--- /dev/null
+/***********************************************************
+
+Copyright (c) 1987, 1988, 1989 X Consortium
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice 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
+X CONSORTIUM 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 X Consortium 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 X Consortium.
+
+
+Copyright 1987, 1988, 1989 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.
+
+******************************************************************/
+/* $XConsortium: miregion.c,v 1.60 94/04/17 20:27:49 dpw Exp $ */
+
+#include <stdio.h>
+#include "miscstruct.h"
+#include "regionstr.h"
+#include "Xprotostr.h"
+#include "gc.h"
+
+#if defined (__GNUC__) && !defined (NO_INLINES)
+#define INLINE __inline
+#else
+#define INLINE
+#endif
+
+/*
+ * hack until callers of these functions can deal with out-of-memory
+ */
+
+extern Bool Must_have_memory;
+
+#ifdef DEBUG
+#define assert(expr) {if (!(expr)) \
+ FatalError("Assertion failed file %s, line %d: expr\n", \
+ __FILE__, __LINE__); }
+#else
+#define assert(expr)
+#endif
+
+#define good(reg) assert(miValidRegion(reg))
+
+/*
+ * The functions in this file implement the Region abstraction used extensively
+ * throughout the X11 sample server. A Region is simply a set of disjoint
+ * (non-overlapping) rectangles, plus an "extent" rectangle which is the
+ * smallest single rectangle that contains all the non-overlapping rectangles.
+ *
+ * A Region is implemented as a "y-x-banded" array of rectangles. This array
+ * imposes two degrees of order. First, all rectangles are sorted by top side
+ * y coordinate first (y1), and then by left side x coordinate (x1).
+ *
+ * Furthermore, the rectangles are grouped into "bands". Each rectangle in a
+ * band has the same top y coordinate (y1), and each has the same bottom y
+ * coordinate (y2). Thus all rectangles in a band differ only in their left
+ * and right side (x1 and x2). Bands are implicit in the array of rectangles:
+ * there is no separate list of band start pointers.
+ *
+ * The y-x band representation does not minimize rectangles. In particular,
+ * if a rectangle vertically crosses a band (the rectangle has scanlines in
+ * the y1 to y2 area spanned by the band), then the rectangle may be broken
+ * down into two or more smaller rectangles stacked one atop the other.
+ *
+ * ----------- -----------
+ * | | | | band 0
+ * | | -------- ----------- --------
+ * | | | | in y-x banded | | | | band 1
+ * | | | | form is | | | |
+ * ----------- | | ----------- --------
+ * | | | | band 2
+ * -------- --------
+ *
+ * An added constraint on the rectangles is that they must cover as much
+ * horizontal area as possible: no two rectangles within 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).
+ *
+ * Adam de Boor wrote most of the original region code. Joel McCormack
+ * substantially modified or rewrote most of the core arithmetic routines,
+ * and added miRegionValidate in order to support several speed improvements
+ * to miValidateTree. Bob Scheifler changed the representation to be more
+ * compact when empty or a single rectangle, and did a bunch of gratuitous
+ * reformatting.
+ */
+
+/* true iff two Boxes overlap */
+#define EXTENTCHECK(r1,r2) \
+ (!( ((r1)->x2 <= (r2)->x1) || \
+ ((r1)->x1 >= (r2)->x2) || \
+ ((r1)->y2 <= (r2)->y1) || \
+ ((r1)->y1 >= (r2)->y2) ) )
+
+/* true iff (x,y) is in Box */
+#define INBOX(r,x,y) \
+ ( ((r)->x2 > x) && \
+ ((r)->x1 <= x) && \
+ ((r)->y2 > y) && \
+ ((r)->y1 <= y) )
+
+/* true iff Box r1 contains Box r2 */
+#define SUBSUMES(r1,r2) \
+ ( ((r1)->x1 <= (r2)->x1) && \
+ ((r1)->x2 >= (r2)->x2) && \
+ ((r1)->y1 <= (r2)->y1) && \
+ ((r1)->y2 >= (r2)->y2) )
+
+#define xallocData(n) (RegDataPtr)xalloc(REGION_SZOF(n))
+#define xfreeData(reg) if ((reg)->data && (reg)->data->size) xfree((reg)->data)
+
+#define RECTALLOC(pReg,n) \
+if (!(pReg)->data || (((pReg)->data->numRects + (n)) > (pReg)->data->size)) \
+ miRectAlloc(pReg, n)
+
+#define ADDRECT(pNextRect,nx1,ny1,nx2,ny2) \
+{ \
+ pNextRect->x1 = nx1; \
+ pNextRect->y1 = ny1; \
+ pNextRect->x2 = nx2; \
+ pNextRect->y2 = ny2; \
+ pNextRect++; \
+}
+
+#define NEWRECT(pReg,pNextRect,nx1,ny1,nx2,ny2) \
+{ \
+ if (!(pReg)->data || ((pReg)->data->numRects == (pReg)->data->size))\
+ { \
+ miRectAlloc(pReg, 1); \
+ pNextRect = REGION_TOP(pReg); \
+ } \
+ ADDRECT(pNextRect,nx1,ny1,nx2,ny2); \
+ pReg->data->numRects++; \
+ assert(pReg->data->numRects<=pReg->data->size); \
+}
+
+
+#define DOWNSIZE(reg,numRects) \
+if (((numRects) < ((reg)->data->size >> 1)) && ((reg)->data->size > 50)) \
+{ \
+ RegDataPtr NewData; \
+ NewData = (RegDataPtr)xrealloc((reg)->data, REGION_SZOF(numRects)); \
+ if (NewData) \
+ { \
+ NewData->size = (numRects); \
+ (reg)->data = NewData; \
+ } \
+}
+
+
+BoxRec miEmptyBox = {0, 0, 0, 0};
+RegDataRec miEmptyData = {0, 0};
+
+#ifdef DEBUG
+int
+miPrintRegion(rgn)
+ RegionPtr rgn;
+{
+ int num, size;
+ register int i;
+ BoxPtr rects;
+
+ num = REGION_NUM_RECTS(rgn);
+ size = REGION_SIZE(rgn);
+ rects = REGION_RECTS(rgn);
+ ErrorF("num: %d size: %d\n", num, size);
+ ErrorF("extents: %d %d %d %d\n",
+ rgn->extents.x1, rgn->extents.y1, rgn->extents.x2, rgn->extents.y2);
+ for (i = 0; i < num; i++)
+ ErrorF("%d %d %d %d \n",
+ rects[i].x1, rects[i].y1, rects[i].x2, rects[i].y2);
+ ErrorF("\n");
+ return(num);
+}
+
+
+Bool
+miRegionsEqual(reg1, reg2)
+ RegionPtr reg1;
+ RegionPtr reg2;
+{
+ int i;
+ BoxPtr rects1, rects2;
+
+ if (reg1->extents.x1 != reg2->extents.x1) return FALSE;
+ if (reg1->extents.x2 != reg2->extents.x2) return FALSE;
+ if (reg1->extents.y1 != reg2->extents.y1) return FALSE;
+ if (reg1->extents.y2 != reg2->extents.y2) return FALSE;
+ if (REGION_NUM_RECTS(reg1) != REGION_NUM_RECTS(reg2)) return FALSE;
+
+ rects1 = REGION_RECTS(reg1);
+ rects2 = REGION_RECTS(reg2);
+ for (i = 0; i != REGION_NUM_RECTS(reg1); i++) {
+ if (rects1[i].x1 != rects2[i].x1) return FALSE;
+ if (rects1[i].x2 != rects2[i].x2) return FALSE;
+ if (rects1[i].y1 != rects2[i].y1) return FALSE;
+ if (rects1[i].y2 != rects2[i].y2) return FALSE;
+ }
+ return TRUE;
+}
+
+Bool
+miValidRegion(reg)
+ RegionPtr reg;
+{
+ register int i, numRects;
+
+ if ((reg->extents.x1 > reg->extents.x2) ||
+ (reg->extents.y1 > reg->extents.y2))
+ return FALSE;
+ numRects = REGION_NUM_RECTS(reg);
+ if (!numRects)
+ return ((reg->extents.x1 == reg->extents.x2) &&
+ (reg->extents.y1 == reg->extents.y2) &&
+ (reg->data->size || (reg->data == &miEmptyData)));
+ else if (numRects == 1)
+ return (!reg->data);
+ else
+ {
+ register BoxPtr pboxP, pboxN;
+ BoxRec box;
+
+ pboxP = REGION_RECTS(reg);
+ box = *pboxP;
+ box.y2 = pboxP[numRects-1].y2;
+ pboxN = pboxP + 1;
+ for (i = numRects; --i > 0; pboxP++, pboxN++)
+ {
+ if ((pboxN->x1 >= pboxN->x2) ||
+ (pboxN->y1 >= pboxN->y2))
+ return FALSE;
+ if (pboxN->x1 < box.x1)
+ box.x1 = pboxN->x1;
+ if (pboxN->x2 > box.x2)
+ box.x2 = pboxN->x2;
+ if ((pboxN->y1 < pboxP->y1) ||
+ ((pboxN->y1 == pboxP->y1) &&
+ ((pboxN->x1 < pboxP->x2) || (pboxN->y2 != pboxP->y2))))
+ return FALSE;
+ }
+ return ((box.x1 == reg->extents.x1) &&
+ (box.x2 == reg->extents.x2) &&
+ (box.y1 == reg->extents.y1) &&
+ (box.y2 == reg->extents.y2));
+ }
+}
+
+#endif /* DEBUG */
+
+
+/*****************************************************************
+ * RegionCreate(rect, size)
+ * This routine does a simple malloc to make a structure of
+ * REGION of "size" number of rectangles.
+ *****************************************************************/
+
+RegionPtr
+miRegionCreate(rect, size)
+ BoxPtr rect;
+ int size;
+{
+ register RegionPtr pReg;
+
+ Must_have_memory = TRUE; /* XXX */
+ pReg = (RegionPtr)xalloc(sizeof(RegionRec));
+ Must_have_memory = FALSE; /* XXX */
+ if (rect)
+ {
+ pReg->extents = *rect;
+ pReg->data = (RegDataPtr)NULL;
+ }
+ else
+ {
+ pReg->extents = miEmptyBox;
+ if ((size > 1) && (pReg->data = xallocData(size)))
+ {
+ pReg->data->size = size;
+ pReg->data->numRects = 0;
+ }
+ else
+ pReg->data = &miEmptyData;
+ }
+ return(pReg);
+}
+
+/*****************************************************************
+ * RegionInit(pReg, rect, size)
+ * Outer region rect is statically allocated.
+ *****************************************************************/
+
+void
+miRegionInit(pReg, rect, size)
+ RegionPtr pReg;
+ BoxPtr rect;
+ int size;
+{
+ if (rect)
+ {
+ pReg->extents = *rect;
+ pReg->data = (RegDataPtr)NULL;
+ }
+ else
+ {
+ pReg->extents = miEmptyBox;
+ if ((size > 1) && (pReg->data = xallocData(size)))
+ {
+ pReg->data->size = size;
+ pReg->data->numRects = 0;
+ }
+ else
+ pReg->data = &miEmptyData;
+ }
+}
+
+void
+miRegionDestroy(pReg)
+ RegionPtr pReg;
+{
+ good(pReg);
+ xfreeData(pReg);
+ xfree(pReg);
+}
+
+void
+miRegionUninit(pReg)
+ RegionPtr pReg;
+{
+ good(pReg);
+ xfreeData(pReg);
+}
+
+Bool
+miRectAlloc(pRgn, n)
+ register RegionPtr pRgn;
+ int n;
+{
+ Must_have_memory = TRUE; /* XXX */
+ if (!pRgn->data)
+ {
+ n++;
+ pRgn->data = xallocData(n);
+ pRgn->data->numRects = 1;
+ *REGION_BOXPTR(pRgn) = pRgn->extents;
+ }
+ else if (!pRgn->data->size)
+ {
+ pRgn->data = xallocData(n);
+ pRgn->data->numRects = 0;
+ }
+ else
+ {
+ if (n == 1)
+ {
+ n = pRgn->data->numRects;
+ if (n > 500) /* XXX pick numbers out of a hat */
+ n = 250;
+ }
+ n += pRgn->data->numRects;
+ pRgn->data = (RegDataPtr)xrealloc(pRgn->data, REGION_SZOF(n));
+ }
+ Must_have_memory = FALSE; /* XXX */
+ pRgn->data->size = n;
+ return TRUE;
+}
+
+Bool
+miRegionCopy(dst, src)
+ register RegionPtr dst;
+ register RegionPtr src;
+{
+ good(dst);
+ good(src);
+ if (dst == src)
+ return TRUE;
+ dst->extents = src->extents;
+ if (!src->data || !src->data->size)
+ {
+ xfreeData(dst);
+ dst->data = src->data;
+ return TRUE;
+ }
+ if (!dst->data || (dst->data->size < src->data->numRects))
+ {
+ xfreeData(dst);
+ Must_have_memory = TRUE; /* XXX */
+ dst->data = xallocData(src->data->numRects);
+ Must_have_memory = FALSE; /* XXX */
+ dst->data->size = src->data->numRects;
+ }
+ dst->data->numRects = src->data->numRects;
+ memmove((char *)REGION_BOXPTR(dst),(char *)REGION_BOXPTR(src),
+ dst->data->numRects * sizeof(BoxRec));
+ return TRUE;
+}
+
+
+/*======================================================================
+ * Generic Region Operator
+ *====================================================================*/
+
+/*-
+ *-----------------------------------------------------------------------
+ * miCoalesce --
+ * Attempt to merge the boxes in the current band with those in the
+ * previous one. We are guaranteed that the current band extends to
+ * the end of the rects array. 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->data->numRects will be decreased.
+ *
+ *-----------------------------------------------------------------------
+ */
+INLINE static int
+miCoalesce (pReg, prevStart, curStart)
+ register RegionPtr 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 int numRects; /* Number rectangles in both bands */
+ register int y2; /* Bottom of current band */
+ /*
+ * Figure out how many rectangles are in the band.
+ */
+ numRects = curStart - prevStart;
+ assert(numRects == pReg->data->numRects - curStart);
+
+ if (!numRects) return curStart;
+
+ /*
+ * The bands may only be coalesced if the bottom of the previous
+ * matches the top scanline of the current.
+ */
+ pPrevBox = REGION_BOX(pReg, prevStart);
+ pCurBox = REGION_BOX(pReg, curStart);
+ if (pPrevBox->y2 != pCurBox->y1) return curStart;
+
+ /*
+ * 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.
+ */
+ y2 = pCurBox->y2;
+
+ do {
+ if ((pPrevBox->x1 != pCurBox->x1) || (pPrevBox->x2 != pCurBox->x2)) {
+ return (curStart);
+ }
+ pPrevBox++;
+ pCurBox++;
+ numRects--;
+ } while (numRects);
+
+ /*
+ * The bands may be merged, so set the bottom y of each box
+ * in the previous band to the bottom y of the current band.
+ */
+ numRects = curStart - prevStart;
+ pReg->data->numRects -= numRects;
+ do {
+ pPrevBox--;
+ pPrevBox->y2 = y2;
+ numRects--;
+ } while (numRects);
+ return prevStart;
+}
+
+
+/* Quicky macro to avoid trivial reject procedure calls to miCoalesce */
+
+#define Coalesce(newReg, prevBand, curBand) \
+ if (curBand - prevBand == newReg->data->numRects - curBand) { \
+ prevBand = miCoalesce(newReg, prevBand, curBand); \
+ } else { \
+ prevBand = curBand; \
+ }
+
+/*-
+ *-----------------------------------------------------------------------
+ * miAppendNonO --
+ * Handle a non-overlapping band for the union and subtract operations.
+ * Just adds the (top/bottom-clipped) rectangles into the region.
+ * Doesn't have to check for subsumption or anything.
+ *
+ * Results:
+ * None.
+ *
+ * Side Effects:
+ * pReg->data->numRects is incremented and the rectangles overwritten
+ * with the rectangles we're passed.
+ *
+ *-----------------------------------------------------------------------
+ */
+
+INLINE static Bool
+miAppendNonO (pReg, r, rEnd, y1, y2)
+ register RegionPtr pReg;
+ register BoxPtr r;
+ BoxPtr rEnd;
+ register int y1;
+ register int y2;
+{
+ register BoxPtr pNextRect;
+ register int newRects;
+
+ newRects = rEnd - r;
+
+ assert(y1 < y2);
+ assert(newRects != 0);
+
+ /* Make sure we have enough space for all rectangles to be added */
+ RECTALLOC(pReg, newRects);
+ pNextRect = REGION_TOP(pReg);
+ pReg->data->numRects += newRects;
+ do {
+ assert(r->x1 < r->x2);
+ ADDRECT(pNextRect, r->x1, y1, r->x2, y2);
+ r++;
+ } while (r != rEnd);
+
+ return TRUE;
+}
+
+#define FindBand(r, rBandEnd, rEnd, ry1) \
+{ \
+ ry1 = r->y1; \
+ rBandEnd = r+1; \
+ while ((rBandEnd != rEnd) && (rBandEnd->y1 == ry1)) { \
+ rBandEnd++; \
+ } \
+}
+
+#define AppendRegions(newReg, r, rEnd) \
+{ \
+ int newRects; \
+ if (newRects = rEnd - r) { \
+ RECTALLOC(newReg, newRects); \
+ memmove((char *)REGION_TOP(newReg),(char *)r, \
+ newRects * sizeof(BoxRec)); \
+ newReg->data->numRects += newRects; \
+ } \
+}
+
+/*-
+ *-----------------------------------------------------------------------
+ * miRegionOp --
+ * Apply an operation to two regions. Called by miUnion, miInverse,
+ * miSubtract, miIntersect.... Both regions MUST have at least one
+ * rectangle, and cannot be the same object.
+ *
+ * Results:
+ * TRUE if successful.
+ *
+ * Side Effects:
+ * The new region is overwritten.
+ * pOverlap set to TRUE if overlapFunc ever returns TRUE.
+ *
+ * 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 Bool
+miRegionOp(newReg, reg1, reg2, overlapFunc, appendNon1, appendNon2, pOverlap)
+ RegionPtr newReg; /* Place to store result */
+ RegionPtr reg1; /* First region in operation */
+ RegionPtr reg2; /* 2d region in operation */
+ Bool (*overlapFunc)(); /* Function to call for over-
+ * lapping bands */
+ Bool appendNon1; /* Append non-overlapping bands */
+ /* in region 1 ? */
+ Bool appendNon2; /* Append non-overlapping bands */
+ /* in region 2 ? */
+ Bool *pOverlap;
+{
+ 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 */
+ short ybot; /* Bottom of intersection */
+ short ytop; /* Top of intersection */
+ RegDataPtr oldData; /* Old data 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*/
+ register int r1y1; /* Temps for r1->y1 and r2->y1 */
+ register int r2y1;
+ int newSize;
+ int numRects;
+
+ /*
+ * Initialization:
+ * set r1, r2, r1End and r2End appropriately, save the rectangles
+ * 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 = REGION_RECTS(reg1);
+ newSize = REGION_NUM_RECTS(reg1);
+ r1End = r1 + newSize;
+ numRects = REGION_NUM_RECTS(reg2);
+ r2 = REGION_RECTS(reg2);
+ r2End = r2 + numRects;
+ assert(r1 != r1End);
+ assert(r2 != r2End);
+
+ oldData = (RegDataPtr)NULL;
+ if (((newReg == reg1) && (newSize > 1)) ||
+ ((newReg == reg2) && (numRects > 1)))
+ {
+ oldData = newReg->data;
+ newReg->data = &miEmptyData;
+ }
+ /* guess at new size */
+ if (numRects > newSize)
+ newSize = numRects;
+ newSize <<= 1;
+ if (!newReg->data)
+ newReg->data = &miEmptyData;
+ else if (newReg->data->size)
+ newReg->data->numRects = 0;
+ if (newSize > newReg->data->size)
+ miRectAlloc(newReg, newSize);
+
+ /*
+ * Initialize ybot.
+ * 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.
+ */
+
+ ybot = min(r1->y1, r2->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 {
+ /*
+ * 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.
+ */
+ assert(r1 != r1End);
+ assert(r2 != r2End);
+
+ FindBand(r1, r1BandEnd, r1End, r1y1);
+ FindBand(r2, r2BandEnd, r2End, r2y1);
+
+ /*
+ * 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 (r1y1 < r2y1) {
+ if (appendNon1) {
+ top = max(r1y1, ybot);
+ bot = min(r1->y2, r2y1);
+ if (top != bot) {
+ curBand = newReg->data->numRects;
+ miAppendNonO(newReg, r1, r1BandEnd, top, bot);
+ Coalesce(newReg, prevBand, curBand);
+ }
+ }
+ ytop = r2y1;
+ } else if (r2y1 < r1y1) {
+ if (appendNon2) {
+ top = max(r2y1, ybot);
+ bot = min(r2->y2, r1y1);
+ if (top != bot) {
+ curBand = newReg->data->numRects;
+ miAppendNonO(newReg, r2, r2BandEnd, top, bot);
+ Coalesce(newReg, prevBand, curBand);
+ }
+ }
+ ytop = r1y1;
+ } else {
+ ytop = r1y1;
+ }
+
+ /*
+ * Now see if we've hit an intersecting band. The two bands only
+ * intersect if ybot > ytop
+ */
+ ybot = min(r1->y2, r2->y2);
+ if (ybot > ytop) {
+ curBand = newReg->data->numRects;
+ (* overlapFunc)(newReg, r1, r1BandEnd, r2, r2BandEnd, ytop, ybot,
+ pOverlap);
+ Coalesce(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 (if any) still has rectangles left.
+ *
+ * We only need to worry about banding and coalescing for the very first
+ * band left. After that, we can just group all remaining boxes,
+ * regardless of how many bands, into one final append to the list.
+ */
+
+ if ((r1 != r1End) && appendNon1) {
+ /* Do first nonOverlap1Func call, which may be able to coalesce */
+ FindBand(r1, r1BandEnd, r1End, r1y1);
+ curBand = newReg->data->numRects;
+ miAppendNonO(newReg, r1, r1BandEnd, max(r1y1, ybot), r1->y2);
+ Coalesce(newReg, prevBand, curBand);
+ /* Just append the rest of the boxes */
+ AppendRegions(newReg, r1BandEnd, r1End);
+
+ } else if ((r2 != r2End) && appendNon2) {
+ /* Do first nonOverlap2Func call, which may be able to coalesce */
+ FindBand(r2, r2BandEnd, r2End, r2y1);
+ curBand = newReg->data->numRects;
+ miAppendNonO(newReg, r2, r2BandEnd, max(r2y1, ybot), r2->y2);
+ Coalesce(newReg, prevBand, curBand);
+ /* Append rest of boxes */
+ AppendRegions(newReg, r2BandEnd, r2End);
+ }
+
+ if (oldData)
+ xfree(oldData);
+
+ if (!(numRects = newReg->data->numRects))
+ {
+ xfreeData(newReg);
+ newReg->data = &miEmptyData;
+ }
+ else if (numRects == 1)
+ {
+ newReg->extents = *REGION_BOXPTR(newReg);
+ xfreeData(newReg);
+ newReg->data = (RegDataPtr)NULL;
+ }
+ else
+ {
+ DOWNSIZE(newReg, numRects);
+ }
+
+ return TRUE;
+}
+
+/*-
+ *-----------------------------------------------------------------------
+ * miSetExtents --
+ * Reset the extents of a region to what they should be. Called by
+ * miSubtract and miIntersect as 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.
+ *
+ *-----------------------------------------------------------------------
+ */
+void
+miSetExtents (pReg)
+ register RegionPtr pReg;
+{
+ register BoxPtr pBox, pBoxEnd;
+
+ if (!pReg->data)
+ return;
+ if (!pReg->data->size)
+ {
+ pReg->extents.x2 = pReg->extents.x1;
+ pReg->extents.y2 = pReg->extents.y1;
+ return;
+ }
+
+ pBox = REGION_BOXPTR(pReg);
+ pBoxEnd = REGION_END(pReg);
+
+ /*
+ * 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...
+ */
+ pReg->extents.x1 = pBox->x1;
+ pReg->extents.y1 = pBox->y1;
+ pReg->extents.x2 = pBoxEnd->x2;
+ pReg->extents.y2 = pBoxEnd->y2;
+
+ assert(pReg->extents.y1 < pReg->extents.y2);
+ while (pBox <= pBoxEnd) {
+ if (pBox->x1 < pReg->extents.x1)
+ pReg->extents.x1 = pBox->x1;
+ if (pBox->x2 > pReg->extents.x2)
+ pReg->extents.x2 = pBox->x2;
+ pBox++;
+ };
+
+ assert(pReg->extents.x1 < pReg->extents.x2);
+}
+
+/*======================================================================
+ * Region Intersection
+ *====================================================================*/
+/*-
+ *-----------------------------------------------------------------------
+ * miIntersectO --
+ * Handle an overlapping band for miIntersect.
+ *
+ * Results:
+ * TRUE if successful.
+ *
+ * Side Effects:
+ * Rectangles may be added to the region.
+ *
+ *-----------------------------------------------------------------------
+ */
+/*ARGSUSED*/
+static Bool
+miIntersectO (pReg, r1, r1End, r2, r2End, y1, y2, pOverlap)
+ register RegionPtr pReg;
+ register BoxPtr r1;
+ BoxPtr r1End;
+ register BoxPtr r2;
+ BoxPtr r2End;
+ short y1;
+ short y2;
+ Bool *pOverlap;
+{
+ register int x1;
+ register int x2;
+ register BoxPtr pNextRect;
+
+ pNextRect = REGION_TOP(pReg);
+
+ assert(y1 < y2);
+ assert(r1 != r1End && r2 != r2End);
+
+ do {
+ 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.
+ */
+ if (x1 < x2)
+ NEWRECT(pReg, pNextRect, x1, y1, x2, y2);
+
+ /*
+ * Advance the pointer(s) with the leftmost right side, since the next
+ * rectangle on that list may still overlap the other region's
+ * current rectangle.
+ */
+ if (r1->x2 == x2) {
+ r1++;
+ }
+ if (r2->x2 == x2) {
+ r2++;
+ }
+ } while ((r1 != r1End) && (r2 != r2End));
+
+ return TRUE;
+}
+
+
+Bool
+miIntersect(newReg, reg1, reg2)
+ register RegionPtr newReg; /* destination Region */
+ register RegionPtr reg1;
+ register RegionPtr reg2; /* source regions */
+{
+ good(reg1);
+ good(reg2);
+ good(newReg);
+ /* check for trivial reject */
+ if (REGION_NIL(reg1) || REGION_NIL(reg2) ||
+ !EXTENTCHECK(®1->extents, ®2->extents))
+ {
+ /* Covers about 20% of all cases */
+ xfreeData(newReg);
+ newReg->extents.x2 = newReg->extents.x1;
+ newReg->extents.y2 = newReg->extents.y1;
+ newReg->data = &miEmptyData;
+ }
+ else if (!reg1->data && !reg2->data)
+ {
+ /* Covers about 80% of cases that aren't trivially rejected */
+ newReg->extents.x1 = max(reg1->extents.x1, reg2->extents.x1);
+ newReg->extents.y1 = max(reg1->extents.y1, reg2->extents.y1);
+ newReg->extents.x2 = min(reg1->extents.x2, reg2->extents.x2);
+ newReg->extents.y2 = min(reg1->extents.y2, reg2->extents.y2);
+ xfreeData(newReg);
+ newReg->data = (RegDataPtr)NULL;
+ }
+ else if (!reg2->data && SUBSUMES(®2->extents, ®1->extents))
+ {
+ return miRegionCopy(newReg, reg1);
+ }
+ else if (!reg1->data && SUBSUMES(®1->extents, ®2->extents))
+ {
+ return miRegionCopy(newReg, reg2);
+ }
+ else if (reg1 == reg2)
+ {
+ return miRegionCopy(newReg, reg1);
+ }
+ else
+ {
+ /* General purpose intersection */
+ Bool overlap; /* result ignored */
+ if (!miRegionOp(newReg, reg1, reg2, miIntersectO, FALSE, FALSE,
+ &overlap))
+ return FALSE;
+ miSetExtents(newReg);
+ }
+
+ good(newReg);
+ return(TRUE);
+}
+
+#define MERGERECT(r) \
+{ \
+ if (r->x1 <= x2) { \
+ /* Merge with current rectangle */ \
+ if (r->x1 < x2) *pOverlap = TRUE; \
+ if (x2 < r->x2) x2 = r->x2; \
+ } else { \
+ /* Add current rectangle, start new one */ \
+ NEWRECT(pReg, pNextRect, x1, y1, x2, y2); \
+ x1 = r->x1; \
+ x2 = r->x2; \
+ } \
+ r++; \
+}
+
+/*======================================================================
+ * Region Union
+ *====================================================================*/
+
+/*-
+ *-----------------------------------------------------------------------
+ * miUnionO --
+ * Handle an overlapping band for the union operation. Picks the
+ * left-most rectangle each time and merges it into the region.
+ *
+ * Results:
+ * TRUE if successful.
+ *
+ * Side Effects:
+ * pReg is overwritten.
+ * pOverlap is set to TRUE if any boxes overlap.
+ *
+ *-----------------------------------------------------------------------
+ */
+static Bool
+miUnionO (pReg, r1, r1End, r2, r2End, y1, y2, pOverlap)
+ register RegionPtr pReg;
+ register BoxPtr r1;
+ BoxPtr r1End;
+ register BoxPtr r2;
+ BoxPtr r2End;
+ short y1;
+ short y2;
+ Bool *pOverlap;
+{
+ register BoxPtr pNextRect;
+ register int x1; /* left and right side of current union */
+ register int x2;
+
+ assert (y1 < y2);
+ assert(r1 != r1End && r2 != r2End);
+
+ pNextRect = REGION_TOP(pReg);
+
+ /* Start off current rectangle */
+ if (r1->x1 < r2->x1)
+ {
+ x1 = r1->x1;
+ x2 = r1->x2;
+ r1++;
+ }
+ else
+ {
+ x1 = r2->x1;
+ x2 = r2->x2;
+ r2++;
+ }
+ while (r1 != r1End && r2 != r2End)
+ {
+ if (r1->x1 < r2->x1) MERGERECT(r1) else MERGERECT(r2);
+ }
+
+ /* Finish off whoever (if any) is left */
+ if (r1 != r1End)
+ {
+ do
+ {
+ MERGERECT(r1);
+ } while (r1 != r1End);
+ }
+ else if (r2 != r2End)
+ {
+ do
+ {
+ MERGERECT(r2);
+ } while (r2 != r2End);
+ }
+
+ /* Add current rectangle */
+ NEWRECT(pReg, pNextRect, x1, y1, x2, y2);
+
+ return TRUE;
+}
+
+Bool
+miUnion(newReg, reg1, reg2)
+ RegionPtr newReg; /* destination Region */
+ register RegionPtr reg1;
+ register RegionPtr reg2; /* source regions */
+{
+ Bool overlap; /* result ignored */
+
+ /* Return TRUE if some overlap between reg1, reg2 */
+ good(reg1);
+ good(reg2);
+ good(newReg);
+ /* checks all the simple cases */
+
+ /*
+ * Region 1 and 2 are the same
+ */
+ if (reg1 == reg2)
+ {
+ return miRegionCopy(newReg, reg1);
+ }
+
+ /*
+ * Region 1 is empty
+ */
+ if (REGION_NIL(reg1))
+ {
+ if (newReg != reg2)
+ return miRegionCopy(newReg, reg2);
+ return TRUE;
+ }
+
+ /*
+ * Region 2 is empty
+ */
+ if (REGION_NIL(reg2))
+ {
+ if (newReg != reg1)
+ return miRegionCopy(newReg, reg1);
+ return TRUE;
+ }
+
+ /*
+ * Region 1 completely subsumes region 2
+ */
+ if (!reg1->data && SUBSUMES(®1->extents, ®2->extents))
+ {
+ if (newReg != reg1)
+ return miRegionCopy(newReg, reg1);
+ return TRUE;
+ }
+
+ /*
+ * Region 2 completely subsumes region 1
+ */
+ if (!reg2->data && SUBSUMES(®2->extents, ®1->extents))
+ {
+ if (newReg != reg2)
+ return miRegionCopy(newReg, reg2);
+ return TRUE;
+ }
+
+ if (!miRegionOp(newReg, reg1, reg2, miUnionO, TRUE, TRUE, &overlap))
+ return FALSE;
+
+ 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);
+ good(newReg);
+ return TRUE;
+}
+
+
+/*======================================================================
+ * Batch Rectangle Union
+ *====================================================================*/
+
+/*-
+ *-----------------------------------------------------------------------
+ * miRegionAppend --
+ *
+ * "Append" the rgn rectangles onto the end of dstrgn, maintaining
+ * knowledge of YX-banding when it's easy. Otherwise, dstrgn just
+ * becomes a non-y-x-banded random collection of rectangles, and not
+ * yet a true region. After a sequence of appends, the caller must
+ * call miRegionValidate to ensure that a valid region is constructed.
+ *
+ * Results:
+ * TRUE if successful.
+ *
+ * Side Effects:
+ * dstrgn is modified if rgn has rectangles.
+ *
+ */
+Bool
+miRegionAppend(dstrgn, rgn)
+ register RegionPtr dstrgn;
+ register RegionPtr rgn;
+{
+ int numRects, dnumRects, size;
+ BoxPtr new, old;
+ Bool prepend;
+
+ if (!rgn->data && (dstrgn->data == &miEmptyData))
+ {
+ dstrgn->extents = rgn->extents;
+ dstrgn->data = (RegDataPtr)NULL;
+ return TRUE;
+ }
+
+ numRects = REGION_NUM_RECTS(rgn);
+ if (!numRects)
+ return TRUE;
+ prepend = FALSE;
+ size = numRects;
+ dnumRects = REGION_NUM_RECTS(dstrgn);
+ if (!dnumRects && (size < 200))
+ size = 200; /* XXX pick numbers out of a hat */
+ RECTALLOC(dstrgn, size);
+ old = REGION_RECTS(rgn);
+ if (!dnumRects)
+ dstrgn->extents = rgn->extents;
+ else if (dstrgn->extents.x2 > dstrgn->extents.x1)
+ {
+ register BoxPtr first, last;
+
+ first = old;
+ last = REGION_BOXPTR(dstrgn) + (dnumRects - 1);
+ if ((first->y1 > last->y2) ||
+ ((first->y1 == last->y1) && (first->y2 == last->y2) &&
+ (first->x1 > last->x2)))
+ {
+ if (rgn->extents.x1 < dstrgn->extents.x1)
+ dstrgn->extents.x1 = rgn->extents.x1;
+ if (rgn->extents.x2 > dstrgn->extents.x2)
+ dstrgn->extents.x2 = rgn->extents.x2;
+ dstrgn->extents.y2 = rgn->extents.y2;
+ }
+ else
+ {
+ first = REGION_BOXPTR(dstrgn);
+ last = old + (numRects - 1);
+ if ((first->y1 > last->y2) ||
+ ((first->y1 == last->y1) && (first->y2 == last->y2) &&
+ (first->x1 > last->x2)))
+ {
+ prepend = TRUE;
+ if (rgn->extents.x1 < dstrgn->extents.x1)
+ dstrgn->extents.x1 = rgn->extents.x1;
+ if (rgn->extents.x2 > dstrgn->extents.x2)
+ dstrgn->extents.x2 = rgn->extents.x2;
+ dstrgn->extents.y1 = rgn->extents.y1;
+ }
+ else
+ dstrgn->extents.x2 = dstrgn->extents.x1;
+ }
+ }
+ if (prepend)
+ {
+ new = REGION_BOX(dstrgn, numRects);
+ if (dnumRects == 1)
+ *new = *REGION_BOXPTR(dstrgn);
+ else
+ memmove((char *)new,(char *)REGION_BOXPTR(dstrgn),
+ dnumRects * sizeof(BoxRec));
+ new = REGION_BOXPTR(dstrgn);
+ }
+ else
+ new = REGION_BOXPTR(dstrgn) + dnumRects;
+ if (numRects == 1)
+ *new = *old;
+ else
+ memmove((char *)new, (char *)old, numRects * sizeof(BoxRec));
+ dstrgn->data->numRects += numRects;
+ return TRUE;
+}
+
+
+#define ExchangeRects(a, b) \
+{ \
+ BoxRec t; \
+ t = rects[a]; \
+ rects[a] = rects[b]; \
+ rects[b] = t; \
+}
+
+static void
+QuickSortRects(rects, numRects)
+ register BoxRec rects[];
+ register int numRects;
+{
+ register int y1;
+ register int x1;
+ register int i, j;
+ register BoxPtr r;
+
+ /* Always called with numRects > 1 */
+
+ do
+ {
+ if (numRects == 2)
+ {
+ if (rects[0].y1 > rects[1].y1 ||
+ (rects[0].y1 == rects[1].y1 && rects[0].x1 > rects[1].x1))
+ ExchangeRects(0, 1);
+ return;
+ }
+
+ /* Choose partition element, stick in location 0 */
+ ExchangeRects(0, numRects >> 1);
+ y1 = rects[0].y1;
+ x1 = rects[0].x1;
+
+ /* Partition array */
+ i = 0;
+ j = numRects;
+ do
+ {
+ r = &(rects[i]);
+ do
+ {
+ r++;
+ i++;
+ } while (i != numRects &&
+ (r->y1 < y1 || (r->y1 == y1 && r->x1 < x1)));
+ r = &(rects[j]);
+ do
+ {
+ r--;
+ j--;
+ } while (y1 < r->y1 || (y1 == r->y1 && x1 < r->x1));
+ if (i < j)
+ ExchangeRects(i, j);
+ } while (i < j);
+
+ /* Move partition element back to middle */
+ ExchangeRects(0, j);
+
+ /* Recurse */
+ if (numRects-j-1 > 1)
+ QuickSortRects(&rects[j+1], numRects-j-1);
+ numRects = j;
+ } while (numRects > 1);
+}
+
+/*-
+ *-----------------------------------------------------------------------
+ * miRegionValidate --
+ *
+ * Take a ``region'' which is a non-y-x-banded random collection of
+ * rectangles, and compute a nice region which is the union of all the
+ * rectangles.
+ *
+ * Results:
+ * TRUE if successful.
+ *
+ * Side Effects:
+ * The passed-in ``region'' may be modified.
+ * pOverlap set to TRUE if any retangles overlapped, else FALSE;
+ *
+ * Strategy:
+ * Step 1. Sort the rectangles into ascending order with primary key y1
+ * and secondary key x1.
+ *
+ * Step 2. Split the rectangles into the minimum number of proper y-x
+ * banded regions. This may require horizontally merging
+ * rectangles, and vertically coalescing bands. With any luck,
+ * this step in an identity tranformation (ala the Box widget),
+ * or a coalescing into 1 box (ala Menus).
+ *
+ * Step 3. Merge the separate regions down to a single region by calling
+ * miUnion. Maximize the work each miUnion call does by using
+ * a binary merge.
+ *
+ *-----------------------------------------------------------------------
+ */
+
+Bool
+miRegionValidate(badreg, pOverlap)
+ RegionPtr badreg;
+ Bool *pOverlap;
+{
+ /* Descriptor for regions under construction in Step 2. */
+ typedef struct {
+ RegionRec reg;
+ int prevBand;
+ int curBand;
+ } RegionInfo;
+
+ int numRects; /* Original numRects for badreg */
+ RegionInfo *ri; /* Array of current regions */
+ int numRI; /* Number of entries used in ri */
+ int sizeRI; /* Number of entries available in ri */
+ int i; /* Index into rects */
+ register int j; /* Index into ri */
+ register RegionInfo *rit; /* &ri[j] */
+ register RegionPtr reg; /* ri[j].reg */
+ register BoxPtr box; /* Current box in rects */
+ register BoxPtr riBox; /* Last box in ri[j].reg */
+ register RegionPtr hreg; /* ri[j_half].reg */
+
+ *pOverlap = FALSE;
+ if (!badreg->data)
+ {
+ good(badreg);
+ return TRUE;
+ }
+ numRects = badreg->data->numRects;
+ if (!numRects)
+ {
+ good(badreg);
+ return TRUE;
+ }
+ if (badreg->extents.x1 < badreg->extents.x2)
+ {
+ if ((numRects) == 1)
+ {
+ xfreeData(badreg);
+ badreg->data = (RegDataPtr) NULL;
+ }
+ else
+ {
+ DOWNSIZE(badreg, numRects);
+ }
+ good(badreg);
+ return TRUE;
+ }
+
+ /* Step 1: Sort the rects array into ascending (y1, x1) order */
+ QuickSortRects(REGION_BOXPTR(badreg), numRects);
+
+ /* Step 2: Scatter the sorted array into the minimum number of regions */
+
+ /* Set up the first region to be the first rectangle in badreg */
+ /* Note that step 2 code will never overflow the ri[0].reg rects array */
+ Must_have_memory = TRUE; /* XXX */
+ ri = (RegionInfo *) xalloc(4 * sizeof(RegionInfo));
+ Must_have_memory = FALSE; /* XXX */
+ sizeRI = 4;
+ numRI = 1;
+ ri[0].prevBand = 0;
+ ri[0].curBand = 0;
+ ri[0].reg = *badreg;
+ box = REGION_BOXPTR(&ri[0].reg);
+ ri[0].reg.extents = *box;
+ ri[0].reg.data->numRects = 1;
+
+ /* Now scatter rectangles into the minimum set of valid regions. If the
+ next rectangle to be added to a region would force an existing rectangle
+ in the region to be split up in order to maintain y-x banding, just
+ forget it. Try the next region. If it doesn't fit cleanly into any
+ region, make a new one. */
+
+ for (i = numRects; --i > 0;)
+ {
+ box++;
+ /* Look for a region to append box to */
+ for (j = numRI, rit = ri; --j >= 0; rit++)
+ {
+ reg = &rit->reg;
+ riBox = REGION_END(reg);
+
+ if (box->y1 == riBox->y1 && box->y2 == riBox->y2)
+ {
+ /* box is in same band as riBox. Merge or append it */
+ if (box->x1 <= riBox->x2)
+ {
+ /* Merge it with riBox */
+ if (box->x1 < riBox->x2) *pOverlap = TRUE;
+ if (box->x2 > riBox->x2) riBox->x2 = box->x2;
+ }
+ else
+ {
+ RECTALLOC(reg, 1);
+ *REGION_TOP(reg) = *box;
+ reg->data->numRects++;
+ }
+ goto NextRect; /* So sue me */
+ }
+ else if (box->y1 >= riBox->y2)
+ {
+ /* Put box into new band */
+ if (reg->extents.x2 < riBox->x2) reg->extents.x2 = riBox->x2;
+ if (reg->extents.x1 > box->x1) reg->extents.x1 = box->x1;
+ Coalesce(reg, rit->prevBand, rit->curBand);
+ rit->curBand = reg->data->numRects;
+ RECTALLOC(reg, 1);
+ *REGION_TOP(reg) = *box;
+ reg->data->numRects++;
+ goto NextRect;
+ }
+ /* Well, this region was inappropriate. Try the next one. */
+ } /* for j */
+
+ /* Uh-oh. No regions were appropriate. Create a new one. */
+ if (sizeRI == numRI)
+ {
+ /* Oops, allocate space for new region information */
+ sizeRI <<= 1;
+ Must_have_memory = TRUE; /* XXX */
+ ri = (RegionInfo *) xrealloc(ri, sizeRI * sizeof(RegionInfo));
+ Must_have_memory = FALSE; /* XXX */
+ rit = &ri[numRI];
+ }
+ numRI++;
+ rit->prevBand = 0;
+ rit->curBand = 0;
+ rit->reg.extents = *box;
+ rit->reg.data = (RegDataPtr)NULL;
+ miRectAlloc(&rit->reg, (i+numRI) / numRI); /* MUST force allocation */
+NextRect: ;
+ } /* for i */
+
+ /* Make a final pass over each region in order to Coalesce and set
+ extents.x2 and extents.y2 */
+
+ for (j = numRI, rit = ri; --j >= 0; rit++)
+ {
+ reg = &rit->reg;
+ riBox = REGION_END(reg);
+ reg->extents.y2 = riBox->y2;
+ if (reg->extents.x2 < riBox->x2) reg->extents.x2 = riBox->x2;
+ Coalesce(reg, rit->prevBand, rit->curBand);
+ if (reg->data->numRects == 1) /* keep unions happy below */
+ {
+ xfreeData(reg);
+ reg->data = (RegDataPtr)NULL;
+ }
+ }
+
+ /* Step 3: Union all regions into a single region */
+ while (numRI > 1)
+ {
+ int half = numRI/2;
+ for (j = numRI & 1; j < (half + (numRI & 1)); j++)
+ {
+ reg = &ri[j].reg;
+ hreg = &ri[j+half].reg;
+ miRegionOp(reg, reg, hreg, miUnionO, TRUE, TRUE, pOverlap);
+ if (hreg->extents.x1 < reg->extents.x1)
+ reg->extents.x1 = hreg->extents.x1;
+ if (hreg->extents.y1 < reg->extents.y1)
+ reg->extents.y1 = hreg->extents.y1;
+ if (hreg->extents.x2 > reg->extents.x2)
+ reg->extents.x2 = hreg->extents.x2;
+ if (hreg->extents.y2 > reg->extents.y2)
+ reg->extents.y2 = hreg->extents.y2;
+ xfreeData(hreg);
+ }
+ numRI -= half;
+ }
+ *badreg = ri[0].reg;
+ xfree(ri);
+ good(badreg);
+ return TRUE;
+}
+
+RegionPtr
+miRectsToRegion(nrects, prect, ctype)
+ int nrects;
+ register xRectangle *prect;
+ int ctype;
+{
+ register RegionPtr pRgn;
+ register RegDataPtr pData;
+ register BoxPtr pBox;
+ register int i;
+ int x1, y1, x2, y2;
+
+ pRgn = miRegionCreate(NullBox, 0);
+ if (!nrects)
+ return pRgn;
+ if (nrects == 1)
+ {
+ x1 = prect->x;
+ y1 = prect->y;
+ if ((x2 = x1 + (int) prect->width) > MAXSHORT)
+ x2 = MAXSHORT;
+ if ((y2 = y1 + (int) prect->height) > MAXSHORT)
+ y2 = MAXSHORT;
+ if (x1 != x2 && y1 != y2)
+ {
+ pRgn->extents.x1 = x1;
+ pRgn->extents.y1 = y1;
+ pRgn->extents.x2 = x2;
+ pRgn->extents.y2 = y2;
+ pRgn->data = (RegDataPtr)NULL;
+ }
+ return pRgn;
+ }
+ Must_have_memory = TRUE; /* XXX */
+ pData = xallocData(nrects);
+ pBox = (BoxPtr) (pData + 1);
+ Must_have_memory = FALSE; /* XXX */
+ for (i = nrects; --i >= 0; prect++)
+ {
+ x1 = prect->x;
+ y1 = prect->y;
+ if ((x2 = x1 + (int) prect->width) > MAXSHORT)
+ x2 = MAXSHORT;
+ if ((y2 = y1 + (int) prect->height) > MAXSHORT)
+ y2 = MAXSHORT;
+ if (x1 != x2 && y1 != y2)
+ {
+ pBox->x1 = x1;
+ pBox->y1 = y1;
+ pBox->x2 = x2;
+ pBox->y2 = y2;
+ pBox++;
+ }
+ }
+ if (pBox != (BoxPtr) (pData + 1))
+ {
+ pData->size = nrects;
+ pData->numRects = pBox - (BoxPtr) (pData + 1);
+ pRgn->data = pData;
+ if (ctype != CT_YXBANDED)
+ {
+ Bool overlap; /* result ignored */
+ pRgn->extents.x1 = pRgn->extents.x2 = 0;
+ miRegionValidate(pRgn, &overlap);
+ }
+ else
+ miSetExtents(pRgn);
+ good(pRgn);
+ }
+ else
+ {
+ xfree (pData);
+ }
+ return pRgn;
+}
+
+/*======================================================================
+ * Region Subtraction
+ *====================================================================*/
+
+
+/*-
+ *-----------------------------------------------------------------------
+ * miSubtractO --
+ * Overlapping band subtraction. x1 is the left-most point not yet
+ * checked.
+ *
+ * Results:
+ * TRUE if successful.
+ *
+ * Side Effects:
+ * pReg may have rectangles added to it.
+ *
+ *-----------------------------------------------------------------------
+ */
+/*ARGSUSED*/
+static Bool
+miSubtractO (pReg, r1, r1End, r2, r2End, y1, y2, pOverlap)
+ register RegionPtr pReg;
+ register BoxPtr r1;
+ BoxPtr r1End;
+ register BoxPtr r2;
+ BoxPtr r2End;
+ register int y1;
+ int y2;
+ Bool *pOverlap;
+{
+ register BoxPtr pNextRect;
+ register int x1;
+
+ x1 = r1->x1;
+
+ assert(y1<y2);
+ assert(r1 != r1End && r2 != r2End);
+
+ pNextRect = REGION_TOP(pReg);
+
+ do
+ {
+ if (r2->x2 <= x1)
+ {
+ /*
+ * Subtrahend entirely to left of minuend: 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);
+ NEWRECT(pReg, pNextRect, x1, y1, r2->x1, y2);
+
+ 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)
+ NEWRECT(pReg, pNextRect, x1, y1, r1->x2, y2);
+ r1++;
+ if (r1 != r1End)
+ x1 = r1->x1;
+ }
+ } while ((r1 != r1End) && (r2 != r2End));
+
+
+ /*
+ * Add remaining minuend rectangles to region.
+ */
+ while (r1 != r1End)
+ {
+ assert(x1<r1->x2);
+ NEWRECT(pReg, pNextRect, x1, y1, r1->x2, y2);
+ r1++;
+ if (r1 != r1End)
+ x1 = r1->x1;
+ }
+ return TRUE;
+}
+
+/*-
+ *-----------------------------------------------------------------------
+ * miSubtract --
+ * Subtract regS from regM and leave the result in regD.
+ * S stands for subtrahend, M for minuend and D for difference.
+ *
+ * Results:
+ * TRUE if successful.
+ *
+ * Side Effects:
+ * regD is overwritten.
+ *
+ *-----------------------------------------------------------------------
+ */
+Bool
+miSubtract(regD, regM, regS)
+ register RegionPtr regD;
+ register RegionPtr regM;
+ register RegionPtr regS;
+{
+ Bool overlap; /* result ignored */
+
+ good(regM);
+ good(regS);
+ good(regD);
+ /* check for trivial rejects */
+ if (REGION_NIL(regM) || REGION_NIL(regS) ||
+ !EXTENTCHECK(®M->extents, ®S->extents))
+ {
+ return miRegionCopy(regD, regM);
+ }
+ else if (regM == regS)
+ {
+ xfreeData(regD);
+ regD->extents.x2 = regD->extents.x1;
+ regD->extents.y2 = regD->extents.y1;
+ regD->data = &miEmptyData;
+ return TRUE;
+ }
+
+ /* Add those rectangles in region 1 that aren't in region 2,
+ do yucky substraction for overlaps, and
+ just throw away rectangles in region 2 that aren't in region 1 */
+ if (!miRegionOp(regD, regM, regS, miSubtractO, TRUE, FALSE, &overlap))
+ return FALSE;
+
+ /*
+ * Can't alter RegD'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 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);
+ good(regD);
+ return TRUE;
+}
+
+/*======================================================================
+ * Region Inversion
+ *====================================================================*/
+
+/*-
+ *-----------------------------------------------------------------------
+ * miInverse --
+ * Take a region and a box and return a region that is everything
+ * in the box but not in the region. The careful reader will note
+ * that this is the same as subtracting the region from the box...
+ *
+ * Results:
+ * TRUE.
+ *
+ * Side Effects:
+ * newReg is overwritten.
+ *
+ *-----------------------------------------------------------------------
+ */
+Bool
+miInverse(newReg, reg1, invRect)
+ RegionPtr newReg; /* Destination region */
+ RegionPtr reg1; /* Region to invert */
+ BoxPtr invRect; /* Bounding box for inversion */
+{
+ RegionRec invReg; /* Quick and dirty region made from the
+ * bounding box */
+ Bool overlap; /* result ignored */
+
+ good(reg1);
+ good(newReg);
+ /* check for trivial rejects */
+ if (REGION_NIL(reg1) || !EXTENTCHECK(invRect, ®1->extents))
+ {
+ newReg->extents = *invRect;
+ xfreeData(newReg);
+ newReg->data = (RegDataPtr)NULL;
+ return TRUE;
+ }
+
+ /* Add those rectangles in region 1 that aren't in region 2,
+ do yucky substraction for overlaps, and
+ just throw away rectangles in region 2 that aren't in region 1 */
+ invReg.extents = *invRect;
+ invReg.data = (RegDataPtr)NULL;
+ if (!miRegionOp(newReg, &invReg, reg1, miSubtractO, TRUE, FALSE, &overlap))
+ return FALSE;
+
+ /*
+ * 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 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(newReg);
+ good(newReg);
+ return TRUE;
+}
+
+/*
+ * RectIn(region, rect)
+ * This routine takes a pointer to a region and a pointer to a box
+ * and determines if the box is outside/inside/partly inside the region.
+ *
+ * The idea is to travel through the list of rectangles trying to cover the
+ * passed box with them. Anytime a piece of the rectangle isn't covered
+ * by a band of rectangles, partOut is set TRUE. Any time a rectangle in
+ * the region covers part of the box, partIn is set TRUE. The process ends
+ * when either the box has been completely covered (we reached a band that
+ * doesn't overlap the box, partIn is TRUE and partOut is false), the
+ * box has been partially covered (partIn == partOut == TRUE -- because of
+ * the banding, the first time this is true we know the box is only
+ * partially in the region) or is outside the region (we reached a band
+ * that doesn't overlap the box at all and partIn is false)
+ */
+
+int
+miRectIn(region, prect)
+ register RegionPtr region;
+ register BoxPtr prect;
+{
+ register int x;
+ register int y;
+ register BoxPtr pbox;
+ register BoxPtr pboxEnd;
+ int partIn, partOut;
+ int numRects;
+
+ good(region);
+ numRects = REGION_NUM_RECTS(region);
+ /* useful optimization */
+ if (!numRects || !EXTENTCHECK(®ion->extents, prect))
+ return(rgnOUT);
+
+ if (numRects == 1)
+ {
+ /* We know that it must be rgnIN or rgnPART */
+ if (SUBSUMES(®ion->extents, prect))
+ return(rgnIN);
+ else
+ return(rgnPART);
+ }
+
+ partOut = FALSE;
+ partIn = FALSE;
+
+ /* (x,y) starts at upper left of rect, moving to the right and down */
+ x = prect->x1;
+ y = prect->y1;
+
+ /* can stop when both partOut and partIn are TRUE, or we reach prect->y2 */
+ for (pbox = REGION_BOXPTR(region), pboxEnd = pbox + numRects;
+ pbox != pboxEnd;
+ pbox++)
+ {
+
+ if (pbox->y2 <= y)
+ continue; /* getting up to speed or skipping remainder of band */
+
+ if (pbox->y1 > y)
+ {
+ partOut = TRUE; /* missed part of rectangle above */
+ if (partIn || (pbox->y1 >= prect->y2))
+ break;
+ y = pbox->y1; /* x guaranteed to be == prect->x1 */
+ }
+
+ if (pbox->x2 <= x)
+ continue; /* not far enough over yet */
+
+ if (pbox->x1 > x)
+ {
+ 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)
+ {
+ y = pbox->y2; /* finished with this band */
+ if (y >= prect->y2)
+ break;
+ x = 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...
+ */
+ partOut = TRUE;
+ break;
+ }
+ }
+
+ return(partIn ? ((y < prect->y2) ? rgnPART : rgnIN) : rgnOUT);
+}
+
+/* TranslateRegion(pReg, x, y)
+ translates in place
+*/
+
+void
+miTranslateRegion(pReg, x, y)
+ register RegionPtr pReg;
+ register int x;
+ register int y;
+{
+ int x1, x2, y1, y2;
+ register int nbox;
+ register BoxPtr pbox;
+
+ good(pReg);
+ pReg->extents.x1 = x1 = pReg->extents.x1 + x;
+ pReg->extents.y1 = y1 = pReg->extents.y1 + y;
+ pReg->extents.x2 = x2 = pReg->extents.x2 + x;
+ pReg->extents.y2 = y2 = pReg->extents.y2 + y;
+ if (((x1 - MINSHORT)|(y1 - MINSHORT)|(MAXSHORT - x2)|(MAXSHORT - y2)) >= 0)
+ {
+ if (pReg->data && (nbox = pReg->data->numRects))
+ {
+ for (pbox = REGION_BOXPTR(pReg); nbox--; pbox++)
+ {
+ pbox->x1 += x;
+ pbox->y1 += y;
+ pbox->x2 += x;
+ pbox->y2 += y;
+ }
+ }
+ return;
+ }
+ if (((x2 - MINSHORT)|(y2 - MINSHORT)|(MAXSHORT - x1)|(MAXSHORT - y1)) <= 0)
+ {
+ pReg->extents.x2 = pReg->extents.x1;
+ pReg->extents.y2 = pReg->extents.y1;
+ xfreeData(pReg);
+ pReg->data = &miEmptyData;
+ return;
+ }
+ if (x1 < MINSHORT)
+ pReg->extents.x1 = MINSHORT;
+ else if (x2 > MAXSHORT)
+ pReg->extents.x2 = MAXSHORT;
+ if (y1 < MINSHORT)
+ pReg->extents.y1 = MINSHORT;
+ else if (y2 > MAXSHORT)
+ pReg->extents.y2 = MAXSHORT;
+ if (pReg->data && (nbox = pReg->data->numRects))
+ {
+ register BoxPtr pboxout;
+
+ for (pboxout = pbox = REGION_BOXPTR(pReg); nbox--; pbox++)
+ {
+ pboxout->x1 = x1 = pbox->x1 + x;
+ pboxout->y1 = y1 = pbox->y1 + y;
+ pboxout->x2 = x2 = pbox->x2 + x;
+ pboxout->y2 = y2 = pbox->y2 + y;
+ if (((x2 - MINSHORT)|(y2 - MINSHORT)|
+ (MAXSHORT - x1)|(MAXSHORT - y1)) <= 0)
+ {
+ pReg->data->numRects--;
+ continue;
+ }
+ if (x1 < MINSHORT)
+ pboxout->x1 = MINSHORT;
+ else if (x2 > MAXSHORT)
+ pboxout->x2 = MAXSHORT;
+ if (y1 < MINSHORT)
+ pboxout->y1 = MINSHORT;
+ else if (y2 > MAXSHORT)
+ pboxout->y2 = MAXSHORT;
+ pboxout++;
+ }
+ if (pboxout != pbox)
+ {
+ if (pReg->data->numRects == 1)
+ {
+ pReg->extents = *REGION_BOXPTR(pReg);
+ xfreeData(pReg);
+ pReg->data = (RegDataPtr)NULL;
+ }
+ else
+ miSetExtents(pReg);
+ }
+ }
+}
+
+void
+miRegionReset(pReg, pBox)
+ RegionPtr pReg;
+ BoxPtr pBox;
+{
+ good(pReg);
+ assert(pBox->x1<=pBox->x2);
+ assert(pBox->y1<=pBox->y2);
+ pReg->extents = *pBox;
+ xfreeData(pReg);
+ pReg->data = (RegDataPtr)NULL;
+}
+
+Bool
+miPointInRegion(pReg, x, y, box)
+ register RegionPtr pReg;
+ register int x, y;
+ BoxPtr box; /* "return" value */
+{
+ register BoxPtr pbox, pboxEnd;
+ int numRects;
+
+ good(pReg);
+ numRects = REGION_NUM_RECTS(pReg);
+ if (!numRects || !INBOX(&pReg->extents, x, y))
+ return(FALSE);
+ if (numRects == 1)
+ {
+ *box = pReg->extents;
+ return(TRUE);
+ }
+ for (pbox = REGION_BOXPTR(pReg), pboxEnd = pbox + numRects;
+ pbox != pboxEnd;
+ pbox++)
+ {
+ if (y >= pbox->y2)
+ continue; /* not there yet */
+ if ((y < pbox->y1) || (x < pbox->x1))
+ break; /* missed it */
+ if (x >= pbox->x2)
+ continue; /* not there yet */
+ *box = *pbox;
+ return(TRUE);
+ }
+ return(FALSE);
+}
+
+Bool
+miRegionNotEmpty(pReg)
+ RegionPtr pReg;
+{
+ good(pReg);
+ return(!REGION_NIL(pReg));
+}
+
+
+void
+miRegionEmpty(pReg)
+ RegionPtr pReg;
+{
+ good(pReg);
+ xfreeData(pReg);
+ pReg->extents.x2 = pReg->extents.x1;
+ pReg->extents.y2 = pReg->extents.y1;
+ pReg->data = &miEmptyData;
+}
+
+BoxPtr
+miRegionExtents(pReg)
+ RegionPtr pReg;
+{
+ good(pReg);
+ return(&pReg->extents);
+}
+
+#define ExchangeSpans(a, b) \
+{ \
+ DDXPointRec tpt; \
+ register int tw; \
+ \
+ tpt = spans[a]; spans[a] = spans[b]; spans[b] = tpt; \
+ tw = widths[a]; widths[a] = widths[b]; widths[b] = tw; \
+}
+
+/* ||| I should apply the merge sort code to rectangle sorting above, and see
+ if mapping time can be improved. But right now I've been at work 12 hours,
+ so forget it.
+*/
+
+static void QuickSortSpans(spans, widths, numSpans)
+ register DDXPointRec spans[];
+ register int widths[];
+ register int numSpans;
+{
+ register int y;
+ register int i, j, m;
+ register DDXPointPtr r;
+
+ /* Always called with numSpans > 1 */
+ /* Sorts only by y, doesn't bother to sort by x */
+
+ do
+ {
+ if (numSpans < 9)
+ {
+ /* Do insertion sort */
+ register int yprev;
+
+ yprev = spans[0].y;
+ i = 1;
+ do
+ { /* while i != numSpans */
+ y = spans[i].y;
+ if (yprev > y)
+ {
+ /* spans[i] is out of order. Move into proper location. */
+ DDXPointRec tpt;
+ int tw, k;
+
+ for (j = 0; y >= spans[j].y; j++) {}
+ tpt = spans[i];
+ tw = widths[i];
+ for (k = i; k != j; k--)
+ {
+ spans[k] = spans[k-1];
+ widths[k] = widths[k-1];
+ }
+ spans[j] = tpt;
+ widths[j] = tw;
+ y = spans[i].y;
+ } /* if out of order */
+ yprev = y;
+ i++;
+ } while (i != numSpans);
+ return;
+ }
+
+ /* Choose partition element, stick in location 0 */
+ m = numSpans / 2;
+ if (spans[m].y > spans[0].y) ExchangeSpans(m, 0);
+ if (spans[m].y > spans[numSpans-1].y) ExchangeSpans(m, numSpans-1);
+ if (spans[m].y > spans[0].y) ExchangeSpans(m, 0);
+ y = spans[0].y;
+
+ /* Partition array */
+ i = 0;
+ j = numSpans;
+ do
+ {
+ r = &(spans[i]);
+ do
+ {
+ r++;
+ i++;
+ } while (i != numSpans && r->y < y);
+ r = &(spans[j]);
+ do
+ {
+ r--;
+ j--;
+ } while (y < r->y);
+ if (i < j)
+ ExchangeSpans(i, j);
+ } while (i < j);
+
+ /* Move partition element back to middle */
+ ExchangeSpans(0, j);
+
+ /* Recurse */
+ if (numSpans-j-1 > 1)
+ QuickSortSpans(&spans[j+1], &widths[j+1], numSpans-j-1);
+ numSpans = j;
+ } while (numSpans > 1);
+}
+
+#define NextBand() \
+{ \
+ clipy1 = pboxBandStart->y1; \
+ clipy2 = pboxBandStart->y2; \
+ pboxBandEnd = pboxBandStart + 1; \
+ while (pboxBandEnd != pboxLast && pboxBandEnd->y1 == clipy1) { \
+ pboxBandEnd++; \
+ } \
+ for (; ppt != pptLast && ppt->y < clipy1; ppt++, pwidth++) {} \
+}
+
+/*
+ Clip a list of scanlines to a region. The caller has allocated the
+ space. FSorted is non-zero if the scanline origins are in ascending
+ order.
+ returns the number of new, clipped scanlines.
+*/
+
+int
+miClipSpans(prgnDst, ppt, pwidth, nspans, pptNew, pwidthNew, fSorted)
+ RegionPtr prgnDst;
+ register DDXPointPtr ppt;
+ register int *pwidth;
+ int nspans;
+ register DDXPointPtr pptNew;
+ int *pwidthNew;
+ int fSorted;
+{
+ register DDXPointPtr pptLast;
+ int *pwidthNewStart; /* the vengeance of Xerox! */
+ register int y, x1, x2;
+ register int numRects;
+
+ good(prgnDst);
+ pptLast = ppt + nspans;
+ pwidthNewStart = pwidthNew;
+
+ if (!prgnDst->data)
+ {
+ /* Do special fast code with clip boundaries in registers(?) */
+ /* It doesn't pay much to make use of fSorted in this case,
+ so we lump everything together. */
+
+ register int clipx1, clipx2, clipy1, clipy2;
+
+ clipx1 = prgnDst->extents.x1;
+ clipy1 = prgnDst->extents.y1;
+ clipx2 = prgnDst->extents.x2;
+ clipy2 = prgnDst->extents.y2;
+
+ for (; ppt != pptLast; ppt++, pwidth++)
+ {
+ y = ppt->y;
+ x1 = ppt->x;
+ if (clipy1 <= y && y < clipy2)
+ {
+ x2 = x1 + *pwidth;
+ if (x1 < clipx1) x1 = clipx1;
+ if (x2 > clipx2) x2 = clipx2;
+ if (x1 < x2)
+ {
+ /* part of span in clip rectangle */
+ pptNew->x = x1;
+ pptNew->y = y;
+ *pwidthNew = x2 - x1;
+ pptNew++;
+ pwidthNew++;
+ }
+ }
+ } /* end for */
+
+ }
+ else if (numRects = prgnDst->data->numRects)
+ {
+ /* Have to clip against many boxes */
+ BoxPtr pboxBandStart, pboxBandEnd;
+ register BoxPtr pbox;
+ register BoxPtr pboxLast;
+ register int clipy1, clipy2;
+
+ /* In this case, taking advantage of sorted spans gains more than
+ the sorting costs. */
+ if ((! fSorted) && (nspans > 1))
+ QuickSortSpans(ppt, pwidth, nspans);
+
+ pboxBandStart = REGION_BOXPTR(prgnDst);
+ pboxLast = pboxBandStart + numRects;
+
+ NextBand();
+
+ for (; ppt != pptLast; )
+ {
+ y = ppt->y;
+ if (y < clipy2)
+ {
+ /* span is in the current band */
+ pbox = pboxBandStart;
+ x1 = ppt->x;
+ x2 = x1 + *pwidth;
+ do
+ { /* For each box in band */
+ register int newx1, newx2;
+
+ newx1 = x1;
+ newx2 = x2;
+ if (newx1 < pbox->x1) newx1 = pbox->x1;
+ if (newx2 > pbox->x2) newx2 = pbox->x2;
+ if (newx1 < newx2)
+ {
+ /* Part of span in clip rectangle */
+ pptNew->x = newx1;
+ pptNew->y = y;
+ *pwidthNew = newx2 - newx1;
+ pptNew++;
+ pwidthNew++;
+ }
+ pbox++;
+ } while (pbox != pboxBandEnd);
+ ppt++;
+ pwidth++;
+ }
+ else
+ {
+ /* Move to next band, adjust ppt as needed */
+ pboxBandStart = pboxBandEnd;
+ if (pboxBandStart == pboxLast)
+ break; /* We're completely done */
+ NextBand();
+ }
+ }
+ }
+ return (pwidthNew - pwidthNewStart);
+}
+
+/* find the band in a region with the most rectangles */
+int
+miFindMaxBand(prgn)
+ RegionPtr prgn;
+{
+ register int nbox;
+ register BoxPtr pbox;
+ register int nThisBand;
+ register int nMaxBand = 0;
+ short yThisBand;
+
+ good(prgn);
+ nbox = REGION_NUM_RECTS(prgn);
+ pbox = REGION_RECTS(prgn);
+
+ while(nbox > 0)
+ {
+ yThisBand = pbox->y1;
+ nThisBand = 0;
+ while((nbox > 0) && (pbox->y1 == yThisBand))
+ {
+ nbox--;
+ pbox++;
+ nThisBand++;
+ }
+ if (nThisBand > nMaxBand)
+ nMaxBand = nThisBand;
+ }
+ return (nMaxBand);
+}
projects / rdpsrv / blobdiff