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-rw-r--r--libX11/src/Region.c3208
1 files changed, 1604 insertions, 1604 deletions
diff --git a/libX11/src/Region.c b/libX11/src/Region.c
index 3003ac52a..41047b242 100644
--- a/libX11/src/Region.c
+++ b/libX11/src/Region.c
@@ -1,1604 +1,1604 @@
-/************************************************************************
-
-Copyright 1987, 1988, 1998 The Open Group
-
-Permission to use, copy, modify, distribute, and sell this software and its
-documentation for any purpose is hereby granted without fee, provided that
-the above copyright notice appear in all copies and that both that
-copyright notice and this permission notice appear in supporting
-documentation.
-
-The above copyright notice and this permission notice shall be included in
-all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
-AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
-CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-Except as contained in this notice, the name of The Open Group shall not be
-used in advertising or otherwise to promote the sale, use or other dealings
-in this Software without prior written authorization from The Open Group.
-
-
-Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts.
-
- All Rights Reserved
-
-Permission to use, copy, modify, and distribute this software and its
-documentation for any purpose and without fee is hereby granted,
-provided that the above copyright notice appear in all copies and that
-both that copyright notice and this permission notice appear in
-supporting documentation, and that the name of Digital not be
-used in advertising or publicity pertaining to distribution of the
-software without specific, written prior permission.
-
-DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
-ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
-DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
-ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
-WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
-ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
-SOFTWARE.
-
-************************************************************************/
-/*
- * The functions in this file implement the Region abstraction, similar to one
- * used in the X11 sample server. A Region is simply an area, as the name
- * implies, and is implemented as a "y-x-banded" array of rectangles. To
- * explain: Each Region is made up of a certain number of rectangles sorted
- * by y coordinate first, and then by x coordinate.
- *
- * Furthermore, the rectangles are banded such that every rectangle with a
- * given upper-left y coordinate (y1) will have the same lower-right y
- * coordinate (y2) and vice versa. If a rectangle has scanlines in a band, it
- * will span the entire vertical distance of the band. This means that some
- * areas that could be merged into a taller rectangle will be represented as
- * several shorter rectangles to account for shorter rectangles to its left
- * or right but within its "vertical scope".
- *
- * An added constraint on the rectangles is that they must cover as much
- * horizontal area as possible. E.g. no two rectangles in a band are allowed
- * to touch.
- *
- * Whenever possible, bands will be merged together to cover a greater vertical
- * distance (and thus reduce the number of rectangles). Two bands can be merged
- * only if the bottom of one touches the top of the other and they have
- * rectangles in the same places (of the same width, of course). This maintains
- * the y-x-banding that's so nice to have...
- */
-
-#ifdef HAVE_CONFIG_H
-#include <config.h>
-#endif
-#include "Xlibint.h"
-#include "Xutil.h"
-#include <X11/Xregion.h>
-#include "poly.h"
-
-#ifdef DEBUG
-#include <stdio.h>
-#define assert(expr) {if (!(expr)) fprintf(stderr,\
-"Assertion failed file %s, line %d: expr\n", __FILE__, __LINE__); }
-#else
-#define assert(expr)
-#endif
-
-typedef int (*overlapProcp)(
- register Region pReg,
- register BoxPtr r1,
- BoxPtr r1End,
- register BoxPtr r2,
- BoxPtr r2End,
- short y1,
- short y2);
-
-typedef int (*nonOverlapProcp)(
- register Region pReg,
- register BoxPtr r,
- BoxPtr rEnd,
- register short y1,
- register short y2);
-
-static void miRegionOp(
- register Region newReg, /* Place to store result */
- Region reg1, /* First region in operation */
- Region reg2, /* 2d region in operation */
- int (*overlapFunc)(
- register Region pReg,
- register BoxPtr r1,
- BoxPtr r1End,
- register BoxPtr r2,
- BoxPtr r2End,
- short y1,
- short y2), /* Function to call for over-
- * lapping bands */
- int (*nonOverlap1Func)(
- register Region pReg,
- register BoxPtr r,
- BoxPtr rEnd,
- register short y1,
- register short y2), /* Function to call for non-
- * overlapping bands in region
- * 1 */
- int (*nonOverlap2Func)(
- register Region pReg,
- register BoxPtr r,
- BoxPtr rEnd,
- register short y1,
- register short y2)); /* Function to call for non-
- * overlapping bands in region
- * 2 */
-
-
-/* Create a new empty region */
-Region
-XCreateRegion(void)
-{
- Region temp;
-
- if (! (temp = ( Region )Xmalloc( (unsigned) sizeof( REGION ))))
- return (Region) NULL;
- if (! (temp->rects = ( BOX * )Xmalloc( (unsigned) sizeof( BOX )))) {
- Xfree((char *) temp);
- return (Region) NULL;
- }
- temp->numRects = 0;
- temp->extents.x1 = 0;
- temp->extents.y1 = 0;
- temp->extents.x2 = 0;
- temp->extents.y2 = 0;
- temp->size = 1;
- return( temp );
-}
-
-int
-XClipBox(
- Region r,
- XRectangle *rect)
-{
- rect->x = r->extents.x1;
- rect->y = r->extents.y1;
- rect->width = r->extents.x2 - r->extents.x1;
- rect->height = r->extents.y2 - r->extents.y1;
- return 1;
-}
-
-int
-XUnionRectWithRegion(
- register XRectangle *rect,
- Region source, Region dest)
-{
- REGION region;
-
- if (!rect->width || !rect->height)
- return 0;
- region.rects = &region.extents;
- region.numRects = 1;
- region.extents.x1 = rect->x;
- region.extents.y1 = rect->y;
- region.extents.x2 = rect->x + rect->width;
- region.extents.y2 = rect->y + rect->height;
- region.size = 1;
-
- return XUnionRegion(&region, source, dest);
-}
-
-/*-
- *-----------------------------------------------------------------------
- * miSetExtents --
- * Reset the extents of a region to what they should be. Called by
- * miSubtract and miIntersect b/c they can't figure it out along the
- * way or do so easily, as miUnion can.
- *
- * Results:
- * None.
- *
- * Side Effects:
- * The region's 'extents' structure is overwritten.
- *
- *-----------------------------------------------------------------------
- */
-static void
-miSetExtents (
- Region pReg)
-{
- register BoxPtr pBox,
- pBoxEnd,
- pExtents;
-
- if (pReg->numRects == 0)
- {
- pReg->extents.x1 = 0;
- pReg->extents.y1 = 0;
- pReg->extents.x2 = 0;
- pReg->extents.y2 = 0;
- return;
- }
-
- pExtents = &pReg->extents;
- pBox = pReg->rects;
- pBoxEnd = &pBox[pReg->numRects - 1];
-
- /*
- * Since pBox is the first rectangle in the region, it must have the
- * smallest y1 and since pBoxEnd is the last rectangle in the region,
- * it must have the largest y2, because of banding. Initialize x1 and
- * x2 from pBox and pBoxEnd, resp., as good things to initialize them
- * to...
- */
- pExtents->x1 = pBox->x1;
- pExtents->y1 = pBox->y1;
- pExtents->x2 = pBoxEnd->x2;
- pExtents->y2 = pBoxEnd->y2;
-
- assert(pExtents->y1 < pExtents->y2);
- while (pBox <= pBoxEnd)
- {
- if (pBox->x1 < pExtents->x1)
- {
- pExtents->x1 = pBox->x1;
- }
- if (pBox->x2 > pExtents->x2)
- {
- pExtents->x2 = pBox->x2;
- }
- pBox++;
- }
- assert(pExtents->x1 < pExtents->x2);
-}
-
-int
-XSetRegion(
- Display *dpy,
- GC gc,
- register Region r)
-{
- register int i;
- register XRectangle *xr, *pr;
- register BOX *pb;
- unsigned long total;
-
- LockDisplay (dpy);
- total = r->numRects * sizeof (XRectangle);
- if ((xr = (XRectangle *) _XAllocTemp(dpy, total))) {
- for (pr = xr, pb = r->rects, i = r->numRects; --i >= 0; pr++, pb++) {
- pr->x = pb->x1;
- pr->y = pb->y1;
- pr->width = pb->x2 - pb->x1;
- pr->height = pb->y2 - pb->y1;
- }
- }
- if (xr || !r->numRects)
- _XSetClipRectangles(dpy, gc, 0, 0, xr, r->numRects, YXBanded);
- if (xr)
- _XFreeTemp(dpy, (char *)xr, total);
- UnlockDisplay(dpy);
- SyncHandle();
- return 1;
-}
-
-int
-XDestroyRegion(
- Region r)
-{
- Xfree( (char *) r->rects );
- Xfree( (char *) r );
- return 1;
-}
-
-
-/* TranslateRegion(pRegion, x, y)
- translates in place
- added by raymond
-*/
-
-int
-XOffsetRegion(
- register Region pRegion,
- register int x,
- register int y)
-{
- register int nbox;
- register BOX *pbox;
-
- pbox = pRegion->rects;
- nbox = pRegion->numRects;
-
- while(nbox--)
- {
- pbox->x1 += x;
- pbox->x2 += x;
- pbox->y1 += y;
- pbox->y2 += y;
- pbox++;
- }
- pRegion->extents.x1 += x;
- pRegion->extents.x2 += x;
- pRegion->extents.y1 += y;
- pRegion->extents.y2 += y;
- return 1;
-}
-
-/*
- Utility procedure Compress:
- Replace r by the region r', where
- p in r' iff (Quantifer m <= dx) (p + m in r), and
- Quantifier is Exists if grow is TRUE, For all if grow is FALSE, and
- (x,y) + m = (x+m,y) if xdir is TRUE; (x,y+m) if xdir is FALSE.
-
- Thus, if xdir is TRUE and grow is FALSE, r is replaced by the region
- of all points p such that p and the next dx points on the same
- horizontal scan line are all in r. We do this using by noting
- that p is the head of a run of length 2^i + k iff p is the head
- of a run of length 2^i and p+2^i is the head of a run of length
- k. Thus, the loop invariant: s contains the region corresponding
- to the runs of length shift. r contains the region corresponding
- to the runs of length 1 + dxo & (shift-1), where dxo is the original
- value of dx. dx = dxo & ~(shift-1). As parameters, s and t are
- scratch regions, so that we don't have to allocate them on every
- call.
-*/
-
-#define ZOpRegion(a,b,c) if (grow) XUnionRegion(a,b,c); \
- else XIntersectRegion(a,b,c)
-#define ZShiftRegion(a,b) if (xdir) XOffsetRegion(a,b,0); \
- else XOffsetRegion(a,0,b)
-#define ZCopyRegion(a,b) XUnionRegion(a,a,b)
-
-static void
-Compress(
- Region r, Region s, Region t,
- register unsigned dx,
- register int xdir, register int grow)
-{
- register unsigned shift = 1;
-
- ZCopyRegion(r, s);
- while (dx) {
- if (dx & shift) {
- ZShiftRegion(r, -(int)shift);
- ZOpRegion(r, s, r);
- dx -= shift;
- if (!dx) break;
- }
- ZCopyRegion(s, t);
- ZShiftRegion(s, -(int)shift);
- ZOpRegion(s, t, s);
- shift <<= 1;
- }
-}
-
-#undef ZOpRegion
-#undef ZShiftRegion
-#undef ZCopyRegion
-
-int
-XShrinkRegion(
- Region r,
- int dx, int dy)
-{
- Region s, t;
- int grow;
-
- if (!dx && !dy) return 0;
- if (! (s = XCreateRegion()) )
- return 0;
- if (! (t = XCreateRegion()) ) {
- XDestroyRegion(s);
- return 0;
- }
- if ((grow = (dx < 0))) dx = -dx;
- if (dx) Compress(r, s, t, (unsigned) 2*dx, TRUE, grow);
- if ((grow = (dy < 0))) dy = -dy;
- if (dy) Compress(r, s, t, (unsigned) 2*dy, FALSE, grow);
- XOffsetRegion(r, dx, dy);
- XDestroyRegion(s);
- XDestroyRegion(t);
- return 0;
-}
-
-
-/*======================================================================
- * Region Intersection
- *====================================================================*/
-/*-
- *-----------------------------------------------------------------------
- * miIntersectO --
- * Handle an overlapping band for miIntersect.
- *
- * Results:
- * None.
- *
- * Side Effects:
- * Rectangles may be added to the region.
- *
- *-----------------------------------------------------------------------
- */
-/* static void*/
-static int
-miIntersectO (
- register Region pReg,
- register BoxPtr r1,
- BoxPtr r1End,
- register BoxPtr r2,
- BoxPtr r2End,
- short y1,
- short y2)
-{
- register short x1;
- register short x2;
- register BoxPtr pNextRect;
-
- pNextRect = &pReg->rects[pReg->numRects];
-
- while ((r1 != r1End) && (r2 != r2End))
- {
- x1 = max(r1->x1,r2->x1);
- x2 = min(r1->x2,r2->x2);
-
- /*
- * If there's any overlap between the two rectangles, add that
- * overlap to the new region.
- * There's no need to check for subsumption because the only way
- * such a need could arise is if some region has two rectangles
- * right next to each other. Since that should never happen...
- */
- if (x1 < x2)
- {
- assert(y1<y2);
-
- MEMCHECK(pReg, pNextRect, pReg->rects);
- pNextRect->x1 = x1;
- pNextRect->y1 = y1;
- pNextRect->x2 = x2;
- pNextRect->y2 = y2;
- pReg->numRects += 1;
- pNextRect++;
- assert(pReg->numRects <= pReg->size);
- }
-
- /*
- * Need to advance the pointers. Shift the one that extends
- * to the right the least, since the other still has a chance to
- * overlap with that region's next rectangle, if you see what I mean.
- */
- if (r1->x2 < r2->x2)
- {
- r1++;
- }
- else if (r2->x2 < r1->x2)
- {
- r2++;
- }
- else
- {
- r1++;
- r2++;
- }
- }
- return 0; /* lint */
-}
-
-int
-XIntersectRegion(
- Region reg1,
- Region reg2, /* source regions */
- register Region newReg) /* destination Region */
-{
- /* check for trivial reject */
- if ( (!(reg1->numRects)) || (!(reg2->numRects)) ||
- (!EXTENTCHECK(&reg1->extents, &reg2->extents)))
- newReg->numRects = 0;
- else
- miRegionOp (newReg, reg1, reg2,
- miIntersectO, NULL, NULL);
-
- /*
- * Can't alter newReg's extents before we call miRegionOp because
- * it might be one of the source regions and miRegionOp depends
- * on the extents of those regions being the same. Besides, this
- * way there's no checking against rectangles that will be nuked
- * due to coalescing, so we have to examine fewer rectangles.
- */
- miSetExtents(newReg);
- return 1;
-}
-
-static void
-miRegionCopy(
- register Region dstrgn,
- register Region rgn)
-
-{
- if (dstrgn != rgn) /* don't want to copy to itself */
- {
- if (dstrgn->size < rgn->numRects)
- {
- if (dstrgn->rects)
- {
- BOX *prevRects = dstrgn->rects;
-
- if (! (dstrgn->rects = (BOX *)
- Xrealloc((char *) dstrgn->rects,
- (unsigned) rgn->numRects * (sizeof(BOX))))) {
- Xfree(prevRects);
- return;
- }
- }
- dstrgn->size = rgn->numRects;
- }
- dstrgn->numRects = rgn->numRects;
- dstrgn->extents.x1 = rgn->extents.x1;
- dstrgn->extents.y1 = rgn->extents.y1;
- dstrgn->extents.x2 = rgn->extents.x2;
- dstrgn->extents.y2 = rgn->extents.y2;
-
- memcpy((char *) dstrgn->rects, (char *) rgn->rects,
- (int) (rgn->numRects * sizeof(BOX)));
- }
-}
-
-/*======================================================================
- * Generic Region Operator
- *====================================================================*/
-
-/*-
- *-----------------------------------------------------------------------
- * miCoalesce --
- * Attempt to merge the boxes in the current band with those in the
- * previous one. Used only by miRegionOp.
- *
- * Results:
- * The new index for the previous band.
- *
- * Side Effects:
- * If coalescing takes place:
- * - rectangles in the previous band will have their y2 fields
- * altered.
- * - pReg->numRects will be decreased.
- *
- *-----------------------------------------------------------------------
- */
-/* static int*/
-static int
-miCoalesce(
- register Region pReg, /* Region to coalesce */
- int prevStart, /* Index of start of previous band */
- int curStart) /* Index of start of current band */
-{
- register BoxPtr pPrevBox; /* Current box in previous band */
- register BoxPtr pCurBox; /* Current box in current band */
- register BoxPtr pRegEnd; /* End of region */
- int curNumRects; /* Number of rectangles in current
- * band */
- int prevNumRects; /* Number of rectangles in previous
- * band */
- int bandY1; /* Y1 coordinate for current band */
-
- pRegEnd = &pReg->rects[pReg->numRects];
-
- pPrevBox = &pReg->rects[prevStart];
- prevNumRects = curStart - prevStart;
-
- /*
- * Figure out how many rectangles are in the current band. Have to do
- * this because multiple bands could have been added in miRegionOp
- * at the end when one region has been exhausted.
- */
- pCurBox = &pReg->rects[curStart];
- bandY1 = pCurBox->y1;
- for (curNumRects = 0;
- (pCurBox != pRegEnd) && (pCurBox->y1 == bandY1);
- curNumRects++)
- {
- pCurBox++;
- }
-
- if (pCurBox != pRegEnd)
- {
- /*
- * If more than one band was added, we have to find the start
- * of the last band added so the next coalescing job can start
- * at the right place... (given when multiple bands are added,
- * this may be pointless -- see above).
- */
- pRegEnd--;
- while (pRegEnd[-1].y1 == pRegEnd->y1)
- {
- pRegEnd--;
- }
- curStart = pRegEnd - pReg->rects;
- pRegEnd = pReg->rects + pReg->numRects;
- }
-
- if ((curNumRects == prevNumRects) && (curNumRects != 0)) {
- pCurBox -= curNumRects;
- /*
- * The bands may only be coalesced if the bottom of the previous
- * matches the top scanline of the current.
- */
- if (pPrevBox->y2 == pCurBox->y1)
- {
- /*
- * Make sure the bands have boxes in the same places. This
- * assumes that boxes have been added in such a way that they
- * cover the most area possible. I.e. two boxes in a band must
- * have some horizontal space between them.
- */
- do
- {
- if ((pPrevBox->x1 != pCurBox->x1) ||
- (pPrevBox->x2 != pCurBox->x2))
- {
- /*
- * The bands don't line up so they can't be coalesced.
- */
- return (curStart);
- }
- pPrevBox++;
- pCurBox++;
- prevNumRects -= 1;
- } while (prevNumRects != 0);
-
- pReg->numRects -= curNumRects;
- pCurBox -= curNumRects;
- pPrevBox -= curNumRects;
-
- /*
- * The bands may be merged, so set the bottom y of each box
- * in the previous band to that of the corresponding box in
- * the current band.
- */
- do
- {
- pPrevBox->y2 = pCurBox->y2;
- pPrevBox++;
- pCurBox++;
- curNumRects -= 1;
- } while (curNumRects != 0);
-
- /*
- * If only one band was added to the region, we have to backup
- * curStart to the start of the previous band.
- *
- * If more than one band was added to the region, copy the
- * other bands down. The assumption here is that the other bands
- * came from the same region as the current one and no further
- * coalescing can be done on them since it's all been done
- * already... curStart is already in the right place.
- */
- if (pCurBox == pRegEnd)
- {
- curStart = prevStart;
- }
- else
- {
- do
- {
- *pPrevBox++ = *pCurBox++;
- } while (pCurBox != pRegEnd);
- }
-
- }
- }
- return (curStart);
-}
-
-/*-
- *-----------------------------------------------------------------------
- * miRegionOp --
- * Apply an operation to two regions. Called by miUnion, miInverse,
- * miSubtract, miIntersect...
- *
- * Results:
- * None.
- *
- * Side Effects:
- * The new region is overwritten.
- *
- * Notes:
- * The idea behind this function is to view the two regions as sets.
- * Together they cover a rectangle of area that this function divides
- * into horizontal bands where points are covered only by one region
- * or by both. For the first case, the nonOverlapFunc is called with
- * each the band and the band's upper and lower extents. For the
- * second, the overlapFunc is called to process the entire band. It
- * is responsible for clipping the rectangles in the band, though
- * this function provides the boundaries.
- * At the end of each band, the new region is coalesced, if possible,
- * to reduce the number of rectangles in the region.
- *
- *-----------------------------------------------------------------------
- */
-/* static void*/
-static void
-miRegionOp(
- register Region newReg, /* Place to store result */
- Region reg1, /* First region in operation */
- Region reg2, /* 2d region in operation */
- int (*overlapFunc)(
- register Region pReg,
- register BoxPtr r1,
- BoxPtr r1End,
- register BoxPtr r2,
- BoxPtr r2End,
- short y1,
- short y2), /* Function to call for over-
- * lapping bands */
- int (*nonOverlap1Func)(
- register Region pReg,
- register BoxPtr r,
- BoxPtr rEnd,
- register short y1,
- register short y2), /* Function to call for non-
- * overlapping bands in region
- * 1 */
- int (*nonOverlap2Func)(
- register Region pReg,
- register BoxPtr r,
- BoxPtr rEnd,
- register short y1,
- register short y2)) /* Function to call for non-
- * overlapping bands in region
- * 2 */
-{
- register BoxPtr r1; /* Pointer into first region */
- register BoxPtr r2; /* Pointer into 2d region */
- BoxPtr r1End; /* End of 1st region */
- BoxPtr r2End; /* End of 2d region */
- register short ybot; /* Bottom of intersection */
- register short ytop; /* Top of intersection */
- BoxPtr oldRects; /* Old rects for newReg */
- int prevBand; /* Index of start of
- * previous band in newReg */
- int curBand; /* Index of start of current
- * band in newReg */
- register BoxPtr r1BandEnd; /* End of current band in r1 */
- register BoxPtr r2BandEnd; /* End of current band in r2 */
- short top; /* Top of non-overlapping
- * band */
- short bot; /* Bottom of non-overlapping
- * band */
-
- /*
- * Initialization:
- * set r1, r2, r1End and r2End appropriately, preserve the important
- * parts of the destination region until the end in case it's one of
- * the two source regions, then mark the "new" region empty, allocating
- * another array of rectangles for it to use.
- */
- r1 = reg1->rects;
- r2 = reg2->rects;
- r1End = r1 + reg1->numRects;
- r2End = r2 + reg2->numRects;
-
- oldRects = newReg->rects;
-
- EMPTY_REGION(newReg);
-
- /*
- * Allocate a reasonable number of rectangles for the new region. The idea
- * is to allocate enough so the individual functions don't need to
- * reallocate and copy the array, which is time consuming, yet we don't
- * have to worry about using too much memory. I hope to be able to
- * nuke the Xrealloc() at the end of this function eventually.
- */
- newReg->size = max(reg1->numRects,reg2->numRects) * 2;
-
- if (! (newReg->rects = (BoxPtr)
- Xmalloc ((unsigned) (sizeof(BoxRec) * newReg->size)))) {
- newReg->size = 0;
- return;
- }
-
- /*
- * Initialize ybot and ytop.
- * In the upcoming loop, ybot and ytop serve different functions depending
- * on whether the band being handled is an overlapping or non-overlapping
- * band.
- * In the case of a non-overlapping band (only one of the regions
- * has points in the band), ybot is the bottom of the most recent
- * intersection and thus clips the top of the rectangles in that band.
- * ytop is the top of the next intersection between the two regions and
- * serves to clip the bottom of the rectangles in the current band.
- * For an overlapping band (where the two regions intersect), ytop clips
- * the top of the rectangles of both regions and ybot clips the bottoms.
- */
- if (reg1->extents.y1 < reg2->extents.y1)
- ybot = reg1->extents.y1;
- else
- ybot = reg2->extents.y1;
-
- /*
- * prevBand serves to mark the start of the previous band so rectangles
- * can be coalesced into larger rectangles. qv. miCoalesce, above.
- * In the beginning, there is no previous band, so prevBand == curBand
- * (curBand is set later on, of course, but the first band will always
- * start at index 0). prevBand and curBand must be indices because of
- * the possible expansion, and resultant moving, of the new region's
- * array of rectangles.
- */
- prevBand = 0;
-
- do
- {
- curBand = newReg->numRects;
-
- /*
- * This algorithm proceeds one source-band (as opposed to a
- * destination band, which is determined by where the two regions
- * intersect) at a time. r1BandEnd and r2BandEnd serve to mark the
- * rectangle after the last one in the current band for their
- * respective regions.
- */
- r1BandEnd = r1;
- while ((r1BandEnd != r1End) && (r1BandEnd->y1 == r1->y1))
- {
- r1BandEnd++;
- }
-
- r2BandEnd = r2;
- while ((r2BandEnd != r2End) && (r2BandEnd->y1 == r2->y1))
- {
- r2BandEnd++;
- }
-
- /*
- * First handle the band that doesn't intersect, if any.
- *
- * Note that attention is restricted to one band in the
- * non-intersecting region at once, so if a region has n
- * bands between the current position and the next place it overlaps
- * the other, this entire loop will be passed through n times.
- */
- if (r1->y1 < r2->y1)
- {
- top = max(r1->y1,ybot);
- bot = min(r1->y2,r2->y1);
-
- if ((top != bot) && (nonOverlap1Func != NULL))
- {
- (* nonOverlap1Func) (newReg, r1, r1BandEnd, top, bot);
- }
-
- ytop = r2->y1;
- }
- else if (r2->y1 < r1->y1)
- {
- top = max(r2->y1,ybot);
- bot = min(r2->y2,r1->y1);
-
- if ((top != bot) && (nonOverlap2Func != NULL))
- {
- (* nonOverlap2Func) (newReg, r2, r2BandEnd, top, bot);
- }
-
- ytop = r1->y1;
- }
- else
- {
- ytop = r1->y1;
- }
-
- /*
- * If any rectangles got added to the region, try and coalesce them
- * with rectangles from the previous band. Note we could just do
- * this test in miCoalesce, but some machines incur a not
- * inconsiderable cost for function calls, so...
- */
- if (newReg->numRects != curBand)
- {
- prevBand = miCoalesce (newReg, prevBand, curBand);
- }
-
- /*
- * Now see if we've hit an intersecting band. The two bands only
- * intersect if ybot > ytop
- */
- ybot = min(r1->y2, r2->y2);
- curBand = newReg->numRects;
- if (ybot > ytop)
- {
- (* overlapFunc) (newReg, r1, r1BandEnd, r2, r2BandEnd, ytop, ybot);
-
- }
-
- if (newReg->numRects != curBand)
- {
- prevBand = miCoalesce (newReg, prevBand, curBand);
- }
-
- /*
- * If we've finished with a band (y2 == ybot) we skip forward
- * in the region to the next band.
- */
- if (r1->y2 == ybot)
- {
- r1 = r1BandEnd;
- }
- if (r2->y2 == ybot)
- {
- r2 = r2BandEnd;
- }
- } while ((r1 != r1End) && (r2 != r2End));
-
- /*
- * Deal with whichever region still has rectangles left.
- */
- curBand = newReg->numRects;
- if (r1 != r1End)
- {
- if (nonOverlap1Func != NULL)
- {
- do
- {
- r1BandEnd = r1;
- while ((r1BandEnd < r1End) && (r1BandEnd->y1 == r1->y1))
- {
- r1BandEnd++;
- }
- (* nonOverlap1Func) (newReg, r1, r1BandEnd,
- max(r1->y1,ybot), r1->y2);
- r1 = r1BandEnd;
- } while (r1 != r1End);
- }
- }
- else if ((r2 != r2End) && (nonOverlap2Func != NULL))
- {
- do
- {
- r2BandEnd = r2;
- while ((r2BandEnd < r2End) && (r2BandEnd->y1 == r2->y1))
- {
- r2BandEnd++;
- }
- (* nonOverlap2Func) (newReg, r2, r2BandEnd,
- max(r2->y1,ybot), r2->y2);
- r2 = r2BandEnd;
- } while (r2 != r2End);
- }
-
- if (newReg->numRects != curBand)
- {
- (void) miCoalesce (newReg, prevBand, curBand);
- }
-
- /*
- * A bit of cleanup. To keep regions from growing without bound,
- * we shrink the array of rectangles to match the new number of
- * rectangles in the region. This never goes to 0, however...
- *
- * Only do this stuff if the number of rectangles allocated is more than
- * twice the number of rectangles in the region (a simple optimization...).
- */
- if (newReg->numRects < (newReg->size >> 1))
- {
- if (REGION_NOT_EMPTY(newReg))
- {
- BoxPtr prev_rects = newReg->rects;
- newReg->size = newReg->numRects;
- newReg->rects = (BoxPtr) Xrealloc ((char *) newReg->rects,
- (unsigned) (sizeof(BoxRec) * newReg->size));
- if (! newReg->rects)
- newReg->rects = prev_rects;
- }
- else
- {
- /*
- * No point in doing the extra work involved in an Xrealloc if
- * the region is empty
- */
- newReg->size = 1;
- Xfree((char *) newReg->rects);
- newReg->rects = (BoxPtr) Xmalloc(sizeof(BoxRec));
- }
- }
- Xfree ((char *) oldRects);
- return;
-}
-
-
-/*======================================================================
- * Region Union
- *====================================================================*/
-
-/*-
- *-----------------------------------------------------------------------
- * miUnionNonO --
- * Handle a non-overlapping band for the union operation. Just
- * Adds the rectangles into the region. Doesn't have to check for
- * subsumption or anything.
- *
- * Results:
- * None.
- *
- * Side Effects:
- * pReg->numRects is incremented and the final rectangles overwritten
- * with the rectangles we're passed.
- *
- *-----------------------------------------------------------------------
- */
-/* static void*/
-static int
-miUnionNonO (
- register Region pReg,
- register BoxPtr r,
- BoxPtr rEnd,
- register short y1,
- register short y2)
-{
- register BoxPtr pNextRect;
-
- pNextRect = &pReg->rects[pReg->numRects];
-
- assert(y1 < y2);
-
- while (r != rEnd)
- {
- assert(r->x1 < r->x2);
- MEMCHECK(pReg, pNextRect, pReg->rects);
- pNextRect->x1 = r->x1;
- pNextRect->y1 = y1;
- pNextRect->x2 = r->x2;
- pNextRect->y2 = y2;
- pReg->numRects += 1;
- pNextRect++;
-
- assert(pReg->numRects<=pReg->size);
- r++;
- }
- return 0; /* lint */
-}
-
-
-/*-
- *-----------------------------------------------------------------------
- * miUnionO --
- * Handle an overlapping band for the union operation. Picks the
- * left-most rectangle each time and merges it into the region.
- *
- * Results:
- * None.
- *
- * Side Effects:
- * Rectangles are overwritten in pReg->rects and pReg->numRects will
- * be changed.
- *
- *-----------------------------------------------------------------------
- */
-
-/* static void*/
-static int
-miUnionO (
- register Region pReg,
- register BoxPtr r1,
- BoxPtr r1End,
- register BoxPtr r2,
- BoxPtr r2End,
- register short y1,
- register short y2)
-{
- register BoxPtr pNextRect;
-
- pNextRect = &pReg->rects[pReg->numRects];
-
-#define MERGERECT(r) \
- if ((pReg->numRects != 0) && \
- (pNextRect[-1].y1 == y1) && \
- (pNextRect[-1].y2 == y2) && \
- (pNextRect[-1].x2 >= r->x1)) \
- { \
- if (pNextRect[-1].x2 < r->x2) \
- { \
- pNextRect[-1].x2 = r->x2; \
- assert(pNextRect[-1].x1<pNextRect[-1].x2); \
- } \
- } \
- else \
- { \
- MEMCHECK(pReg, pNextRect, pReg->rects); \
- pNextRect->y1 = y1; \
- pNextRect->y2 = y2; \
- pNextRect->x1 = r->x1; \
- pNextRect->x2 = r->x2; \
- pReg->numRects += 1; \
- pNextRect += 1; \
- } \
- assert(pReg->numRects<=pReg->size);\
- r++;
-
- assert (y1<y2);
- while ((r1 != r1End) && (r2 != r2End))
- {
- if (r1->x1 < r2->x1)
- {
- MERGERECT(r1);
- }
- else
- {
- MERGERECT(r2);
- }
- }
-
- if (r1 != r1End)
- {
- do
- {
- MERGERECT(r1);
- } while (r1 != r1End);
- }
- else while (r2 != r2End)
- {
- MERGERECT(r2);
- }
- return 0; /* lint */
-}
-
-int
-XUnionRegion(
- Region reg1,
- Region reg2, /* source regions */
- Region newReg) /* destination Region */
-{
- /* checks all the simple cases */
-
- /*
- * Region 1 and 2 are the same or region 1 is empty
- */
- if ( (reg1 == reg2) || (!(reg1->numRects)) )
- {
- if (newReg != reg2)
- miRegionCopy(newReg, reg2);
- return 1;
- }
-
- /*
- * if nothing to union (region 2 empty)
- */
- if (!(reg2->numRects))
- {
- if (newReg != reg1)
- miRegionCopy(newReg, reg1);
- return 1;
- }
-
- /*
- * Region 1 completely subsumes region 2
- */
- if ((reg1->numRects == 1) &&
- (reg1->extents.x1 <= reg2->extents.x1) &&
- (reg1->extents.y1 <= reg2->extents.y1) &&
- (reg1->extents.x2 >= reg2->extents.x2) &&
- (reg1->extents.y2 >= reg2->extents.y2))
- {
- if (newReg != reg1)
- miRegionCopy(newReg, reg1);
- return 1;
- }
-
- /*
- * Region 2 completely subsumes region 1
- */
- if ((reg2->numRects == 1) &&
- (reg2->extents.x1 <= reg1->extents.x1) &&
- (reg2->extents.y1 <= reg1->extents.y1) &&
- (reg2->extents.x2 >= reg1->extents.x2) &&
- (reg2->extents.y2 >= reg1->extents.y2))
- {
- if (newReg != reg2)
- miRegionCopy(newReg, reg2);
- return 1;
- }
-
- miRegionOp (newReg, reg1, reg2, miUnionO,
- miUnionNonO, miUnionNonO);
-
- newReg->extents.x1 = min(reg1->extents.x1, reg2->extents.x1);
- newReg->extents.y1 = min(reg1->extents.y1, reg2->extents.y1);
- newReg->extents.x2 = max(reg1->extents.x2, reg2->extents.x2);
- newReg->extents.y2 = max(reg1->extents.y2, reg2->extents.y2);
-
- return 1;
-}
-
-
-/*======================================================================
- * Region Subtraction
- *====================================================================*/
-
-/*-
- *-----------------------------------------------------------------------
- * miSubtractNonO --
- * Deal with non-overlapping band for subtraction. Any parts from
- * region 2 we discard. Anything from region 1 we add to the region.
- *
- * Results:
- * None.
- *
- * Side Effects:
- * pReg may be affected.
- *
- *-----------------------------------------------------------------------
- */
-/* static void*/
-static int
-miSubtractNonO1 (
- register Region pReg,
- register BoxPtr r,
- BoxPtr rEnd,
- register short y1,
- register short y2)
-{
- register BoxPtr pNextRect;
-
- pNextRect = &pReg->rects[pReg->numRects];
-
- assert(y1<y2);
-
- while (r != rEnd)
- {
- assert(r->x1<r->x2);
- MEMCHECK(pReg, pNextRect, pReg->rects);
- pNextRect->x1 = r->x1;
- pNextRect->y1 = y1;
- pNextRect->x2 = r->x2;
- pNextRect->y2 = y2;
- pReg->numRects += 1;
- pNextRect++;
-
- assert(pReg->numRects <= pReg->size);
-
- r++;
- }
- return 0; /* lint */
-}
-
-/*-
- *-----------------------------------------------------------------------
- * miSubtractO --
- * Overlapping band subtraction. x1 is the left-most point not yet
- * checked.
- *
- * Results:
- * None.
- *
- * Side Effects:
- * pReg may have rectangles added to it.
- *
- *-----------------------------------------------------------------------
- */
-/* static void*/
-static int
-miSubtractO (
- register Region pReg,
- register BoxPtr r1,
- BoxPtr r1End,
- register BoxPtr r2,
- BoxPtr r2End,
- register short y1,
- register short y2)
-{
- register BoxPtr pNextRect;
- register int x1;
-
- x1 = r1->x1;
-
- assert(y1<y2);
- pNextRect = &pReg->rects[pReg->numRects];
-
- while ((r1 != r1End) && (r2 != r2End))
- {
- if (r2->x2 <= x1)
- {
- /*
- * Subtrahend missed the boat: go to next subtrahend.
- */
- r2++;
- }
- else if (r2->x1 <= x1)
- {
- /*
- * Subtrahend preceeds minuend: nuke left edge of minuend.
- */
- x1 = r2->x2;
- if (x1 >= r1->x2)
- {
- /*
- * Minuend completely covered: advance to next minuend and
- * reset left fence to edge of new minuend.
- */
- r1++;
- if (r1 != r1End)
- x1 = r1->x1;
- }
- else
- {
- /*
- * Subtrahend now used up since it doesn't extend beyond
- * minuend
- */
- r2++;
- }
- }
- else if (r2->x1 < r1->x2)
- {
- /*
- * Left part of subtrahend covers part of minuend: add uncovered
- * part of minuend to region and skip to next subtrahend.
- */
- assert(x1<r2->x1);
- MEMCHECK(pReg, pNextRect, pReg->rects);
- pNextRect->x1 = x1;
- pNextRect->y1 = y1;
- pNextRect->x2 = r2->x1;
- pNextRect->y2 = y2;
- pReg->numRects += 1;
- pNextRect++;
-
- assert(pReg->numRects<=pReg->size);
-
- x1 = r2->x2;
- if (x1 >= r1->x2)
- {
- /*
- * Minuend used up: advance to new...
- */
- r1++;
- if (r1 != r1End)
- x1 = r1->x1;
- }
- else
- {
- /*
- * Subtrahend used up
- */
- r2++;
- }
- }
- else
- {
- /*
- * Minuend used up: add any remaining piece before advancing.
- */
- if (r1->x2 > x1)
- {
- MEMCHECK(pReg, pNextRect, pReg->rects);
- pNextRect->x1 = x1;
- pNextRect->y1 = y1;
- pNextRect->x2 = r1->x2;
- pNextRect->y2 = y2;
- pReg->numRects += 1;
- pNextRect++;
- assert(pReg->numRects<=pReg->size);
- }
- r1++;
- if (r1 != r1End)
- x1 = r1->x1;
- }
- }
-
- /*
- * Add remaining minuend rectangles to region.
- */
- while (r1 != r1End)
- {
- assert(x1<r1->x2);
- MEMCHECK(pReg, pNextRect, pReg->rects);
- pNextRect->x1 = x1;
- pNextRect->y1 = y1;
- pNextRect->x2 = r1->x2;
- pNextRect->y2 = y2;
- pReg->numRects += 1;
- pNextRect++;
-
- assert(pReg->numRects<=pReg->size);
-
- r1++;
- if (r1 != r1End)
- {
- x1 = r1->x1;
- }
- }
- return 0; /* lint */
-}
-
-/*-
- *-----------------------------------------------------------------------
- * miSubtract --
- * Subtract regS from regM and leave the result in regD.
- * S stands for subtrahend, M for minuend and D for difference.
- *
- * Results:
- * TRUE.
- *
- * Side Effects:
- * regD is overwritten.
- *
- *-----------------------------------------------------------------------
- */
-
-int
-XSubtractRegion(
- Region regM,
- Region regS,
- register Region regD)
-{
- /* check for trivial reject */
- if ( (!(regM->numRects)) || (!(regS->numRects)) ||
- (!EXTENTCHECK(&regM->extents, &regS->extents)) )
- {
- miRegionCopy(regD, regM);
- return 1;
- }
-
- miRegionOp (regD, regM, regS, miSubtractO,
- miSubtractNonO1, NULL);
-
- /*
- * Can't alter newReg's extents before we call miRegionOp because
- * it might be one of the source regions and miRegionOp depends
- * on the extents of those regions being the unaltered. Besides, this
- * way there's no checking against rectangles that will be nuked
- * due to coalescing, so we have to examine fewer rectangles.
- */
- miSetExtents (regD);
- return 1;
-}
-
-int
-XXorRegion(Region sra, Region srb, Region dr)
-{
- Region tra, trb;
-
- if (! (tra = XCreateRegion()) )
- return 0;
- if (! (trb = XCreateRegion()) ) {
- XDestroyRegion(tra);
- return 0;
- }
- (void) XSubtractRegion(sra,srb,tra);
- (void) XSubtractRegion(srb,sra,trb);
- (void) XUnionRegion(tra,trb,dr);
- XDestroyRegion(tra);
- XDestroyRegion(trb);
- return 0;
-}
-
-/*
- * Check to see if the region is empty. Assumes a region is passed
- * as a parameter
- */
-int
-XEmptyRegion(
- Region r)
-{
- if( r->numRects == 0 ) return TRUE;
- else return FALSE;
-}
-
-/*
- * Check to see if two regions are equal
- */
-int
-XEqualRegion(Region r1, Region r2)
-{
- int i;
-
- if( r1->numRects != r2->numRects ) return FALSE;
- else if( r1->numRects == 0 ) return TRUE;
- else if ( r1->extents.x1 != r2->extents.x1 ) return FALSE;
- else if ( r1->extents.x2 != r2->extents.x2 ) return FALSE;
- else if ( r1->extents.y1 != r2->extents.y1 ) return FALSE;
- else if ( r1->extents.y2 != r2->extents.y2 ) return FALSE;
- else for( i=0; i < r1->numRects; i++ ) {
- if ( r1->rects[i].x1 != r2->rects[i].x1 ) return FALSE;
- else if ( r1->rects[i].x2 != r2->rects[i].x2 ) return FALSE;
- else if ( r1->rects[i].y1 != r2->rects[i].y1 ) return FALSE;
- else if ( r1->rects[i].y2 != r2->rects[i].y2 ) return FALSE;
- }
- return TRUE;
-}
-
-int
-XPointInRegion(
- Region pRegion,
- int x, int y)
-{
- int i;
-
- if (pRegion->numRects == 0)
- return FALSE;
- if (!INBOX(pRegion->extents, x, y))
- return FALSE;
- for (i=0; i<pRegion->numRects; i++)
- {
- if (INBOX (pRegion->rects[i], x, y))
- return TRUE;
- }
- return FALSE;
-}
-
-int
-XRectInRegion(
- register Region region,
- int rx, int ry,
- unsigned int rwidth, unsigned int rheight)
-{
- register BoxPtr pbox;
- register BoxPtr pboxEnd;
- Box rect;
- register BoxPtr prect = &rect;
- int partIn, partOut;
-
- prect->x1 = rx;
- prect->y1 = ry;
- prect->x2 = rwidth + rx;
- prect->y2 = rheight + ry;
-
- /* this is (just) a useful optimization */
- if ((region->numRects == 0) || !EXTENTCHECK(&region->extents, prect))
- return(RectangleOut);
-
- partOut = FALSE;
- partIn = FALSE;
-
- /* can stop when both partOut and partIn are TRUE, or we reach prect->y2 */
- for (pbox = region->rects, pboxEnd = pbox + region->numRects;
- pbox < pboxEnd;
- pbox++)
- {
-
- if (pbox->y2 <= ry)
- continue; /* getting up to speed or skipping remainder of band */
-
- if (pbox->y1 > ry)
- {
- partOut = TRUE; /* missed part of rectangle above */
- if (partIn || (pbox->y1 >= prect->y2))
- break;
- ry = pbox->y1; /* x guaranteed to be == prect->x1 */
- }
-
- if (pbox->x2 <= rx)
- continue; /* not far enough over yet */
-
- if (pbox->x1 > rx)
- {
- partOut = TRUE; /* missed part of rectangle to left */
- if (partIn)
- break;
- }
-
- if (pbox->x1 < prect->x2)
- {
- partIn = TRUE; /* definitely overlap */
- if (partOut)
- break;
- }
-
- if (pbox->x2 >= prect->x2)
- {
- ry = pbox->y2; /* finished with this band */
- if (ry >= prect->y2)
- break;
- rx = prect->x1; /* reset x out to left again */
- } else
- {
- /*
- * Because boxes in a band are maximal width, if the first box
- * to overlap the rectangle doesn't completely cover it in that
- * band, the rectangle must be partially out, since some of it
- * will be uncovered in that band. partIn will have been set true
- * by now...
- */
- break;
- }
-
- }
-
- return(partIn ? ((ry < prect->y2) ? RectanglePart : RectangleIn) :
- RectangleOut);
-}
+/************************************************************************
+
+Copyright 1987, 1988, 1998 The Open Group
+
+Permission to use, copy, modify, distribute, and sell this software and its
+documentation for any purpose is hereby granted without fee, provided that
+the above copyright notice appear in all copies and that both that
+copyright notice and this permission notice appear in supporting
+documentation.
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+Except as contained in this notice, the name of The Open Group shall not be
+used in advertising or otherwise to promote the sale, use or other dealings
+in this Software without prior written authorization from The Open Group.
+
+
+Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts.
+
+ All Rights Reserved
+
+Permission to use, copy, modify, and distribute this software and its
+documentation for any purpose and without fee is hereby granted,
+provided that the above copyright notice appear in all copies and that
+both that copyright notice and this permission notice appear in
+supporting documentation, and that the name of Digital not be
+used in advertising or publicity pertaining to distribution of the
+software without specific, written prior permission.
+
+DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
+ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
+DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
+ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+SOFTWARE.
+
+************************************************************************/
+/*
+ * The functions in this file implement the Region abstraction, similar to one
+ * used in the X11 sample server. A Region is simply an area, as the name
+ * implies, and is implemented as a "y-x-banded" array of rectangles. To
+ * explain: Each Region is made up of a certain number of rectangles sorted
+ * by y coordinate first, and then by x coordinate.
+ *
+ * Furthermore, the rectangles are banded such that every rectangle with a
+ * given upper-left y coordinate (y1) will have the same lower-right y
+ * coordinate (y2) and vice versa. If a rectangle has scanlines in a band, it
+ * will span the entire vertical distance of the band. This means that some
+ * areas that could be merged into a taller rectangle will be represented as
+ * several shorter rectangles to account for shorter rectangles to its left
+ * or right but within its "vertical scope".
+ *
+ * An added constraint on the rectangles is that they must cover as much
+ * horizontal area as possible. E.g. no two rectangles in a band are allowed
+ * to touch.
+ *
+ * Whenever possible, bands will be merged together to cover a greater vertical
+ * distance (and thus reduce the number of rectangles). Two bands can be merged
+ * only if the bottom of one touches the top of the other and they have
+ * rectangles in the same places (of the same width, of course). This maintains
+ * the y-x-banding that's so nice to have...
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include "Xlibint.h"
+#include "Xutil.h"
+#include <X11/Xregion.h>
+#include "poly.h"
+
+#ifdef DEBUG
+#include <stdio.h>
+#define assert(expr) {if (!(expr)) fprintf(stderr,\
+"Assertion failed file %s, line %d: expr\n", __FILE__, __LINE__); }
+#else
+#define assert(expr)
+#endif
+
+typedef int (*overlapProcp)(
+ register Region pReg,
+ register BoxPtr r1,
+ BoxPtr r1End,
+ register BoxPtr r2,
+ BoxPtr r2End,
+ short y1,
+ short y2);
+
+typedef int (*nonOverlapProcp)(
+ register Region pReg,
+ register BoxPtr r,
+ BoxPtr rEnd,
+ register short y1,
+ register short y2);
+
+static void miRegionOp(
+ register Region newReg, /* Place to store result */
+ Region reg1, /* First region in operation */
+ Region reg2, /* 2d region in operation */
+ int (*overlapFunc)(
+ register Region pReg,
+ register BoxPtr r1,
+ BoxPtr r1End,
+ register BoxPtr r2,
+ BoxPtr r2End,
+ short y1,
+ short y2), /* Function to call for over-
+ * lapping bands */
+ int (*nonOverlap1Func)(
+ register Region pReg,
+ register BoxPtr r,
+ BoxPtr rEnd,
+ register short y1,
+ register short y2), /* Function to call for non-
+ * overlapping bands in region
+ * 1 */
+ int (*nonOverlap2Func)(
+ register Region pReg,
+ register BoxPtr r,
+ BoxPtr rEnd,
+ register short y1,
+ register short y2)); /* Function to call for non-
+ * overlapping bands in region
+ * 2 */
+
+
+/* Create a new empty region */
+Region
+XCreateRegion(void)
+{
+ Region temp;
+
+ if (! (temp = ( Region )Xmalloc( (unsigned) sizeof( REGION ))))
+ return (Region) NULL;
+ if (! (temp->rects = ( BOX * )Xmalloc( (unsigned) sizeof( BOX )))) {
+ Xfree((char *) temp);
+ return (Region) NULL;
+ }
+ temp->numRects = 0;
+ temp->extents.x1 = 0;
+ temp->extents.y1 = 0;
+ temp->extents.x2 = 0;
+ temp->extents.y2 = 0;
+ temp->size = 1;
+ return( temp );
+}
+
+int
+XClipBox(
+ Region r,
+ XRectangle *rect)
+{
+ rect->x = r->extents.x1;
+ rect->y = r->extents.y1;
+ rect->width = r->extents.x2 - r->extents.x1;
+ rect->height = r->extents.y2 - r->extents.y1;
+ return 1;
+}
+
+int
+XUnionRectWithRegion(
+ register XRectangle *rect,
+ Region source, Region dest)
+{
+ REGION region;
+
+ if (!rect->width || !rect->height)
+ return 0;
+ region.rects = &region.extents;
+ region.numRects = 1;
+ region.extents.x1 = rect->x;
+ region.extents.y1 = rect->y;
+ region.extents.x2 = rect->x + rect->width;
+ region.extents.y2 = rect->y + rect->height;
+ region.size = 1;
+
+ return XUnionRegion(&region, source, dest);
+}
+
+/*-
+ *-----------------------------------------------------------------------
+ * miSetExtents --
+ * Reset the extents of a region to what they should be. Called by
+ * miSubtract and miIntersect b/c they can't figure it out along the
+ * way or do so easily, as miUnion can.
+ *
+ * Results:
+ * None.
+ *
+ * Side Effects:
+ * The region's 'extents' structure is overwritten.
+ *
+ *-----------------------------------------------------------------------
+ */
+static void
+miSetExtents (
+ Region pReg)
+{
+ register BoxPtr pBox,
+ pBoxEnd,
+ pExtents;
+
+ if (pReg->numRects == 0)
+ {
+ pReg->extents.x1 = 0;
+ pReg->extents.y1 = 0;
+ pReg->extents.x2 = 0;
+ pReg->extents.y2 = 0;
+ return;
+ }
+
+ pExtents = &pReg->extents;
+ pBox = pReg->rects;
+ pBoxEnd = &pBox[pReg->numRects - 1];
+
+ /*
+ * Since pBox is the first rectangle in the region, it must have the
+ * smallest y1 and since pBoxEnd is the last rectangle in the region,
+ * it must have the largest y2, because of banding. Initialize x1 and
+ * x2 from pBox and pBoxEnd, resp., as good things to initialize them
+ * to...
+ */
+ pExtents->x1 = pBox->x1;
+ pExtents->y1 = pBox->y1;
+ pExtents->x2 = pBoxEnd->x2;
+ pExtents->y2 = pBoxEnd->y2;
+
+ assert(pExtents->y1 < pExtents->y2);
+ while (pBox <= pBoxEnd)
+ {
+ if (pBox->x1 < pExtents->x1)
+ {
+ pExtents->x1 = pBox->x1;
+ }
+ if (pBox->x2 > pExtents->x2)
+ {
+ pExtents->x2 = pBox->x2;
+ }
+ pBox++;
+ }
+ assert(pExtents->x1 < pExtents->x2);
+}
+
+int
+XSetRegion(
+ Display *dpy,
+ GC gc,
+ register Region r)
+{
+ register int i;
+ register XRectangle *xr, *pr;
+ register BOX *pb;
+ unsigned long total;
+
+ LockDisplay (dpy);
+ total = r->numRects * sizeof (XRectangle);
+ if ((xr = (XRectangle *) _XAllocTemp(dpy, total))) {
+ for (pr = xr, pb = r->rects, i = r->numRects; --i >= 0; pr++, pb++) {
+ pr->x = pb->x1;
+ pr->y = pb->y1;
+ pr->width = pb->x2 - pb->x1;
+ pr->height = pb->y2 - pb->y1;
+ }
+ }
+ if (xr || !r->numRects)
+ _XSetClipRectangles(dpy, gc, 0, 0, xr, r->numRects, YXBanded);
+ if (xr)
+ _XFreeTemp(dpy, (char *)xr, total);
+ UnlockDisplay(dpy);
+ SyncHandle();
+ return 1;
+}
+
+int
+XDestroyRegion(
+ Region r)
+{
+ Xfree( (char *) r->rects );
+ Xfree( (char *) r );
+ return 1;
+}
+
+
+/* TranslateRegion(pRegion, x, y)
+ translates in place
+ added by raymond
+*/
+
+int
+XOffsetRegion(
+ register Region pRegion,
+ register int x,
+ register int y)
+{
+ register int nbox;
+ register BOX *pbox;
+
+ pbox = pRegion->rects;
+ nbox = pRegion->numRects;
+
+ while(nbox--)
+ {
+ pbox->x1 += x;
+ pbox->x2 += x;
+ pbox->y1 += y;
+ pbox->y2 += y;
+ pbox++;
+ }
+ pRegion->extents.x1 += x;
+ pRegion->extents.x2 += x;
+ pRegion->extents.y1 += y;
+ pRegion->extents.y2 += y;
+ return 1;
+}
+
+/*
+ Utility procedure Compress:
+ Replace r by the region r', where
+ p in r' iff (Quantifer m <= dx) (p + m in r), and
+ Quantifier is Exists if grow is TRUE, For all if grow is FALSE, and
+ (x,y) + m = (x+m,y) if xdir is TRUE; (x,y+m) if xdir is FALSE.
+
+ Thus, if xdir is TRUE and grow is FALSE, r is replaced by the region
+ of all points p such that p and the next dx points on the same
+ horizontal scan line are all in r. We do this using by noting
+ that p is the head of a run of length 2^i + k iff p is the head
+ of a run of length 2^i and p+2^i is the head of a run of length
+ k. Thus, the loop invariant: s contains the region corresponding
+ to the runs of length shift. r contains the region corresponding
+ to the runs of length 1 + dxo & (shift-1), where dxo is the original
+ value of dx. dx = dxo & ~(shift-1). As parameters, s and t are
+ scratch regions, so that we don't have to allocate them on every
+ call.
+*/
+
+#define ZOpRegion(a,b,c) if (grow) XUnionRegion(a,b,c); \
+ else XIntersectRegion(a,b,c)
+#define ZShiftRegion(a,b) if (xdir) XOffsetRegion(a,b,0); \
+ else XOffsetRegion(a,0,b)
+#define ZCopyRegion(a,b) XUnionRegion(a,a,b)
+
+static void
+Compress(
+ Region r, Region s, Region t,
+ register unsigned dx,
+ register int xdir, register int grow)
+{
+ register unsigned shift = 1;
+
+ ZCopyRegion(r, s);
+ while (dx) {
+ if (dx & shift) {
+ ZShiftRegion(r, -(int)shift);
+ ZOpRegion(r, s, r);
+ dx -= shift;
+ if (!dx) break;
+ }
+ ZCopyRegion(s, t);
+ ZShiftRegion(s, -(int)shift);
+ ZOpRegion(s, t, s);
+ shift <<= 1;
+ }
+}
+
+#undef ZOpRegion
+#undef ZShiftRegion
+#undef ZCopyRegion
+
+int
+XShrinkRegion(
+ Region r,
+ int dx, int dy)
+{
+ Region s, t;
+ int grow;
+
+ if (!dx && !dy) return 0;
+ if (! (s = XCreateRegion()) )
+ return 0;
+ if (! (t = XCreateRegion()) ) {
+ XDestroyRegion(s);
+ return 0;
+ }
+ if ((grow = (dx < 0))) dx = -dx;
+ if (dx) Compress(r, s, t, (unsigned) 2*dx, TRUE, grow);
+ if ((grow = (dy < 0))) dy = -dy;
+ if (dy) Compress(r, s, t, (unsigned) 2*dy, FALSE, grow);
+ XOffsetRegion(r, dx, dy);
+ XDestroyRegion(s);
+ XDestroyRegion(t);
+ return 0;
+}
+
+
+/*======================================================================
+ * Region Intersection
+ *====================================================================*/
+/*-
+ *-----------------------------------------------------------------------
+ * miIntersectO --
+ * Handle an overlapping band for miIntersect.
+ *
+ * Results:
+ * None.
+ *
+ * Side Effects:
+ * Rectangles may be added to the region.
+ *
+ *-----------------------------------------------------------------------
+ */
+/* static void*/
+static int
+miIntersectO (
+ register Region pReg,
+ register BoxPtr r1,
+ BoxPtr r1End,
+ register BoxPtr r2,
+ BoxPtr r2End,
+ short y1,
+ short y2)
+{
+ register short x1;
+ register short x2;
+ register BoxPtr pNextRect;
+
+ pNextRect = &pReg->rects[pReg->numRects];
+
+ while ((r1 != r1End) && (r2 != r2End))
+ {
+ x1 = max(r1->x1,r2->x1);
+ x2 = min(r1->x2,r2->x2);
+
+ /*
+ * If there's any overlap between the two rectangles, add that
+ * overlap to the new region.
+ * There's no need to check for subsumption because the only way
+ * such a need could arise is if some region has two rectangles
+ * right next to each other. Since that should never happen...
+ */
+ if (x1 < x2)
+ {
+ assert(y1<y2);
+
+ MEMCHECK(pReg, pNextRect, pReg->rects);
+ pNextRect->x1 = x1;
+ pNextRect->y1 = y1;
+ pNextRect->x2 = x2;
+ pNextRect->y2 = y2;
+ pReg->numRects += 1;
+ pNextRect++;
+ assert(pReg->numRects <= pReg->size);
+ }
+
+ /*
+ * Need to advance the pointers. Shift the one that extends
+ * to the right the least, since the other still has a chance to
+ * overlap with that region's next rectangle, if you see what I mean.
+ */
+ if (r1->x2 < r2->x2)
+ {
+ r1++;
+ }
+ else if (r2->x2 < r1->x2)
+ {
+ r2++;
+ }
+ else
+ {
+ r1++;
+ r2++;
+ }
+ }
+ return 0; /* lint */
+}
+
+int
+XIntersectRegion(
+ Region reg1,
+ Region reg2, /* source regions */
+ register Region newReg) /* destination Region */
+{
+ /* check for trivial reject */
+ if ( (!(reg1->numRects)) || (!(reg2->numRects)) ||
+ (!EXTENTCHECK(&reg1->extents, &reg2->extents)))
+ newReg->numRects = 0;
+ else
+ miRegionOp (newReg, reg1, reg2,
+ miIntersectO, NULL, NULL);
+
+ /*
+ * Can't alter newReg's extents before we call miRegionOp because
+ * it might be one of the source regions and miRegionOp depends
+ * on the extents of those regions being the same. Besides, this
+ * way there's no checking against rectangles that will be nuked
+ * due to coalescing, so we have to examine fewer rectangles.
+ */
+ miSetExtents(newReg);
+ return 1;
+}
+
+static void
+miRegionCopy(
+ register Region dstrgn,
+ register Region rgn)
+
+{
+ if (dstrgn != rgn) /* don't want to copy to itself */
+ {
+ if (dstrgn->size < rgn->numRects)
+ {
+ if (dstrgn->rects)
+ {
+ BOX *prevRects = dstrgn->rects;
+
+ if (! (dstrgn->rects = (BOX *)
+ Xrealloc((char *) dstrgn->rects,
+ (unsigned) rgn->numRects * (sizeof(BOX))))) {
+ Xfree(prevRects);
+ return;
+ }
+ }
+ dstrgn->size = rgn->numRects;
+ }
+ dstrgn->numRects = rgn->numRects;
+ dstrgn->extents.x1 = rgn->extents.x1;
+ dstrgn->extents.y1 = rgn->extents.y1;
+ dstrgn->extents.x2 = rgn->extents.x2;
+ dstrgn->extents.y2 = rgn->extents.y2;
+
+ memcpy((char *) dstrgn->rects, (char *) rgn->rects,
+ (int) (rgn->numRects * sizeof(BOX)));
+ }
+}
+
+/*======================================================================
+ * Generic Region Operator
+ *====================================================================*/
+
+/*-
+ *-----------------------------------------------------------------------
+ * miCoalesce --
+ * Attempt to merge the boxes in the current band with those in the
+ * previous one. Used only by miRegionOp.
+ *
+ * Results:
+ * The new index for the previous band.
+ *
+ * Side Effects:
+ * If coalescing takes place:
+ * - rectangles in the previous band will have their y2 fields
+ * altered.
+ * - pReg->numRects will be decreased.
+ *
+ *-----------------------------------------------------------------------
+ */
+/* static int*/
+static int
+miCoalesce(
+ register Region pReg, /* Region to coalesce */
+ int prevStart, /* Index of start of previous band */
+ int curStart) /* Index of start of current band */
+{
+ register BoxPtr pPrevBox; /* Current box in previous band */
+ register BoxPtr pCurBox; /* Current box in current band */
+ register BoxPtr pRegEnd; /* End of region */
+ int curNumRects; /* Number of rectangles in current
+ * band */
+ int prevNumRects; /* Number of rectangles in previous
+ * band */
+ int bandY1; /* Y1 coordinate for current band */
+
+ pRegEnd = &pReg->rects[pReg->numRects];
+
+ pPrevBox = &pReg->rects[prevStart];
+ prevNumRects = curStart - prevStart;
+
+ /*
+ * Figure out how many rectangles are in the current band. Have to do
+ * this because multiple bands could have been added in miRegionOp
+ * at the end when one region has been exhausted.
+ */
+ pCurBox = &pReg->rects[curStart];
+ bandY1 = pCurBox->y1;
+ for (curNumRects = 0;
+ (pCurBox != pRegEnd) && (pCurBox->y1 == bandY1);
+ curNumRects++)
+ {
+ pCurBox++;
+ }
+
+ if (pCurBox != pRegEnd)
+ {
+ /*
+ * If more than one band was added, we have to find the start
+ * of the last band added so the next coalescing job can start
+ * at the right place... (given when multiple bands are added,
+ * this may be pointless -- see above).
+ */
+ pRegEnd--;
+ while (pRegEnd[-1].y1 == pRegEnd->y1)
+ {
+ pRegEnd--;
+ }
+ curStart = pRegEnd - pReg->rects;
+ pRegEnd = pReg->rects + pReg->numRects;
+ }
+
+ if ((curNumRects == prevNumRects) && (curNumRects != 0)) {
+ pCurBox -= curNumRects;
+ /*
+ * The bands may only be coalesced if the bottom of the previous
+ * matches the top scanline of the current.
+ */
+ if (pPrevBox->y2 == pCurBox->y1)
+ {
+ /*
+ * Make sure the bands have boxes in the same places. This
+ * assumes that boxes have been added in such a way that they
+ * cover the most area possible. I.e. two boxes in a band must
+ * have some horizontal space between them.
+ */
+ do
+ {
+ if ((pPrevBox->x1 != pCurBox->x1) ||
+ (pPrevBox->x2 != pCurBox->x2))
+ {
+ /*
+ * The bands don't line up so they can't be coalesced.
+ */
+ return (curStart);
+ }
+ pPrevBox++;
+ pCurBox++;
+ prevNumRects -= 1;
+ } while (prevNumRects != 0);
+
+ pReg->numRects -= curNumRects;
+ pCurBox -= curNumRects;
+ pPrevBox -= curNumRects;
+
+ /*
+ * The bands may be merged, so set the bottom y of each box
+ * in the previous band to that of the corresponding box in
+ * the current band.
+ */
+ do
+ {
+ pPrevBox->y2 = pCurBox->y2;
+ pPrevBox++;
+ pCurBox++;
+ curNumRects -= 1;
+ } while (curNumRects != 0);
+
+ /*
+ * If only one band was added to the region, we have to backup
+ * curStart to the start of the previous band.
+ *
+ * If more than one band was added to the region, copy the
+ * other bands down. The assumption here is that the other bands
+ * came from the same region as the current one and no further
+ * coalescing can be done on them since it's all been done
+ * already... curStart is already in the right place.
+ */
+ if (pCurBox == pRegEnd)
+ {
+ curStart = prevStart;
+ }
+ else
+ {
+ do
+ {
+ *pPrevBox++ = *pCurBox++;
+ } while (pCurBox != pRegEnd);
+ }
+
+ }
+ }
+ return (curStart);
+}
+
+/*-
+ *-----------------------------------------------------------------------
+ * miRegionOp --
+ * Apply an operation to two regions. Called by miUnion, miInverse,
+ * miSubtract, miIntersect...
+ *
+ * Results:
+ * None.
+ *
+ * Side Effects:
+ * The new region is overwritten.
+ *
+ * Notes:
+ * The idea behind this function is to view the two regions as sets.
+ * Together they cover a rectangle of area that this function divides
+ * into horizontal bands where points are covered only by one region
+ * or by both. For the first case, the nonOverlapFunc is called with
+ * each the band and the band's upper and lower extents. For the
+ * second, the overlapFunc is called to process the entire band. It
+ * is responsible for clipping the rectangles in the band, though
+ * this function provides the boundaries.
+ * At the end of each band, the new region is coalesced, if possible,
+ * to reduce the number of rectangles in the region.
+ *
+ *-----------------------------------------------------------------------
+ */
+/* static void*/
+static void
+miRegionOp(
+ register Region newReg, /* Place to store result */
+ Region reg1, /* First region in operation */
+ Region reg2, /* 2d region in operation */
+ int (*overlapFunc)(
+ register Region pReg,
+ register BoxPtr r1,
+ BoxPtr r1End,
+ register BoxPtr r2,
+ BoxPtr r2End,
+ short y1,
+ short y2), /* Function to call for over-
+ * lapping bands */
+ int (*nonOverlap1Func)(
+ register Region pReg,
+ register BoxPtr r,
+ BoxPtr rEnd,
+ register short y1,
+ register short y2), /* Function to call for non-
+ * overlapping bands in region
+ * 1 */
+ int (*nonOverlap2Func)(
+ register Region pReg,
+ register BoxPtr r,
+ BoxPtr rEnd,
+ register short y1,
+ register short y2)) /* Function to call for non-
+ * overlapping bands in region
+ * 2 */
+{
+ register BoxPtr r1; /* Pointer into first region */
+ register BoxPtr r2; /* Pointer into 2d region */
+ BoxPtr r1End; /* End of 1st region */
+ BoxPtr r2End; /* End of 2d region */
+ register short ybot; /* Bottom of intersection */
+ register short ytop; /* Top of intersection */
+ BoxPtr oldRects; /* Old rects for newReg */
+ int prevBand; /* Index of start of
+ * previous band in newReg */
+ int curBand; /* Index of start of current
+ * band in newReg */
+ register BoxPtr r1BandEnd; /* End of current band in r1 */
+ register BoxPtr r2BandEnd; /* End of current band in r2 */
+ short top; /* Top of non-overlapping
+ * band */
+ short bot; /* Bottom of non-overlapping
+ * band */
+
+ /*
+ * Initialization:
+ * set r1, r2, r1End and r2End appropriately, preserve the important
+ * parts of the destination region until the end in case it's one of
+ * the two source regions, then mark the "new" region empty, allocating
+ * another array of rectangles for it to use.
+ */
+ r1 = reg1->rects;
+ r2 = reg2->rects;
+ r1End = r1 + reg1->numRects;
+ r2End = r2 + reg2->numRects;
+
+ oldRects = newReg->rects;
+
+ EMPTY_REGION(newReg);
+
+ /*
+ * Allocate a reasonable number of rectangles for the new region. The idea
+ * is to allocate enough so the individual functions don't need to
+ * reallocate and copy the array, which is time consuming, yet we don't
+ * have to worry about using too much memory. I hope to be able to
+ * nuke the Xrealloc() at the end of this function eventually.
+ */
+ newReg->size = max(reg1->numRects,reg2->numRects) * 2;
+
+ if (! (newReg->rects = (BoxPtr)
+ Xmalloc ((unsigned) (sizeof(BoxRec) * newReg->size)))) {
+ newReg->size = 0;
+ return;
+ }
+
+ /*
+ * Initialize ybot and ytop.
+ * In the upcoming loop, ybot and ytop serve different functions depending
+ * on whether the band being handled is an overlapping or non-overlapping
+ * band.
+ * In the case of a non-overlapping band (only one of the regions
+ * has points in the band), ybot is the bottom of the most recent
+ * intersection and thus clips the top of the rectangles in that band.
+ * ytop is the top of the next intersection between the two regions and
+ * serves to clip the bottom of the rectangles in the current band.
+ * For an overlapping band (where the two regions intersect), ytop clips
+ * the top of the rectangles of both regions and ybot clips the bottoms.
+ */
+ if (reg1->extents.y1 < reg2->extents.y1)
+ ybot = reg1->extents.y1;
+ else
+ ybot = reg2->extents.y1;
+
+ /*
+ * prevBand serves to mark the start of the previous band so rectangles
+ * can be coalesced into larger rectangles. qv. miCoalesce, above.
+ * In the beginning, there is no previous band, so prevBand == curBand
+ * (curBand is set later on, of course, but the first band will always
+ * start at index 0). prevBand and curBand must be indices because of
+ * the possible expansion, and resultant moving, of the new region's
+ * array of rectangles.
+ */
+ prevBand = 0;
+
+ do
+ {
+ curBand = newReg->numRects;
+
+ /*
+ * This algorithm proceeds one source-band (as opposed to a
+ * destination band, which is determined by where the two regions
+ * intersect) at a time. r1BandEnd and r2BandEnd serve to mark the
+ * rectangle after the last one in the current band for their
+ * respective regions.
+ */
+ r1BandEnd = r1;
+ while ((r1BandEnd != r1End) && (r1BandEnd->y1 == r1->y1))
+ {
+ r1BandEnd++;
+ }
+
+ r2BandEnd = r2;
+ while ((r2BandEnd != r2End) && (r2BandEnd->y1 == r2->y1))
+ {
+ r2BandEnd++;
+ }
+
+ /*
+ * First handle the band that doesn't intersect, if any.
+ *
+ * Note that attention is restricted to one band in the
+ * non-intersecting region at once, so if a region has n
+ * bands between the current position and the next place it overlaps
+ * the other, this entire loop will be passed through n times.
+ */
+ if (r1->y1 < r2->y1)
+ {
+ top = max(r1->y1,ybot);
+ bot = min(r1->y2,r2->y1);
+
+ if ((top != bot) && (nonOverlap1Func != NULL))
+ {
+ (* nonOverlap1Func) (newReg, r1, r1BandEnd, top, bot);
+ }
+
+ ytop = r2->y1;
+ }
+ else if (r2->y1 < r1->y1)
+ {
+ top = max(r2->y1,ybot);
+ bot = min(r2->y2,r1->y1);
+
+ if ((top != bot) && (nonOverlap2Func != NULL))
+ {
+ (* nonOverlap2Func) (newReg, r2, r2BandEnd, top, bot);
+ }
+
+ ytop = r1->y1;
+ }
+ else
+ {
+ ytop = r1->y1;
+ }
+
+ /*
+ * If any rectangles got added to the region, try and coalesce them
+ * with rectangles from the previous band. Note we could just do
+ * this test in miCoalesce, but some machines incur a not
+ * inconsiderable cost for function calls, so...
+ */
+ if (newReg->numRects != curBand)
+ {
+ prevBand = miCoalesce (newReg, prevBand, curBand);
+ }
+
+ /*
+ * Now see if we've hit an intersecting band. The two bands only
+ * intersect if ybot > ytop
+ */
+ ybot = min(r1->y2, r2->y2);
+ curBand = newReg->numRects;
+ if (ybot > ytop)
+ {
+ (* overlapFunc) (newReg, r1, r1BandEnd, r2, r2BandEnd, ytop, ybot);
+
+ }
+
+ if (newReg->numRects != curBand)
+ {
+ prevBand = miCoalesce (newReg, prevBand, curBand);
+ }
+
+ /*
+ * If we've finished with a band (y2 == ybot) we skip forward
+ * in the region to the next band.
+ */
+ if (r1->y2 == ybot)
+ {
+ r1 = r1BandEnd;
+ }
+ if (r2->y2 == ybot)
+ {
+ r2 = r2BandEnd;
+ }
+ } while ((r1 != r1End) && (r2 != r2End));
+
+ /*
+ * Deal with whichever region still has rectangles left.
+ */
+ curBand = newReg->numRects;
+ if (r1 != r1End)
+ {
+ if (nonOverlap1Func != NULL)
+ {
+ do
+ {
+ r1BandEnd = r1;
+ while ((r1BandEnd < r1End) && (r1BandEnd->y1 == r1->y1))
+ {
+ r1BandEnd++;
+ }
+ (* nonOverlap1Func) (newReg, r1, r1BandEnd,
+ max(r1->y1,ybot), r1->y2);
+ r1 = r1BandEnd;
+ } while (r1 != r1End);
+ }
+ }
+ else if ((r2 != r2End) && (nonOverlap2Func != NULL))
+ {
+ do
+ {
+ r2BandEnd = r2;
+ while ((r2BandEnd < r2End) && (r2BandEnd->y1 == r2->y1))
+ {
+ r2BandEnd++;
+ }
+ (* nonOverlap2Func) (newReg, r2, r2BandEnd,
+ max(r2->y1,ybot), r2->y2);
+ r2 = r2BandEnd;
+ } while (r2 != r2End);
+ }
+
+ if (newReg->numRects != curBand)
+ {
+ (void) miCoalesce (newReg, prevBand, curBand);
+ }
+
+ /*
+ * A bit of cleanup. To keep regions from growing without bound,
+ * we shrink the array of rectangles to match the new number of
+ * rectangles in the region. This never goes to 0, however...
+ *
+ * Only do this stuff if the number of rectangles allocated is more than
+ * twice the number of rectangles in the region (a simple optimization...).
+ */
+ if (newReg->numRects < (newReg->size >> 1))
+ {
+ if (REGION_NOT_EMPTY(newReg))
+ {
+ BoxPtr prev_rects = newReg->rects;
+ newReg->size = newReg->numRects;
+ newReg->rects = (BoxPtr) Xrealloc ((char *) newReg->rects,
+ (unsigned) (sizeof(BoxRec) * newReg->size));
+ if (! newReg->rects)
+ newReg->rects = prev_rects;
+ }
+ else
+ {
+ /*
+ * No point in doing the extra work involved in an Xrealloc if
+ * the region is empty
+ */
+ newReg->size = 1;
+ Xfree((char *) newReg->rects);
+ newReg->rects = (BoxPtr) Xmalloc(sizeof(BoxRec));
+ }
+ }
+ Xfree ((char *) oldRects);
+ return;
+}
+
+
+/*======================================================================
+ * Region Union
+ *====================================================================*/
+
+/*-
+ *-----------------------------------------------------------------------
+ * miUnionNonO --
+ * Handle a non-overlapping band for the union operation. Just
+ * Adds the rectangles into the region. Doesn't have to check for
+ * subsumption or anything.
+ *
+ * Results:
+ * None.
+ *
+ * Side Effects:
+ * pReg->numRects is incremented and the final rectangles overwritten
+ * with the rectangles we're passed.
+ *
+ *-----------------------------------------------------------------------
+ */
+/* static void*/
+static int
+miUnionNonO (
+ register Region pReg,
+ register BoxPtr r,
+ BoxPtr rEnd,
+ register short y1,
+ register short y2)
+{
+ register BoxPtr pNextRect;
+
+ pNextRect = &pReg->rects[pReg->numRects];
+
+ assert(y1 < y2);
+
+ while (r != rEnd)
+ {
+ assert(r->x1 < r->x2);
+ MEMCHECK(pReg, pNextRect, pReg->rects);
+ pNextRect->x1 = r->x1;
+ pNextRect->y1 = y1;
+ pNextRect->x2 = r->x2;
+ pNextRect->y2 = y2;
+ pReg->numRects += 1;
+ pNextRect++;
+
+ assert(pReg->numRects<=pReg->size);
+ r++;
+ }
+ return 0; /* lint */
+}
+
+
+/*-
+ *-----------------------------------------------------------------------
+ * miUnionO --
+ * Handle an overlapping band for the union operation. Picks the
+ * left-most rectangle each time and merges it into the region.
+ *
+ * Results:
+ * None.
+ *
+ * Side Effects:
+ * Rectangles are overwritten in pReg->rects and pReg->numRects will
+ * be changed.
+ *
+ *-----------------------------------------------------------------------
+ */
+
+/* static void*/
+static int
+miUnionO (
+ register Region pReg,
+ register BoxPtr r1,
+ BoxPtr r1End,
+ register BoxPtr r2,
+ BoxPtr r2End,
+ register short y1,
+ register short y2)
+{
+ register BoxPtr pNextRect;
+
+ pNextRect = &pReg->rects[pReg->numRects];
+
+#define MERGERECT(r) \
+ if ((pReg->numRects != 0) && \
+ (pNextRect[-1].y1 == y1) && \
+ (pNextRect[-1].y2 == y2) && \
+ (pNextRect[-1].x2 >= r->x1)) \
+ { \
+ if (pNextRect[-1].x2 < r->x2) \
+ { \
+ pNextRect[-1].x2 = r->x2; \
+ assert(pNextRect[-1].x1<pNextRect[-1].x2); \
+ } \
+ } \
+ else \
+ { \
+ MEMCHECK(pReg, pNextRect, pReg->rects); \
+ pNextRect->y1 = y1; \
+ pNextRect->y2 = y2; \
+ pNextRect->x1 = r->x1; \
+ pNextRect->x2 = r->x2; \
+ pReg->numRects += 1; \
+ pNextRect += 1; \
+ } \
+ assert(pReg->numRects<=pReg->size);\
+ r++;
+
+ assert (y1<y2);
+ while ((r1 != r1End) && (r2 != r2End))
+ {
+ if (r1->x1 < r2->x1)
+ {
+ MERGERECT(r1);
+ }
+ else
+ {
+ MERGERECT(r2);
+ }
+ }
+
+ if (r1 != r1End)
+ {
+ do
+ {
+ MERGERECT(r1);
+ } while (r1 != r1End);
+ }
+ else while (r2 != r2End)
+ {
+ MERGERECT(r2);
+ }
+ return 0; /* lint */
+}
+
+int
+XUnionRegion(
+ Region reg1,
+ Region reg2, /* source regions */
+ Region newReg) /* destination Region */
+{
+ /* checks all the simple cases */
+
+ /*
+ * Region 1 and 2 are the same or region 1 is empty
+ */
+ if ( (reg1 == reg2) || (!(reg1->numRects)) )
+ {
+ if (newReg != reg2)
+ miRegionCopy(newReg, reg2);
+ return 1;
+ }
+
+ /*
+ * if nothing to union (region 2 empty)
+ */
+ if (!(reg2->numRects))
+ {
+ if (newReg != reg1)
+ miRegionCopy(newReg, reg1);
+ return 1;
+ }
+
+ /*
+ * Region 1 completely subsumes region 2
+ */
+ if ((reg1->numRects == 1) &&
+ (reg1->extents.x1 <= reg2->extents.x1) &&
+ (reg1->extents.y1 <= reg2->extents.y1) &&
+ (reg1->extents.x2 >= reg2->extents.x2) &&
+ (reg1->extents.y2 >= reg2->extents.y2))
+ {
+ if (newReg != reg1)
+ miRegionCopy(newReg, reg1);
+ return 1;
+ }
+
+ /*
+ * Region 2 completely subsumes region 1
+ */
+ if ((reg2->numRects == 1) &&
+ (reg2->extents.x1 <= reg1->extents.x1) &&
+ (reg2->extents.y1 <= reg1->extents.y1) &&
+ (reg2->extents.x2 >= reg1->extents.x2) &&
+ (reg2->extents.y2 >= reg1->extents.y2))
+ {
+ if (newReg != reg2)
+ miRegionCopy(newReg, reg2);
+ return 1;
+ }
+
+ miRegionOp (newReg, reg1, reg2, miUnionO,
+ miUnionNonO, miUnionNonO);
+
+ newReg->extents.x1 = min(reg1->extents.x1, reg2->extents.x1);
+ newReg->extents.y1 = min(reg1->extents.y1, reg2->extents.y1);
+ newReg->extents.x2 = max(reg1->extents.x2, reg2->extents.x2);
+ newReg->extents.y2 = max(reg1->extents.y2, reg2->extents.y2);
+
+ return 1;
+}
+
+
+/*======================================================================
+ * Region Subtraction
+ *====================================================================*/
+
+/*-
+ *-----------------------------------------------------------------------
+ * miSubtractNonO --
+ * Deal with non-overlapping band for subtraction. Any parts from
+ * region 2 we discard. Anything from region 1 we add to the region.
+ *
+ * Results:
+ * None.
+ *
+ * Side Effects:
+ * pReg may be affected.
+ *
+ *-----------------------------------------------------------------------
+ */
+/* static void*/
+static int
+miSubtractNonO1 (
+ register Region pReg,
+ register BoxPtr r,
+ BoxPtr rEnd,
+ register short y1,
+ register short y2)
+{
+ register BoxPtr pNextRect;
+
+ pNextRect = &pReg->rects[pReg->numRects];
+
+ assert(y1<y2);
+
+ while (r != rEnd)
+ {
+ assert(r->x1<r->x2);
+ MEMCHECK(pReg, pNextRect, pReg->rects);
+ pNextRect->x1 = r->x1;
+ pNextRect->y1 = y1;
+ pNextRect->x2 = r->x2;
+ pNextRect->y2 = y2;
+ pReg->numRects += 1;
+ pNextRect++;
+
+ assert(pReg->numRects <= pReg->size);
+
+ r++;
+ }
+ return 0; /* lint */
+}
+
+/*-
+ *-----------------------------------------------------------------------
+ * miSubtractO --
+ * Overlapping band subtraction. x1 is the left-most point not yet
+ * checked.
+ *
+ * Results:
+ * None.
+ *
+ * Side Effects:
+ * pReg may have rectangles added to it.
+ *
+ *-----------------------------------------------------------------------
+ */
+/* static void*/
+static int
+miSubtractO (
+ register Region pReg,
+ register BoxPtr r1,
+ BoxPtr r1End,
+ register BoxPtr r2,
+ BoxPtr r2End,
+ register short y1,
+ register short y2)
+{
+ register BoxPtr pNextRect;
+ register int x1;
+
+ x1 = r1->x1;
+
+ assert(y1<y2);
+ pNextRect = &pReg->rects[pReg->numRects];
+
+ while ((r1 != r1End) && (r2 != r2End))
+ {
+ if (r2->x2 <= x1)
+ {
+ /*
+ * Subtrahend missed the boat: go to next subtrahend.
+ */
+ r2++;
+ }
+ else if (r2->x1 <= x1)
+ {
+ /*
+ * Subtrahend preceeds minuend: nuke left edge of minuend.
+ */
+ x1 = r2->x2;
+ if (x1 >= r1->x2)
+ {
+ /*
+ * Minuend completely covered: advance to next minuend and
+ * reset left fence to edge of new minuend.
+ */
+ r1++;
+ if (r1 != r1End)
+ x1 = r1->x1;
+ }
+ else
+ {
+ /*
+ * Subtrahend now used up since it doesn't extend beyond
+ * minuend
+ */
+ r2++;
+ }
+ }
+ else if (r2->x1 < r1->x2)
+ {
+ /*
+ * Left part of subtrahend covers part of minuend: add uncovered
+ * part of minuend to region and skip to next subtrahend.
+ */
+ assert(x1<r2->x1);
+ MEMCHECK(pReg, pNextRect, pReg->rects);
+ pNextRect->x1 = x1;
+ pNextRect->y1 = y1;
+ pNextRect->x2 = r2->x1;
+ pNextRect->y2 = y2;
+ pReg->numRects += 1;
+ pNextRect++;
+
+ assert(pReg->numRects<=pReg->size);
+
+ x1 = r2->x2;
+ if (x1 >= r1->x2)
+ {
+ /*
+ * Minuend used up: advance to new...
+ */
+ r1++;
+ if (r1 != r1End)
+ x1 = r1->x1;
+ }
+ else
+ {
+ /*
+ * Subtrahend used up
+ */
+ r2++;
+ }
+ }
+ else
+ {
+ /*
+ * Minuend used up: add any remaining piece before advancing.
+ */
+ if (r1->x2 > x1)
+ {
+ MEMCHECK(pReg, pNextRect, pReg->rects);
+ pNextRect->x1 = x1;
+ pNextRect->y1 = y1;
+ pNextRect->x2 = r1->x2;
+ pNextRect->y2 = y2;
+ pReg->numRects += 1;
+ pNextRect++;
+ assert(pReg->numRects<=pReg->size);
+ }
+ r1++;
+ if (r1 != r1End)
+ x1 = r1->x1;
+ }
+ }
+
+ /*
+ * Add remaining minuend rectangles to region.
+ */
+ while (r1 != r1End)
+ {
+ assert(x1<r1->x2);
+ MEMCHECK(pReg, pNextRect, pReg->rects);
+ pNextRect->x1 = x1;
+ pNextRect->y1 = y1;
+ pNextRect->x2 = r1->x2;
+ pNextRect->y2 = y2;
+ pReg->numRects += 1;
+ pNextRect++;
+
+ assert(pReg->numRects<=pReg->size);
+
+ r1++;
+ if (r1 != r1End)
+ {
+ x1 = r1->x1;
+ }
+ }
+ return 0; /* lint */
+}
+
+/*-
+ *-----------------------------------------------------------------------
+ * miSubtract --
+ * Subtract regS from regM and leave the result in regD.
+ * S stands for subtrahend, M for minuend and D for difference.
+ *
+ * Results:
+ * TRUE.
+ *
+ * Side Effects:
+ * regD is overwritten.
+ *
+ *-----------------------------------------------------------------------
+ */
+
+int
+XSubtractRegion(
+ Region regM,
+ Region regS,
+ register Region regD)
+{
+ /* check for trivial reject */
+ if ( (!(regM->numRects)) || (!(regS->numRects)) ||
+ (!EXTENTCHECK(&regM->extents, &regS->extents)) )
+ {
+ miRegionCopy(regD, regM);
+ return 1;
+ }
+
+ miRegionOp (regD, regM, regS, miSubtractO,
+ miSubtractNonO1, NULL);
+
+ /*
+ * Can't alter newReg's extents before we call miRegionOp because
+ * it might be one of the source regions and miRegionOp depends
+ * on the extents of those regions being the unaltered. Besides, this
+ * way there's no checking against rectangles that will be nuked
+ * due to coalescing, so we have to examine fewer rectangles.
+ */
+ miSetExtents (regD);
+ return 1;
+}
+
+int
+XXorRegion(Region sra, Region srb, Region dr)
+{
+ Region tra, trb;
+
+ if (! (tra = XCreateRegion()) )
+ return 0;
+ if (! (trb = XCreateRegion()) ) {
+ XDestroyRegion(tra);
+ return 0;
+ }
+ (void) XSubtractRegion(sra,srb,tra);
+ (void) XSubtractRegion(srb,sra,trb);
+ (void) XUnionRegion(tra,trb,dr);
+ XDestroyRegion(tra);
+ XDestroyRegion(trb);
+ return 0;
+}
+
+/*
+ * Check to see if the region is empty. Assumes a region is passed
+ * as a parameter
+ */
+int
+XEmptyRegion(
+ Region r)
+{
+ if( r->numRects == 0 ) return TRUE;
+ else return FALSE;
+}
+
+/*
+ * Check to see if two regions are equal
+ */
+int
+XEqualRegion(Region r1, Region r2)
+{
+ int i;
+
+ if( r1->numRects != r2->numRects ) return FALSE;
+ else if( r1->numRects == 0 ) return TRUE;
+ else if ( r1->extents.x1 != r2->extents.x1 ) return FALSE;
+ else if ( r1->extents.x2 != r2->extents.x2 ) return FALSE;
+ else if ( r1->extents.y1 != r2->extents.y1 ) return FALSE;
+ else if ( r1->extents.y2 != r2->extents.y2 ) return FALSE;
+ else for( i=0; i < r1->numRects; i++ ) {
+ if ( r1->rects[i].x1 != r2->rects[i].x1 ) return FALSE;
+ else if ( r1->rects[i].x2 != r2->rects[i].x2 ) return FALSE;
+ else if ( r1->rects[i].y1 != r2->rects[i].y1 ) return FALSE;
+ else if ( r1->rects[i].y2 != r2->rects[i].y2 ) return FALSE;
+ }
+ return TRUE;
+}
+
+int
+XPointInRegion(
+ Region pRegion,
+ int x, int y)
+{
+ int i;
+
+ if (pRegion->numRects == 0)
+ return FALSE;
+ if (!INBOX(pRegion->extents, x, y))
+ return FALSE;
+ for (i=0; i<pRegion->numRects; i++)
+ {
+ if (INBOX (pRegion->rects[i], x, y))
+ return TRUE;
+ }
+ return FALSE;
+}
+
+int
+XRectInRegion(
+ register Region region,
+ int rx, int ry,
+ unsigned int rwidth, unsigned int rheight)
+{
+ register BoxPtr pbox;
+ register BoxPtr pboxEnd;
+ Box rect;
+ register BoxPtr prect = &rect;
+ int partIn, partOut;
+
+ prect->x1 = rx;
+ prect->y1 = ry;
+ prect->x2 = rwidth + rx;
+ prect->y2 = rheight + ry;
+
+ /* this is (just) a useful optimization */
+ if ((region->numRects == 0) || !EXTENTCHECK(&region->extents, prect))
+ return(RectangleOut);
+
+ partOut = FALSE;
+ partIn = FALSE;
+
+ /* can stop when both partOut and partIn are TRUE, or we reach prect->y2 */
+ for (pbox = region->rects, pboxEnd = pbox + region->numRects;
+ pbox < pboxEnd;
+ pbox++)
+ {
+
+ if (pbox->y2 <= ry)
+ continue; /* getting up to speed or skipping remainder of band */
+
+ if (pbox->y1 > ry)
+ {
+ partOut = TRUE; /* missed part of rectangle above */
+ if (partIn || (pbox->y1 >= prect->y2))
+ break;
+ ry = pbox->y1; /* x guaranteed to be == prect->x1 */
+ }
+
+ if (pbox->x2 <= rx)
+ continue; /* not far enough over yet */
+
+ if (pbox->x1 > rx)
+ {
+ partOut = TRUE; /* missed part of rectangle to left */
+ if (partIn)
+ break;
+ }
+
+ if (pbox->x1 < prect->x2)
+ {
+ partIn = TRUE; /* definitely overlap */
+ if (partOut)
+ break;
+ }
+
+ if (pbox->x2 >= prect->x2)
+ {
+ ry = pbox->y2; /* finished with this band */
+ if (ry >= prect->y2)
+ break;
+ rx = prect->x1; /* reset x out to left again */
+ } else
+ {
+ /*
+ * Because boxes in a band are maximal width, if the first box
+ * to overlap the rectangle doesn't completely cover it in that
+ * band, the rectangle must be partially out, since some of it
+ * will be uncovered in that band. partIn will have been set true
+ * by now...
+ */
+ break;
+ }
+
+ }
+
+ return(partIn ? ((ry < prect->y2) ? RectanglePart : RectangleIn) :
+ RectangleOut);
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-10 14:55:13 +0000