dmxAttachScreen() via the dix layer's FindAllResources
 *  function.  It walks all resources, compares them to the screen
 *  number passed in as \a n and calls the appropriate DMX function to
 *  create the associated resource on the back-end server. */
static void dmxBECreateResources(pointer value, XID id, RESTYPE type,
				 pointer n)
{
    int        scrnNum = (int)n;
    ScreenPtr  pScreen = screenInfo.screens[scrnNum];

    if ((type & TypeMask) == (RT_WINDOW & TypeMask)) {
	/* Window resources are created below in dmxBECreateWindowTree */
    } else if ((type & TypeMask) == (RT_PIXMAP & TypeMask)) {
	PixmapPtr  pPix = value;
	if (pPix->drawable.pScreen->myNum == scrnNum) {
	    dmxBECreatePixmap(pPix);
	    dmxBERestorePixmap(pPix);
	}
    } else if ((type & TypeMask) == (RT_GC & TypeMask)) {
	GCPtr  pGC = value;
	if (pGC->pScreen->myNum == scrnNum) {
	    /* Create the GC on the back-end server */
	    dmxBECreateGC(pScreen, pGC);
	    /* Create any pixmaps associated with this GC */
	    if (!pGC->tileIsPixel) {
		dmxBECreatePixmap(pGC->tile.pixmap);
		dmxBERestorePixmap(pGC->tile.pixmap);
	    }
	    if (pGC->stipple != pScreen->PixmapPerDepth[0]) {
		dmxBECreatePixmap(pGC->stipple);
		dmxBERestorePixmap(pGC->stipple);
	    }
	    if (pGC->font != defaultFont) {
		(void)dmxBELoadFont(pScreen, pGC->font);
	    }
	    /* Update the GC on the back-end server */
	    dmxChangeGC(pGC, -1L);
	}
    } else if ((type & TypeMask) == (RT_FONT & TypeMask)) {
	(void)dmxBELoadFont(pScreen, (FontPtr)value);
    } else if ((type & TypeMask) == (RT_CURSOR & TypeMask)) {
	dmxBECreateCursor(pScreen, (CursorPtr)value);
    } else if ((type & TypeMask) == (RT_COLORMAP & TypeMask)) {
	ColormapPtr  pCmap = value;
	if (pCmap->pScreen->myNum == scrnNum)
	    (void)dmxBECreateColormap((ColormapPtr)value);
#if 0
#ifdef RENDER
    /* TODO: Recreate Picture and GlyphSet resources */
    } else if ((type & TypeMask) == (PictureType & TypeMask)) {
	/* Picture resources are created when windows are created */
    } else if ((type & TypeMask) == (GlyphSetType & TypeMask)) {
	dmxBEFreeGlyphSet(pScreen, (GlyphSetPtr)value);
#endif
#endif
    } else {
	/* Other resource types??? */
    }
}

/** Create window hierachy on back-end server.  The window tree is
 *  created in a special order (bottom most subwindow first) so that the
 *  #dmxCreateNonRootWindow() function does not need to recursively call
 *  itself to create each window's parents.  This is required so that we
 *  have the opportunity to create each window's border and background
 *  pixmaps (where appropriate) before the window is created. */
static void dmxBECreateWindowTree(int idx)
{
    DMXScreenInfo *dmxScreen = &dmxScreens[idx];
    WindowPtr      pRoot     = WindowTable[idx];
    dmxWinPrivPtr  pWinPriv  = DMX_GET_WINDOW_PRIV(pRoot);
    WindowPtr      pWin;

    /* Create the pixmaps associated with the root window */
    if (!pRoot->borderIsPixel) {
	dmxBECreatePixmap(pRoot->border.pixmap);
	dmxBERestorePixmap(pRoot->border.pixmap);
    }
    if (pRoot->backgroundState == BackgroundPixmap) {
	dmxBECreatePixmap(pRoot->background.pixmap);
	dmxBERestorePixmap(pRoot->background.pixmap);
    }

    /* Create root window first */
    dmxScreen->rootWin = pWinPriv->window = dmxCreateRootWindow(pRoot);
    XMapWindow(dmxScreen->beDisplay, dmxScreen->rootWin);

    pWin = pRoot->lastChild;
    while (pWin) {
	pWinPriv = DMX_GET_WINDOW_PRIV(pWin);

	/* Create the pixmaps regardless of whether or not the
	 * window is created or not due to lazy window creation.
	 */
	if (!pWin->borderIsPixel) {
	    dmxBECreatePixmap(pWin->border.pixmap);
	    dmxBERestorePixmap(pWin->border.pixmap);
	}
	if (pWin->backgroundState == BackgroundPixmap) {
	    dmxBECreatePixmap(pWin->background.pixmap);
	    dmxBERestorePixmap(pWin->background.pixmap);
	}

	/* Reset the window attributes */
	dmxGetDefaultWindowAttributes(pWin,
				      &pWinPriv->cmap,
				      &pWinPriv->visual);

	/* Create the window */
	if (pWinPriv->mapped && !pWinPriv->offscreen)
	    dmxCreateAndRealizeWindow(pWin, TRUE);

	/* Next, create the bottom-most child */
	if (pWin->lastChild) {
	    pWin = pWin->lastChild;
	    continue;
	}

	/* If the window has no children, move on to the next higher window */
	while (!pWin->prevSib && (pWin != pRoot))
	    pWin = pWin->parent;

	if (pWin->prevSib) {
	    pWin = pWin->prevSib;
	    continue;
	}

	/* When we reach the root window, we are finished */
	if (pWin == pRoot)
	    break;
    }
}

/* Refresh screen by generating exposure events for all windows */
static void dmxForceExposures(int idx)
{
    ScreenPtr      pScreen   = screenInfo.screens[idx];
    WindowPtr  pRoot     = WindowTable[idx];
    Bool       anyMarked = FALSE;
    WindowPtr  pChild;

    for (pChild = pRoot->firstChild; pChild; pChild = pChild->nextSib)
	anyMarked |= pScreen->MarkOverlappedWindows(pChild, pChild,
						    (WindowPtr *)NULL);
    if (anyMarked) {
	/* If any windows have been marked, set the root window's
	 * clipList to be broken since it will be recalculated in
	 * ValidateTree()
	 */
	REGION_BREAK(pScreen, &pRoot->clipList);
	pScreen->ValidateTree(pRoot, NULL, VTBroken);
	pScreen->HandleExposures(pRoot);
	if (pScreen->PostValidateTree)
	    pScreen->PostValidateTree(pRoot, NULL, VTBroken);
    }
}

/** Compare the new and old screens to see if they are compatible. */
static Bool dmxCompareScreens(DMXScreenInfo *new, DMXScreenInfo *old)
{
    int i;

    if (new->beWidth != old->beWidth) return FALSE;
    if (new->beHeight != old->beHeight) return FALSE;
    if (new->beDepth != old->beDepth) return FALSE;
    if (new->beBPP != old->beBPP) return FALSE;

    if (new->beNumDepths != old->beNumDepths) return FALSE;
    for (i = 0; i < old->beNumDepths; i++)
	if (new->beDepths[i] != old->beDepths[i]) return FALSE;

    if (new->beNumPixmapFormats != old->beNumPixmapFormats) return FALSE;
    for (i = 0; i < old->beNumPixmapFormats; i++) {
	if (new->bePixmapFormats[i].depth !=
	    old->bePixmapFormats[i].depth) return FALSE;
	if (new->bePixmapFormats[i].bits_per_pixel !=
	    old->bePixmapFormats[i].bits_per_pixel) return FALSE;
	if (new->bePixmapFormats[i].scanline_pad !=
	    old->bePixmapFormats[i].scanline_pad) return FALSE;
    }

    if (new->beNumVisuals != old->beNumVisuals) return FALSE;
    for (i = 0; i < old->beNumVisuals; i++) {
	if (new->beVisuals[i].visualid !=
	    old->beVisuals[i].visualid) return FALSE;
	if (new->beVisuals[i].screen !=
	    old->beVisuals[i].screen) return FALSE;
	if (new->beVisuals[i].depth !=
	    old->beVisuals[i].depth) return FALSE;
	if (new->beVisuals[i].class !=
	    old->beVisuals[i].class) return FALSE;
	if (new->beVisuals[i].red_mask !=
	    old->beVisuals[i].red_mask) return FALSE;
	if (new->beVisuals[i].green_mask !=
	    old->beVisuals[i].green_mask) return FALSE;
	if (new->beVisuals[i].blue_mask !=
	    old->beVisuals[i].blue_mask) return FALSE;
	if (new->beVisuals[i].colormap_size !=
	    old->beVisuals[i].colormap_size) return FALSE;
	if (new->beVisuals[i].bits_per_rgb !=
	    old->beVisuals[i].bits_per_rgb) return FALSE;
    }

    if (new->beDefVisualIndex != old->beDefVisualIndex) return FALSE;

    return TRUE;
}

/** Reattach previously detached back-end screen. */
int dmxAttachScreen(int idx, DMXScreenAttributesPtr attr)
{
    ScreenPtr      pScreen   = screenInfo.screens[idx];
    DMXScreenInfo *dmxScreen = &dmxScreens[idx];
    CARD32         scrnNum   = idx;
    DMXScreenInfo  oldDMXScreen;
    int            i;

    /* Return failure if dynamic addition/removal of screens is disabled */
    if (!dmxAddRemoveScreens) {
	dmxLog(dmxWarning,
	       "Attempting to add a screen, but the AddRemoveScreen\n");
	dmxLog(dmxWarning,
	       "extension has not been enabled.  To enable this extension\n");
	dmxLog(dmxWarning,
	       "add the \"-addremovescreens\" option either to the command\n");
	dmxLog(dmxWarning,
	       "line or in the configuration file.\n");
	return 1;
    }

    /* Cannot add a screen that does not exist */
    if (idx < 0 || idx >= dmxNumScreens) return 1;

    /* Cannot attach to a screen that is already opened */
    if (dmxScreen->beDisplay) {
	dmxLog(dmxWarning,
	       "Attempting to add screen #%d but a screen already exists\n",
	       idx);
	return 1;
    }

    dmxLogOutput(dmxScreen, "Attaching screen #%d\n", idx);

    /* Save old info */
    oldDMXScreen = *dmxScreen;

    /* Copy the name to the new screen */
    dmxScreen->name = strdup(attr->displayName);

    /* Open display and get all of the screen info */
    if (!dmxOpenDisplay(dmxScreen)) {
	dmxLog(dmxWarning,
               "dmxOpenDisplay: Unable to open display %s\n",
               dmxScreen->name);

	/* Restore the old screen */
	*dmxScreen = oldDMXScreen;
	return 1;
    }

    dmxSetErrorHandler(dmxScreen);
    dmxCheckForWM(dmxScreen);
    dmxGetScreenAttribs(dmxScreen);

    if (!dmxGetVisualInfo(dmxScreen)) {
	dmxLog(dmxWarning, "dmxGetVisualInfo: No matching visuals found\n");
	XFree(dmxScreen->beVisuals);
	XCloseDisplay(dmxScreen->beDisplay);

	/* Restore the old screen */
	*dmxScreen = oldDMXScreen;
	return 1;
    }

    dmxGetColormaps(dmxScreen);
    dmxGetPixmapFormats(dmxScreen);

    /* Verify that the screen to be added has the same info as the
     * previously added screen. */
    if (!dmxCompareScreens(dmxScreen, &oldDMXScreen)) {
	dmxLog(dmxWarning,
	       "New screen data (%s) does not match previously\n",
	       dmxScreen->name);
	dmxLog(dmxWarning,
	       "attached screen data (%s)\n",
	       oldDMXScreen.name);
	dmxLog(dmxWarning,
	       "All data must match in order to attach to screen #%d\n",
	       idx);
	XFree(dmxScreen->beVisuals);
	XFree(dmxScreen->beDepths);
	XFree(dmxScreen->bePixmapFormats);
	XCloseDisplay(dmxScreen->beDisplay);

	/* Restore the old screen */
	*dmxScreen = oldDMXScreen;
	return 1;
    }

    /* Initialize the BE screen resources */
    dmxBEScreenInit(idx, screenInfo.screens[idx]);

    /* TODO: Handle GLX visual initialization.  GLXProxy needs to be
     * updated to handle dynamic addition/removal of screens. */

    /* Create default stipple */
    dmxBECreatePixmap(pScreen->PixmapPerDepth[0]);
    dmxBERestorePixmap(pScreen->PixmapPerDepth[0]);

    /* Create the scratch GCs */
    dmxBECreateScratchGCs(idx);

    /* Create the default font */
    (void)dmxBELoadFont(pScreen, defaultFont);

    /* Create all resources that don't depend on windows */
    for (i = currentMaxClients; --i >= 0; )
	if (clients[i])
	    FindAllClientResources(clients[i], dmxBECreateResources,
				   (pointer)idx);

    /* Create window hierarchy (top down) */
    dmxBECreateWindowTree(idx);

    /* Refresh screen by generating exposure events for all windows */
    dmxForceExposures(idx);

    dmxSync(&dmxScreens[idx], TRUE);

    /* We used these to compare the old and new screens.  They are no
     * longer needed since we have a newly attached screen, so we can
     * now free the old screen's resources. */
    XFree(oldDMXScreen.beVisuals);
    XFree(oldDMXScreen.beDepths);
    XFree(oldDMXScreen.bePixmapFormats);
    /* TODO: should oldDMXScreen.name be freed?? */

#ifdef PANORAMIX
    if (!noPanoramiXExtension)
	return dmxConfigureScreenWindows(1, &scrnNum, attr, NULL);
    else
#endif
	return 0; /* Success */
}

/*
 * Resources that may have state on the BE server and need to be freed:
 *
 * RT_NONE
 * RT_WINDOW
 * RT_PIXMAP
 * RT_GC
 * RT_FONT
 * RT_CURSOR
 * RT_COLORMAP
 * RT_CMAPENTRY
 * RT_OTHERCLIENT
 * RT_PASSIVEGRAB
 * XRT_WINDOW
 * XRT_PIXMAP
 * XRT_GC
 * XRT_COLORMAP
 * XRT_PICTURE
 * PictureType
 * PictFormatType
 * GlyphSetType
 * ClientType
 * EventType
 * RT_INPUTCLIENT
 * XETrapType
 * RTCounter
 * RTAwait
 * RTAlarmClient
 * RT_XKBCLIENT
 * RTContext
 * TagResType
 * StalledResType
 * RT_APPGROUP
 * SecurityAuthorizationResType
 * RTEventClient
 * __glXContextRes
 * __glXClientRes
 * __glXPixmapRes
 * __glXWindowRes
 * __glXPbufferRes
 */

#ifdef PANORAMIX
/** Search the Xinerama XRT_PIXMAP resources for the pixmap that needs
 *  to have its image saved. */
static void dmxBEFindPixmapImage(pointer value, XID id, RESTYPE type,
				 pointer p)
{
    if ((type & TypeMask) == (XRT_PIXMAP & TypeMask)) {
	PixmapPtr      pDst     = (PixmapPtr)p;
	int            idx      = pDst->drawable.pScreen->myNum;
	PanoramiXRes  *pXinPix  = (PanoramiXRes *)value;
	PixmapPtr      pPix;
	int            i;

	pPix = (PixmapPtr)LookupIDByType(pXinPix->info[idx].id, RT_PIXMAP);
	if (pPix != pDst) return; /* Not a match.... Next! */

	for (i = 0; i < PanoramiXNumScreens; i++) {
	    PixmapPtr      pSrc;
	    dmxPixPrivPtr  pSrcPriv = NULL;

	    if (i == idx) continue; /* Self replication is bad */

	    pSrc =
		(PixmapPtr)LookupIDByType(pXinPix->info[i].id, RT_PIXMAP);
	    pSrcPriv = DMX_GET_PIXMAP_PRIV(pSrc);
	    if (pSrcPriv->pixmap) {
		FoundPixImage = True;
		return;
	    }
	}
    }
}
#endif

/** Save the pixmap image only when there is not another screen with
 *  that pixmap from which the image can be read when the screen is
 *  reattached.  To do this, we first try to find a pixmap on another
 *  screen corresponding to the one we are trying to save.  If we find
 *  one, then we do not need to save the image data since during
 *  reattachment, the image data can be read from that other pixmap.
 *  However, if we do not find one, then we need to save the image data.
 *  The common case for these are for the default stipple and root
 *  tile. */
static void dmxBESavePixmap(PixmapPtr pPixmap)
{
#ifdef PANORAMIX
    int i;

    /* If Xinerama is not active, there's nothing we can do (see comment
     * in #else below for more info). */
    if (noPanoramiXExtension) return;

    FoundPixImage = False;
    for (i = currentMaxClients; --i >= 0; )
	if (clients[i])
	    FindAllClientResources(clients[i], dmxBEFindPixmapImage,
				   (pointer)pPixmap);

    /* Save the image only if there is no other screens that have a
     * pixmap that corresponds to the one we are trying to save. */
    if (!FoundPixImage) {
	dmxPixPrivPtr  pPixPriv = DMX_GET_PIXMAP_PRIV(pPixmap);

	if (!pPixPriv->detachedImage) {
	    ScreenPtr      pScreen   = pPixmap->drawable.pScreen;
	    DMXScreenInfo *dmxScreen = &dmxScreens[pScreen->myNum];

	    pPixPriv->detachedImage = XGetImage(dmxScreen->beDisplay,
						pPixPriv->pixmap,
						0, 0,
						pPixmap->drawable.width,
						pPixmap->drawable.height,
						-1,
						ZPixmap);
	    if (!pPixPriv->detachedImage)
		dmxLog(dmxWarning, "Cannot save pixmap image\n");
	}
    }
#else
    /* NOTE: The only time there is a pixmap on another screen that
     * corresponds to the one we are trying to save is when Xinerama is
     * active.  Otherwise, the pixmap image data is only stored on a
     * single screen, which means that once it is detached, that data is
     * lost.  We could save the data here, but then that would require
     * us to implement the ability for Xdmx to keep the pixmap up to
     * date while the screen is detached, which is beyond the scope of
     * the current project. */
    return;
#endif
}

/** Destroy resources on the back-end server.  This function is called
 *  from #dmxDetachScreen() via the dix layer's FindAllResources
 *  function.  It walks all resources, compares them to the screen
 *  number passed in as \a n and calls the appropriate DMX function to
 *  free the associated resource on the back-end server. */
static void dmxBEDestroyResources(pointer value, XID id, RESTYPE type,
				  pointer n)
{
    int        scrnNum = (int)n;
    ScreenPtr  pScreen = screenInfo.screens[scrnNum];

    if ((type & TypeMask) == (RT_WINDOW & TypeMask)) {
	/* Window resources are destroyed below in dmxBEDestroyWindowTree */
    } else if ((type & TypeMask) == (RT_PIXMAP & TypeMask)) {
	PixmapPtr  pPix = value;
	if (pPix->drawable.pScreen->myNum == scrnNum) {
	    dmxBESavePixmap(pPix);
	    dmxBEFreePixmap(pPix);
	}
    } else if ((type & TypeMask) == (RT_GC & TypeMask)) {
	GCPtr  pGC = value;
	if (pGC->pScreen->myNum == scrnNum)
	    dmxBEFreeGC(pGC);
    } else if ((type & TypeMask) == (RT_FONT & TypeMask)) {
	dmxBEFreeFont(pScreen, (FontPtr)value);
    } else if ((type & TypeMask) == (RT_CURSOR & TypeMask)) {
	dmxBEFreeCursor(pScreen, (CursorPtr)value);
    } else if ((type & TypeMask) == (RT_COLORMAP & TypeMask)) {
	ColormapPtr  pCmap = value;
	if (pCmap->pScreen->myNum == scrnNum)
	    dmxBEFreeColormap((ColormapPtr)value);
#ifdef RENDER
    } else if ((type & TypeMask) == (PictureType & TypeMask)) {
	PicturePtr  pPict = value;
	if (pPict->pDrawable->pScreen->myNum == scrnNum)
	    dmxBEFreePicture((PicturePtr)value);
    } else if ((type & TypeMask) == (GlyphSetType & TypeMask)) {
	dmxBEFreeGlyphSet(pScreen, (GlyphSetPtr)value);
#endif
    } else {
	/* Other resource types??? */
    }
}

/** Destroy the scratch GCs that are created per depth. */
static void dmxBEDestroyScratchGCs(int scrnNum)
{
    ScreenPtr  pScreen = screenInfo.screens[scrnNum];
    GCPtr     *ppGC    = pScreen->GCperDepth;
    int        i;

    for (i = 0; i <= pScreen->numDepths; i++)
	dmxBEFreeGC(ppGC[i]);
}

/** Destroy window hierachy on back-end server.  To ensure that all
 *  XDestroyWindow() calls succeed, they must be performed in a bottom
 *  up order so that windows are not destroyed before their children.
 *  XDestroyWindow(), which is called from #dmxBEDestrowWindow(), will
 *  destroy a window as well as all of it's children. */
static void dmxBEDestroyWindowTree(int idx)
{
    WindowPtr  pWin   = WindowTable[idx];
    WindowPtr  pChild = pWin;

    while (1) {
	if (pChild->firstChild) {
	    pChild = pChild->firstChild;
	    continue;
	}

	/* Destroy the window */
	dmxBEDestroyWindow(pChild);

	/* Make sure we destroy the window's border and background
	 * pixmaps if they exist */
	if (!pChild->borderIsPixel) {
	    dmxBESavePixmap(pChild->border.pixmap);
	    dmxBEFreePixmap(pChild->border.pixmap);
	}
	if (pChild->backgroundState == BackgroundPixmap) {
	    dmxBESavePixmap(pChild->background.pixmap);
	    dmxBEFreePixmap(pChild->background.pixmap);
	}

	while (!pChild->nextSib && (pChild != pWin)) {
	    pChild = pChild->parent;
	    dmxBEDestroyWindow(pChild);
	    if (!pChild->borderIsPixel) {
		dmxBESavePixmap(pChild->border.pixmap);
		dmxBEFreePixmap(pChild->border.pixmap);
	    }
	    if (pChild->backgroundState == BackgroundPixmap) {
		dmxBESavePixmap(pChild->background.pixmap);
		dmxBEFreePixmap(pChild->background.pixmap);
	    }
	}

	if (pChild == pWin)
	    break;

	pChild = pChild->nextSib;
    }
}

/** Detach back-end screen. */
int dmxDetachScreen(int idx)
{
    DMXScreenInfo *dmxScreen = &dmxScreens[idx];
    int            i;

    /* Return failure if dynamic addition/removal of screens is disabled */
    if (!dmxAddRemoveScreens) {
	dmxLog(dmxWarning,
	       "Attempting to remove a screen, but the AddRemoveScreen\n");
	dmxLog(dmxWarning,
	       "extension has not been enabled.  To enable this extension\n");
	dmxLog(dmxWarning,
	       "add the \"-addremovescreens\" option either to the command\n");
	dmxLog(dmxWarning,
	       "line or in the configuration file.\n");
	return 1;
    }

    /* Cannot remove a screen that does not exist */
    if (idx < 0 || idx >= dmxNumScreens) return 1;

    /* Cannot detach from a screen that is not opened */
    if (!dmxScreen->beDisplay) {
	dmxLog(dmxWarning,
	       "Attempting to remove screen #%d but it has not been opened\n",
	       idx);
	return 1;
    }

    dmxLogOutput(dmxScreen, "Detaching screen #%d\n", idx);

    /* Detach input */
    dmxInputDetachAll(dmxScreen);

    /* Save all relevant state (TODO) */

    /* Free all non-window resources related to this screen */
    for (i = currentMaxClients; --i >= 0; )
	if (clients[i])
	    FindAllClientResources(clients[i], dmxBEDestroyResources,
				   (pointer)idx);

    /* Free scratch GCs */
    dmxBEDestroyScratchGCs(idx);

    /* Free window resources related to this screen */
    dmxBEDestroyWindowTree(idx);

    /* Free default stipple */
    dmxBESavePixmap(screenInfo.screens[idx]->PixmapPerDepth[0]);
    dmxBEFreePixmap(screenInfo.screens[idx]->PixmapPerDepth[0]);

    /* Free the remaining screen resources and close the screen */
    dmxBECloseScreen(screenInfo.screens[idx]);

    /* Adjust the cursor boundaries (paints detached console window) */
    dmxAdjustCursorBoundaries();

    return 0; /* Success */
}