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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.
+
+******************************************************************/
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#include <math.h>
+#include <X11/X.h>
+#include "gcstruct.h"
+#include "windowstr.h"
+#include "pixmapstr.h"
+#include "mifpoly.h"
+
+static int GetFPolyYBounds(SppPointPtr pts, int n, double yFtrans,
+ int *by, int *ty);
+
+/*
+ * Written by Todd Newman; April. 1987.
+ *
+ * Fill a convex polygon. If the given polygon
+ * is not convex, then the result is undefined.
+ * The algorithm is to order the edges from smallest
+ * y to largest by partitioning the array into a left
+ * edge list and a right edge list. The algorithm used
+ * to traverse each edge is digital differencing analyzer
+ * line algorithm with y as the major axis. There's some funny linear
+ * interpolation involved because of the subpixel postioning.
+ */
+void
+miFillSppPoly(dst, pgc, count, ptsIn, xTrans, yTrans, xFtrans, yFtrans)
+ DrawablePtr dst;
+ GCPtr pgc;
+ int count; /* number of points */
+ SppPointPtr ptsIn; /* the points */
+ int xTrans, yTrans; /* Translate each point by this */
+ double xFtrans, yFtrans; /* translate before conversion
+ by this amount. This provides
+ a mechanism to match rounding
+ errors with any shape that must
+ meet the polygon exactly.
+ */
+{
+ double xl = 0.0, xr = 0.0, /* x vals of left and right edges */
+ ml = 0.0, /* left edge slope */
+ mr = 0.0, /* right edge slope */
+ dy, /* delta y */
+ i; /* loop counter */
+ int y, /* current scanline */
+ j,
+ imin, /* index of vertex with smallest y */
+ ymin, /* y-extents of polygon */
+ ymax,
+ *width,
+ *FirstWidth, /* output buffer */
+ *Marked; /* set if this vertex has been used */
+ int left, right, /* indices to first endpoints */
+ nextleft,
+ nextright; /* indices to second endpoints */
+ DDXPointPtr ptsOut,
+ FirstPoint; /* output buffer */
+
+ if (pgc->miTranslate)
+ {
+ xTrans += dst->x;
+ yTrans += dst->y;
+ }
+
+ imin = GetFPolyYBounds(ptsIn, count, yFtrans, &ymin, &ymax);
+
+ y = ymax - ymin + 1;
+ if ((count < 3) || (y <= 0))
+ return;
+ ptsOut = FirstPoint = (DDXPointPtr)xalloc(sizeof(DDXPointRec) * y);
+ width = FirstWidth = (int *) xalloc(sizeof(int) * y);
+ Marked = (int *) xalloc(sizeof(int) * count);
+
+ if(!ptsOut || !width || !Marked)
+ {
+ if (Marked) xfree(Marked);
+ if (width) xfree(width);
+ if (ptsOut) xfree(ptsOut);
+ return;
+ }
+
+ for(j = 0; j < count; j++)
+ Marked[j] = 0;
+ nextleft = nextright = imin;
+ Marked[imin] = -1;
+ y = ICEIL(ptsIn[nextleft].y + yFtrans);
+
+ /*
+ * loop through all edges of the polygon
+ */
+ do
+ {
+ /* add a left edge if we need to */
+ if ((y > (ptsIn[nextleft].y + yFtrans) ||
+ ISEQUAL(y, ptsIn[nextleft].y + yFtrans)) &&
+ Marked[nextleft] != 1)
+ {
+ Marked[nextleft]++;
+ left = nextleft++;
+
+ /* find the next edge, considering the end conditions */
+ if (nextleft >= count)
+ nextleft = 0;
+
+ /* now compute the starting point and slope */
+ dy = ptsIn[nextleft].y - ptsIn[left].y;
+ if (dy != 0.0)
+ {
+ ml = (ptsIn[nextleft].x - ptsIn[left].x) / dy;
+ dy = y - (ptsIn[left].y + yFtrans);
+ xl = (ptsIn[left].x + xFtrans) + ml * max(dy, 0);
+ }
+ }
+
+ /* add a right edge if we need to */
+ if ((y > ptsIn[nextright].y + yFtrans) ||
+ (ISEQUAL(y, ptsIn[nextright].y + yFtrans)
+ && Marked[nextright] != 1))
+ {
+ Marked[nextright]++;
+ right = nextright--;
+
+ /* find the next edge, considering the end conditions */
+ if (nextright < 0)
+ nextright = count - 1;
+
+ /* now compute the starting point and slope */
+ dy = ptsIn[nextright].y - ptsIn[right].y;
+ if (dy != 0.0)
+ {
+ mr = (ptsIn[nextright].x - ptsIn[right].x) / dy;
+ dy = y - (ptsIn[right].y + yFtrans);
+ xr = (ptsIn[right].x + xFtrans) + mr * max(dy, 0);
+ }
+ }
+
+
+ /*
+ * generate scans to fill while we still have
+ * a right edge as well as a left edge.
+ */
+ i = (min(ptsIn[nextleft].y, ptsIn[nextright].y) + yFtrans) - y;
+
+ if (i < EPSILON)
+ {
+ if(Marked[nextleft] && Marked[nextright])
+ {
+ /* Arrgh, we're trapped! (no more points)
+ * Out, we've got to get out of here before this decadence saps
+ * our will completely! */
+ break;
+ }
+ continue;
+ }
+ else
+ {
+ j = (int) i;
+ if(!j)
+ j++;
+ }
+ while (j > 0)
+ {
+ int cxl, cxr;
+
+ ptsOut->y = (y) + yTrans;
+
+ cxl = ICEIL(xl);
+ cxr = ICEIL(xr);
+ /* reverse the edges if necessary */
+ if (xl < xr)
+ {
+ *(width++) = cxr - cxl;
+ (ptsOut++)->x = cxl + xTrans;
+ }
+ else
+ {
+ *(width++) = cxl - cxr;
+ (ptsOut++)->x = cxr + xTrans;
+ }
+ y++;
+
+ /* increment down the edges */
+ xl += ml;
+ xr += mr;
+ j--;
+ }
+ } while (y <= ymax);
+
+ /* Finally, fill the spans we've collected */
+ (*pgc->ops->FillSpans)(dst, pgc,
+ ptsOut-FirstPoint, FirstPoint, FirstWidth, 1);
+ xfree(Marked);
+ xfree(FirstWidth);
+ xfree(FirstPoint);
+}
+
+
+/* Find the index of the point with the smallest y.also return the
+ * smallest and largest y */
+static
+int
+GetFPolyYBounds(
+ SppPointPtr pts,
+ int n,
+ double yFtrans,
+ int *by,
+ int *ty)
+{
+ SppPointPtr ptMin;
+ double ymin, ymax;
+ SppPointPtr ptsStart = pts;
+
+ ptMin = pts;
+ ymin = ymax = (pts++)->y;
+
+ while (--n > 0) {
+ if (pts->y < ymin)
+ {
+ ptMin = pts;
+ ymin = pts->y;
+ }
+ if(pts->y > ymax)
+ ymax = pts->y;
+
+ pts++;
+ }
+
+ *by = ICEIL(ymin + yFtrans);
+ *ty = ICEIL(ymax + yFtrans - 1);
+ return(ptMin-ptsStart);
+}