/*********************************************************** Copyright 1987, 1998 The Open Group All Rights Reserved. The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. Except as contained in this notice, the name of The Open Group shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization from The Open Group. Copyright 1987 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. ******************************************************************/ /* $TOG: mifpolycon.c /main/13 1998/02/09 14:47:05 kaleb $ */ #include #include #include "mi.h" #include "mifpoly.h" static int GetFPolyYBounds(); #ifdef ICEILTEMPDECL ICEILTEMPDECL #endif /* * 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(GdkDrawable *dst, GdkGC *pgc, int count, SppPointPtr ptsIn, int xTrans, int yTrans, double xFtrans, double yFtrans) #if 0 GdkDrawable* dst; GdkGC* 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. */ #endif { 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, *Marked; /* set if this vertex has been used */ register int left, right, /* indices to first endpoints */ nextleft, nextright; /* indices to second endpoints */ GdkSpan* ptsOut, *FirstPoint; /* output buffer */ imin = GetFPolyYBounds(ptsIn, count, yFtrans, &ymin, &ymax); y = ymax - ymin + 1; if ((count < 3) || (y <= 0)) return; ptsOut = FirstPoint = (GdkSpan*)ALLOCATE_LOCAL(sizeof(GdkSpan) * y); Marked = (int *) ALLOCATE_LOCAL(sizeof(int) * count); if(!ptsOut || !Marked) { if (Marked) DEALLOCATE_LOCAL(Marked); if (ptsOut) DEALLOCATE_LOCAL(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) { ptsOut->width = cxr - cxl; (ptsOut++)->x = cxl + xTrans; } else { ptsOut->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 */ gdk_fb_fill_spans(dst, pgc, FirstPoint, ptsOut-FirstPoint, TRUE); DEALLOCATE_LOCAL(Marked); DEALLOCATE_LOCAL(FirstPoint); } /* Find the index of the point with the smallest y.also return the * smallest and largest y */ static int GetFPolyYBounds(pts, n, yFtrans, by, ty) register SppPointPtr pts; int n; double yFtrans; int *by, *ty; { register 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); }