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Diffstat (limited to 'mi/mifpolycon.c')
| -rw-r--r-- | mi/mifpolycon.c | 277 |
1 files changed, 277 insertions, 0 deletions
diff --git a/mi/mifpolycon.c b/mi/mifpolycon.c new file mode 100644 index 000000000..0b6655186 --- /dev/null +++ b/mi/mifpolycon.c @@ -0,0 +1,277 @@ +/*********************************************************** + +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: mifpolycon.c,v 1.4 2001/02/09 02:05:21 xorgcvs Exp $ */ +#include <math.h> +#include "X.h" +#include "gcstruct.h" +#include "windowstr.h" +#include "pixmapstr.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(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, xr, /* x vals of left and right edges */ + ml, /* left edge slope */ + mr, /* 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 */ + register 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)ALLOCATE_LOCAL(sizeof(DDXPointRec) * y); + width = FirstWidth = (int *) ALLOCATE_LOCAL(sizeof(int) * y); + Marked = (int *) ALLOCATE_LOCAL(sizeof(int) * count); + + if(!ptsOut || !width || !Marked) + { + if (Marked) DEALLOCATE_LOCAL(Marked); + if (width) DEALLOCATE_LOCAL(width); + 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) + { + *(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); + DEALLOCATE_LOCAL(Marked); + DEALLOCATE_LOCAL(FirstWidth); + 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); +} |