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Diffstat (limited to 'mi/mipolycon.c')
| -rw-r--r-- | mi/mipolycon.c | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/mi/mipolycon.c b/mi/mipolycon.c new file mode 100644 index 000000000..9daf44543 --- /dev/null +++ b/mi/mipolycon.c @@ -0,0 +1,245 @@ +/*********************************************************** + +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: mipolycon.c,v 1.4 2001/02/09 02:05:21 xorgcvs Exp $ */ +#include "gcstruct.h" +#include "pixmap.h" +#include "miscanfill.h" + +static int getPolyYBounds(); + +/* + * convexpoly.c + * + * Written by Brian Kelleher; Dec. 1985. + * + * 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 an extension of Bresenham's + * line algorithm with y as the major axis. + * For a derivation of the algorithm, see the author of + * this code. + */ +Bool +miFillConvexPoly(dst, pgc, count, ptsIn) + DrawablePtr dst; + GCPtr pgc; + int count; /* number of points */ + DDXPointPtr ptsIn; /* the points */ +{ + register int xl, xr; /* x vals of left and right edges */ + register int dl, dr; /* decision variables */ + register int ml, m1l; /* left edge slope and slope+1 */ + int mr, m1r; /* right edge slope and slope+1 */ + int incr1l, incr2l; /* left edge error increments */ + int incr1r, incr2r; /* right edge error increments */ + int dy; /* delta y */ + int y; /* current scanline */ + int left, right; /* indices to first endpoints */ + int i; /* loop counter */ + int nextleft, nextright; /* indices to second endpoints */ + DDXPointPtr ptsOut, FirstPoint; /* output buffer */ + int *width, *FirstWidth; /* output buffer */ + int imin; /* index of smallest vertex (in y) */ + int ymin; /* y-extents of polygon */ + int ymax; + + /* + * find leftx, bottomy, rightx, topy, and the index + * of bottomy. Also translate the points. + */ + imin = getPolyYBounds(ptsIn, count, &ymin, &ymax); + + dy = ymax - ymin + 1; + if ((count < 3) || (dy < 0)) + return(TRUE); + ptsOut = FirstPoint = (DDXPointPtr )ALLOCATE_LOCAL(sizeof(DDXPointRec)*dy); + width = FirstWidth = (int *)ALLOCATE_LOCAL(sizeof(int) * dy); + if(!FirstPoint || !FirstWidth) + { + if (FirstWidth) DEALLOCATE_LOCAL(FirstWidth); + if (FirstPoint) DEALLOCATE_LOCAL(FirstPoint); + return(FALSE); + } + + nextleft = nextright = imin; + y = ptsIn[nextleft].y; + + /* + * loop through all edges of the polygon + */ + do { + /* + * add a left edge if we need to + */ + if (ptsIn[nextleft].y == y) { + left = nextleft; + + /* + * find the next edge, considering the end + * conditions of the array. + */ + nextleft++; + if (nextleft >= count) + nextleft = 0; + + /* + * now compute all of the random information + * needed to run the iterative algorithm. + */ + BRESINITPGON(ptsIn[nextleft].y-ptsIn[left].y, + ptsIn[left].x,ptsIn[nextleft].x, + xl, dl, ml, m1l, incr1l, incr2l); + } + + /* + * add a right edge if we need to + */ + if (ptsIn[nextright].y == y) { + right = nextright; + + /* + * find the next edge, considering the end + * conditions of the array. + */ + nextright--; + if (nextright < 0) + nextright = count-1; + + /* + * now compute all of the random information + * needed to run the iterative algorithm. + */ + BRESINITPGON(ptsIn[nextright].y-ptsIn[right].y, + ptsIn[right].x,ptsIn[nextright].x, + xr, dr, mr, m1r, incr1r, incr2r); + } + + /* + * 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) - y; + /* in case we're called with non-convex polygon */ + if(i < 0) + { + DEALLOCATE_LOCAL(FirstWidth); + DEALLOCATE_LOCAL(FirstPoint); + return(TRUE); + } + while (i-- > 0) + { + ptsOut->y = y; + + /* + * reverse the edges if necessary + */ + if (xl < xr) + { + *(width++) = xr - xl; + (ptsOut++)->x = xl; + } + else + { + *(width++) = xl - xr; + (ptsOut++)->x = xr; + } + y++; + + /* increment down the edges */ + BRESINCRPGON(dl, xl, ml, m1l, incr1l, incr2l); + BRESINCRPGON(dr, xr, mr, m1r, incr1r, incr2r); + } + } while (y != ymax); + + /* + * Finally, fill the <remaining> spans + */ + (*pgc->ops->FillSpans)(dst, pgc, + ptsOut-FirstPoint,FirstPoint,FirstWidth, + 1); + DEALLOCATE_LOCAL(FirstWidth); + DEALLOCATE_LOCAL(FirstPoint); + return(TRUE); +} + + +/* + * Find the index of the point with the smallest y. + */ +static +int +getPolyYBounds(pts, n, by, ty) + DDXPointPtr pts; + int n; + int *by, *ty; +{ + register DDXPointPtr ptMin; + int ymin, ymax; + DDXPointPtr 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 = ymin; + *ty = ymax; + return(ptMin-ptsStart); +} |