316 lines
7.6 KiB
C
316 lines
7.6 KiB
C
/* $XFree86: xc/programs/Xserver/mi/midash.c,v 1.4 2001/12/14 20:00:21 dawes Exp $ */
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/***********************************************************
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Copyright 1987, 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 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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/* $Xorg: midash.c,v 1.4 2001/02/09 02:05:20 xorgcvs Exp $ */
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#ifdef HAVE_DIX_CONFIG_H
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#include <dix-config.h>
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#endif
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#include "regionstr.h"
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#include "mistruct.h"
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#include "mifpoly.h"
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static miDashPtr CheckDashStorage(miDashPtr *ppseg, int nseg, int *pnsegMax);
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/* return a list of DashRec. there will be an extra
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entry at the end holding the last point of the polyline.
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this means that the code that actually draws dashes can
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get a pair of points for every dash. only the point in the last
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dash record is useful; the other fields are not used.
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nseg is the number of segments, not the number of points.
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example:
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dash1.start
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dash2.start
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dash3.start
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last-point
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defines a list of segments
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(dash1.pt, dash2.pt)
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(dash2.pt, dash3.pt)
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(dash3.pt, last-point)
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and nseg == 3.
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NOTE:
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EVEN_DASH == ~ODD_DASH
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NOTE ALSO:
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miDashLines may return 0 segments, going from pt[0] to pt[0] with one dash.
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*/
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miDashPtr
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miDashLine(npt, ppt, nDash, pDash, offset, pnseg)
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int npt;
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DDXPointPtr ppt;
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unsigned int nDash;
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unsigned char *pDash;
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unsigned int offset;
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int *pnseg;
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{
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DDXPointRec pt1, pt2;
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int lenCur; /* npt used from this dash */
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int lenMax; /* npt in this dash */
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int iDash = 0; /* index of current dash */
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int which; /* EVEN_DASH or ODD_DASH */
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miDashPtr pseg; /* list of dash segments */
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miDashPtr psegBase; /* start of list */
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int nseg = 0; /* number of dashes so far */
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int nsegMax = 0; /* num segs we can fit in this list */
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int x, y, len;
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int adx, ady, signdx, signdy;
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int du, dv, e1, e2, e, base_e = 0;
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lenCur = offset;
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which = EVEN_DASH;
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while(lenCur >= pDash[iDash])
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{
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lenCur -= pDash[iDash];
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iDash++;
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if (iDash >= nDash)
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iDash = 0;
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which = ~which;
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}
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lenMax = pDash[iDash];
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psegBase = (miDashPtr)NULL;
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pt2 = ppt[0]; /* just in case there is only one point */
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while(--npt)
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{
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if (PtEqual(ppt[0], ppt[1]))
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{
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ppt++;
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continue; /* no duplicated points in polyline */
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}
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pt1 = *ppt++;
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pt2 = *ppt;
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adx = pt2.x - pt1.x;
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ady = pt2.y - pt1.y;
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signdx = sign(adx);
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signdy = sign(ady);
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adx = abs(adx);
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ady = abs(ady);
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if (adx > ady)
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{
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du = adx;
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dv = ady;
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len = adx;
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}
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else
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{
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du = ady;
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dv = adx;
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len = ady;
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}
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e1 = dv * 2;
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e2 = e1 - 2*du;
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e = e1 - du;
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x = pt1.x;
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y = pt1.y;
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nseg++;
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pseg = CheckDashStorage(&psegBase, nseg, &nsegMax);
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if (!pseg)
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return (miDashPtr)NULL;
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pseg->pt = pt1;
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pseg->e1 = e1;
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pseg->e2 = e2;
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base_e = pseg->e = e;
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pseg->which = which;
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pseg->newLine = 1;
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while (len--)
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{
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if (adx > ady)
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{
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/* X_AXIS */
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if (((signdx > 0) && (e < 0)) ||
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((signdx <=0) && (e <=0))
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)
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{
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e += e1;
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}
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else
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{
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y += signdy;
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e += e2;
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}
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x += signdx;
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}
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else
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{
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/* Y_AXIS */
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if (((signdx > 0) && (e < 0)) ||
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((signdx <=0) && (e <=0))
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)
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{
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e +=e1;
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}
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else
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{
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x += signdx;
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e += e2;
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}
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y += signdy;
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}
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lenCur++;
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if (lenCur >= lenMax && (len || npt <= 1))
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{
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nseg++;
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pseg = CheckDashStorage(&psegBase, nseg, &nsegMax);
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if (!pseg)
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return (miDashPtr)NULL;
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pseg->pt.x = x;
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pseg->pt.y = y;
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pseg->e1 = e1;
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pseg->e2 = e2;
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pseg->e = e;
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which = ~which;
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pseg->which = which;
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pseg->newLine = 0;
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/* move on to next dash */
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iDash++;
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if (iDash >= nDash)
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iDash = 0;
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lenMax = pDash[iDash];
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lenCur = 0;
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}
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} /* while len-- */
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} /* while --npt */
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if (lenCur == 0 && nseg != 0)
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{
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nseg--;
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which = ~which;
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}
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*pnseg = nseg;
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pseg = CheckDashStorage(&psegBase, nseg+1, &nsegMax);
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if (!pseg)
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return (miDashPtr)NULL;
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pseg->pt = pt2;
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pseg->e = base_e;
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pseg->which = which;
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pseg->newLine = 0;
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return psegBase;
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}
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#define NSEGDELTA 16
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/* returns a pointer to the pseg[nseg-1], growing the storage as
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necessary. this interface seems unnecessarily cumbersome.
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*/
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static
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miDashPtr
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CheckDashStorage(
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miDashPtr *ppseg, /* base pointer */
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int nseg, /* number of segment we want to write to */
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int *pnsegMax) /* size (in segments) of list so far */
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{
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if (nseg > *pnsegMax)
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{
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miDashPtr newppseg;
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*pnsegMax += NSEGDELTA;
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newppseg = (miDashPtr)xrealloc(*ppseg,
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(*pnsegMax)*sizeof(miDashRec));
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if (!newppseg)
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{
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xfree(*ppseg);
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return (miDashPtr)NULL;
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}
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*ppseg = newppseg;
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}
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return(*ppseg+(nseg-1));
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}
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_X_EXPORT void
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miStepDash (dist, pDashIndex, pDash, numInDashList, pDashOffset)
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int dist; /* distance to step */
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int *pDashIndex; /* current dash */
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unsigned char *pDash; /* dash list */
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int numInDashList; /* total length of dash list */
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int *pDashOffset; /* offset into current dash */
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{
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int dashIndex, dashOffset;
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int totallen;
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int i;
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dashIndex = *pDashIndex;
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dashOffset = *pDashOffset;
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if (dist < pDash[dashIndex] - dashOffset)
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{
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*pDashOffset = dashOffset + dist;
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return;
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}
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dist -= pDash[dashIndex] - dashOffset;
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if (++dashIndex == numInDashList)
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dashIndex = 0;
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totallen = 0;
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for (i = 0; i < numInDashList; i++)
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totallen += pDash[i];
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if (totallen <= dist)
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dist = dist % totallen;
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while (dist >= pDash[dashIndex])
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{
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dist -= pDash[dashIndex];
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if (++dashIndex == numInDashList)
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dashIndex = 0;
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}
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*pDashIndex = dashIndex;
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*pDashOffset = dist;
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}
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