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1613 lines
41 KiB
C
1613 lines
41 KiB
C
/************************************************************************
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Copyright 1987, 1988, 1998 The Open Group
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Permission to use, copy, modify, distribute, and sell this software and its
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documentation for any purpose is hereby granted without fee, provided that
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the above copyright notice appear in all copies and that both that
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copyright notice and this permission notice appear in supporting
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documentation.
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
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AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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Except as contained in this notice, the name of The Open Group shall not be
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used in advertising or otherwise to promote the sale, use or other dealings
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in this Software without prior written authorization from The Open Group.
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Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts.
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All Rights Reserved
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Permission to use, copy, modify, and distribute this software and its
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documentation for any purpose and without fee is hereby granted,
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provided that the above copyright notice appear in all copies and that
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both that copyright notice and this permission notice appear in
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supporting documentation, and that the name of Digital not be
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used in advertising or publicity pertaining to distribution of the
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software without specific, written prior permission.
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DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
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ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
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DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
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ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
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WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
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ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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SOFTWARE.
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************************************************************************/
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/*
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* The functions in this file implement the Region abstraction, similar to one
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* used in the X11 sample server. A Region is simply an area, as the name
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* implies, and is implemented as a "y-x-banded" array of rectangles. To
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* explain: Each Region is made up of a certain number of rectangles sorted
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* by y coordinate first, and then by x coordinate.
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*
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* Furthermore, the rectangles are banded such that every rectangle with a
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* given upper-left y coordinate (y1) will have the same lower-right y
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* coordinate (y2) and vice versa. If a rectangle has scanlines in a band, it
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* will span the entire vertical distance of the band. This means that some
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* areas that could be merged into a taller rectangle will be represented as
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* several shorter rectangles to account for shorter rectangles to its left
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* or right but within its "vertical scope".
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*
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* An added constraint on the rectangles is that they must cover as much
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* horizontal area as possible. E.g. no two rectangles in a band are allowed
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* to touch.
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*
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* Whenever possible, bands will be merged together to cover a greater vertical
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* distance (and thus reduce the number of rectangles). Two bands can be merged
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* only if the bottom of one touches the top of the other and they have
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* rectangles in the same places (of the same width, of course). This maintains
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* the y-x-banding that's so nice to have...
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*/
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#include <string.h>
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#include "Xlibint.h"
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#include "Xutil.h"
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#include "Xregion.h"
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#ifndef min
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#define min(a,b) (((a) < (b)) ? (a) : (b))
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#endif
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#ifndef max
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#define max(a,b) (((a) > (b)) ? (a) : (b))
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#endif
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#ifdef DEBUG
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#include <stdio.h>
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#define assert(expr) {if (!(expr)) fprintf(stderr,\
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"Assertion failed file %s, line %d: expr\n", __FILE__, __LINE__); }
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#else
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#define assert(expr)
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#endif
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typedef int (*overlapProcp)(
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register Region pReg,
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register BoxPtr r1,
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BoxPtr r1End,
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register BoxPtr r2,
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BoxPtr r2End,
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short y1,
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short y2);
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typedef int (*nonOverlapProcp)(
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register Region pReg,
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register BoxPtr r,
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BoxPtr rEnd,
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register short y1,
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register short y2);
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static void miRegionOp(
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register Region newReg, /* Place to store result */
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Region reg1, /* First region in operation */
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Region reg2, /* 2d region in operation */
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int (*overlapFunc)(
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register Region pReg,
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register BoxPtr r1,
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BoxPtr r1End,
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register BoxPtr r2,
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BoxPtr r2End,
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short y1,
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short y2), /* Function to call for over-
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* lapping bands */
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int (*nonOverlap1Func)(
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register Region pReg,
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register BoxPtr r,
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BoxPtr rEnd,
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register short y1,
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register short y2), /* Function to call for non-
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* overlapping bands in region
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* 1 */
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int (*nonOverlap2Func)(
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register Region pReg,
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register BoxPtr r,
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BoxPtr rEnd,
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register short y1,
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register short y2)); /* Function to call for non-
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* overlapping bands in region
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* 2 */
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/* Create a new empty region */
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Region
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XCreateRegion(void)
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{
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Region temp;
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if (! (temp = Xmalloc(sizeof( REGION ))))
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return (Region) NULL;
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if (! (temp->rects = Xmalloc(sizeof( BOX )))) {
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Xfree(temp);
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return (Region) NULL;
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}
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temp->numRects = 0;
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temp->extents.x1 = 0;
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temp->extents.y1 = 0;
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temp->extents.x2 = 0;
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temp->extents.y2 = 0;
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temp->size = 1;
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return( temp );
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}
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int
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XClipBox(
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Region r,
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XRectangle *rect)
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{
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rect->x = r->extents.x1;
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rect->y = r->extents.y1;
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rect->width = r->extents.x2 - r->extents.x1;
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rect->height = r->extents.y2 - r->extents.y1;
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return 1;
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}
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int
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XUnionRectWithRegion(
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register XRectangle *rect,
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Region source, Region dest)
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{
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REGION region;
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if (!rect->width || !rect->height)
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return 0;
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region.rects = ®ion.extents;
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region.numRects = 1;
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region.extents.x1 = rect->x;
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region.extents.y1 = rect->y;
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region.extents.x2 = rect->x + rect->width;
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region.extents.y2 = rect->y + rect->height;
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region.size = 1;
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return XUnionRegion(®ion, source, dest);
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}
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/*-
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*-----------------------------------------------------------------------
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* miSetExtents --
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* Reset the extents of a region to what they should be. Called by
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* miSubtract and miIntersect b/c they can't figure it out along the
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* way or do so easily, as miUnion can.
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*
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* Results:
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* None.
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*
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* Side Effects:
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* The region's 'extents' structure is overwritten.
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*
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*-----------------------------------------------------------------------
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*/
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static void
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miSetExtents (
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Region pReg)
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{
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register BoxPtr pBox,
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pBoxEnd,
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pExtents;
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if (pReg->numRects == 0)
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{
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pReg->extents.x1 = 0;
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pReg->extents.y1 = 0;
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pReg->extents.x2 = 0;
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pReg->extents.y2 = 0;
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return;
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}
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pExtents = &pReg->extents;
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pBox = pReg->rects;
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pBoxEnd = &pBox[pReg->numRects - 1];
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/*
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* Since pBox is the first rectangle in the region, it must have the
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* smallest y1 and since pBoxEnd is the last rectangle in the region,
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* it must have the largest y2, because of banding. Initialize x1 and
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* x2 from pBox and pBoxEnd, resp., as good things to initialize them
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* to...
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*/
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pExtents->x1 = pBox->x1;
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pExtents->y1 = pBox->y1;
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pExtents->x2 = pBoxEnd->x2;
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pExtents->y2 = pBoxEnd->y2;
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assert(pExtents->y1 < pExtents->y2);
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while (pBox <= pBoxEnd)
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{
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if (pBox->x1 < pExtents->x1)
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{
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pExtents->x1 = pBox->x1;
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}
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if (pBox->x2 > pExtents->x2)
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{
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pExtents->x2 = pBox->x2;
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}
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pBox++;
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}
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assert(pExtents->x1 < pExtents->x2);
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}
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#if 0
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int
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XSetRegion(
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Display *dpy,
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GC gc,
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register Region r)
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{
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register int i;
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register XRectangle *xr, *pr;
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register BOX *pb;
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unsigned long total;
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LockDisplay (dpy);
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total = r->numRects * sizeof (XRectangle);
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if ((xr = (XRectangle *) _XAllocTemp(dpy, total))) {
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for (pr = xr, pb = r->rects, i = r->numRects; --i >= 0; pr++, pb++) {
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pr->x = pb->x1;
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pr->y = pb->y1;
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pr->width = pb->x2 - pb->x1;
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pr->height = pb->y2 - pb->y1;
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}
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}
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if (xr || !r->numRects)
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_XSetClipRectangles(dpy, gc, 0, 0, xr, r->numRects, YXBanded);
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if (xr)
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_XFreeTemp(dpy, (char *)xr, total);
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UnlockDisplay(dpy);
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SyncHandle();
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return 1;
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}
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#endif
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int
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XDestroyRegion(
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Region r)
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{
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Xfree( (char *) r->rects );
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Xfree( (char *) r );
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return 1;
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}
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/* TranslateRegion(pRegion, x, y)
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translates in place
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added by raymond
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*/
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int
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XOffsetRegion(
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register Region pRegion,
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register int x,
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register int y)
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{
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register int nbox;
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register BOX *pbox;
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pbox = pRegion->rects;
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nbox = pRegion->numRects;
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while(nbox--)
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{
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pbox->x1 += x;
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pbox->x2 += x;
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pbox->y1 += y;
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pbox->y2 += y;
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pbox++;
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}
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pRegion->extents.x1 += x;
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pRegion->extents.x2 += x;
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pRegion->extents.y1 += y;
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pRegion->extents.y2 += y;
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return 1;
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}
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/*
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Utility procedure Compress:
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Replace r by the region r', where
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p in r' iff (Quantifer m <= dx) (p + m in r), and
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Quantifier is Exists if grow is TRUE, For all if grow is FALSE, and
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(x,y) + m = (x+m,y) if xdir is TRUE; (x,y+m) if xdir is FALSE.
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Thus, if xdir is TRUE and grow is FALSE, r is replaced by the region
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of all points p such that p and the next dx points on the same
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horizontal scan line are all in r. We do this using by noting
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that p is the head of a run of length 2^i + k iff p is the head
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of a run of length 2^i and p+2^i is the head of a run of length
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k. Thus, the loop invariant: s contains the region corresponding
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to the runs of length shift. r contains the region corresponding
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to the runs of length 1 + dxo & (shift-1), where dxo is the original
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value of dx. dx = dxo & ~(shift-1). As parameters, s and t are
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scratch regions, so that we don't have to allocate them on every
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call.
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*/
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#define ZOpRegion(a,b,c) if (grow) XUnionRegion(a,b,c); \
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else XIntersectRegion(a,b,c)
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#define ZShiftRegion(a,b) if (xdir) XOffsetRegion(a,b,0); \
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else XOffsetRegion(a,0,b)
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#define ZCopyRegion(a,b) XUnionRegion(a,a,b)
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static void
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Compress(
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Region r, Region s, Region t,
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register unsigned dx,
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register int xdir, register int grow)
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{
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register unsigned shift = 1;
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ZCopyRegion(r, s);
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while (dx) {
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if (dx & shift) {
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ZShiftRegion(r, -(int)shift);
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ZOpRegion(r, s, r);
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dx -= shift;
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if (!dx) break;
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}
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ZCopyRegion(s, t);
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ZShiftRegion(s, -(int)shift);
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ZOpRegion(s, t, s);
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shift <<= 1;
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}
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}
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#undef ZOpRegion
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#undef ZShiftRegion
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#undef ZCopyRegion
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int
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XShrinkRegion(
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Region r,
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int dx, int dy)
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{
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Region s, t;
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int grow;
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if (!dx && !dy) return 0;
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if (! (s = XCreateRegion()) )
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return 0;
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if (! (t = XCreateRegion()) ) {
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XDestroyRegion(s);
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return 0;
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}
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if ((grow = (dx < 0))) dx = -dx;
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if (dx) Compress(r, s, t, (unsigned) 2*dx, TRUE, grow);
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if ((grow = (dy < 0))) dy = -dy;
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if (dy) Compress(r, s, t, (unsigned) 2*dy, FALSE, grow);
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XOffsetRegion(r, dx, dy);
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XDestroyRegion(s);
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XDestroyRegion(t);
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return 0;
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}
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/*======================================================================
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* Region Intersection
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*====================================================================*/
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/*-
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*-----------------------------------------------------------------------
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* miIntersectO --
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* Handle an overlapping band for miIntersect.
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*
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* Results:
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* None.
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*
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* Side Effects:
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* Rectangles may be added to the region.
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*
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*-----------------------------------------------------------------------
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*/
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/* static void*/
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static int
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miIntersectO (
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register Region pReg,
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register BoxPtr r1,
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BoxPtr r1End,
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register BoxPtr r2,
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BoxPtr r2End,
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short y1,
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short y2)
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{
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register short x1;
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register short x2;
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register BoxPtr pNextRect;
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pNextRect = &pReg->rects[pReg->numRects];
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while ((r1 != r1End) && (r2 != r2End))
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{
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x1 = max(r1->x1,r2->x1);
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x2 = min(r1->x2,r2->x2);
|
||
|
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/*
|
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* If there's any overlap between the two rectangles, add that
|
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* overlap to the new region.
|
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* There's no need to check for subsumption because the only way
|
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* such a need could arise is if some region has two rectangles
|
||
* right next to each other. Since that should never happen...
|
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*/
|
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if (x1 < x2)
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{
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assert(y1<y2);
|
||
|
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MEMCHECK(pReg, pNextRect, pReg->rects);
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pNextRect->x1 = x1;
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pNextRect->y1 = y1;
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pNextRect->x2 = x2;
|
||
pNextRect->y2 = y2;
|
||
pReg->numRects += 1;
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pNextRect++;
|
||
assert(pReg->numRects <= pReg->size);
|
||
}
|
||
|
||
/*
|
||
* Need to advance the pointers. Shift the one that extends
|
||
* to the right the least, since the other still has a chance to
|
||
* overlap with that region's next rectangle, if you see what I mean.
|
||
*/
|
||
if (r1->x2 < r2->x2)
|
||
{
|
||
r1++;
|
||
}
|
||
else if (r2->x2 < r1->x2)
|
||
{
|
||
r2++;
|
||
}
|
||
else
|
||
{
|
||
r1++;
|
||
r2++;
|
||
}
|
||
}
|
||
return 0; /* lint */
|
||
}
|
||
|
||
int
|
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XIntersectRegion(
|
||
Region reg1,
|
||
Region reg2, /* source regions */
|
||
register Region newReg) /* destination Region */
|
||
{
|
||
/* check for trivial reject */
|
||
if ( (!(reg1->numRects)) || (!(reg2->numRects)) ||
|
||
(!EXTENTCHECK(®1->extents, ®2->extents)))
|
||
newReg->numRects = 0;
|
||
else
|
||
miRegionOp (newReg, reg1, reg2,
|
||
miIntersectO, NULL, NULL);
|
||
|
||
/*
|
||
* Can't alter newReg's extents before we call miRegionOp because
|
||
* it might be one of the source regions and miRegionOp depends
|
||
* on the extents of those regions being the same. Besides, this
|
||
* way there's no checking against rectangles that will be nuked
|
||
* due to coalescing, so we have to examine fewer rectangles.
|
||
*/
|
||
miSetExtents(newReg);
|
||
return 1;
|
||
}
|
||
|
||
static int
|
||
miRegionCopy(
|
||
register Region dstrgn,
|
||
register Region rgn)
|
||
|
||
{
|
||
if (dstrgn != rgn) /* don't want to copy to itself */
|
||
{
|
||
if (dstrgn->size < rgn->numRects)
|
||
{
|
||
if (dstrgn->rects)
|
||
{
|
||
BOX *prevRects = dstrgn->rects;
|
||
|
||
dstrgn->rects = Xrealloc(dstrgn->rects,
|
||
rgn->numRects * (sizeof(BOX)));
|
||
if (! dstrgn->rects) {
|
||
Xfree(prevRects);
|
||
dstrgn->size = 0;
|
||
return 0;
|
||
}
|
||
}
|
||
dstrgn->size = rgn->numRects;
|
||
}
|
||
dstrgn->numRects = rgn->numRects;
|
||
dstrgn->extents.x1 = rgn->extents.x1;
|
||
dstrgn->extents.y1 = rgn->extents.y1;
|
||
dstrgn->extents.x2 = rgn->extents.x2;
|
||
dstrgn->extents.y2 = rgn->extents.y2;
|
||
|
||
memcpy((char *) dstrgn->rects, (char *) rgn->rects,
|
||
(int) (rgn->numRects * sizeof(BOX)));
|
||
}
|
||
return 1;
|
||
}
|
||
|
||
/*======================================================================
|
||
* Generic Region Operator
|
||
*====================================================================*/
|
||
|
||
/*-
|
||
*-----------------------------------------------------------------------
|
||
* miCoalesce --
|
||
* Attempt to merge the boxes in the current band with those in the
|
||
* previous one. Used only by miRegionOp.
|
||
*
|
||
* Results:
|
||
* The new index for the previous band.
|
||
*
|
||
* Side Effects:
|
||
* If coalescing takes place:
|
||
* - rectangles in the previous band will have their y2 fields
|
||
* altered.
|
||
* - pReg->numRects will be decreased.
|
||
*
|
||
*-----------------------------------------------------------------------
|
||
*/
|
||
/* static int*/
|
||
static int
|
||
miCoalesce(
|
||
register Region pReg, /* Region to coalesce */
|
||
int prevStart, /* Index of start of previous band */
|
||
int curStart) /* Index of start of current band */
|
||
{
|
||
register BoxPtr pPrevBox; /* Current box in previous band */
|
||
register BoxPtr pCurBox; /* Current box in current band */
|
||
register BoxPtr pRegEnd; /* End of region */
|
||
int curNumRects; /* Number of rectangles in current
|
||
* band */
|
||
int prevNumRects; /* Number of rectangles in previous
|
||
* band */
|
||
int bandY1; /* Y1 coordinate for current band */
|
||
|
||
pRegEnd = &pReg->rects[pReg->numRects];
|
||
|
||
pPrevBox = &pReg->rects[prevStart];
|
||
prevNumRects = curStart - prevStart;
|
||
|
||
/*
|
||
* Figure out how many rectangles are in the current band. Have to do
|
||
* this because multiple bands could have been added in miRegionOp
|
||
* at the end when one region has been exhausted.
|
||
*/
|
||
pCurBox = &pReg->rects[curStart];
|
||
bandY1 = pCurBox->y1;
|
||
for (curNumRects = 0;
|
||
(pCurBox != pRegEnd) && (pCurBox->y1 == bandY1);
|
||
curNumRects++)
|
||
{
|
||
pCurBox++;
|
||
}
|
||
|
||
if (pCurBox != pRegEnd)
|
||
{
|
||
/*
|
||
* If more than one band was added, we have to find the start
|
||
* of the last band added so the next coalescing job can start
|
||
* at the right place... (given when multiple bands are added,
|
||
* this may be pointless -- see above).
|
||
*/
|
||
pRegEnd--;
|
||
while (pRegEnd[-1].y1 == pRegEnd->y1)
|
||
{
|
||
pRegEnd--;
|
||
}
|
||
curStart = pRegEnd - pReg->rects;
|
||
pRegEnd = pReg->rects + pReg->numRects;
|
||
}
|
||
|
||
if ((curNumRects == prevNumRects) && (curNumRects != 0)) {
|
||
pCurBox -= curNumRects;
|
||
/*
|
||
* The bands may only be coalesced if the bottom of the previous
|
||
* matches the top scanline of the current.
|
||
*/
|
||
if (pPrevBox->y2 == pCurBox->y1)
|
||
{
|
||
/*
|
||
* Make sure the bands have boxes in the same places. This
|
||
* assumes that boxes have been added in such a way that they
|
||
* cover the most area possible. I.e. two boxes in a band must
|
||
* have some horizontal space between them.
|
||
*/
|
||
do
|
||
{
|
||
if ((pPrevBox->x1 != pCurBox->x1) ||
|
||
(pPrevBox->x2 != pCurBox->x2))
|
||
{
|
||
/*
|
||
* The bands don't line up so they can't be coalesced.
|
||
*/
|
||
return (curStart);
|
||
}
|
||
pPrevBox++;
|
||
pCurBox++;
|
||
prevNumRects -= 1;
|
||
} while (prevNumRects != 0);
|
||
|
||
pReg->numRects -= curNumRects;
|
||
pCurBox -= curNumRects;
|
||
pPrevBox -= curNumRects;
|
||
|
||
/*
|
||
* The bands may be merged, so set the bottom y of each box
|
||
* in the previous band to that of the corresponding box in
|
||
* the current band.
|
||
*/
|
||
do
|
||
{
|
||
pPrevBox->y2 = pCurBox->y2;
|
||
pPrevBox++;
|
||
pCurBox++;
|
||
curNumRects -= 1;
|
||
} while (curNumRects != 0);
|
||
|
||
/*
|
||
* If only one band was added to the region, we have to backup
|
||
* curStart to the start of the previous band.
|
||
*
|
||
* If more than one band was added to the region, copy the
|
||
* other bands down. The assumption here is that the other bands
|
||
* came from the same region as the current one and no further
|
||
* coalescing can be done on them since it's all been done
|
||
* already... curStart is already in the right place.
|
||
*/
|
||
if (pCurBox == pRegEnd)
|
||
{
|
||
curStart = prevStart;
|
||
}
|
||
else
|
||
{
|
||
do
|
||
{
|
||
*pPrevBox++ = *pCurBox++;
|
||
} while (pCurBox != pRegEnd);
|
||
}
|
||
|
||
}
|
||
}
|
||
return (curStart);
|
||
}
|
||
|
||
/*-
|
||
*-----------------------------------------------------------------------
|
||
* miRegionOp --
|
||
* Apply an operation to two regions. Called by miUnion, miInverse,
|
||
* miSubtract, miIntersect...
|
||
*
|
||
* Results:
|
||
* None.
|
||
*
|
||
* Side Effects:
|
||
* The new region is overwritten.
|
||
*
|
||
* Notes:
|
||
* The idea behind this function is to view the two regions as sets.
|
||
* Together they cover a rectangle of area that this function divides
|
||
* into horizontal bands where points are covered only by one region
|
||
* or by both. For the first case, the nonOverlapFunc is called with
|
||
* each the band and the band's upper and lower extents. For the
|
||
* second, the overlapFunc is called to process the entire band. It
|
||
* is responsible for clipping the rectangles in the band, though
|
||
* this function provides the boundaries.
|
||
* At the end of each band, the new region is coalesced, if possible,
|
||
* to reduce the number of rectangles in the region.
|
||
*
|
||
*-----------------------------------------------------------------------
|
||
*/
|
||
/* static void*/
|
||
static void
|
||
miRegionOp(
|
||
register Region newReg, /* Place to store result */
|
||
Region reg1, /* First region in operation */
|
||
Region reg2, /* 2d region in operation */
|
||
int (*overlapFunc)(
|
||
register Region pReg,
|
||
register BoxPtr r1,
|
||
BoxPtr r1End,
|
||
register BoxPtr r2,
|
||
BoxPtr r2End,
|
||
short y1,
|
||
short y2), /* Function to call for over-
|
||
* lapping bands */
|
||
int (*nonOverlap1Func)(
|
||
register Region pReg,
|
||
register BoxPtr r,
|
||
BoxPtr rEnd,
|
||
register short y1,
|
||
register short y2), /* Function to call for non-
|
||
* overlapping bands in region
|
||
* 1 */
|
||
int (*nonOverlap2Func)(
|
||
register Region pReg,
|
||
register BoxPtr r,
|
||
BoxPtr rEnd,
|
||
register short y1,
|
||
register short y2)) /* Function to call for non-
|
||
* overlapping bands in region
|
||
* 2 */
|
||
{
|
||
register BoxPtr r1; /* Pointer into first region */
|
||
register BoxPtr r2; /* Pointer into 2d region */
|
||
BoxPtr r1End; /* End of 1st region */
|
||
BoxPtr r2End; /* End of 2d region */
|
||
register short ybot; /* Bottom of intersection */
|
||
register short ytop; /* Top of intersection */
|
||
BoxPtr oldRects; /* Old rects for newReg */
|
||
int prevBand; /* Index of start of
|
||
* previous band in newReg */
|
||
int curBand; /* Index of start of current
|
||
* band in newReg */
|
||
register BoxPtr r1BandEnd; /* End of current band in r1 */
|
||
register BoxPtr r2BandEnd; /* End of current band in r2 */
|
||
short top; /* Top of non-overlapping
|
||
* band */
|
||
short bot; /* Bottom of non-overlapping
|
||
* band */
|
||
|
||
/*
|
||
* Initialization:
|
||
* set r1, r2, r1End and r2End appropriately, preserve the important
|
||
* parts of the destination region until the end in case it's one of
|
||
* the two source regions, then mark the "new" region empty, allocating
|
||
* another array of rectangles for it to use.
|
||
*/
|
||
r1 = reg1->rects;
|
||
r2 = reg2->rects;
|
||
r1End = r1 + reg1->numRects;
|
||
r2End = r2 + reg2->numRects;
|
||
|
||
oldRects = newReg->rects;
|
||
|
||
EMPTY_REGION(newReg);
|
||
|
||
/*
|
||
* Allocate a reasonable number of rectangles for the new region. The idea
|
||
* is to allocate enough so the individual functions don't need to
|
||
* reallocate and copy the array, which is time consuming, yet we don't
|
||
* have to worry about using too much memory. I hope to be able to
|
||
* nuke the Xrealloc() at the end of this function eventually.
|
||
*/
|
||
newReg->size = max(reg1->numRects,reg2->numRects) * 2;
|
||
|
||
if (! (newReg->rects = Xmalloc (sizeof(BoxRec) * newReg->size))) {
|
||
newReg->size = 0;
|
||
return;
|
||
}
|
||
|
||
/*
|
||
* Initialize ybot and ytop.
|
||
* In the upcoming loop, ybot and ytop serve different functions depending
|
||
* on whether the band being handled is an overlapping or non-overlapping
|
||
* band.
|
||
* In the case of a non-overlapping band (only one of the regions
|
||
* has points in the band), ybot is the bottom of the most recent
|
||
* intersection and thus clips the top of the rectangles in that band.
|
||
* ytop is the top of the next intersection between the two regions and
|
||
* serves to clip the bottom of the rectangles in the current band.
|
||
* For an overlapping band (where the two regions intersect), ytop clips
|
||
* the top of the rectangles of both regions and ybot clips the bottoms.
|
||
*/
|
||
if (reg1->extents.y1 < reg2->extents.y1)
|
||
ybot = reg1->extents.y1;
|
||
else
|
||
ybot = reg2->extents.y1;
|
||
|
||
/*
|
||
* prevBand serves to mark the start of the previous band so rectangles
|
||
* can be coalesced into larger rectangles. qv. miCoalesce, above.
|
||
* In the beginning, there is no previous band, so prevBand == curBand
|
||
* (curBand is set later on, of course, but the first band will always
|
||
* start at index 0). prevBand and curBand must be indices because of
|
||
* the possible expansion, and resultant moving, of the new region's
|
||
* array of rectangles.
|
||
*/
|
||
prevBand = 0;
|
||
|
||
do
|
||
{
|
||
curBand = newReg->numRects;
|
||
|
||
/*
|
||
* This algorithm proceeds one source-band (as opposed to a
|
||
* destination band, which is determined by where the two regions
|
||
* intersect) at a time. r1BandEnd and r2BandEnd serve to mark the
|
||
* rectangle after the last one in the current band for their
|
||
* respective regions.
|
||
*/
|
||
r1BandEnd = r1;
|
||
while ((r1BandEnd != r1End) && (r1BandEnd->y1 == r1->y1))
|
||
{
|
||
r1BandEnd++;
|
||
}
|
||
|
||
r2BandEnd = r2;
|
||
while ((r2BandEnd != r2End) && (r2BandEnd->y1 == r2->y1))
|
||
{
|
||
r2BandEnd++;
|
||
}
|
||
|
||
/*
|
||
* First handle the band that doesn't intersect, if any.
|
||
*
|
||
* Note that attention is restricted to one band in the
|
||
* non-intersecting region at once, so if a region has n
|
||
* bands between the current position and the next place it overlaps
|
||
* the other, this entire loop will be passed through n times.
|
||
*/
|
||
if (r1->y1 < r2->y1)
|
||
{
|
||
top = max(r1->y1,ybot);
|
||
bot = min(r1->y2,r2->y1);
|
||
|
||
if ((top != bot) && (nonOverlap1Func != NULL))
|
||
{
|
||
(* nonOverlap1Func) (newReg, r1, r1BandEnd, top, bot);
|
||
}
|
||
|
||
ytop = r2->y1;
|
||
}
|
||
else if (r2->y1 < r1->y1)
|
||
{
|
||
top = max(r2->y1,ybot);
|
||
bot = min(r2->y2,r1->y1);
|
||
|
||
if ((top != bot) && (nonOverlap2Func != NULL))
|
||
{
|
||
(* nonOverlap2Func) (newReg, r2, r2BandEnd, top, bot);
|
||
}
|
||
|
||
ytop = r1->y1;
|
||
}
|
||
else
|
||
{
|
||
ytop = r1->y1;
|
||
}
|
||
|
||
/*
|
||
* If any rectangles got added to the region, try and coalesce them
|
||
* with rectangles from the previous band. Note we could just do
|
||
* this test in miCoalesce, but some machines incur a not
|
||
* inconsiderable cost for function calls, so...
|
||
*/
|
||
if (newReg->numRects != curBand)
|
||
{
|
||
prevBand = miCoalesce (newReg, prevBand, curBand);
|
||
}
|
||
|
||
/*
|
||
* Now see if we've hit an intersecting band. The two bands only
|
||
* intersect if ybot > ytop
|
||
*/
|
||
ybot = min(r1->y2, r2->y2);
|
||
curBand = newReg->numRects;
|
||
if (ybot > ytop)
|
||
{
|
||
(* overlapFunc) (newReg, r1, r1BandEnd, r2, r2BandEnd, ytop, ybot);
|
||
|
||
}
|
||
|
||
if (newReg->numRects != curBand)
|
||
{
|
||
prevBand = miCoalesce (newReg, prevBand, curBand);
|
||
}
|
||
|
||
/*
|
||
* If we've finished with a band (y2 == ybot) we skip forward
|
||
* in the region to the next band.
|
||
*/
|
||
if (r1->y2 == ybot)
|
||
{
|
||
r1 = r1BandEnd;
|
||
}
|
||
if (r2->y2 == ybot)
|
||
{
|
||
r2 = r2BandEnd;
|
||
}
|
||
} while ((r1 != r1End) && (r2 != r2End));
|
||
|
||
/*
|
||
* Deal with whichever region still has rectangles left.
|
||
*/
|
||
curBand = newReg->numRects;
|
||
if (r1 != r1End)
|
||
{
|
||
if (nonOverlap1Func != NULL)
|
||
{
|
||
do
|
||
{
|
||
r1BandEnd = r1;
|
||
while ((r1BandEnd < r1End) && (r1BandEnd->y1 == r1->y1))
|
||
{
|
||
r1BandEnd++;
|
||
}
|
||
(* nonOverlap1Func) (newReg, r1, r1BandEnd,
|
||
max(r1->y1,ybot), r1->y2);
|
||
r1 = r1BandEnd;
|
||
} while (r1 != r1End);
|
||
}
|
||
}
|
||
else if ((r2 != r2End) && (nonOverlap2Func != NULL))
|
||
{
|
||
do
|
||
{
|
||
r2BandEnd = r2;
|
||
while ((r2BandEnd < r2End) && (r2BandEnd->y1 == r2->y1))
|
||
{
|
||
r2BandEnd++;
|
||
}
|
||
(* nonOverlap2Func) (newReg, r2, r2BandEnd,
|
||
max(r2->y1,ybot), r2->y2);
|
||
r2 = r2BandEnd;
|
||
} while (r2 != r2End);
|
||
}
|
||
|
||
if (newReg->numRects != curBand)
|
||
{
|
||
(void) miCoalesce (newReg, prevBand, curBand);
|
||
}
|
||
|
||
/*
|
||
* A bit of cleanup. To keep regions from growing without bound,
|
||
* we shrink the array of rectangles to match the new number of
|
||
* rectangles in the region. This never goes to 0, however...
|
||
*
|
||
* Only do this stuff if the number of rectangles allocated is more than
|
||
* twice the number of rectangles in the region (a simple optimization...).
|
||
*/
|
||
if (newReg->numRects < (newReg->size >> 1))
|
||
{
|
||
if (REGION_NOT_EMPTY(newReg))
|
||
{
|
||
BoxPtr prev_rects = newReg->rects;
|
||
newReg->rects = Xrealloc (newReg->rects,
|
||
sizeof(BoxRec) * newReg->numRects);
|
||
if (! newReg->rects)
|
||
newReg->rects = prev_rects;
|
||
else
|
||
newReg->size = newReg->numRects;
|
||
}
|
||
else
|
||
{
|
||
/*
|
||
* No point in doing the extra work involved in an Xrealloc if
|
||
* the region is empty
|
||
*/
|
||
newReg->size = 1;
|
||
Xfree(newReg->rects);
|
||
newReg->rects = Xmalloc(sizeof(BoxRec));
|
||
}
|
||
}
|
||
Xfree (oldRects);
|
||
return;
|
||
}
|
||
|
||
|
||
/*======================================================================
|
||
* Region Union
|
||
*====================================================================*/
|
||
|
||
/*-
|
||
*-----------------------------------------------------------------------
|
||
* miUnionNonO --
|
||
* Handle a non-overlapping band for the union operation. Just
|
||
* Adds the rectangles into the region. Doesn't have to check for
|
||
* subsumption or anything.
|
||
*
|
||
* Results:
|
||
* None.
|
||
*
|
||
* Side Effects:
|
||
* pReg->numRects is incremented and the final rectangles overwritten
|
||
* with the rectangles we're passed.
|
||
*
|
||
*-----------------------------------------------------------------------
|
||
*/
|
||
/* static void*/
|
||
static int
|
||
miUnionNonO (
|
||
register Region pReg,
|
||
register BoxPtr r,
|
||
BoxPtr rEnd,
|
||
register short y1,
|
||
register short y2)
|
||
{
|
||
register BoxPtr pNextRect;
|
||
|
||
pNextRect = &pReg->rects[pReg->numRects];
|
||
|
||
assert(y1 < y2);
|
||
|
||
while (r != rEnd)
|
||
{
|
||
assert(r->x1 < r->x2);
|
||
MEMCHECK(pReg, pNextRect, pReg->rects);
|
||
pNextRect->x1 = r->x1;
|
||
pNextRect->y1 = y1;
|
||
pNextRect->x2 = r->x2;
|
||
pNextRect->y2 = y2;
|
||
pReg->numRects += 1;
|
||
pNextRect++;
|
||
|
||
assert(pReg->numRects<=pReg->size);
|
||
r++;
|
||
}
|
||
return 0; /* lint */
|
||
}
|
||
|
||
|
||
/*-
|
||
*-----------------------------------------------------------------------
|
||
* miUnionO --
|
||
* Handle an overlapping band for the union operation. Picks the
|
||
* left-most rectangle each time and merges it into the region.
|
||
*
|
||
* Results:
|
||
* None.
|
||
*
|
||
* Side Effects:
|
||
* Rectangles are overwritten in pReg->rects and pReg->numRects will
|
||
* be changed.
|
||
*
|
||
*-----------------------------------------------------------------------
|
||
*/
|
||
|
||
/* static void*/
|
||
static int
|
||
miUnionO (
|
||
register Region pReg,
|
||
register BoxPtr r1,
|
||
BoxPtr r1End,
|
||
register BoxPtr r2,
|
||
BoxPtr r2End,
|
||
register short y1,
|
||
register short y2)
|
||
{
|
||
register BoxPtr pNextRect;
|
||
|
||
pNextRect = &pReg->rects[pReg->numRects];
|
||
|
||
#define MERGERECT(r) \
|
||
if ((pReg->numRects != 0) && \
|
||
(pNextRect[-1].y1 == y1) && \
|
||
(pNextRect[-1].y2 == y2) && \
|
||
(pNextRect[-1].x2 >= r->x1)) \
|
||
{ \
|
||
if (pNextRect[-1].x2 < r->x2) \
|
||
{ \
|
||
pNextRect[-1].x2 = r->x2; \
|
||
assert(pNextRect[-1].x1<pNextRect[-1].x2); \
|
||
} \
|
||
} \
|
||
else \
|
||
{ \
|
||
MEMCHECK(pReg, pNextRect, pReg->rects); \
|
||
pNextRect->y1 = y1; \
|
||
pNextRect->y2 = y2; \
|
||
pNextRect->x1 = r->x1; \
|
||
pNextRect->x2 = r->x2; \
|
||
pReg->numRects += 1; \
|
||
pNextRect += 1; \
|
||
} \
|
||
assert(pReg->numRects<=pReg->size);\
|
||
r++;
|
||
|
||
assert (y1<y2);
|
||
while ((r1 != r1End) && (r2 != r2End))
|
||
{
|
||
if (r1->x1 < r2->x1)
|
||
{
|
||
MERGERECT(r1);
|
||
}
|
||
else
|
||
{
|
||
MERGERECT(r2);
|
||
}
|
||
}
|
||
|
||
if (r1 != r1End)
|
||
{
|
||
do
|
||
{
|
||
MERGERECT(r1);
|
||
} while (r1 != r1End);
|
||
}
|
||
else while (r2 != r2End)
|
||
{
|
||
MERGERECT(r2);
|
||
}
|
||
return 0; /* lint */
|
||
}
|
||
|
||
int
|
||
XUnionRegion(
|
||
Region reg1,
|
||
Region reg2, /* source regions */
|
||
Region newReg) /* destination Region */
|
||
{
|
||
/* checks all the simple cases */
|
||
|
||
/*
|
||
* Region 1 and 2 are the same or region 1 is empty
|
||
*/
|
||
if ( (reg1 == reg2) || (!(reg1->numRects)) )
|
||
{
|
||
if (newReg != reg2)
|
||
return miRegionCopy(newReg, reg2);
|
||
return 1;
|
||
}
|
||
|
||
/*
|
||
* if nothing to union (region 2 empty)
|
||
*/
|
||
if (!(reg2->numRects))
|
||
{
|
||
if (newReg != reg1)
|
||
return miRegionCopy(newReg, reg1);
|
||
return 1;
|
||
}
|
||
|
||
/*
|
||
* Region 1 completely subsumes region 2
|
||
*/
|
||
if ((reg1->numRects == 1) &&
|
||
(reg1->extents.x1 <= reg2->extents.x1) &&
|
||
(reg1->extents.y1 <= reg2->extents.y1) &&
|
||
(reg1->extents.x2 >= reg2->extents.x2) &&
|
||
(reg1->extents.y2 >= reg2->extents.y2))
|
||
{
|
||
if (newReg != reg1)
|
||
return miRegionCopy(newReg, reg1);
|
||
return 1;
|
||
}
|
||
|
||
/*
|
||
* Region 2 completely subsumes region 1
|
||
*/
|
||
if ((reg2->numRects == 1) &&
|
||
(reg2->extents.x1 <= reg1->extents.x1) &&
|
||
(reg2->extents.y1 <= reg1->extents.y1) &&
|
||
(reg2->extents.x2 >= reg1->extents.x2) &&
|
||
(reg2->extents.y2 >= reg1->extents.y2))
|
||
{
|
||
if (newReg != reg2)
|
||
return miRegionCopy(newReg, reg2);
|
||
return 1;
|
||
}
|
||
|
||
miRegionOp (newReg, reg1, reg2, miUnionO,
|
||
miUnionNonO, miUnionNonO);
|
||
|
||
newReg->extents.x1 = min(reg1->extents.x1, reg2->extents.x1);
|
||
newReg->extents.y1 = min(reg1->extents.y1, reg2->extents.y1);
|
||
newReg->extents.x2 = max(reg1->extents.x2, reg2->extents.x2);
|
||
newReg->extents.y2 = max(reg1->extents.y2, reg2->extents.y2);
|
||
|
||
return 1;
|
||
}
|
||
|
||
|
||
/*======================================================================
|
||
* Region Subtraction
|
||
*====================================================================*/
|
||
|
||
/*-
|
||
*-----------------------------------------------------------------------
|
||
* miSubtractNonO --
|
||
* Deal with non-overlapping band for subtraction. Any parts from
|
||
* region 2 we discard. Anything from region 1 we add to the region.
|
||
*
|
||
* Results:
|
||
* None.
|
||
*
|
||
* Side Effects:
|
||
* pReg may be affected.
|
||
*
|
||
*-----------------------------------------------------------------------
|
||
*/
|
||
/* static void*/
|
||
static int
|
||
miSubtractNonO1 (
|
||
register Region pReg,
|
||
register BoxPtr r,
|
||
BoxPtr rEnd,
|
||
register short y1,
|
||
register short y2)
|
||
{
|
||
register BoxPtr pNextRect;
|
||
|
||
pNextRect = &pReg->rects[pReg->numRects];
|
||
|
||
assert(y1<y2);
|
||
|
||
while (r != rEnd)
|
||
{
|
||
assert(r->x1<r->x2);
|
||
MEMCHECK(pReg, pNextRect, pReg->rects);
|
||
pNextRect->x1 = r->x1;
|
||
pNextRect->y1 = y1;
|
||
pNextRect->x2 = r->x2;
|
||
pNextRect->y2 = y2;
|
||
pReg->numRects += 1;
|
||
pNextRect++;
|
||
|
||
assert(pReg->numRects <= pReg->size);
|
||
|
||
r++;
|
||
}
|
||
return 0; /* lint */
|
||
}
|
||
|
||
/*-
|
||
*-----------------------------------------------------------------------
|
||
* miSubtractO --
|
||
* Overlapping band subtraction. x1 is the left-most point not yet
|
||
* checked.
|
||
*
|
||
* Results:
|
||
* None.
|
||
*
|
||
* Side Effects:
|
||
* pReg may have rectangles added to it.
|
||
*
|
||
*-----------------------------------------------------------------------
|
||
*/
|
||
/* static void*/
|
||
static int
|
||
miSubtractO (
|
||
register Region pReg,
|
||
register BoxPtr r1,
|
||
BoxPtr r1End,
|
||
register BoxPtr r2,
|
||
BoxPtr r2End,
|
||
register short y1,
|
||
register short y2)
|
||
{
|
||
register BoxPtr pNextRect;
|
||
register int x1;
|
||
|
||
x1 = r1->x1;
|
||
|
||
assert(y1<y2);
|
||
pNextRect = &pReg->rects[pReg->numRects];
|
||
|
||
while ((r1 != r1End) && (r2 != r2End))
|
||
{
|
||
if (r2->x2 <= x1)
|
||
{
|
||
/*
|
||
* Subtrahend missed the boat: go to next subtrahend.
|
||
*/
|
||
r2++;
|
||
}
|
||
else if (r2->x1 <= x1)
|
||
{
|
||
/*
|
||
* Subtrahend preceds minuend: nuke left edge of minuend.
|
||
*/
|
||
x1 = r2->x2;
|
||
if (x1 >= r1->x2)
|
||
{
|
||
/*
|
||
* Minuend completely covered: advance to next minuend and
|
||
* reset left fence to edge of new minuend.
|
||
*/
|
||
r1++;
|
||
if (r1 != r1End)
|
||
x1 = r1->x1;
|
||
}
|
||
else
|
||
{
|
||
/*
|
||
* Subtrahend now used up since it doesn't extend beyond
|
||
* minuend
|
||
*/
|
||
r2++;
|
||
}
|
||
}
|
||
else if (r2->x1 < r1->x2)
|
||
{
|
||
/*
|
||
* Left part of subtrahend covers part of minuend: add uncovered
|
||
* part of minuend to region and skip to next subtrahend.
|
||
*/
|
||
assert(x1<r2->x1);
|
||
MEMCHECK(pReg, pNextRect, pReg->rects);
|
||
pNextRect->x1 = x1;
|
||
pNextRect->y1 = y1;
|
||
pNextRect->x2 = r2->x1;
|
||
pNextRect->y2 = y2;
|
||
pReg->numRects += 1;
|
||
pNextRect++;
|
||
|
||
assert(pReg->numRects<=pReg->size);
|
||
|
||
x1 = r2->x2;
|
||
if (x1 >= r1->x2)
|
||
{
|
||
/*
|
||
* Minuend used up: advance to new...
|
||
*/
|
||
r1++;
|
||
if (r1 != r1End)
|
||
x1 = r1->x1;
|
||
}
|
||
else
|
||
{
|
||
/*
|
||
* Subtrahend used up
|
||
*/
|
||
r2++;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/*
|
||
* Minuend used up: add any remaining piece before advancing.
|
||
*/
|
||
if (r1->x2 > x1)
|
||
{
|
||
MEMCHECK(pReg, pNextRect, pReg->rects);
|
||
pNextRect->x1 = x1;
|
||
pNextRect->y1 = y1;
|
||
pNextRect->x2 = r1->x2;
|
||
pNextRect->y2 = y2;
|
||
pReg->numRects += 1;
|
||
pNextRect++;
|
||
assert(pReg->numRects<=pReg->size);
|
||
}
|
||
r1++;
|
||
if (r1 != r1End)
|
||
x1 = r1->x1;
|
||
}
|
||
}
|
||
|
||
/*
|
||
* Add remaining minuend rectangles to region.
|
||
*/
|
||
while (r1 != r1End)
|
||
{
|
||
assert(x1<r1->x2);
|
||
MEMCHECK(pReg, pNextRect, pReg->rects);
|
||
pNextRect->x1 = x1;
|
||
pNextRect->y1 = y1;
|
||
pNextRect->x2 = r1->x2;
|
||
pNextRect->y2 = y2;
|
||
pReg->numRects += 1;
|
||
pNextRect++;
|
||
|
||
assert(pReg->numRects<=pReg->size);
|
||
|
||
r1++;
|
||
if (r1 != r1End)
|
||
{
|
||
x1 = r1->x1;
|
||
}
|
||
}
|
||
return 0; /* lint */
|
||
}
|
||
|
||
/*-
|
||
*-----------------------------------------------------------------------
|
||
* miSubtract --
|
||
* Subtract regS from regM and leave the result in regD.
|
||
* S stands for subtrahend, M for minuend and D for difference.
|
||
*
|
||
* Results:
|
||
* TRUE.
|
||
*
|
||
* Side Effects:
|
||
* regD is overwritten.
|
||
*
|
||
*-----------------------------------------------------------------------
|
||
*/
|
||
|
||
int
|
||
XSubtractRegion(
|
||
Region regM,
|
||
Region regS,
|
||
register Region regD)
|
||
{
|
||
/* check for trivial reject */
|
||
if ( (!(regM->numRects)) || (!(regS->numRects)) ||
|
||
(!EXTENTCHECK(®M->extents, ®S->extents)) )
|
||
{
|
||
return miRegionCopy(regD, regM);
|
||
}
|
||
|
||
miRegionOp (regD, regM, regS, miSubtractO,
|
||
miSubtractNonO1, NULL);
|
||
|
||
/*
|
||
* Can't alter newReg's extents before we call miRegionOp because
|
||
* it might be one of the source regions and miRegionOp depends
|
||
* on the extents of those regions being the unaltered. Besides, this
|
||
* way there's no checking against rectangles that will be nuked
|
||
* due to coalescing, so we have to examine fewer rectangles.
|
||
*/
|
||
miSetExtents (regD);
|
||
return 1;
|
||
}
|
||
|
||
int
|
||
XXorRegion(Region sra, Region srb, Region dr)
|
||
{
|
||
Region tra, trb;
|
||
|
||
if (! (tra = XCreateRegion()) )
|
||
return 0;
|
||
if (! (trb = XCreateRegion()) ) {
|
||
XDestroyRegion(tra);
|
||
return 0;
|
||
}
|
||
(void) XSubtractRegion(sra,srb,tra);
|
||
(void) XSubtractRegion(srb,sra,trb);
|
||
(void) XUnionRegion(tra,trb,dr);
|
||
XDestroyRegion(tra);
|
||
XDestroyRegion(trb);
|
||
return 0;
|
||
}
|
||
|
||
/*
|
||
* Check to see if the region is empty. Assumes a region is passed
|
||
* as a parameter
|
||
*/
|
||
int
|
||
XEmptyRegion(
|
||
Region r)
|
||
{
|
||
if( r->numRects == 0 ) return TRUE;
|
||
else return FALSE;
|
||
}
|
||
|
||
/*
|
||
* Check to see if two regions are equal
|
||
*/
|
||
int
|
||
XEqualRegion(Region r1, Region r2)
|
||
{
|
||
int i;
|
||
|
||
if( r1->numRects != r2->numRects ) return FALSE;
|
||
else if( r1->numRects == 0 ) return TRUE;
|
||
else if ( r1->extents.x1 != r2->extents.x1 ) return FALSE;
|
||
else if ( r1->extents.x2 != r2->extents.x2 ) return FALSE;
|
||
else if ( r1->extents.y1 != r2->extents.y1 ) return FALSE;
|
||
else if ( r1->extents.y2 != r2->extents.y2 ) return FALSE;
|
||
else for( i=0; i < r1->numRects; i++ ) {
|
||
if ( r1->rects[i].x1 != r2->rects[i].x1 ) return FALSE;
|
||
else if ( r1->rects[i].x2 != r2->rects[i].x2 ) return FALSE;
|
||
else if ( r1->rects[i].y1 != r2->rects[i].y1 ) return FALSE;
|
||
else if ( r1->rects[i].y2 != r2->rects[i].y2 ) return FALSE;
|
||
}
|
||
return TRUE;
|
||
}
|
||
|
||
int
|
||
XPointInRegion(
|
||
Region pRegion,
|
||
int x, int y)
|
||
{
|
||
int i;
|
||
|
||
if (pRegion->numRects == 0)
|
||
return FALSE;
|
||
if (!INBOX(pRegion->extents, x, y))
|
||
return FALSE;
|
||
for (i=0; i<pRegion->numRects; i++)
|
||
{
|
||
if (INBOX (pRegion->rects[i], x, y))
|
||
return TRUE;
|
||
}
|
||
return FALSE;
|
||
}
|
||
|
||
int
|
||
XRectInRegion(
|
||
register Region region,
|
||
int rx, int ry,
|
||
unsigned int rwidth, unsigned int rheight)
|
||
{
|
||
register BoxPtr pbox;
|
||
register BoxPtr pboxEnd;
|
||
Box rect;
|
||
register BoxPtr prect = ▭
|
||
int partIn, partOut;
|
||
|
||
prect->x1 = rx;
|
||
prect->y1 = ry;
|
||
prect->x2 = rwidth + rx;
|
||
prect->y2 = rheight + ry;
|
||
|
||
/* this is (just) a useful optimization */
|
||
if ((region->numRects == 0) || !EXTENTCHECK(®ion->extents, prect))
|
||
return(RectangleOut);
|
||
|
||
partOut = FALSE;
|
||
partIn = FALSE;
|
||
|
||
/* can stop when both partOut and partIn are TRUE, or we reach prect->y2 */
|
||
for (pbox = region->rects, pboxEnd = pbox + region->numRects;
|
||
pbox < pboxEnd;
|
||
pbox++)
|
||
{
|
||
|
||
if (pbox->y2 <= ry)
|
||
continue; /* getting up to speed or skipping remainder of band */
|
||
|
||
if (pbox->y1 > ry)
|
||
{
|
||
partOut = TRUE; /* missed part of rectangle above */
|
||
if (partIn || (pbox->y1 >= prect->y2))
|
||
break;
|
||
ry = pbox->y1; /* x guaranteed to be == prect->x1 */
|
||
}
|
||
|
||
if (pbox->x2 <= rx)
|
||
continue; /* not far enough over yet */
|
||
|
||
if (pbox->x1 > rx)
|
||
{
|
||
partOut = TRUE; /* missed part of rectangle to left */
|
||
if (partIn)
|
||
break;
|
||
}
|
||
|
||
if (pbox->x1 < prect->x2)
|
||
{
|
||
partIn = TRUE; /* definitely overlap */
|
||
if (partOut)
|
||
break;
|
||
}
|
||
|
||
if (pbox->x2 >= prect->x2)
|
||
{
|
||
ry = pbox->y2; /* finished with this band */
|
||
if (ry >= prect->y2)
|
||
break;
|
||
rx = prect->x1; /* reset x out to left again */
|
||
} else
|
||
{
|
||
/*
|
||
* Because boxes in a band are maximal width, if the first box
|
||
* to overlap the rectangle doesn't completely cover it in that
|
||
* band, the rectangle must be partially out, since some of it
|
||
* will be uncovered in that band. partIn will have been set true
|
||
* by now...
|
||
*/
|
||
break;
|
||
}
|
||
|
||
}
|
||
|
||
return(partIn ? ((ry < prect->y2) ? RectanglePart : RectangleIn) :
|
||
RectangleOut);
|
||
}
|