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+/***********************************************************
+
+Copyright 1987, 1998 The Open Group
+
+Permission to use, copy, modify, distribute, and sell this software and its
+documentation for any purpose is hereby granted without fee, provided that
+the above copyright notice appear in all copies and that both that
+copyright notice and this permission notice appear in supporting
+documentation.
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+Except as contained in this notice, the name of The Open Group shall not be
+used in advertising or otherwise to promote the sale, use or other dealings
+in this Software without prior written authorization from The Open Group.
+
+
+Copyright 1987 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.
+
+******************************************************************/
+/* $Xorg: midash.c,v 1.4 2001/02/09 02:05:20 xorgcvs Exp $ */
+#include "miscstruct.h"
+#include "mistruct.h"
+#include "mifpoly.h"
+
+static miDashPtr CheckDashStorage();
+
+/* return a list of DashRec. there will be an extra
+entry at the end holding the last point of the polyline.
+ this means that the code that actually draws dashes can
+get a pair of points for every dash. only the point in the last
+dash record is useful; the other fields are not used.
+ nseg is the number of segments, not the number of points.
+
+example:
+
+ dash1.start
+ dash2.start
+ dash3.start
+ last-point
+
+defines a list of segments
+ (dash1.pt, dash2.pt)
+ (dash2.pt, dash3.pt)
+ (dash3.pt, last-point)
+and nseg == 3.
+
+NOTE:
+ EVEN_DASH == ~ODD_DASH
+
+NOTE ALSO:
+ miDashLines may return 0 segments, going from pt[0] to pt[0] with one dash.
+*/
+
+miDashPtr
+miDashLine(npt, ppt, nDash, pDash, offset, pnseg)
+int npt;
+DDXPointPtr ppt;
+unsigned int nDash;
+unsigned char *pDash;
+unsigned int offset;
+int *pnseg;
+{
+ DDXPointRec pt1, pt2;
+ int lenCur; /* npt used from this dash */
+ int lenMax; /* npt in this dash */
+ int iDash = 0; /* index of current dash */
+ int which; /* EVEN_DASH or ODD_DASH */
+ miDashPtr pseg; /* list of dash segments */
+ miDashPtr psegBase; /* start of list */
+ int nseg = 0; /* number of dashes so far */
+ int nsegMax = 0; /* num segs we can fit in this list */
+
+ int x, y, len;
+ int adx, ady, signdx, signdy;
+ int du, dv, e1, e2, e, base_e = 0;
+
+ lenCur = offset;
+ which = EVEN_DASH;
+ while(lenCur >= pDash[iDash])
+ {
+ lenCur -= pDash[iDash];
+ iDash++;
+ if (iDash >= nDash)
+ iDash = 0;
+ which = ~which;
+ }
+ lenMax = pDash[iDash];
+
+ psegBase = (miDashPtr)NULL;
+ pt2 = ppt[0]; /* just in case there is only one point */
+
+ while(--npt)
+ {
+ if (PtEqual(ppt[0], ppt[1]))
+ {
+ ppt++;
+ continue; /* no duplicated points in polyline */
+ }
+ pt1 = *ppt++;
+ pt2 = *ppt;
+
+ adx = pt2.x - pt1.x;
+ ady = pt2.y - pt1.y;
+ signdx = sign(adx);
+ signdy = sign(ady);
+ adx = abs(adx);
+ ady = abs(ady);
+
+ if (adx > ady)
+ {
+ du = adx;
+ dv = ady;
+ len = adx;
+ }
+ else
+ {
+ du = ady;
+ dv = adx;
+ len = ady;
+ }
+
+ e1 = dv * 2;
+ e2 = e1 - 2*du;
+ e = e1 - du;
+ x = pt1.x;
+ y = pt1.y;
+
+ nseg++;
+ pseg = CheckDashStorage(&psegBase, nseg, &nsegMax);
+ if (!pseg)
+ return (miDashPtr)NULL;
+ pseg->pt = pt1;
+ pseg->e1 = e1;
+ pseg->e2 = e2;
+ base_e = pseg->e = e;
+ pseg->which = which;
+ pseg->newLine = 1;
+
+ while (len--)
+ {
+ if (adx > ady)
+ {
+ /* X_AXIS */
+ if (((signdx > 0) && (e < 0)) ||
+ ((signdx <=0) && (e <=0))
+ )
+ {
+ e += e1;
+ }
+ else
+ {
+ y += signdy;
+ e += e2;
+ }
+ x += signdx;
+ }
+ else
+ {
+ /* Y_AXIS */
+ if (((signdx > 0) && (e < 0)) ||
+ ((signdx <=0) && (e <=0))
+ )
+ {
+ e +=e1;
+ }
+ else
+ {
+ x += signdx;
+ e += e2;
+ }
+ y += signdy;
+ }
+
+ lenCur++;
+ if (lenCur >= lenMax && (len || npt <= 1))
+ {
+ nseg++;
+ pseg = CheckDashStorage(&psegBase, nseg, &nsegMax);
+ if (!pseg)
+ return (miDashPtr)NULL;
+ pseg->pt.x = x;
+ pseg->pt.y = y;
+ pseg->e1 = e1;
+ pseg->e2 = e2;
+ pseg->e = e;
+ which = ~which;
+ pseg->which = which;
+ pseg->newLine = 0;
+
+ /* move on to next dash */
+ iDash++;
+ if (iDash >= nDash)
+ iDash = 0;
+ lenMax = pDash[iDash];
+ lenCur = 0;
+ }
+ } /* while len-- */
+ } /* while --npt */
+
+ if (lenCur == 0 && nseg != 0)
+ {
+ nseg--;
+ which = ~which;
+ }
+ *pnseg = nseg;
+ pseg = CheckDashStorage(&psegBase, nseg+1, &nsegMax);
+ if (!pseg)
+ return (miDashPtr)NULL;
+ pseg->pt = pt2;
+ pseg->e = base_e;
+ pseg->which = which;
+ pseg->newLine = 0;
+ return psegBase;
+}
+
+
+#define NSEGDELTA 16
+
+/* returns a pointer to the pseg[nseg-1], growing the storage as
+necessary. this interface seems unnecessarily cumbersome.
+
+*/
+
+static
+miDashPtr
+CheckDashStorage(ppseg, nseg, pnsegMax)
+miDashPtr *ppseg; /* base pointer */
+int nseg; /* number of segment we want to write to */
+int *pnsegMax; /* size (in segments) of list so far */
+{
+ if (nseg > *pnsegMax)
+ {
+ miDashPtr newppseg;
+
+ *pnsegMax += NSEGDELTA;
+ newppseg = (miDashPtr)xrealloc(*ppseg,
+ (*pnsegMax)*sizeof(miDashRec));
+ if (!newppseg)
+ {
+ xfree(*ppseg);
+ return (miDashPtr)NULL;
+ }
+ *ppseg = newppseg;
+ }
+ return(*ppseg+(nseg-1));
+}
+
+void
+miStepDash (dist, pDashIndex, pDash, numInDashList, pDashOffset)
+ int dist; /* distance to step */
+ int *pDashIndex; /* current dash */
+ unsigned char *pDash; /* dash list */
+ int numInDashList; /* total length of dash list */
+ int *pDashOffset; /* offset into current dash */
+{
+ int dashIndex, dashOffset;
+ int totallen;
+ int i;
+
+ dashIndex = *pDashIndex;
+ dashOffset = *pDashOffset;
+ if (dist < pDash[dashIndex] - dashOffset)
+ {
+ *pDashOffset = dashOffset + dist;
+ return;
+ }
+ dist -= pDash[dashIndex] - dashOffset;
+ if (++dashIndex == numInDashList)
+ dashIndex = 0;
+ totallen = 0;
+ for (i = 0; i < numInDashList; i++)
+ totallen += pDash[i];
+ if (totallen <= dist)
+ dist = dist % totallen;
+ while (dist >= pDash[dashIndex])
+ {
+ dist -= pDash[dashIndex];
+ if (++dashIndex == numInDashList)
+ dashIndex = 0;
+ }
+ *pDashIndex = dashIndex;
+ *pDashOffset = dist;
+}
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