path: root/mi/mioverlay.c

#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif

#include <X11/X.h>
#include "scrnintstr.h"
#include "validate.h"
#include "windowstr.h"
#include "mi.h"
#include "gcstruct.h"
#include "regionstr.h"
#include "mivalidate.h"
#include "mioverlay.h"
#include "migc.h"

#include "globals.h"


typedef struct {
   RegionRec 	exposed;
   RegionRec	borderExposed;
   RegionPtr	borderVisible;
   DDXPointRec	oldAbsCorner;
} miOverlayValDataRec, *miOverlayValDataPtr;

typedef struct _TreeRec {
   WindowPtr		pWin;
   struct _TreeRec 	*parent;
   struct _TreeRec 	*firstChild; 
   struct _TreeRec 	*lastChild; 
   struct _TreeRec 	*prevSib; 
   struct _TreeRec 	*nextSib;
   RegionRec 		borderClip;
   RegionRec 		clipList;
   unsigned		visibility;
   miOverlayValDataPtr  valdata;
} miOverlayTreeRec, *miOverlayTreePtr;

typedef struct {
   miOverlayTreePtr	tree;
} miOverlayWindowRec, *miOverlayWindowPtr;

typedef struct {
   CloseScreenProcPtr   	CloseScreen;
   CreateWindowProcPtr  	CreateWindow;
   DestroyWindowProcPtr 	DestroyWindow;
   UnrealizeWindowProcPtr	UnrealizeWindow;
   RealizeWindowProcPtr		RealizeWindow;
   miOverlayTransFunc		MakeTransparent;
   miOverlayInOverlayFunc	InOverlay;
   Bool				underlayMarked;
   Bool				copyUnderlay;
} miOverlayScreenRec, *miOverlayScreenPtr;

static unsigned long miOverlayGeneration = 0;
static int miOverlayWindowIndex = -1;
static int miOverlayScreenIndex = -1;

static void RebuildTree(WindowPtr);
static Bool HasUnderlayChildren(WindowPtr);
static void MarkUnderlayWindow(WindowPtr);
static Bool CollectUnderlayChildrenRegions(WindowPtr, RegionPtr);

static Bool miOverlayCloseScreen(int, ScreenPtr);
static Bool miOverlayCreateWindow(WindowPtr);
static Bool miOverlayDestroyWindow(WindowPtr);
static Bool miOverlayUnrealizeWindow(WindowPtr);
static Bool miOverlayRealizeWindow(WindowPtr);
static void miOverlayMarkWindow(WindowPtr);
static void miOverlayReparentWindow(WindowPtr, WindowPtr);
static void miOverlayRestackWindow(WindowPtr, WindowPtr);
static Bool miOverlayMarkOverlappedWindows(WindowPtr, WindowPtr, WindowPtr*);
static void miOverlayMarkUnrealizedWindow(WindowPtr, WindowPtr, Bool);
static int miOverlayValidateTree(WindowPtr, WindowPtr, VTKind);
static void miOverlayHandleExposures(WindowPtr);
static void miOverlayMoveWindow(WindowPtr, int, int, WindowPtr, VTKind);
static void miOverlayWindowExposures(WindowPtr, RegionPtr, RegionPtr);
static void miOverlayResizeWindow(WindowPtr, int, int, unsigned int,
					unsigned int, WindowPtr);
static void miOverlayClearToBackground(WindowPtr, int, int, int, int, Bool);

#ifdef SHAPE
static void miOverlaySetShape(WindowPtr);
#endif
static void miOverlayChangeBorderWidth(WindowPtr, unsigned int);

#define MIOVERLAY_GET_SCREEN_PRIVATE(pScreen) \
	((miOverlayScreenPtr)((pScreen)->devPrivates[miOverlayScreenIndex].ptr))
#define MIOVERLAY_GET_WINDOW_PRIVATE(pWin) \
	((miOverlayWindowPtr)((pWin)->devPrivates[miOverlayWindowIndex].ptr))
#define MIOVERLAY_GET_WINDOW_TREE(pWin) \
	(MIOVERLAY_GET_WINDOW_PRIVATE(pWin)->tree)

#define IN_UNDERLAY(w) MIOVERLAY_GET_WINDOW_TREE(w)
#define IN_OVERLAY(w) !MIOVERLAY_GET_WINDOW_TREE(w)

#define MARK_OVERLAY(w) miMarkWindow(w)
#define MARK_UNDERLAY(w) MarkUnderlayWindow(w)

#define HasParentRelativeBorder(w) (!(w)->borderIsPixel && \
                                    HasBorder(w) && \
                                    (w)->backgroundState == ParentRelative)

_X_EXPORT Bool
miInitOverlay(
    ScreenPtr pScreen, 
    miOverlayInOverlayFunc inOverlayFunc,
    miOverlayTransFunc transFunc
){
    miOverlayScreenPtr	pScreenPriv;

    if(!inOverlayFunc || !transFunc) return FALSE;

    if(miOverlayGeneration != serverGeneration) {
	if(((miOverlayScreenIndex = AllocateScreenPrivateIndex()) < 0) ||
	   ((miOverlayWindowIndex = AllocateWindowPrivateIndex()) < 0))
	    return FALSE;
	
	miOverlayGeneration = serverGeneration;
    }

    if(!AllocateWindowPrivate(pScreen, miOverlayWindowIndex,
				sizeof(miOverlayWindowRec)))
	return FALSE;

    if(!(pScreenPriv = xalloc(sizeof(miOverlayScreenRec))))
	return FALSE;

    pScreen->devPrivates[miOverlayScreenIndex].ptr = (pointer)pScreenPriv;

    pScreenPriv->InOverlay = inOverlayFunc;
    pScreenPriv->MakeTransparent = transFunc;
    pScreenPriv->underlayMarked = FALSE;


    pScreenPriv->CloseScreen = pScreen->CloseScreen;
    pScreenPriv->CreateWindow = pScreen->CreateWindow;
    pScreenPriv->DestroyWindow = pScreen->DestroyWindow;
    pScreenPriv->UnrealizeWindow = pScreen->UnrealizeWindow;
    pScreenPriv->RealizeWindow = pScreen->RealizeWindow;

    pScreen->CloseScreen = miOverlayCloseScreen;
    pScreen->CreateWindow = miOverlayCreateWindow;
    pScreen->DestroyWindow = miOverlayDestroyWindow;
    pScreen->UnrealizeWindow = miOverlayUnrealizeWindow;
    pScreen->RealizeWindow = miOverlayRealizeWindow;

    pScreen->ReparentWindow = miOverlayReparentWindow;
    pScreen->RestackWindow = miOverlayRestackWindow;
    pScreen->MarkOverlappedWindows = miOverlayMarkOverlappedWindows;
    pScreen->MarkUnrealizedWindow = miOverlayMarkUnrealizedWindow;
    pScreen->ValidateTree = miOverlayValidateTree;
    pScreen->HandleExposures = miOverlayHandleExposures;
    pScreen->MoveWindow = miOverlayMoveWindow;
    pScreen->WindowExposures = miOverlayWindowExposures;
    pScreen->ResizeWindow = miOverlayResizeWindow;
    pScreen->MarkWindow = miOverlayMarkWindow;
    pScreen->ClearToBackground = miOverlayClearToBackground;
#ifdef SHAPE
    pScreen->SetShape = miOverlaySetShape;
#endif
    pScreen->ChangeBorderWidth = miOverlayChangeBorderWidth;

    return TRUE;
}


static Bool 
miOverlayCloseScreen(int i, ScreenPtr pScreen)
{
   miOverlayScreenPtr pScreenPriv = MIOVERLAY_GET_SCREEN_PRIVATE(pScreen);

   pScreen->CloseScreen = pScreenPriv->CloseScreen; 
   pScreen->CreateWindow = pScreenPriv->CreateWindow;
   pScreen->DestroyWindow = pScreenPriv->DestroyWindow;
   pScreen->UnrealizeWindow = pScreenPriv->UnrealizeWindow;
   pScreen->RealizeWindow = pScreenPriv->RealizeWindow;

   xfree(pScreenPriv);

   return (*pScreen->CloseScreen)(i, pScreen);
}


static Bool 
miOverlayCreateWindow(WindowPtr pWin)
{
    ScreenPtr pScreen = pWin->drawable.pScreen;
    miOverlayScreenPtr pScreenPriv = MIOVERLAY_GET_SCREEN_PRIVATE(pScreen);
    miOverlayWindowPtr pWinPriv = MIOVERLAY_GET_WINDOW_PRIVATE(pWin);
    miOverlayTreePtr pTree = NULL;
    Bool result = TRUE;

    pWinPriv->tree = NULL;

    if(!pWin->parent || !((*pScreenPriv->InOverlay)(pWin))) {
	if(!(pTree = (miOverlayTreePtr)xcalloc(1, sizeof(miOverlayTreeRec))))
	   return FALSE;
    }

    if(pScreenPriv->CreateWindow) {
	pScreen->CreateWindow = pScreenPriv->CreateWindow;
	result = (*pScreen->CreateWindow)(pWin);
	pScreen->CreateWindow = miOverlayCreateWindow;
    }
	
    if (pTree) {
	if(result) {
	    pTree->pWin = pWin;
	    pTree->visibility = VisibilityNotViewable;
	    pWinPriv->tree = pTree;
	    if(pWin->parent) {
		REGION_NULL(pScreen, &(pTree->borderClip));
		REGION_NULL(pScreen, &(pTree->clipList));
		RebuildTree(pWin);
	    } else {
		BoxRec fullBox;
		fullBox.x1 = 0;
		fullBox.y1 = 0;
		fullBox.x2 = pScreen->width;
		fullBox.y2 = pScreen->height;
		REGION_INIT(pScreen, &(pTree->borderClip), &fullBox, 1);
		REGION_INIT(pScreen, &(pTree->clipList), &fullBox, 1);
	    }
	} else xfree(pTree);
    }

    return TRUE;
}


static Bool 
miOverlayDestroyWindow(WindowPtr pWin)
{
    ScreenPtr pScreen = pWin->drawable.pScreen;
    miOverlayScreenPtr pScreenPriv = MIOVERLAY_GET_SCREEN_PRIVATE(pScreen);
    miOverlayTreePtr pTree = MIOVERLAY_GET_WINDOW_TREE(pWin);
    Bool result = TRUE;

    if (pTree) {
	if(pTree->prevSib)
	   pTree->prevSib->nextSib = pTree->nextSib;
	else if(pTree->parent)
	   pTree->parent->firstChild = pTree->nextSib;

	if(pTree->nextSib)
	   pTree->nextSib->prevSib = pTree->prevSib;
	else if(pTree->parent)
	   pTree->parent->lastChild = pTree->prevSib;

	REGION_UNINIT(pScreen, &(pTree->borderClip));
	REGION_UNINIT(pScreen, &(pTree->clipList));
	xfree(pTree);
    }

    if(pScreenPriv->DestroyWindow) {
	pScreen->DestroyWindow = pScreenPriv->DestroyWindow;
	result = (*pScreen->DestroyWindow)(pWin);
	pScreen->DestroyWindow = miOverlayDestroyWindow;
    }

    return result;
}

static Bool 
miOverlayUnrealizeWindow(WindowPtr pWin)
{
    ScreenPtr pScreen = pWin->drawable.pScreen;
    miOverlayScreenPtr pScreenPriv = MIOVERLAY_GET_SCREEN_PRIVATE(pScreen);
    miOverlayTreePtr pTree = MIOVERLAY_GET_WINDOW_TREE(pWin);
    Bool result = TRUE;

    if(pTree) pTree->visibility = VisibilityNotViewable;

    if(pScreenPriv->UnrealizeWindow) {
	pScreen->UnrealizeWindow = pScreenPriv->UnrealizeWindow;
	result = (*pScreen->UnrealizeWindow)(pWin);
	pScreen->UnrealizeWindow = miOverlayUnrealizeWindow;
    }

    return result;
}


static Bool 
miOverlayRealizeWindow(WindowPtr pWin)
{
    ScreenPtr pScreen = pWin->drawable.pScreen;
    miOverlayScreenPtr pScreenPriv = MIOVERLAY_GET_SCREEN_PRIVATE(pScreen);
    Bool result = TRUE;

    if(pScreenPriv->RealizeWindow) {
	pScreen->RealizeWindow = pScreenPriv->RealizeWindow;
	result = (*pScreen->RealizeWindow)(pWin);
	pScreen->RealizeWindow = miOverlayRealizeWindow;
    }

    /* we only need to catch the root window realization */

    if(result && !pWin->parent && !((*pScreenPriv->InOverlay)(pWin)))
    {
	BoxRec box;
	box.x1 = box.y1 = 0;
	box.x2 = pWin->drawable.width;
	box.y2 = pWin->drawable.height;
	(*pScreenPriv->MakeTransparent)(pScreen, 1, &box);
    }

    return result;
}


static void 
miOverlayReparentWindow(WindowPtr pWin, WindowPtr pPriorParent)
{
    if(IN_UNDERLAY(pWin) || HasUnderlayChildren(pWin)) {
	/* This could probably be more optimal */
	RebuildTree(WindowTable[pWin->drawable.pScreen->myNum]->firstChild);
    }	
}

static void 
miOverlayRestackWindow(WindowPtr pWin, WindowPtr oldNextSib)
{
    if(IN_UNDERLAY(pWin) || HasUnderlayChildren(pWin)) {
	/* This could probably be more optimal */
	RebuildTree(pWin);
    }	
}


static Bool
miOverlayMarkOverlappedWindows(
    WindowPtr pWin,
    WindowPtr pFirst,
    WindowPtr *pLayerWin
){
    ScreenPtr pScreen = pWin->drawable.pScreen;
    WindowPtr pChild, pLast;
    Bool overMarked, underMarked, doUnderlay, markAll;
    miOverlayTreePtr pTree = NULL, tLast, tChild;
    BoxPtr box;
    
    overMarked = underMarked = markAll = FALSE;

    if(pLayerWin) *pLayerWin = pWin; /* hah! */

    doUnderlay = (IN_UNDERLAY(pWin) || HasUnderlayChildren(pWin));

    box = REGION_EXTENTS(pScreen, &pWin->borderSize);

    if((pChild = pFirst)) {
	pLast = pChild->parent->lastChild;
	while (1) {
	    if (pChild == pWin) markAll = TRUE;

	    if(doUnderlay && IN_UNDERLAY(pChild))
		pTree = MIOVERLAY_GET_WINDOW_TREE(pChild);

	    if(pChild->viewable) {
                if (REGION_BROKEN (pScreen, &pChild->winSize))
                    SetWinSize (pChild);
                if (REGION_BROKEN (pScreen, &pChild->borderSize))
		    SetBorderSize (pChild);

	    	if (markAll || 
		    RECT_IN_REGION(pScreen, &pChild->borderSize, box))
		{
		    MARK_OVERLAY(pChild);
		    overMarked = TRUE;
		    if(doUnderlay && IN_UNDERLAY(pChild)) {
			MARK_UNDERLAY(pChild);
			underMarked = TRUE;
		    }
		    if (pChild->firstChild) {
			pChild = pChild->firstChild;
			continue;
		    }
		}
	    }
	    while (!pChild->nextSib && (pChild != pLast)) {
		pChild = pChild->parent;
		if(doUnderlay && IN_UNDERLAY(pChild))
		    pTree = MIOVERLAY_GET_WINDOW_TREE(pChild);
	    }

	    if(pChild == pWin) markAll = FALSE;

	    if (pChild == pLast) break;

	    pChild = pChild->nextSib;
	}
	if(overMarked)
	    MARK_OVERLAY(pWin->parent);
    } 

    if(doUnderlay && !pTree) {
	if(!(pTree = MIOVERLAY_GET_WINDOW_TREE(pWin))) {
 	    pChild = pWin->lastChild;
	    while(1) {
		if((pTree = MIOVERLAY_GET_WINDOW_TREE(pChild)))
		    break;

		if(pChild->lastChild) {
		    pChild = pChild->lastChild;
		    continue;
		}

		while(!pChild->prevSib) pChild = pChild->parent;

		pChild = pChild->prevSib;
	    }
	}
    }
   
    if(pTree && pTree->nextSib) {
	tChild = pTree->parent->lastChild;
	tLast = pTree->nextSib;	

	while(1) {
	    if(tChild->pWin->viewable) { 
                if (REGION_BROKEN (pScreen, &tChild->pWin->winSize))
                    SetWinSize (tChild->pWin);
                if (REGION_BROKEN (pScreen, &tChild->pWin->borderSize))
		    SetBorderSize (tChild->pWin);

		if(RECT_IN_REGION(pScreen, &(tChild->pWin->borderSize), box)) 
	        {
		    MARK_UNDERLAY(tChild->pWin);
		    underMarked = TRUE;
	        }
	    }

	    if(tChild->lastChild) {
		tChild = tChild->lastChild;
		continue;
	    }

	    while(!tChild->prevSib && (tChild != tLast))
		tChild = tChild->parent;

	    if(tChild == tLast) break;

	    tChild = tChild->prevSib;
	}
    }

    if(underMarked) {
	MARK_UNDERLAY(pTree->parent->pWin);
	MIOVERLAY_GET_SCREEN_PRIVATE(pScreen)->underlayMarked = TRUE;	
    }

    return (underMarked || overMarked);
}


static void
miOverlayComputeClips(
    WindowPtr pParent, 
    RegionPtr universe,
    VTKind kind,
    RegionPtr exposed
){
    ScreenPtr pScreen = pParent->drawable.pScreen;
    int oldVis, newVis, dx, dy;
    BoxRec borderSize;
    RegionPtr borderVisible;
    RegionRec childUniverse, childUnion;
    miOverlayTreePtr tParent = MIOVERLAY_GET_WINDOW_TREE(pParent);
    miOverlayTreePtr tChild;
    Bool overlap;

    borderSize.x1 = pParent->drawable.x - wBorderWidth(pParent);
    borderSize.y1 = pParent->drawable.y - wBorderWidth(pParent);
    dx = (int) pParent->drawable.x + (int) pParent->drawable.width + 
						wBorderWidth(pParent);
    if (dx > 32767) dx = 32767;
    borderSize.x2 = dx;
    dy = (int) pParent->drawable.y + (int) pParent->drawable.height + 
						wBorderWidth(pParent);
    if (dy > 32767) dy = 32767;
    borderSize.y2 = dy;
  
    oldVis = tParent->visibility;
    switch (RECT_IN_REGION( pScreen, universe, &borderSize)) {
	case rgnIN:
	    newVis = VisibilityUnobscured;
	    break;
	case rgnPART:
	    newVis = VisibilityPartiallyObscured;
#ifdef SHAPE
	    {
		RegionPtr   pBounding;

		if ((pBounding = wBoundingShape (pParent))) {
		    switch (miShapedWindowIn (pScreen, universe, pBounding,
					      &borderSize,
					      pParent->drawable.x,
 					      pParent->drawable.y))
		    {
		    case rgnIN:
			newVis = VisibilityUnobscured;
			break;
		    case rgnOUT:
			newVis = VisibilityFullyObscured;
			break;
		    }
		}
	    }
#endif
	    break;
	default:
	    newVis = VisibilityFullyObscured;
	    break;
    }
    tParent->visibility = newVis;

    dx = pParent->drawable.x - tParent->valdata->oldAbsCorner.x;
    dy = pParent->drawable.y - tParent->valdata->oldAbsCorner.y;

    switch (kind) {
    case VTMap:
    case VTStack:
    case VTUnmap:
	break;
    case VTMove:
	if ((oldVis == newVis) &&
	    ((oldVis == VisibilityFullyObscured) ||
	     (oldVis == VisibilityUnobscured)))
	{
	    tChild = tParent;
	    while (1) {
		if (tChild->pWin->viewable) {
		    if (tChild->visibility != VisibilityFullyObscured) {
			REGION_TRANSLATE( pScreen, &tChild->borderClip, dx, dy);
			REGION_TRANSLATE( pScreen, &tChild->clipList, dx, dy);
		
			tChild->pWin->drawable.serialNumber = 
							 NEXT_SERIAL_NUMBER;
                        if (pScreen->ClipNotify)
                            (* pScreen->ClipNotify) (tChild->pWin, dx, dy);
		    }
		    if (tChild->valdata) {
			REGION_NULL(pScreen, &tChild->valdata->borderExposed);
			if (HasParentRelativeBorder(tChild->pWin)){
			    REGION_SUBTRACT(pScreen,
					 &tChild->valdata->borderExposed,
					 &tChild->borderClip,
					 &tChild->pWin->winSize);
			}
			REGION_NULL(pScreen, &tChild->valdata->exposed);
		    }
		    if (tChild->firstChild) {
			tChild = tChild->firstChild;
			continue;
		    }
		}
		while (!tChild->nextSib && (tChild != tParent))
		    tChild = tChild->parent;
		if (tChild == tParent)
		    break;
		tChild = tChild->nextSib;
	    }
	    return;
	}
	/* fall through */
    default:
    	if (dx || dy)  {
	    REGION_TRANSLATE( pScreen, &tParent->borderClip, dx, dy);
	    REGION_TRANSLATE( pScreen, &tParent->clipList, dx, dy);
    	} 
	break;
    case VTBroken:
	REGION_EMPTY (pScreen, &tParent->borderClip);
	REGION_EMPTY (pScreen, &tParent->clipList);
	break;
    }

    borderVisible = tParent->valdata->borderVisible;
    REGION_NULL(pScreen, &tParent->valdata->borderExposed);
    REGION_NULL(pScreen, &tParent->valdata->exposed);

    if (HasBorder (pParent)) {
    	if (borderVisible) {
	    REGION_SUBTRACT( pScreen, exposed, universe, borderVisible);
	    REGION_DESTROY( pScreen, borderVisible);
    	} else
	    REGION_SUBTRACT( pScreen, exposed, universe, &tParent->borderClip);

	if (HasParentRelativeBorder(pParent) && (dx || dy))
	    REGION_SUBTRACT( pScreen, &tParent->valdata->borderExposed,
				  universe, &pParent->winSize);
	else
	    REGION_SUBTRACT( pScreen, &tParent->valdata->borderExposed,
			       exposed, &pParent->winSize);

    	REGION_COPY( pScreen, &tParent->borderClip, universe);    
    	REGION_INTERSECT( pScreen, universe, universe, &pParent->winSize);
    }
    else
    	REGION_COPY( pScreen, &tParent->borderClip, universe);

    if ((tChild = tParent->firstChild) && pParent->mapped) {
	REGION_NULL(pScreen, &childUniverse);
	REGION_NULL(pScreen, &childUnion);

	for (; tChild; tChild = tChild->nextSib) {
	    if (tChild->pWin->viewable)
		REGION_APPEND( pScreen, &childUnion, &tChild->pWin->borderSize);
	}

	REGION_VALIDATE( pScreen, &childUnion, &overlap);

	for (tChild = tParent->firstChild;
	     tChild;
	     tChild = tChild->nextSib)
 	{
	    if (tChild->pWin->viewable) {
		if (tChild->valdata) {
		    REGION_INTERSECT( pScreen, &childUniverse, universe,
					    &tChild->pWin->borderSize);
		    miOverlayComputeClips (tChild->pWin, &childUniverse, 
						kind, exposed);
		}
		if (overlap)
		    REGION_SUBTRACT( pScreen, universe, universe,
					  &tChild->pWin->borderSize);
	    }
	}
	if (!overlap)
	    REGION_SUBTRACT( pScreen, universe, universe, &childUnion);
	REGION_UNINIT( pScreen, &childUnion);
	REGION_UNINIT( pScreen, &childUniverse);
    } 

    if (oldVis == VisibilityFullyObscured ||
	oldVis == VisibilityNotViewable)
    {
	REGION_COPY( pScreen, &tParent->valdata->exposed, universe);
    }
    else if (newVis != VisibilityFullyObscured &&
	     newVis != VisibilityNotViewable)
    {
    	REGION_SUBTRACT( pScreen, &tParent->valdata->exposed,
			       universe, &tParent->clipList);
    }
    
    /* HACK ALERT - copying contents of regions, instead of regions */
    {
	RegionRec   tmp;

	tmp = tParent->clipList;
	tParent->clipList = *universe;
	*universe = tmp;
    }

    pParent->drawable.serialNumber = NEXT_SERIAL_NUMBER;

    if (pScreen->ClipNotify)
        (* pScreen->ClipNotify) (pParent, dx, dy);
}


static void 
miOverlayMarkWindow(WindowPtr pWin)
{
    miOverlayTreePtr pTree = NULL;
    WindowPtr pChild, pGrandChild;
   
    miMarkWindow(pWin);

    /* look for UnmapValdata among immediate children */

    if(!(pChild = pWin->firstChild)) return;

    for( ; pChild; pChild = pChild->nextSib) {
	if(pChild->valdata == UnmapValData) {
	    if(IN_UNDERLAY(pChild)) {
		pTree = MIOVERLAY_GET_WINDOW_TREE(pChild);
		pTree->valdata = (miOverlayValDataPtr)UnmapValData; 
		continue;
	    } else {	
	        if(!(pGrandChild = pChild->firstChild))
		   continue;

		while(1) {
		    if(IN_UNDERLAY(pGrandChild)) {
			pTree = MIOVERLAY_GET_WINDOW_TREE(pGrandChild);
			pTree->valdata = (miOverlayValDataPtr)UnmapValData; 
		    } else if(pGrandChild->firstChild) {	
			pGrandChild = pGrandChild->firstChild;
			continue;
		    }

		    while(!pGrandChild->nextSib && (pGrandChild != pChild))
			pGrandChild = pGrandChild->parent;

		    if(pChild == pGrandChild) break;
		
		    pGrandChild = pGrandChild->nextSib;
		}
	    }
        }
    }

    if(pTree) {
	MARK_UNDERLAY(pTree->parent->pWin);
	MIOVERLAY_GET_SCREEN_PRIVATE(
		pWin->drawable.pScreen)->underlayMarked = TRUE;
    }
}

static void
miOverlayMarkUnrealizedWindow(
    WindowPtr pChild,
    WindowPtr pWin,
    Bool fromConfigure
){
    if ((pChild != pWin) || fromConfigure) {
	miOverlayTreePtr pTree;

        REGION_EMPTY(pChild->drawable.pScreen, &pChild->clipList);
        if (pChild->drawable.pScreen->ClipNotify)
            (* pChild->drawable.pScreen->ClipNotify)(pChild, 0, 0);
        REGION_EMPTY(pChild->drawable.pScreen, &pChild->borderClip);
	if((pTree = MIOVERLAY_GET_WINDOW_TREE(pChild))) {
	    if(pTree->valdata != (miOverlayValDataPtr)UnmapValData) {
		REGION_EMPTY(pChild->drawable.pScreen, &pTree->clipList);
		REGION_EMPTY(pChild->drawable.pScreen, &pTree->borderClip);
	    }
	}
    }
}


static int 
miOverlayValidateTree(
    WindowPtr pParent,
    WindowPtr pChild,   /* first child effected */
    VTKind    kind
){
    ScreenPtr pScreen = pParent->drawable.pScreen;
    miOverlayScreenPtr pPriv = MIOVERLAY_GET_SCREEN_PRIVATE(pScreen);
    RegionRec totalClip, childClip, exposed;
    miOverlayTreePtr tParent, tChild, tWin;
    Bool overlap;
    WindowPtr newParent;

    if(!pPriv->underlayMarked)
	goto SKIP_UNDERLAY;

    if (!pChild) pChild = pParent->firstChild;

    REGION_NULL(pScreen, &totalClip);
    REGION_NULL(pScreen, &childClip);
    REGION_NULL(pScreen, &exposed);

    newParent = pParent;

    while(IN_OVERLAY(newParent))
    	newParent = newParent->parent;

    tParent = MIOVERLAY_GET_WINDOW_TREE(newParent);

    if(IN_UNDERLAY(pChild))
	tChild = MIOVERLAY_GET_WINDOW_TREE(pChild);
    else
	tChild = tParent->firstChild;

    if (REGION_BROKEN (pScreen, &tParent->clipList) &&
        !REGION_BROKEN (pScreen, &tParent->borderClip))
    {
	kind = VTBroken;
	REGION_COPY (pScreen, &totalClip, &tParent->borderClip);
	REGION_INTERSECT (pScreen, &totalClip, &totalClip,
						 &tParent->pWin->winSize);
        
        for (tWin = tParent->firstChild; tWin != tChild; tWin = tWin->nextSib) {
            if (tWin->pWin->viewable)
                REGION_SUBTRACT (pScreen, &totalClip, &totalClip, 
					&tWin->pWin->borderSize);
        }        
        REGION_EMPTY (pScreen, &tParent->clipList);
    } else {
	for(tWin = tChild; tWin; tWin = tWin->nextSib) {
	    if(tWin->valdata)
		REGION_APPEND(pScreen, &totalClip, &tWin->borderClip);
	}
	REGION_VALIDATE(pScreen, &totalClip, &overlap);
    }

    if(kind != VTStack)
	REGION_UNION(pScreen, &totalClip, &totalClip, &tParent->clipList);
	
    for(tWin = tChild; tWin; tWin = tWin->nextSib) {
	if(tWin->valdata) {
	    if(tWin->pWin->viewable) {
		REGION_INTERSECT(pScreen, &childClip, &totalClip,
					&tWin->pWin->borderSize);
		miOverlayComputeClips(tWin->pWin, &childClip, kind, &exposed);
		REGION_SUBTRACT(pScreen, &totalClip, &totalClip,
					&tWin->pWin->borderSize);
	    } else {  /* Means we are unmapping */
                REGION_EMPTY(pScreen, &tWin->clipList);
                REGION_EMPTY( pScreen, &tWin->borderClip);
		tWin->valdata = NULL;
	    }
	}
    }

    REGION_UNINIT(pScreen, &childClip);

    if(!((*pPriv->InOverlay)(newParent))) {
	REGION_NULL(pScreen, &tParent->valdata->exposed);
	REGION_NULL(pScreen, &tParent->valdata->borderExposed);
    }

    switch (kind) {
    case VTStack:
	break;
    default:
    	if(!((*pPriv->InOverlay)(newParent))) 
	    REGION_SUBTRACT(pScreen, &tParent->valdata->exposed, &totalClip, 
						&tParent->clipList);
	/* fall through */
    case VTMap:
	REGION_COPY( pScreen, &tParent->clipList, &totalClip);
    	if(!((*pPriv->InOverlay)(newParent))) 
	    newParent->drawable.serialNumber = NEXT_SERIAL_NUMBER;
	break;
    }

    REGION_UNINIT( pScreen, &totalClip);
    REGION_UNINIT( pScreen, &exposed);

SKIP_UNDERLAY:

    miValidateTree(pParent, pChild, kind);

    return 1;
}


static void
miOverlayHandleExposures(WindowPtr pWin)
{
    ScreenPtr pScreen = pWin->drawable.pScreen;
    miOverlayScreenPtr pPriv = MIOVERLAY_GET_SCREEN_PRIVATE(pScreen);
    WindowPtr pChild;
    ValidatePtr val;
    void (* WindowExposures)(WindowPtr, RegionPtr, RegionPtr);

    WindowExposures = pWin->drawable.pScreen->WindowExposures;
    if(pPriv->underlayMarked) {
	miOverlayTreePtr pTree;
	miOverlayValDataPtr mival;

	pChild = pWin;
	while(IN_OVERLAY(pChild))
	    pChild = pChild->parent;

	pTree = MIOVERLAY_GET_WINDOW_TREE(pChild);

	while (1) {
	    if((mival = pTree->valdata)) {
		if(!((*pPriv->InOverlay)(pTree->pWin))) {
		    if (REGION_NOTEMPTY(pScreen, &mival->borderExposed))
			(*pWin->drawable.pScreen->PaintWindowBorder)(
				pTree->pWin, &mival->borderExposed, PW_BORDER);
		    REGION_UNINIT(pScreen, &mival->borderExposed);

		    (*WindowExposures)(pTree->pWin,&mival->exposed,NullRegion);
		    REGION_UNINIT(pScreen, &mival->exposed);
		}
		xfree(mival);
		pTree->valdata = NULL;
		if (pTree->firstChild) {
		    pTree = pTree->firstChild;
		    continue;
		}
	    }
	    while (!pTree->nextSib && (pTree->pWin != pChild))
	    	pTree = pTree->parent;
	    if (pTree->pWin == pChild)
		break;
	    pTree = pTree->nextSib;
        }
	pPriv->underlayMarked = FALSE;
    }

    pChild = pWin;
    while (1) {
	if ( (val = pChild->valdata) ) {
	    if(!((*pPriv->InOverlay)(pChild))) {
		REGION_UNION(pScreen, &val->after.exposed, &val->after.exposed,
			&val->after.borderExposed);

		if (REGION_NOTEMPTY(pScreen, &val->after.exposed)) {
		   (*(MIOVERLAY_GET_SCREEN_PRIVATE(pScreen)->MakeTransparent))(
				pScreen, 
				REGION_NUM_RECTS(&val->after.exposed),
				REGION_RECTS(&val->after.exposed));
		}
	    } else {
		if (REGION_NOTEMPTY(pScreen, &val->after.borderExposed))
		    (*pChild->drawable.pScreen->PaintWindowBorder)(pChild,
						    &val->after.borderExposed,
						    PW_BORDER);
		(*WindowExposures)(pChild, &val->after.exposed, NullRegion);
	    }
	    REGION_UNINIT(pScreen, &val->after.borderExposed);
	    REGION_UNINIT(pScreen, &val->after.exposed);
	    xfree(val);
	    pChild->valdata = (ValidatePtr)NULL;
	    if (pChild->firstChild)
	    {
		pChild = pChild->firstChild;
		continue;
	    }
	}
	while (!pChild->nextSib && (pChild != pWin))
	    pChild = pChild->parent;
	if (pChild == pWin)
	    break;
	pChild = pChild->nextSib;
    }
}


static void
miOverlayMoveWindow(
    WindowPtr pWin,
    int x,
    int y,
    WindowPtr pNextSib,
    VTKind kind
){
    ScreenPtr pScreen = pWin->drawable.pScreen;
    miOverlayTreePtr pTree = MIOVERLAY_GET_WINDOW_TREE(pWin);
    WindowPtr pParent, windowToValidate;
    Bool WasViewable = (Bool)(pWin->viewable);
    short bw;
    RegionRec overReg, underReg;
    DDXPointRec oldpt;
#ifdef DO_SAVE_UNDERS
    Bool dosave = FALSE;
#endif

    if (!(pParent = pWin->parent))
       return ;
    bw = wBorderWidth (pWin);

    oldpt.x = pWin->drawable.x;
    oldpt.y = pWin->drawable.y;
    if (WasViewable) {
	REGION_NULL(pScreen, &overReg);
	REGION_NULL(pScreen, &underReg);
	if(pTree) {
	    REGION_COPY(pScreen, &overReg, &pWin->borderClip);
	    REGION_COPY(pScreen, &underReg, &pTree->borderClip);
        } else {
	    REGION_COPY(pScreen, &overReg, &pWin->borderClip);
	    CollectUnderlayChildrenRegions(pWin, &underReg);
	}
	(*pScreen->MarkOverlappedWindows)(pWin, pWin, NULL);
    }
    pWin->origin.x = x + (int)bw;
    pWin->origin.y = y + (int)bw;
    x = pWin->drawable.x = pParent->drawable.x + x + (int)bw;
    y = pWin->drawable.y = pParent->drawable.y + y + (int)bw;

    SetWinSize (pWin);
    SetBorderSize (pWin);

    (*pScreen->PositionWindow)(pWin, x, y);

    windowToValidate = MoveWindowInStack(pWin, pNextSib);

    ResizeChildrenWinSize(pWin, x - oldpt.x, y - oldpt.y, 0, 0);

    if (WasViewable) {
	miOverlayScreenPtr pPriv = MIOVERLAY_GET_SCREEN_PRIVATE(pScreen);
	(*pScreen->MarkOverlappedWindows) (pWin, windowToValidate, NULL);

#ifdef DO_SAVE_UNDERS
	if (DO_SAVE_UNDERS(pWin))
	    dosave = (*pScreen->ChangeSaveUnder)(pWin, windowToValidate);
#endif /* DO_SAVE_UNDERS */

	(*pScreen->ValidateTree)(pWin->parent, NullWindow, kind);
	if(REGION_NOTEMPTY(pScreen, &underReg)) {
	    pPriv->copyUnderlay = TRUE;
	    (* pWin->drawable.pScreen->CopyWindow)(pWin, oldpt, &underReg);
	}
	REGION_UNINIT(pScreen, &underReg);
	if(REGION_NOTEMPTY(pScreen, &overReg)) {
	    pPriv->copyUnderlay = FALSE;
	    (* pWin->drawable.pScreen->CopyWindow)(pWin, oldpt, &overReg);
	}
	REGION_UNINIT(pScreen, &overReg);
	(*pScreen->HandleExposures)(pWin->parent);

#ifdef DO_SAVE_UNDERS
	if (dosave)
	    (*pScreen->PostChangeSaveUnder)(pWin, windowToValidate);
#endif /* DO_SAVE_UNDERS */
	if (pScreen->PostValidateTree)
	    (*pScreen->PostValidateTree)(pWin->parent, NullWindow, kind);
    }
    if (pWin->realized)
	WindowsRestructured ();
}

#ifndef RECTLIMIT
#define RECTLIMIT 25
#endif

static void 
miOverlayWindowExposures(
    WindowPtr pWin,
    RegionPtr prgn,
    RegionPtr other_exposed
){
    RegionPtr   exposures = prgn;
    ScreenPtr pScreen = pWin->drawable.pScreen;

    if (pWin->backStorage && prgn)
	exposures = (*pScreen->RestoreAreas)(pWin, prgn);
    if ((prgn && !REGION_NIL(prgn)) || 
	(exposures && !REGION_NIL(exposures)) || other_exposed)
    {
	RegionRec   expRec;
	int	    clientInterested;

	clientInterested = (pWin->eventMask|wOtherEventMasks(pWin)) &
		 	    ExposureMask;
	if (other_exposed) {
	    if (exposures) {
		REGION_UNION(pScreen, other_exposed, exposures, other_exposed);
		if (exposures != prgn)
		    REGION_DESTROY(pScreen, exposures);
	    }
	    exposures = other_exposed;
	}
	if (clientInterested && exposures && 
	   (REGION_NUM_RECTS(exposures) > RECTLIMIT))
	{
            miOverlayScreenPtr pPriv = MIOVERLAY_GET_SCREEN_PRIVATE(pScreen);
	    BoxRec box;

	    box = *REGION_EXTENTS(pScreen, exposures);
	    if (exposures == prgn) {
		exposures = &expRec;
		REGION_INIT(pScreen, exposures, &box, 1);
		REGION_RESET(pScreen, prgn, &box);
	    } else {
		REGION_RESET(pScreen, exposures, &box);
		REGION_UNION(pScreen, prgn, prgn, exposures);
	    }
	    /* This is the only reason why we are replacing mi's version
               of this file */
	    
	    if(!((*pPriv->InOverlay)(pWin))) {
		miOverlayTreePtr pTree = MIOVERLAY_GET_WINDOW_TREE(pWin);
		REGION_INTERSECT(pScreen, prgn, prgn, &pTree->clipList);
	    } else
		REGION_INTERSECT(pScreen, prgn, prgn, &pWin->clipList);

	    /* need to clear out new areas of backing store, too */
	    if (pWin->backStorage)
		(void) (*pScreen->ClearBackingStore)(
					     pWin,
					     box.x1 - pWin->drawable.x,
					     box.y1 - pWin->drawable.y,
					     box.x2 - box.x1,
					     box.y2 - box.y1,
					     FALSE);
	}
	if (prgn && !REGION_NIL(prgn))
	    (*pScreen->PaintWindowBackground)(
			pWin, prgn, PW_BACKGROUND);
	if (clientInterested && exposures && !REGION_NIL(exposures))
	    miSendExposures(pWin, exposures,
			    pWin->drawable.x, pWin->drawable.y);
	if (exposures == &expRec) {
	    REGION_UNINIT(pScreen, exposures);
	} 
	else if (exposures && exposures != prgn && exposures != other_exposed)
	    REGION_DESTROY(pScreen, exposures);
	if (prgn)
	    REGION_EMPTY(pScreen, prgn);
    }
    else if (exposures && exposures != prgn)
	REGION_DESTROY(pScreen, exposures);
}


typedef struct {
   RegionPtr over;
   RegionPtr under;
} miOverlayTwoRegions; 

static int
miOverlayRecomputeExposures (
    WindowPtr	pWin,
    pointer	value 
){
    ScreenPtr pScreen;
    miOverlayTwoRegions	*pValid = (miOverlayTwoRegions*)value;
    miOverlayTreePtr pTree = MIOVERLAY_GET_WINDOW_TREE(pWin);

    /* This prevents warning about pScreen not being used. */
    pWin->drawable.pScreen = pScreen = pWin->drawable.pScreen;

    if (pWin->valdata) {
	/*
	 * compute exposed regions of this window
	 */
	REGION_SUBTRACT(pScreen, &pWin->valdata->after.exposed,
			&pWin->clipList, pValid->over);
	/*
	 * compute exposed regions of the border
	 */
	REGION_SUBTRACT(pScreen, &pWin->valdata->after.borderExposed,
			     &pWin->borderClip, &pWin->winSize);
	REGION_SUBTRACT(pScreen, &pWin->valdata->after.borderExposed,
			     &pWin->valdata->after.borderExposed, pValid->over);
    } 

    if(pTree && pTree->valdata) {
	REGION_SUBTRACT(pScreen, &pTree->valdata->exposed,
			&pTree->clipList, pValid->under);
	REGION_SUBTRACT(pScreen, &pTree->valdata->borderExposed,
			     &pTree->borderClip, &pWin->winSize);
	REGION_SUBTRACT(pScreen, &pTree->valdata->borderExposed,
			     &pTree->valdata->borderExposed, pValid->under);    
    } else if (!pWin->valdata)
	return WT_NOMATCH;

    return WT_WALKCHILDREN;
}

static void
miOverlayResizeWindow(
    WindowPtr pWin,
    int x, int y,
    unsigned int w, unsigned int h,
    WindowPtr pSib
){
    ScreenPtr pScreen = pWin->drawable.pScreen;
    WindowPtr pParent;
    miOverlayTreePtr tChild, pTree;
    Bool WasViewable = (Bool)(pWin->viewable);
    unsigned short width = pWin->drawable.width;
    unsigned short height = pWin->drawable.height;
    short oldx = pWin->drawable.x;
    short oldy = pWin->drawable.y;
    int bw = wBorderWidth (pWin);
    short dw, dh;
    DDXPointRec oldpt;
    RegionPtr oldRegion = NULL, oldRegion2 = NULL;
    WindowPtr pFirstChange;
    WindowPtr pChild;
    RegionPtr	gravitate[StaticGravity + 1];
    RegionPtr	gravitate2[StaticGravity + 1];
    unsigned 	g;
    int		nx, ny;		/* destination x,y */
    int		newx, newy;	/* new inner window position */
    RegionPtr	pRegion = NULL;
    RegionPtr	destClip, destClip2;
    RegionPtr	oldWinClip = NULL, oldWinClip2 = NULL;	
    RegionPtr	borderVisible = NullRegion; 
    RegionPtr	borderVisible2 = NullRegion; 
    RegionPtr	bsExposed = NullRegion;	    /* backing store exposures */
    Bool	shrunk = FALSE; /* shrunk in an inner dimension */
    Bool	moved = FALSE;	/* window position changed */
#ifdef DO_SAVE_UNDERS
    Bool	dosave = FALSE;
#endif
    Bool	doUnderlay;

    /* if this is a root window, can't be resized */
    if (!(pParent = pWin->parent))
	return ;

    pTree = MIOVERLAY_GET_WINDOW_TREE(pWin);
    doUnderlay = ((pTree) || HasUnderlayChildren(pWin));
    newx = pParent->drawable.x + x + bw;
    newy = pParent->drawable.y + y + bw;
    if (WasViewable)
    {
	/*
	 * save the visible region of the window
	 */
	oldRegion = REGION_CREATE(pScreen, NullBox, 1);
	REGION_COPY(pScreen, oldRegion, &pWin->winSize);
	if(doUnderlay) {
	    oldRegion2 = REGION_CREATE(pScreen, NullBox, 1);
	    REGION_COPY(pScreen, oldRegion2, &pWin->winSize);
	}

	/*
	 * categorize child windows into regions to be moved
	 */
	for (g = 0; g <= StaticGravity; g++)
	    gravitate[g] = gravitate2[g] = NULL;
	for (pChild = pWin->firstChild; pChild; pChild = pChild->nextSib) {
	    g = pChild->winGravity;
	    if (g != UnmapGravity) {
		if (!gravitate[g])
		    gravitate[g] = REGION_CREATE(pScreen, NullBox, 1);
		REGION_UNION(pScreen, gravitate[g],
				   gravitate[g], &pChild->borderClip);
		
		if(doUnderlay) {
		    if (!gravitate2[g])
			gravitate2[g] = REGION_CREATE(pScreen, NullBox, 0);
		
		    if((tChild = MIOVERLAY_GET_WINDOW_TREE(pChild))) {
		        REGION_UNION(pScreen, gravitate2[g],
				   gravitate2[g], &tChild->borderClip);
		    } else 
			CollectUnderlayChildrenRegions(pChild, gravitate2[g]);
		}
	    } else {
		UnmapWindow(pChild, TRUE);
	    }
	}
	(*pScreen->MarkOverlappedWindows)(pWin, pWin, NULL);


	oldWinClip = oldWinClip2 = NULL;
	if (pWin->bitGravity != ForgetGravity) {
	    oldWinClip = REGION_CREATE(pScreen, NullBox, 1);
	    REGION_COPY(pScreen, oldWinClip, &pWin->clipList);
	    if(pTree) {
		oldWinClip2 = REGION_CREATE(pScreen, NullBox, 1);
		REGION_COPY(pScreen, oldWinClip2, &pTree->clipList);
	    }
	}
	/*
	 * if the window is changing size, borderExposed
	 * can't be computed correctly without some help.
	 */
	if (pWin->drawable.height > h || pWin->drawable.width > w)
	    shrunk = TRUE;

	if (newx != oldx || newy != oldy)
	    moved = TRUE;

	if ((pWin->drawable.height != h || pWin->drawable.width != w) &&
	    HasBorder (pWin))
	{
	    borderVisible = REGION_CREATE(pScreen, NullBox, 1);
	    if(pTree)
		borderVisible2 = REGION_CREATE(pScreen, NullBox, 1);
	    /* for tiled borders, we punt and draw the whole thing */
	    if (pWin->borderIsPixel || !moved)
	    {
		if (shrunk || moved)
		    REGION_SUBTRACT(pScreen, borderVisible,
					  &pWin->borderClip,
					  &pWin->winSize);
		else
		    REGION_COPY(pScreen, borderVisible,
					    &pWin->borderClip);
		if(pTree) {
		    if (shrunk || moved)
			REGION_SUBTRACT(pScreen, borderVisible,
					  &pTree->borderClip,
					  &pWin->winSize);
		    else
			REGION_COPY(pScreen, borderVisible,
					    &pTree->borderClip);
		}
	    }
	}
    }
    pWin->origin.x = x + bw;
    pWin->origin.y = y + bw;
    pWin->drawable.height = h;
    pWin->drawable.width = w;

    x = pWin->drawable.x = newx;
    y = pWin->drawable.y = newy;

    SetWinSize (pWin);
    SetBorderSize (pWin);

    dw = (int)w - (int)width;
    dh = (int)h - (int)height;
    ResizeChildrenWinSize(pWin, x - oldx, y - oldy, dw, dh);

    /* let the hardware adjust background and border pixmaps, if any */
    (*pScreen->PositionWindow)(pWin, x, y);

    pFirstChange = MoveWindowInStack(pWin, pSib);

    if (WasViewable) {
	pRegion = REGION_CREATE(pScreen, NullBox, 1);
	if (pWin->backStorage)
	    REGION_COPY(pScreen, pRegion, &pWin->clipList);

	(*pScreen->MarkOverlappedWindows)(pWin, pFirstChange, NULL);

	pWin->valdata->before.resized = TRUE;
	pWin->valdata->before.borderVisible = borderVisible;
	if(pTree)
	    pTree->valdata->borderVisible = borderVisible2;

#ifdef DO_SAVE_UNDERS
	if (DO_SAVE_UNDERS(pWin))
	    dosave = (*pScreen->ChangeSaveUnder)(pWin, pFirstChange);
#endif /* DO_SAVE_UNDERS */

	(*pScreen->ValidateTree)(pWin->parent, pFirstChange, VTOther);
	/*
	 * the entire window is trashed unless bitGravity
	 * recovers portions of it
	 */
	REGION_COPY(pScreen, &pWin->valdata->after.exposed, &pWin->clipList);
	if(pTree)
	    REGION_COPY(pScreen, &pTree->valdata->exposed, &pTree->clipList);
    }

    GravityTranslate (x, y, oldx, oldy, dw, dh, pWin->bitGravity, &nx, &ny);

    if (pWin->backStorage && ((pWin->backingStore == Always) || WasViewable)) {
	if (!WasViewable)
	    pRegion = &pWin->clipList; /* a convenient empty region */
	if (pWin->bitGravity == ForgetGravity)
	    bsExposed = (*pScreen->TranslateBackingStore)
				(pWin, 0, 0, NullRegion, oldx, oldy);
	else
	    bsExposed = (*pScreen->TranslateBackingStore)
			     (pWin, nx - x, ny - y, pRegion, oldx, oldy);
    }

    if (WasViewable) {
	miOverlayScreenPtr pPriv = MIOVERLAY_GET_SCREEN_PRIVATE(pScreen);
	miOverlayTwoRegions TwoRegions;

	/* avoid the border */
	if (HasBorder (pWin)) {
	    int	offx, offy, dx, dy;

	    /* kruft to avoid double translates for each gravity */
	    offx = 0;
	    offy = 0;
	    for (g = 0; g <= StaticGravity; g++) {
		if (!gravitate[g] && !gravitate2[g])
		    continue;

		/* align winSize to gravitate[g].
		 * winSize is in new coordinates,
		 * gravitate[g] is still in old coordinates */
		GravityTranslate (x, y, oldx, oldy, dw, dh, g, &nx, &ny);
		
		dx = (oldx - nx) - offx;
		dy = (oldy - ny) - offy;
		if (dx || dy) {
		    REGION_TRANSLATE(pScreen, &pWin->winSize, dx, dy);
		    offx += dx;
		    offy += dy;
		}
		if(gravitate[g])
		    REGION_INTERSECT(pScreen, gravitate[g], gravitate[g],
				 &pWin->winSize);
		if(gravitate2[g])
		    REGION_INTERSECT(pScreen, gravitate2[g], gravitate2[g],
				 &pWin->winSize);
	    }
	    /* get winSize back where it belongs */
	    if (offx || offy)
		REGION_TRANSLATE(pScreen, &pWin->winSize, -offx, -offy);
	}
	/*
	 * add screen bits to the appropriate bucket
	 */

	if (oldWinClip2)
	{
	    REGION_COPY(pScreen, pRegion, oldWinClip2);
	    REGION_TRANSLATE(pScreen, pRegion, nx - oldx, ny - oldy);
	    REGION_INTERSECT(pScreen, oldWinClip2, pRegion, &pTree->clipList);

	    for (g = pWin->bitGravity + 1; g <= StaticGravity; g++) {
		if (gravitate2[g])
		    REGION_SUBTRACT(pScreen, oldWinClip2, oldWinClip2,
					gravitate2[g]);
	    }
	    REGION_TRANSLATE(pScreen, oldWinClip2, oldx - nx, oldy - ny);
	    g = pWin->bitGravity;
	    if (!gravitate2[g])
		gravitate2[g] = oldWinClip2;
	    else {
		REGION_UNION(pScreen,gravitate2[g],gravitate2[g],oldWinClip2);
		REGION_DESTROY(pScreen, oldWinClip2);
	    }
	}

	if (oldWinClip)
	{
	    /*
	     * clip to new clipList
	     */
	    REGION_COPY(pScreen, pRegion, oldWinClip);
	    REGION_TRANSLATE(pScreen, pRegion, nx - oldx, ny - oldy);
	    REGION_INTERSECT(pScreen, oldWinClip, pRegion, &pWin->clipList);
	    /*
	     * don't step on any gravity bits which will be copied after this
	     * region.	Note -- this assumes that the regions will be copied
	     * in gravity order.
	     */
	    for (g = pWin->bitGravity + 1; g <= StaticGravity; g++) {
		if (gravitate[g])
		    REGION_SUBTRACT(pScreen, oldWinClip, oldWinClip,
					gravitate[g]);
	    }
	    REGION_TRANSLATE(pScreen, oldWinClip, oldx - nx, oldy - ny);
	    g = pWin->bitGravity;
	    if (!gravitate[g])
		gravitate[g] = oldWinClip;
	    else {
		REGION_UNION(pScreen, gravitate[g], gravitate[g], oldWinClip);
		REGION_DESTROY(pScreen, oldWinClip);
	    }
	}

	/*
	 * move the bits on the screen
	 */

	destClip = destClip2 = NULL;

	for (g = 0; g <= StaticGravity; g++) {
	    if (!gravitate[g] && !gravitate2[g])
		continue;

	    GravityTranslate (x, y, oldx, oldy, dw, dh, g, &nx, &ny);

	    oldpt.x = oldx + (x - nx);
	    oldpt.y = oldy + (y - ny);

	    /* Note that gravitate[g] is *translated* by CopyWindow */

	    /* only copy the remaining useful bits */

	    if(gravitate[g])
		REGION_INTERSECT(pScreen, gravitate[g], 
				 gravitate[g], oldRegion);
	    if(gravitate2[g])
		REGION_INTERSECT(pScreen, gravitate2[g], 
				 gravitate2[g], oldRegion2);

	    /* clip to not overwrite already copied areas */

	    if (destClip && gravitate[g]) {
		REGION_TRANSLATE(pScreen, destClip, oldpt.x - x, oldpt.y - y);
		REGION_SUBTRACT(pScreen, gravitate[g], gravitate[g], destClip);
		REGION_TRANSLATE(pScreen, destClip, x - oldpt.x, y - oldpt.y);
	    }
	    if (destClip2 && gravitate2[g]) {
		REGION_TRANSLATE(pScreen, destClip2, oldpt.x - x, oldpt.y - y);
		REGION_SUBTRACT(pScreen,gravitate2[g],gravitate2[g],destClip2);
		REGION_TRANSLATE(pScreen, destClip2, x - oldpt.x, y - oldpt.y);
	    }

	    /* and move those bits */

	    if (oldpt.x != x || oldpt.y != y) {
		if(gravitate2[g]) {
		    pPriv->copyUnderlay = TRUE;
		    (*pWin->drawable.pScreen->CopyWindow)(
						pWin, oldpt, gravitate2[g]);
		}
		if(gravitate[g]) {
		    pPriv->copyUnderlay = FALSE;
		    (*pWin->drawable.pScreen->CopyWindow)(
						pWin, oldpt, gravitate[g]);
		}
	    }

	    /* remove any overwritten bits from the remaining useful bits */

	    if(gravitate[g])
		REGION_SUBTRACT(pScreen, oldRegion, oldRegion, gravitate[g]);
	    if(gravitate2[g])
		REGION_SUBTRACT(pScreen, oldRegion2, oldRegion2, gravitate2[g]);

	    /*
	     * recompute exposed regions of child windows
	     */
	

	    for (pChild = pWin->firstChild; pChild; pChild = pChild->nextSib) {
		if (pChild->winGravity != g)
		    continue;

		TwoRegions.over = gravitate[g];
		TwoRegions.under = gravitate2[g];

		TraverseTree (pChild, miOverlayRecomputeExposures, 
					(pointer)(&TwoRegions));
	    }

	    /*
	     * remove the successfully copied regions of the
	     * window from its exposed region
	     */

	    if (g == pWin->bitGravity) {
		if(gravitate[g])
		    REGION_SUBTRACT(pScreen, &pWin->valdata->after.exposed,
				&pWin->valdata->after.exposed, gravitate[g]);
		if(gravitate2[g] && pTree) 
		    REGION_SUBTRACT(pScreen, &pTree->valdata->exposed,
				&pTree->valdata->exposed, gravitate2[g]);
	    }
	    if(gravitate[g]) {
		if (!destClip)
		    destClip = gravitate[g];
		else {
		    REGION_UNION(pScreen, destClip, destClip, gravitate[g]);
		    REGION_DESTROY(pScreen, gravitate[g]);
		}
	    }
	    if(gravitate2[g]) {
		if (!destClip2)
		    destClip2 = gravitate2[g];
		else {
		    REGION_UNION(pScreen, destClip2, destClip2, gravitate2[g]);
		    REGION_DESTROY(pScreen, gravitate2[g]);
		}
	    }
	}

	REGION_DESTROY(pScreen, pRegion);
	REGION_DESTROY(pScreen, oldRegion);
	if(doUnderlay)
	    REGION_DESTROY(pScreen, oldRegion2);
	if (destClip)
	    REGION_DESTROY(pScreen, destClip);
	if (destClip2)
	    REGION_DESTROY(pScreen, destClip2);
	if (bsExposed) {
	    RegionPtr	valExposed = NullRegion;

	    if (pWin->valdata)
		valExposed = &pWin->valdata->after.exposed;
	    (*pScreen->WindowExposures) (pWin, valExposed, bsExposed);
	    if (valExposed)
		REGION_EMPTY(pScreen, valExposed);
	    REGION_DESTROY(pScreen, bsExposed);
	}
	(*pScreen->HandleExposures)(pWin->parent);
#ifdef DO_SAVE_UNDERS
	if (dosave)
	    (*pScreen->PostChangeSaveUnder)(pWin, pFirstChange);
#endif /* DO_SAVE_UNDERS */
	if (pScreen->PostValidateTree)
	    (*pScreen->PostValidateTree)(pWin->parent, pFirstChange, VTOther);
    }
    else if (bsExposed) {
	(*pScreen->WindowExposures) (pWin, NullRegion, bsExposed);
	REGION_DESTROY(pScreen, bsExposed);
    }
    if (pWin->realized)
	WindowsRestructured ();
}


#ifdef SHAPE
static void
miOverlaySetShape(WindowPtr pWin)
{
    Bool	WasViewable = (Bool)(pWin->viewable);
    ScreenPtr 	pScreen = pWin->drawable.pScreen;
    RegionPtr	pOldClip = NULL, bsExposed;
#ifdef DO_SAVE_UNDERS
    Bool	dosave = FALSE;
#endif

    if (WasViewable) {
	(*pScreen->MarkOverlappedWindows)(pWin, pWin, NULL);

	if (HasBorder (pWin)) {
	    RegionPtr borderVisible;

	    borderVisible = REGION_CREATE(pScreen, NullBox, 1);
	    REGION_SUBTRACT(pScreen, borderVisible,
				      &pWin->borderClip, &pWin->winSize);
	    pWin->valdata->before.borderVisible = borderVisible;
	    pWin->valdata->before.resized = TRUE;
	    if(IN_UNDERLAY(pWin)) {
		miOverlayTreePtr pTree = MIOVERLAY_GET_WINDOW_TREE(pWin);
		RegionPtr borderVisible2;

		borderVisible2 = REGION_CREATE(pScreen, NULL, 1);
		REGION_SUBTRACT(pScreen, borderVisible2,
				      &pTree->borderClip, &pWin->winSize);
		pTree->valdata->borderVisible = borderVisible2;
	    }
	}
    }

    SetWinSize (pWin);
    SetBorderSize (pWin);

    ResizeChildrenWinSize(pWin, 0, 0, 0, 0);

    if (WasViewable) {
	if (pWin->backStorage) {
	    pOldClip = REGION_CREATE(pScreen, NullBox, 1);
	    REGION_COPY(pScreen, pOldClip, &pWin->clipList);
	}

	(*pScreen->MarkOverlappedWindows)(pWin, pWin, NULL);

#ifdef DO_SAVE_UNDERS
	if (DO_SAVE_UNDERS(pWin))
	    dosave = (*pScreen->ChangeSaveUnder)(pWin, pWin);
#endif /* DO_SAVE_UNDERS */

	(*pScreen->ValidateTree)(pWin->parent, NullWindow, VTOther);
    }

    if (pWin->backStorage && ((pWin->backingStore == Always) || WasViewable)) {
	if (!WasViewable)
	    pOldClip = &pWin->clipList; /* a convenient empty region */
	bsExposed = (*pScreen->TranslateBackingStore)
			     (pWin, 0, 0, pOldClip,
			      pWin->drawable.x, pWin->drawable.y);
	if (WasViewable)
	    REGION_DESTROY(pScreen, pOldClip);
	if (bsExposed)
	{
	    RegionPtr	valExposed = NullRegion;
    
	    if (pWin->valdata)
		valExposed = &pWin->valdata->after.exposed;
	    (*pScreen->WindowExposures) (pWin, valExposed, bsExposed);
	    if (valExposed)
		REGION_EMPTY(pScreen, valExposed);
	    REGION_DESTROY(pScreen, bsExposed);
	}
    }
    if (WasViewable) {
	(*pScreen->HandleExposures)(pWin->parent);
#ifdef DO_SAVE_UNDERS
	if (dosave)
	    (*pScreen->PostChangeSaveUnder)(pWin, pWin);
#endif /* DO_SAVE_UNDERS */
	if (pScreen->PostValidateTree)
	    (*pScreen->PostValidateTree)(pWin->parent, NullWindow, VTOther);
    }
    if (pWin->realized)
	WindowsRestructured ();
    CheckCursorConfinement(pWin);
}
#endif



static void
miOverlayChangeBorderWidth(
    WindowPtr pWin,
    unsigned int width
){
    int oldwidth;
    ScreenPtr pScreen;
    Bool WasViewable = (Bool)(pWin->viewable);
    Bool HadBorder;
#ifdef DO_SAVE_UNDERS
    Bool	dosave = FALSE;
#endif

    oldwidth = wBorderWidth (pWin);
    if (oldwidth == width)
	return;
    HadBorder = HasBorder(pWin);
    pScreen = pWin->drawable.pScreen;
    if (WasViewable && (width < oldwidth))
	(*pScreen->MarkOverlappedWindows)(pWin, pWin, NULL);

    pWin->borderWidth = width;
    SetBorderSize (pWin);

    if (WasViewable) {
	if (width > oldwidth) {
	    (*pScreen->MarkOverlappedWindows)(pWin, pWin, NULL);

	    if (HadBorder) {
		RegionPtr   borderVisible;
		borderVisible = REGION_CREATE(pScreen, NULL, 1);
		REGION_SUBTRACT(pScreen, borderVisible,
				      &pWin->borderClip, &pWin->winSize);
		pWin->valdata->before.borderVisible = borderVisible;
		if(IN_UNDERLAY(pWin)) {
		    miOverlayTreePtr pTree = MIOVERLAY_GET_WINDOW_TREE(pWin);
		    RegionPtr borderVisible2;

		    borderVisible2 = REGION_CREATE(pScreen, NULL, 1);
		    REGION_SUBTRACT(pScreen, borderVisible2,
				      &pTree->borderClip, &pWin->winSize);
		    pTree->valdata->borderVisible = borderVisible2;
		}
	    }
	}
#ifdef DO_SAVE_UNDERS
	if (DO_SAVE_UNDERS(pWin))
	    dosave = (*pScreen->ChangeSaveUnder)(pWin, pWin->nextSib);
#endif /* DO_SAVE_UNDERS */
	(*pScreen->ValidateTree)(pWin->parent, pWin, VTOther);
	(*pScreen->HandleExposures)(pWin->parent);

#ifdef DO_SAVE_UNDERS
	if (dosave)
	    (*pScreen->PostChangeSaveUnder)(pWin, pWin->nextSib);
#endif /* DO_SAVE_UNDERS */
	if (pScreen->PostValidateTree)
	    (*pScreen->PostValidateTree)(pWin->parent, pWin, VTOther);
    }
    if (pWin->realized)
	WindowsRestructured ();
}

/*  We need this as an addition since the xf86 common code doesn't
    know about the second tree which is static to this file.  */

_X_EXPORT void
miOverlaySetRootClip(ScreenPtr pScreen, Bool enable)
{
    WindowPtr pRoot = WindowTable[pScreen->myNum];
    miOverlayTreePtr pTree = MIOVERLAY_GET_WINDOW_TREE(pRoot);

    MARK_UNDERLAY(pRoot);

    if(enable) {
	BoxRec box;
	
	box.x1 = 0;
	box.y1 = 0;
	box.x2 = pScreen->width;
	box.y2 = pScreen->height;

	REGION_RESET(pScreen, &pTree->borderClip, &box);
    } else 
	REGION_EMPTY(pScreen, &pTree->borderClip);

    REGION_BREAK(pScreen, &pTree->clipList);
}

static void 
miOverlayClearToBackground(
    WindowPtr pWin,
    int x, int y,
    int w, int h,
    Bool generateExposures
)
{
    miOverlayTreePtr pTree = MIOVERLAY_GET_WINDOW_TREE(pWin);
    BoxRec box;
    RegionRec reg;
    RegionPtr pBSReg = NullRegion;
    ScreenPtr pScreen = pWin->drawable.pScreen;
    miOverlayScreenPtr pScreenPriv = MIOVERLAY_GET_SCREEN_PRIVATE(pScreen);
    RegionPtr clipList;
    BoxPtr  extents;
    int     x1, y1, x2, y2;

    x1 = pWin->drawable.x + x;
    y1 = pWin->drawable.y + y;
    if (w)
        x2 = x1 + (int) w;
    else
        x2 = x1 + (int) pWin->drawable.width - (int) x;
    if (h)
        y2 = y1 + h;    
    else
        y2 = y1 + (int) pWin->drawable.height - (int) y;

    clipList = ((*pScreenPriv->InOverlay)(pWin)) ? &pWin->clipList :
                                                 &pTree->clipList;

    extents = REGION_EXTENTS(pScreen, clipList);
    
    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 = y2 = y1 = 0;

    box.x1 = x1; box.x2 = x2;
    box.y1 = y1; box.y2 = y2;

    REGION_INIT(pScreen, &reg, &box, 1);
    if (pWin->backStorage) {
        pBSReg = (* pScreen->ClearBackingStore)(pWin, x, y, w, h,
                                                 generateExposures);
    }

    REGION_INTERSECT(pScreen, &reg, &reg, clipList);
    if (generateExposures)
        (*pScreen->WindowExposures)(pWin, &reg, pBSReg);
    else if (pWin->backgroundState != None)
        (*pScreen->PaintWindowBackground)(pWin, &reg, PW_BACKGROUND);
    REGION_UNINIT(pScreen, &reg);
    if (pBSReg)
        REGION_DESTROY(pScreen, pBSReg);
}


/****************************************************************/

/* not used */
_X_EXPORT Bool
miOverlayGetPrivateClips(
    WindowPtr pWin,
    RegionPtr *borderClip,
    RegionPtr *clipList
){
    miOverlayTreePtr pTree = MIOVERLAY_GET_WINDOW_TREE(pWin);
	
    if(pTree) {
 	*borderClip = &(pTree->borderClip);
	*clipList = &(pTree->clipList);
	return TRUE;
    }

    *borderClip = *clipList = NULL;

    return FALSE;
}

_X_EXPORT void 
miOverlaySetTransFunction (
   ScreenPtr pScreen, 
   miOverlayTransFunc transFunc
){
    MIOVERLAY_GET_SCREEN_PRIVATE(pScreen)->MakeTransparent = transFunc;
}

_X_EXPORT Bool 
miOverlayCopyUnderlay(ScreenPtr pScreen)
{
    return MIOVERLAY_GET_SCREEN_PRIVATE(pScreen)->copyUnderlay;
}

_X_EXPORT void
miOverlayComputeCompositeClip(GCPtr pGC, WindowPtr pWin)
{
    ScreenPtr       pScreen = pGC->pScreen;
    miOverlayTreePtr pTree = MIOVERLAY_GET_WINDOW_TREE(pWin);
    RegionPtr       pregWin;
    Bool            freeTmpClip, freeCompClip;

    if(!pTree) {
	miComputeCompositeClip(pGC, &pWin->drawable);
	return;
    }

    if (pGC->subWindowMode == IncludeInferiors) {
	pregWin = REGION_CREATE(pScreen, NullBox, 1);
	freeTmpClip = TRUE;
	if (pWin->parent || (screenIsSaved != SCREEN_SAVER_ON) ||
		!HasSaverWindow (pScreen->myNum))
	{
            REGION_INTERSECT(pScreen,pregWin,&pTree->borderClip,&pWin->winSize);
	}
    } else {
	pregWin = &pTree->clipList;
	freeTmpClip = FALSE;
    }
    freeCompClip = pGC->freeCompClip;
    if (pGC->clientClipType == CT_NONE) {
	if (freeCompClip) 
	    REGION_DESTROY(pScreen, pGC->pCompositeClip);
	pGC->pCompositeClip = pregWin;
	pGC->freeCompClip = freeTmpClip;
    } else {
	REGION_TRANSLATE(pScreen, pGC->clientClip,
				pWin->drawable.x + pGC->clipOrg.x,
				pWin->drawable.y + pGC->clipOrg.y);

	if (freeCompClip) {
	    REGION_INTERSECT(pGC->pScreen, pGC->pCompositeClip,
					    pregWin, pGC->clientClip);
	    if (freeTmpClip)
		REGION_DESTROY(pScreen, pregWin);
	} else if (freeTmpClip) {
	    REGION_INTERSECT(pScreen, pregWin, pregWin, pGC->clientClip);
	    pGC->pCompositeClip = pregWin;
	} else {
	    pGC->pCompositeClip = REGION_CREATE(pScreen, NullBox, 0);
	    REGION_INTERSECT(pScreen, pGC->pCompositeClip,
				       pregWin, pGC->clientClip);
	}
	pGC->freeCompClip = TRUE;
	REGION_TRANSLATE(pScreen, pGC->clientClip,
				-(pWin->drawable.x + pGC->clipOrg.x),
				-(pWin->drawable.y + pGC->clipOrg.y));
    }
}

_X_EXPORT Bool
miOverlayCollectUnderlayRegions(
    WindowPtr pWin,
    RegionPtr *region
){
    miOverlayTreePtr pTree = MIOVERLAY_GET_WINDOW_TREE(pWin);

    if(pTree) {
	*region = &pTree->borderClip;
	return FALSE;
    }

    *region = REGION_CREATE(pWin->drawable.pScreen, NullBox, 0);
    
    CollectUnderlayChildrenRegions(pWin, *region);

    return TRUE;
}


static miOverlayTreePtr
DoLeaf(
    WindowPtr pWin, 
    miOverlayTreePtr parent, 
    miOverlayTreePtr prevSib
){
    miOverlayTreePtr pTree = MIOVERLAY_GET_WINDOW_TREE(pWin);
    
    pTree->parent = parent;
    pTree->firstChild = NULL;
    pTree->lastChild = NULL;
    pTree->prevSib = prevSib;
    pTree->nextSib = NULL;

    if(prevSib)
	prevSib->nextSib = pTree;

    if(!parent->firstChild)
	parent->firstChild = parent->lastChild = pTree;
    else if(parent->lastChild == prevSib)
	parent->lastChild = pTree;
   
    return pTree;
}

static void 
RebuildTree(WindowPtr pWin)
{
    miOverlayTreePtr parent, prevSib, tChild;
    WindowPtr pChild;

    prevSib = tChild = NULL;

    pWin = pWin->parent;

    while(IN_OVERLAY(pWin))
	pWin = pWin->parent;

    parent = MIOVERLAY_GET_WINDOW_TREE(pWin);

    pChild = pWin->firstChild;
    parent->firstChild = parent->lastChild = NULL;

    while(1) {
	if(IN_UNDERLAY(pChild))
	   prevSib = tChild = DoLeaf(pChild, parent, prevSib);

	if(pChild->firstChild) {
	    if(IN_UNDERLAY(pChild)) {
		parent = tChild;
		prevSib = NULL;
	    }
	    pChild = pChild->firstChild;
	    continue;
	}

	while(!pChild->nextSib) {
	    pChild = pChild->parent;
	    if(pChild == pWin) return;
	    if(IN_UNDERLAY(pChild)) {
		prevSib = tChild = MIOVERLAY_GET_WINDOW_TREE(pChild);
		parent = tChild->parent;
	    }
	}

	pChild = pChild->nextSib;
    }
}


static Bool
HasUnderlayChildren(WindowPtr pWin)
{
    WindowPtr pChild;

    if(!(pChild = pWin->firstChild)) 
	return FALSE;

    while(1) {
	if(IN_UNDERLAY(pChild))
	   return TRUE;

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

	while(!pChild->nextSib && (pWin != pChild))
	    pChild = pChild->parent;

	if(pChild == pWin) break;

	pChild = pChild->nextSib;
    }

    return FALSE;
}


static Bool
CollectUnderlayChildrenRegions(WindowPtr pWin, RegionPtr pReg)
{
    WindowPtr pChild;
    miOverlayTreePtr pTree;
    Bool hasUnderlay;

    if(!(pChild = pWin->firstChild)) 
	return FALSE;

    hasUnderlay = FALSE;

    while(1) {
	if((pTree = MIOVERLAY_GET_WINDOW_TREE(pChild))) {
	    REGION_APPEND(pScreen, pReg, &pTree->borderClip);
	    hasUnderlay = TRUE;
	} else
	if(pChild->firstChild) {
	    pChild = pChild->firstChild;
	    continue;
	}

	while(!pChild->nextSib && (pWin != pChild))
	    pChild = pChild->parent;

	if(pChild == pWin) break;

	pChild = pChild->nextSib;
    }

    if(hasUnderlay) {
	Bool overlap;
	REGION_VALIDATE(pScreen, pReg, &overlap);
    } 

    return hasUnderlay;
}


static void 
MarkUnderlayWindow(WindowPtr pWin)
{
    miOverlayTreePtr pTree = MIOVERLAY_GET_WINDOW_TREE(pWin);

    if(pTree->valdata) return;
    pTree->valdata = (miOverlayValDataPtr)xnfalloc(sizeof(miOverlayValDataRec));
    pTree->valdata->oldAbsCorner.x = pWin->drawable.x;
    pTree->valdata->oldAbsCorner.y = pWin->drawable.y;
    pTree->valdata->borderVisible = NullRegion;
}