1 /*
2  * mivaltree.c --
3  *	Functions for recalculating window clip lists. Main function
4  *	is miValidateTree.
5  *
6 
7 Copyright 1987, 1988, 1989, 1998  The Open Group
8 
9 Permission to use, copy, modify, distribute, and sell this software and its
10 documentation for any purpose is hereby granted without fee, provided that
11 the above copyright notice appear in all copies and that both that
12 copyright notice and this permission notice appear in supporting
13 documentation.
14 
15 The above copyright notice and this permission notice shall be included in
16 all copies or substantial portions of the Software.
17 
18 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
21 OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
22 AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
23 CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
24 
25 Except as contained in this notice, the name of The Open Group shall not be
26 used in advertising or otherwise to promote the sale, use or other dealings
27 in this Software without prior written authorization from The Open Group.
28 
29  *
30  * Copyright 1987, 1988, 1989 by
31  * Digital Equipment Corporation, Maynard, Massachusetts,
32  *
33  *                         All Rights Reserved
34  *
35  * Permission to use, copy, modify, and distribute this software and its
36  * documentation for any purpose and without fee is hereby granted,
37  * provided that the above copyright notice appear in all copies and that
38  * both that copyright notice and this permission notice appear in
39  * supporting documentation, and that the name of Digital not be
40  * used in advertising or publicity pertaining to distribution of the
41  * software without specific, written prior permission.
42  *
43  * DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
44  * ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
45  * DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
46  * ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
47  * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
48  * ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
49  * SOFTWARE.
50  *
51  ******************************************************************/
52 
53 /* The panoramix components contained the following notice */
54 /*****************************************************************
55 
56 Copyright (c) 1991, 1997 Digital Equipment Corporation, Maynard, Massachusetts.
57 
58 Permission is hereby granted, free of charge, to any person obtaining a copy
59 of this software and associated documentation files (the "Software"), to deal
60 in the Software without restriction, including without limitation the rights
61 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
62 copies of the Software.
63 
64 The above copyright notice and this permission notice shall be included in
65 all copies or substantial portions of the Software.
66 
67 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
68 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
69 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
70 DIGITAL EQUIPMENT CORPORATION BE LIABLE FOR ANY CLAIM, DAMAGES, INCLUDING,
71 BUT NOT LIMITED TO CONSEQUENTIAL OR INCIDENTAL DAMAGES, OR OTHER LIABILITY,
72 WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
73 IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
74 
75 Except as contained in this notice, the name of Digital Equipment Corporation
76 shall not be used in advertising or otherwise to promote the sale, use or other
77 dealings in this Software without prior written authorization from Digital
78 Equipment Corporation.
79 
80 ******************************************************************/
81 
82  /*
83   * Aug '86: Susan Angebranndt -- original code
84   * July '87: Adam de Boor -- substantially modified and commented
85   * Summer '89: Joel McCormack -- so fast you wouldn't believe it possible.
86   *             In particular, much improved code for window mapping and
87   *             circulating.
88   *             Bob Scheifler -- avoid miComputeClips for unmapped windows,
89   *                              valdata changes
90   */
91 #ifdef HAVE_DIX_CONFIG_H
92 #include <dix-config.h>
93 #endif
94 
95 #include    <X11/X.h>
96 #include    "scrnintstr.h"
97 #include    "validate.h"
98 #include    "windowstr.h"
99 #include    "mi.h"
100 #include    "regionstr.h"
101 #include    "mivalidate.h"
102 #include    "globals.h"
103 #ifdef COMPOSITE
104 #include    "compint.h"
105 #endif
106 
107 /*
108  * Compute the visibility of a shaped window
109  */
110 int
miShapedWindowIn(RegionPtr universe,RegionPtr bounding,BoxPtr rect,int x,int y)111 miShapedWindowIn(RegionPtr universe, RegionPtr bounding,
112                  BoxPtr rect, int x, int y)
113 {
114     BoxRec box;
115     BoxPtr boundBox;
116     int nbox;
117     Bool someIn, someOut;
118     int t, x1, y1, x2, y2;
119 
120     nbox = RegionNumRects(bounding);
121     boundBox = RegionRects(bounding);
122     someIn = someOut = FALSE;
123     x1 = rect->x1;
124     y1 = rect->y1;
125     x2 = rect->x2;
126     y2 = rect->y2;
127     while (nbox--) {
128         if ((t = boundBox->x1 + x) < x1)
129             t = x1;
130         box.x1 = t;
131         if ((t = boundBox->y1 + y) < y1)
132             t = y1;
133         box.y1 = t;
134         if ((t = boundBox->x2 + x) > x2)
135             t = x2;
136         box.x2 = t;
137         if ((t = boundBox->y2 + y) > y2)
138             t = y2;
139         box.y2 = t;
140         if (box.x1 > box.x2)
141             box.x2 = box.x1;
142         if (box.y1 > box.y2)
143             box.y2 = box.y1;
144         switch (RegionContainsRect(universe, &box)) {
145         case rgnIN:
146             if (someOut)
147                 return rgnPART;
148             someIn = TRUE;
149             break;
150         case rgnOUT:
151             if (someIn)
152                 return rgnPART;
153             someOut = TRUE;
154             break;
155         default:
156             return rgnPART;
157         }
158         boundBox++;
159     }
160     if (someIn)
161         return rgnIN;
162     return rgnOUT;
163 }
164 
165 /*
166  * Manual redirected windows are treated as transparent; they do not obscure
167  * siblings or parent windows
168  */
169 
170 #ifdef COMPOSITE
171 #define TreatAsTransparent(w)	((w)->redirectDraw == RedirectDrawManual)
172 #else
173 #define TreatAsTransparent(w)	FALSE
174 #endif
175 
176 #define HasParentRelativeBorder(w) (!(w)->borderIsPixel && \
177 				    HasBorder(w) && \
178 				    (w)->backgroundState == ParentRelative)
179 
180 /*
181  *-----------------------------------------------------------------------
182  * miComputeClips --
183  *	Recompute the clipList, borderClip, exposed and borderExposed
184  *	regions for pParent and its children. Only viewable windows are
185  *	taken into account.
186  *
187  * Results:
188  *	None.
189  *
190  * Side Effects:
191  *	clipList, borderClip, exposed and borderExposed are altered.
192  *	A VisibilityNotify event may be generated on the parent window.
193  *
194  *-----------------------------------------------------------------------
195  */
196 static void
miComputeClips(WindowPtr pParent,ScreenPtr pScreen,RegionPtr universe,VTKind kind,RegionPtr exposed)197 miComputeClips(WindowPtr pParent,
198                ScreenPtr pScreen,
199                RegionPtr universe, VTKind kind, RegionPtr exposed)
200 {                               /* for intermediate calculations */
201     int dx, dy;
202     RegionRec childUniverse;
203     WindowPtr pChild;
204     int oldVis, newVis;
205     BoxRec borderSize;
206     RegionRec childUnion;
207     Bool overlap;
208     RegionPtr borderVisible;
209 
210     /*
211      * Figure out the new visibility of this window.
212      * The extent of the universe should be the same as the extent of
213      * the borderSize region. If the window is unobscured, this rectangle
214      * will be completely inside the universe (the universe will cover it
215      * completely). If the window is completely obscured, none of the
216      * universe will cover the rectangle.
217      */
218     borderSize.x1 = pParent->drawable.x - wBorderWidth(pParent);
219     borderSize.y1 = pParent->drawable.y - wBorderWidth(pParent);
220     dx = (int) pParent->drawable.x + (int) pParent->drawable.width +
221         wBorderWidth(pParent);
222     if (dx > 32767)
223         dx = 32767;
224     borderSize.x2 = dx;
225     dy = (int) pParent->drawable.y + (int) pParent->drawable.height +
226         wBorderWidth(pParent);
227     if (dy > 32767)
228         dy = 32767;
229     borderSize.y2 = dy;
230 
231 #ifdef COMPOSITE
232     /*
233      * In redirected drawing case, reset universe to borderSize
234      */
235     if (pParent->redirectDraw != RedirectDrawNone) {
236         if (TreatAsTransparent(pParent))
237             RegionEmpty(universe);
238         compSetRedirectBorderClip (pParent, universe);
239         RegionCopy(universe, &pParent->borderSize);
240     }
241 #endif
242 
243     oldVis = pParent->visibility;
244     switch (RegionContainsRect(universe, &borderSize)) {
245     case rgnIN:
246         newVis = VisibilityUnobscured;
247         break;
248     case rgnPART:
249         newVis = VisibilityPartiallyObscured;
250         {
251             RegionPtr pBounding;
252 
253             if ((pBounding = wBoundingShape(pParent))) {
254                 switch (miShapedWindowIn(universe, pBounding,
255                                          &borderSize,
256                                          pParent->drawable.x,
257                                          pParent->drawable.y)) {
258                 case rgnIN:
259                     newVis = VisibilityUnobscured;
260                     break;
261                 case rgnOUT:
262                     newVis = VisibilityFullyObscured;
263                     break;
264                 }
265             }
266         }
267         break;
268     default:
269         newVis = VisibilityFullyObscured;
270         break;
271     }
272     pParent->visibility = newVis;
273     if (oldVis != newVis &&
274         ((pParent->
275           eventMask | wOtherEventMasks(pParent)) & VisibilityChangeMask))
276         SendVisibilityNotify(pParent);
277 
278     dx = pParent->drawable.x - pParent->valdata->before.oldAbsCorner.x;
279     dy = pParent->drawable.y - pParent->valdata->before.oldAbsCorner.y;
280 
281     /*
282      * avoid computations when dealing with simple operations
283      */
284 
285     switch (kind) {
286     case VTMap:
287     case VTStack:
288     case VTUnmap:
289         break;
290     case VTMove:
291         if ((oldVis == newVis) &&
292             ((oldVis == VisibilityFullyObscured) ||
293              (oldVis == VisibilityUnobscured))) {
294             pChild = pParent;
295             while (1) {
296                 if (pChild->viewable) {
297                     if (pChild->visibility != VisibilityFullyObscured) {
298                         RegionTranslate(&pChild->borderClip, dx, dy);
299                         RegionTranslate(&pChild->clipList, dx, dy);
300                         pChild->drawable.serialNumber = NEXT_SERIAL_NUMBER;
301                         if (pScreen->ClipNotify)
302                             (*pScreen->ClipNotify) (pChild, dx, dy);
303 
304                     }
305                     if (pChild->valdata) {
306                         RegionNull(&pChild->valdata->after.borderExposed);
307                         if (HasParentRelativeBorder(pChild)) {
308                             RegionSubtract(&pChild->valdata->after.
309                                            borderExposed, &pChild->borderClip,
310                                            &pChild->winSize);
311                         }
312                         RegionNull(&pChild->valdata->after.exposed);
313                     }
314                     if (pChild->firstChild) {
315                         pChild = pChild->firstChild;
316                         continue;
317                     }
318                 }
319                 while (!pChild->nextSib && (pChild != pParent))
320                     pChild = pChild->parent;
321                 if (pChild == pParent)
322                     break;
323                 pChild = pChild->nextSib;
324             }
325             return;
326         }
327         /* fall through */
328     default:
329         /*
330          * To calculate exposures correctly, we have to translate the old
331          * borderClip and clipList regions to the window's new location so there
332          * is a correspondence between pieces of the new and old clipping regions.
333          */
334         if (dx || dy) {
335             /*
336              * We translate the old clipList because that will be exposed or copied
337              * if gravity is right.
338              */
339             RegionTranslate(&pParent->borderClip, dx, dy);
340             RegionTranslate(&pParent->clipList, dx, dy);
341         }
342         break;
343     case VTBroken:
344         RegionEmpty(&pParent->borderClip);
345         RegionEmpty(&pParent->clipList);
346         break;
347     }
348 
349     borderVisible = pParent->valdata->before.borderVisible;
350     RegionNull(&pParent->valdata->after.borderExposed);
351     RegionNull(&pParent->valdata->after.exposed);
352 
353     /*
354      * Since the borderClip must not be clipped by the children, we do
355      * the border exposure first...
356      *
357      * 'universe' is the window's borderClip. To figure the exposures, remove
358      * the area that used to be exposed from the new.
359      * This leaves a region of pieces that weren't exposed before.
360      */
361 
362     if (HasBorder(pParent)) {
363         if (borderVisible) {
364             /*
365              * when the border changes shape, the old visible portions
366              * of the border will be saved by DIX in borderVisible --
367              * use that region and destroy it
368              */
369             RegionSubtract(exposed, universe, borderVisible);
370             RegionDestroy(borderVisible);
371         }
372         else {
373             RegionSubtract(exposed, universe, &pParent->borderClip);
374         }
375         if (HasParentRelativeBorder(pParent) && (dx || dy))
376             RegionSubtract(&pParent->valdata->after.borderExposed,
377                            universe, &pParent->winSize);
378         else
379             RegionSubtract(&pParent->valdata->after.borderExposed,
380                            exposed, &pParent->winSize);
381 
382         RegionCopy(&pParent->borderClip, universe);
383 
384         /*
385          * To get the right clipList for the parent, and to make doubly sure
386          * that no child overlaps the parent's border, we remove the parent's
387          * border from the universe before proceeding.
388          */
389 
390         RegionIntersect(universe, universe, &pParent->winSize);
391     }
392     else
393         RegionCopy(&pParent->borderClip, universe);
394 
395     if ((pChild = pParent->firstChild) && pParent->mapped) {
396         RegionNull(&childUniverse);
397         RegionNull(&childUnion);
398         if ((pChild->drawable.y < pParent->lastChild->drawable.y) ||
399             ((pChild->drawable.y == pParent->lastChild->drawable.y) &&
400              (pChild->drawable.x < pParent->lastChild->drawable.x))) {
401             for (; pChild; pChild = pChild->nextSib) {
402                 if (pChild->viewable && !TreatAsTransparent(pChild))
403                     RegionAppend(&childUnion, &pChild->borderSize);
404             }
405         }
406         else {
407             for (pChild = pParent->lastChild; pChild; pChild = pChild->prevSib) {
408                 if (pChild->viewable && !TreatAsTransparent(pChild))
409                     RegionAppend(&childUnion, &pChild->borderSize);
410             }
411         }
412         RegionValidate(&childUnion, &overlap);
413 
414         for (pChild = pParent->firstChild; pChild; pChild = pChild->nextSib) {
415             if (pChild->viewable) {
416                 /*
417                  * If the child is viewable, we want to remove its extents
418                  * from the current universe, but we only re-clip it if
419                  * it's been marked.
420                  */
421                 if (pChild->valdata) {
422                     /*
423                      * Figure out the new universe from the child's
424                      * perspective and recurse.
425                      */
426                     RegionIntersect(&childUniverse,
427                                     universe, &pChild->borderSize);
428                     miComputeClips(pChild, pScreen, &childUniverse, kind,
429                                    exposed);
430                 }
431                 /*
432                  * Once the child has been processed, we remove its extents
433                  * from the current universe, thus denying its space to any
434                  * other sibling.
435                  */
436                 if (overlap && !TreatAsTransparent(pChild))
437                     RegionSubtract(universe, universe, &pChild->borderSize);
438             }
439         }
440         if (!overlap)
441             RegionSubtract(universe, universe, &childUnion);
442         RegionUninit(&childUnion);
443         RegionUninit(&childUniverse);
444     }                           /* if any children */
445 
446     /*
447      * 'universe' now contains the new clipList for the parent window.
448      *
449      * To figure the exposure of the window we subtract the old clip from the
450      * new, just as for the border.
451      */
452 
453     if (oldVis == VisibilityFullyObscured || oldVis == VisibilityNotViewable) {
454         RegionCopy(&pParent->valdata->after.exposed, universe);
455     }
456     else if (newVis != VisibilityFullyObscured &&
457              newVis != VisibilityNotViewable) {
458         RegionSubtract(&pParent->valdata->after.exposed,
459                        universe, &pParent->clipList);
460     }
461 
462     /* HACK ALERT - copying contents of regions, instead of regions */
463     {
464         RegionRec tmp;
465 
466         tmp = pParent->clipList;
467         pParent->clipList = *universe;
468         *universe = tmp;
469     }
470 
471 #ifdef NOTDEF
472     RegionCopy(&pParent->clipList, universe);
473 #endif
474 
475     pParent->drawable.serialNumber = NEXT_SERIAL_NUMBER;
476 
477     if (pScreen->ClipNotify)
478         (*pScreen->ClipNotify) (pParent, dx, dy);
479 }
480 
481 static void
miTreeObscured(WindowPtr pParent)482 miTreeObscured(WindowPtr pParent)
483 {
484     WindowPtr pChild;
485     int oldVis;
486 
487     pChild = pParent;
488     while (1) {
489         if (pChild->viewable) {
490             oldVis = pChild->visibility;
491             if (oldVis != (pChild->visibility = VisibilityFullyObscured) &&
492                 ((pChild->
493                   eventMask | wOtherEventMasks(pChild)) & VisibilityChangeMask))
494                 SendVisibilityNotify(pChild);
495             if (pChild->firstChild) {
496                 pChild = pChild->firstChild;
497                 continue;
498             }
499         }
500         while (!pChild->nextSib && (pChild != pParent))
501             pChild = pChild->parent;
502         if (pChild == pParent)
503             break;
504         pChild = pChild->nextSib;
505     }
506 }
507 
508 static RegionPtr
getBorderClip(WindowPtr pWin)509 getBorderClip(WindowPtr pWin)
510 {
511 #ifdef COMPOSITE
512     if (pWin->redirectDraw != RedirectDrawNone)
513         return compGetRedirectBorderClip(pWin);
514     else
515 #endif
516         return &pWin->borderClip;
517 }
518 
519 /*
520  *-----------------------------------------------------------------------
521  * miValidateTree --
522  *	Recomputes the clip list for pParent and all its inferiors.
523  *
524  * Results:
525  *	Always returns 1.
526  *
527  * Side Effects:
528  *	The clipList, borderClip, exposed, and borderExposed regions for
529  *	each marked window are altered.
530  *
531  * Notes:
532  *	This routine assumes that all affected windows have been marked
533  *	(valdata created) and their winSize and borderSize regions
534  *	adjusted to correspond to their new positions. The borderClip and
535  *	clipList regions should not have been touched.
536  *
537  *	The top-most level is treated differently from all lower levels
538  *	because pParent is unchanged. For the top level, we merge the
539  *	regions taken up by the marked children back into the clipList
540  *	for pParent, thus forming a region from which the marked children
541  *	can claim their areas. For lower levels, where the old clipList
542  *	and borderClip are invalid, we can't do this and have to do the
543  *	extra operations done in miComputeClips, but this is much faster
544  *	e.g. when only one child has moved...
545  *
546  *-----------------------------------------------------------------------
547  */
548  /*ARGSUSED*/ int
miValidateTree(WindowPtr pParent,WindowPtr pChild,VTKind kind)549 miValidateTree(WindowPtr pParent,       /* Parent to validate */
550                WindowPtr pChild,        /* First child of pParent that was
551                                          * affected */
552                VTKind kind      /* What kind of configuration caused call */
553     )
554 {
555     RegionRec totalClip;        /* Total clipping region available to
556                                  * the marked children. pParent's clipList
557                                  * merged with the borderClips of all
558                                  * the marked children. */
559     RegionRec childClip;        /* The new borderClip for the current
560                                  * child */
561     RegionRec childUnion;       /* the space covered by borderSize for
562                                  * all marked children */
563     RegionRec exposed;          /* For intermediate calculations */
564     ScreenPtr pScreen;
565     WindowPtr pWin;
566     Bool overlap;
567     int viewvals;
568     Bool forward;
569 
570     pScreen = pParent->drawable.pScreen;
571     if (pChild == NullWindow)
572         pChild = pParent->firstChild;
573 
574     RegionNull(&childClip);
575     RegionNull(&exposed);
576 
577     /*
578      * compute the area of the parent window occupied
579      * by the marked children + the parent itself.  This
580      * is the area which can be divied up among the marked
581      * children in their new configuration.
582      */
583     RegionNull(&totalClip);
584     viewvals = 0;
585     if (RegionBroken(&pParent->clipList) && !RegionBroken(&pParent->borderClip)) {
586         kind = VTBroken;
587         /*
588          * When rebuilding clip lists after out of memory,
589          * assume everything is busted.
590          */
591         forward = TRUE;
592         RegionCopy(&totalClip, &pParent->borderClip);
593         RegionIntersect(&totalClip, &totalClip, &pParent->winSize);
594 
595         for (pWin = pParent->firstChild; pWin != pChild; pWin = pWin->nextSib) {
596             if (pWin->viewable && !TreatAsTransparent(pWin))
597                 RegionSubtract(&totalClip, &totalClip, &pWin->borderSize);
598         }
599         for (pWin = pChild; pWin; pWin = pWin->nextSib)
600             if (pWin->valdata && pWin->viewable)
601                 viewvals++;
602 
603         RegionEmpty(&pParent->clipList);
604     }
605     else {
606         if ((pChild->drawable.y < pParent->lastChild->drawable.y) ||
607             ((pChild->drawable.y == pParent->lastChild->drawable.y) &&
608              (pChild->drawable.x < pParent->lastChild->drawable.x))) {
609             forward = TRUE;
610             for (pWin = pChild; pWin; pWin = pWin->nextSib) {
611                 if (pWin->valdata) {
612                     RegionAppend(&totalClip, getBorderClip(pWin));
613                     if (pWin->viewable)
614                         viewvals++;
615                 }
616             }
617         }
618         else {
619             forward = FALSE;
620             pWin = pParent->lastChild;
621             while (1) {
622                 if (pWin->valdata) {
623                     RegionAppend(&totalClip, getBorderClip(pWin));
624                     if (pWin->viewable)
625                         viewvals++;
626                 }
627                 if (pWin == pChild)
628                     break;
629                 pWin = pWin->prevSib;
630             }
631         }
632         RegionValidate(&totalClip, &overlap);
633     }
634 
635     /*
636      * Now go through the children of the root and figure their new
637      * borderClips from the totalClip, passing that off to miComputeClips
638      * to handle recursively. Once that's done, we remove the child
639      * from the totalClip to clip any siblings below it.
640      */
641 
642     overlap = TRUE;
643     if (kind != VTStack) {
644         RegionUnion(&totalClip, &totalClip, &pParent->clipList);
645         if (viewvals > 1) {
646             /*
647              * precompute childUnion to discover whether any of them
648              * overlap.  This seems redundant, but performance studies
649              * have demonstrated that the cost of this loop is
650              * lower than the cost of multiple Subtracts in the
651              * loop below.
652              */
653             RegionNull(&childUnion);
654             if (forward) {
655                 for (pWin = pChild; pWin; pWin = pWin->nextSib)
656                     if (pWin->valdata && pWin->viewable &&
657                         !TreatAsTransparent(pWin))
658                         RegionAppend(&childUnion, &pWin->borderSize);
659             }
660             else {
661                 pWin = pParent->lastChild;
662                 while (1) {
663                     if (pWin->valdata && pWin->viewable &&
664                         !TreatAsTransparent(pWin))
665                         RegionAppend(&childUnion, &pWin->borderSize);
666                     if (pWin == pChild)
667                         break;
668                     pWin = pWin->prevSib;
669                 }
670             }
671             RegionValidate(&childUnion, &overlap);
672             if (overlap)
673                 RegionUninit(&childUnion);
674         }
675     }
676 
677     for (pWin = pChild; pWin != NullWindow; pWin = pWin->nextSib) {
678         if (pWin->viewable) {
679             if (pWin->valdata) {
680                 RegionIntersect(&childClip, &totalClip, &pWin->borderSize);
681                 miComputeClips(pWin, pScreen, &childClip, kind, &exposed);
682                 if (overlap && !TreatAsTransparent(pWin)) {
683                     RegionSubtract(&totalClip, &totalClip, &pWin->borderSize);
684                 }
685             }
686             else if (pWin->visibility == VisibilityNotViewable) {
687                 miTreeObscured(pWin);
688             }
689         }
690         else {
691             if (pWin->valdata) {
692                 RegionEmpty(&pWin->clipList);
693                 if (pScreen->ClipNotify)
694                     (*pScreen->ClipNotify) (pWin, 0, 0);
695                 RegionEmpty(&pWin->borderClip);
696                 pWin->valdata = NULL;
697             }
698         }
699     }
700 
701     RegionUninit(&childClip);
702     if (!overlap) {
703         RegionSubtract(&totalClip, &totalClip, &childUnion);
704         RegionUninit(&childUnion);
705     }
706 
707     RegionNull(&pParent->valdata->after.exposed);
708     RegionNull(&pParent->valdata->after.borderExposed);
709 
710     /*
711      * each case below is responsible for updating the
712      * clipList and serial number for the parent window
713      */
714 
715     switch (kind) {
716     case VTStack:
717         break;
718     default:
719         /*
720          * totalClip contains the new clipList for the parent. Figure out
721          * exposures and obscures as per miComputeClips and reset the parent's
722          * clipList.
723          */
724         RegionSubtract(&pParent->valdata->after.exposed,
725                        &totalClip, &pParent->clipList);
726         /* fall through */
727     case VTMap:
728         RegionCopy(&pParent->clipList, &totalClip);
729         pParent->drawable.serialNumber = NEXT_SERIAL_NUMBER;
730         break;
731     }
732 
733     RegionUninit(&totalClip);
734     RegionUninit(&exposed);
735     if (pScreen->ClipNotify)
736         (*pScreen->ClipNotify) (pParent, 0, 0);
737     return 1;
738 }
739