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Diffstat (limited to 'gdk/gdkregion-generic.c')
| -rw-r--r-- | gdk/gdkregion-generic.c | 1505 |
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diff --git a/gdk/gdkregion-generic.c b/gdk/gdkregion-generic.c new file mode 100644 index 0000000000..0319f939f4 --- /dev/null +++ b/gdk/gdkregion-generic.c @@ -0,0 +1,1505 @@ +/* $TOG: Region.c /main/31 1998/02/06 17:50:22 kaleb $ */ +/************************************************************************ + +Copyright 1987, 1988, 1998 The Open Group + +All Rights Reserved. + +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. + +************************************************************************/ +/* $XFree86: xc/lib/X11/Region.c,v 1.5 1999/05/09 10:50:01 dawes Exp $ */ +/* + * 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... + */ + +#include <gdkregion.h> +#include "gdkregion-generic.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 void (*overlapFunc) (GdkRegion *pReg, + GdkRegionBox *r1, + GdkRegionBox *r1End, + GdkRegionBox *r2, + GdkRegionBox *r2End, + gint y1, + gint y2); +typedef void (*nonOverlapFunc) (GdkRegion *pReg, + GdkRegionBox *r, + GdkRegionBox *rEnd, + gint y1, + gint y2); + +static void miRegionCopy (GdkRegion *dstrgn, + GdkRegion *rgn); +static void miRegionOp (GdkRegion *newReg, + GdkRegion *reg1, + GdkRegion *reg2, + overlapFunc overlapFn, + nonOverlapFunc nonOverlap1Fn, + nonOverlapFunc nonOverlap2Fn); + +/* Create a new empty region */ + +GdkRegion * +gdk_region_new () +{ + GdkRegion *temp; + + temp = g_new (GdkRegion, 1); + temp->rects = g_new (GdkRegionBox, 1); + + temp->numRects = 0; + temp->extents.x1 = 0; + temp->extents.y1 = 0; + temp->extents.x2 = 0; + temp->extents.y2 = 0; + temp->size = 1; + + return temp; +} + +GdkRegion * +gdk_region_rectangle (GdkRectangle *rectangle) +{ + GdkRegion *temp; + + if (rectangle->width <= 0 || rectangle->height <= 0) + return gdk_region_new(); + + temp = g_new (GdkRegion, 1); + temp->rects = g_new (GdkRegionBox, 1); + + temp->numRects = 1; + temp->extents.x1 = temp->rects[0].x1 = rectangle->x; + temp->extents.y1 = temp->rects[0].y1 = rectangle->y; + temp->extents.x2 = temp->rects[0].x2 = rectangle->x + rectangle->width; + temp->extents.y2 = temp->rects[0].y2 = rectangle->y + rectangle->height; + temp->size = 1; + + return temp; +} + +GdkRegion * +gdk_region_copy (GdkRegion *region) +{ + GdkRegion *temp; + + temp = g_new (GdkRegion, 1); + temp->rects = g_new (GdkRegionBox, region->numRects); + + temp->numRects = region->numRects; + temp->extents = region->extents; + temp->size = region->numRects; + + memcpy (temp->rects, region->rects, region->numRects * sizeof (GdkRegionBox)); + + return temp; +} + +void +gdk_region_get_clipbox (GdkRegion *r, GdkRectangle *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; +} + +void +gdk_region_union_with_rect (GdkRegion *region, + GdkRectangle *rect) +{ + GdkRegion tmp_region; + + if (!rect->width || !rect->height) + return; + + tmp_region.rects = &tmp_region.extents; + tmp_region.numRects = 1; + tmp_region.extents.x1 = rect->x; + tmp_region.extents.y1 = rect->y; + tmp_region.extents.x2 = rect->x + rect->width; + tmp_region.extents.y2 = rect->y + rect->height; + tmp_region.size = 1; + + gdk_region_union (region, &tmp_region); +} + +/*- + *----------------------------------------------------------------------- + * 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 (GdkRegion *pReg) +{ + GdkRegionBox *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); +} + +void +gdk_region_destroy (GdkRegion *r) +{ + g_free (r->rects); + g_free (r); +} + + +/* TranslateRegion(pRegion, x, y) + translates in place + added by raymond +*/ + +void +gdk_region_offset (GdkRegion *region, + gint x, + gint y) +{ + int nbox; + GdkRegionBox *pbox; + + pbox = region->rects; + nbox = region->numRects; + + while(nbox--) + { + pbox->x1 += x; + pbox->x2 += x; + pbox->y1 += y; + pbox->y2 += y; + pbox++; + } + region->extents.x1 += x; + region->extents.x2 += x; + region->extents.y1 += y; + region->extents.y2 += y; +} + +/* + 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) if (grow) gdk_region_union (a, b); \ + else gdk_region_intersect (a,b) +#define ZShiftRegion(a,b) if (xdir) gdk_region_offset (a,b,0); \ + else gdk_region_offset (a,0,b) + +static void +Compress(GdkRegion *r, + GdkRegion *s, + GdkRegion *t, + guint dx, + int xdir, + int grow) +{ + guint shift = 1; + + miRegionCopy (s, r); + while (dx) + { + if (dx & shift) + { + ZShiftRegion(r, -(int)shift); + ZOpRegion(r, s); + dx -= shift; + if (!dx) break; + } + miRegionCopy (t, s); + ZShiftRegion(s, -(int)shift); + ZOpRegion(s, t); + shift <<= 1; + } +} + +#undef ZOpRegion +#undef ZShiftRegion +#undef ZCopyRegion + +void +gdk_region_shrink (GdkRegion *r, + int dx, + int dy) +{ + GdkRegion *s, *t; + int grow; + + if (!dx && !dy) + return; + + s = gdk_region_new (); + t = gdk_region_new (); + + grow = (dx < 0); + if (grow) + dx = -dx; + if (dx) + Compress(r, s, t, (unsigned) 2*dx, TRUE, grow); + + grow = (dy < 0); + if (grow) + dy = -dy; + if (dy) + Compress(r, s, t, (unsigned) 2*dy, FALSE, grow); + + gdk_region_offset (r, dx, dy); + gdk_region_destroy (s); + gdk_region_destroy (t); +} + + +/*====================================================================== + * Region Intersection + *====================================================================*/ +/*- + *----------------------------------------------------------------------- + * miIntersectO -- + * Handle an overlapping band for miIntersect. + * + * Results: + * None. + * + * Side Effects: + * Rectangles may be added to the region. + * + *----------------------------------------------------------------------- + */ +/* static void*/ +static void +miIntersectO (GdkRegion *pReg, + GdkRegionBox *r1, + GdkRegionBox *r1End, + GdkRegionBox *r2, + GdkRegionBox *r2End, + gint y1, + gint y2) +{ + int x1; + int x2; + GdkRegionBox *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++; + } + } +} + +void +gdk_region_intersect (GdkRegion *region, + GdkRegion *other) +{ + /* check for trivial reject */ + if ((!(region->numRects)) || (!(other->numRects)) || + (!EXTENTCHECK(®ion->extents, &other->extents))) + region->numRects = 0; + else + miRegionOp (region, region, other, + miIntersectO, (nonOverlapFunc) NULL, (nonOverlapFunc) NULL); + + /* + * Can't alter region's extents before miRegionOp depends on the + * extents of the regions being unchanged. Besides, this way there's + * no checking against rectangles that will be nuked due to + * coalescing, so we have to examine fewer rectangles. + */ + miSetExtents(region); +} + +static void +miRegionCopy(GdkRegion *dstrgn, GdkRegion *rgn) +{ + if (dstrgn != rgn) /* don't want to copy to itself */ + { + if (dstrgn->size < rgn->numRects) + { + dstrgn->rects = g_renew (GdkRegionBox, dstrgn->rects, rgn->numRects); + 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 (dstrgn->rects, rgn->rects, rgn->numRects * sizeof (GdkRegionBox)); + } +} + + +/*====================================================================== + * 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 (GdkRegion *pReg, /* Region to coalesce */ + gint prevStart, /* Index of start of previous band */ + gint curStart) /* Index of start of current band */ +{ + GdkRegionBox *pPrevBox; /* Current box in previous band */ + GdkRegionBox *pCurBox; /* Current box in current band */ + GdkRegionBox *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(GdkRegion *newReg, + GdkRegion *reg1, + GdkRegion *reg2, + overlapFunc overlapFn, /* Function to call for over- + * lapping bands */ + nonOverlapFunc nonOverlap1Fn, /* Function to call for non- + * overlapping bands in region + * 1 */ + nonOverlapFunc nonOverlap2Fn) /* Function to call for non- + * overlapping bands in region + * 2 */ +{ + GdkRegionBox *r1; /* Pointer into first region */ + GdkRegionBox *r2; /* Pointer into 2d region */ + GdkRegionBox *r1End; /* End of 1st region */ + GdkRegionBox *r2End; /* End of 2d region */ + int ybot; /* Bottom of intersection */ + int ytop; /* Top of intersection */ + GdkRegionBox *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 */ + GdkRegionBox *r1BandEnd; /* End of current band in r1 */ + GdkRegionBox *r2BandEnd; /* End of current band in r2 */ + int top; /* Top of non-overlapping + * band */ + int 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; + newReg->rects = g_new (GdkRegionBox, newReg->size); + + /* + * 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) && (nonOverlap1Fn != (void (*)())NULL)) + { + (* nonOverlap1Fn) (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) && (nonOverlap2Fn != (void (*)())NULL)) + { + (* nonOverlap2Fn) (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) + { + (* overlapFn) (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 (nonOverlap1Fn != (nonOverlapFunc )NULL) + { + do + { + r1BandEnd = r1; + while ((r1BandEnd < r1End) && (r1BandEnd->y1 == r1->y1)) + { + r1BandEnd++; + } + (* nonOverlap1Fn) (newReg, r1, r1BandEnd, + MAX (r1->y1,ybot), r1->y2); + r1 = r1BandEnd; + } while (r1 != r1End); + } + } + else if ((r2 != r2End) && (nonOverlap2Fn != (nonOverlapFunc) NULL)) + { + do + { + r2BandEnd = r2; + while ((r2BandEnd < r2End) && (r2BandEnd->y1 == r2->y1)) + { + r2BandEnd++; + } + (* nonOverlap2Fn) (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)) + { + newReg->size = newReg->numRects; + newReg->rects = g_renew (GdkRegionBox, newReg->rects, newReg->size); + } + else + { + /* + * No point in doing the extra work involved in an Xrealloc if + * the region is empty + */ + newReg->size = 1; + g_free (newReg->rects); + newReg->rects = g_new (GdkRegionBox, 1); + } + } + g_free (oldRects); +} + + +/*====================================================================== + * 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 +miUnionNonO (GdkRegion *pReg, + GdkRegionBox *r, + GdkRegionBox *rEnd, + gint y1, + gint y2) +{ + GdkRegionBox *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++; + } +} + + +/*- + *----------------------------------------------------------------------- + * 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 void +miUnionO (GdkRegion *pReg, + GdkRegionBox *r1, + GdkRegionBox *r1End, + GdkRegionBox *r2, + GdkRegionBox *r2End, + gint y1, + gint y2) +{ + GdkRegionBox * 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); + } +} + +void +gdk_region_union (GdkRegion *region, + GdkRegion *other) +{ + /* checks all the simple cases */ + + /* + * region and other are the same or other is empty + */ + if ((region == other) || (!(other->numRects))) + return; + + /* + * region is empty + */ + if (!(region->numRects)) + { + miRegionCopy (region, other); + return; + } + + /* + * region completely subsumes otehr + */ + if ((region->numRects == 1) && + (region->extents.x1 <= other->extents.x1) && + (region->extents.y1 <= other->extents.y1) && + (region->extents.x2 >= other->extents.x2) && + (region->extents.y2 >= other->extents.y2)) + return; + + /* + * other completely subsumes region + */ + if ((other->numRects == 1) && + (other->extents.x1 <= region->extents.x1) && + (other->extents.y1 <= region->extents.y1) && + (other->extents.x2 >= region->extents.x2) && + (other->extents.y2 >= region->extents.y2)) + { + miRegionCopy(region, other); + return; + } + + miRegionOp (region, region, other, miUnionO, + miUnionNonO, miUnionNonO); + + region->extents.x1 = MIN (region->extents.x1, other->extents.x1); + region->extents.y1 = MIN (region->extents.y1, other->extents.y1); + region->extents.x2 = MAX (region->extents.x2, other->extents.x2); + region->extents.y2 = MAX (region->extents.y2, other->extents.y2); +} + + +/*====================================================================== + * 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 void +miSubtractNonO1 (GdkRegion *pReg, + GdkRegionBox *r, + GdkRegionBox *rEnd, + gint y1, + gint y2) +{ + GdkRegionBox * 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++; + } +} + +/*- + *----------------------------------------------------------------------- + * 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 void +miSubtractO (GdkRegion *pReg, + GdkRegionBox *r1, + GdkRegionBox *r1End, + GdkRegionBox *r2, + GdkRegionBox *r2End, + gint y1, + gint y2) +{ + GdkRegionBox * pNextRect; + 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++; + 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; + } + } +} + +/*- + *----------------------------------------------------------------------- + * gdk_region_subtract -- + * Subtract other from region and leave the result in region. + * + * Results: + * TRUE. + * + * Side Effects: + * region is overwritten. + * + *----------------------------------------------------------------------- + */ + +void +gdk_region_subtract (GdkRegion *region, + GdkRegion *other) +{ + /* check for trivial reject */ + if ((!(region->numRects)) || (!(other->numRects)) || + (!EXTENTCHECK(®ion->extents, &other->extents))) + return; + + miRegionOp (region, region, other, miSubtractO, + miSubtractNonO1, (nonOverlapFunc) NULL); + + /* + * Can't alter region's extents before we call miRegionOp because 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 (region); +} + +void +gdk_region_xor (GdkRegion *sra, + GdkRegion *srb) +{ + GdkRegion *trb; + + trb = gdk_region_copy (srb); + + gdk_region_subtract (trb, sra); + gdk_region_subtract (sra, srb); + + gdk_region_union (sra,trb); + + gdk_region_destroy (trb); +} + +/* + * Check to see if the region is empty. Assumes a region is passed + * as a parameter + */ +gboolean +gdk_region_empty (GdkRegion *r) +{ + if (r->numRects == 0) + return TRUE; + else + return FALSE; +} + +/* + * Check to see if two regions are equal + */ +gboolean +gdk_region_equal (GdkRegion *r1, + GdkRegion *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; +} + +gboolean +gdk_region_point_in (GdkRegion *region, + int x, + int y) +{ + int i; + + if (region->numRects == 0) + return FALSE; + if (!INBOX(region->extents, x, y)) + return FALSE; + for (i=0; i<region->numRects; i++) + { + if (INBOX (region->rects[i], x, y)) + return TRUE; + } + return FALSE; +} + +GdkOverlapType +gdk_region_rect_in (GdkRegion *region, + GdkRectangle *rectangle) +{ + GdkRegionBox *pbox; + GdkRegionBox *pboxEnd; + GdkRegionBox rect; + GdkRegionBox *prect = ▭ + gboolean partIn, partOut; + + gint rx = rectangle->x; + gint ry = rectangle->y; + + prect->x1 = rx; + prect->y1 = ry; + prect->x2 = rx + rectangle->width; + prect->y2 = ry + rectangle->height; + + /* this is (just) a useful optimization */ + if ((region->numRects == 0) || !EXTENTCHECK (®ion->extents, prect)) + return GDK_OVERLAP_RECTANGLE_IN; + + 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) ? + GDK_OVERLAP_RECTANGLE_PART : GDK_OVERLAP_RECTANGLE_IN) : + GDK_OVERLAP_RECTANGLE_OUT); +} |