| 1 | /*********************************************************** |
| 2 | |
| 3 | Copyright 1987, 1998 The Open Group |
| 4 | |
| 5 | Permission to use, copy, modify, distribute, and sell this software and its |
| 6 | documentation for any purpose is hereby granted without fee, provided that |
| 7 | the above copyright notice appear in all copies and that both that |
| 8 | copyright notice and this permission notice appear in supporting |
| 9 | documentation. |
| 10 | |
| 11 | The above copyright notice and this permission notice shall be included in |
| 12 | all copies or substantial portions of the Software. |
| 13 | |
| 14 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 15 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 16 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| 17 | OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN |
| 18 | AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
| 19 | CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| 20 | |
| 21 | Except as contained in this notice, the name of The Open Group shall not be |
| 22 | used in advertising or otherwise to promote the sale, use or other dealings |
| 23 | in this Software without prior written authorization from The Open Group. |
| 24 | |
| 25 | Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts. |
| 26 | |
| 27 | All Rights Reserved |
| 28 | |
| 29 | Permission to use, copy, modify, and distribute this software and its |
| 30 | documentation for any purpose and without fee is hereby granted, |
| 31 | provided that the above copyright notice appear in all copies and that |
| 32 | both that copyright notice and this permission notice appear in |
| 33 | supporting documentation, and that the name of Digital not be |
| 34 | used in advertising or publicity pertaining to distribution of the |
| 35 | software without specific, written prior permission. |
| 36 | |
| 37 | DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING |
| 38 | ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL |
| 39 | DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR |
| 40 | ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, |
| 41 | WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, |
| 42 | ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS |
| 43 | SOFTWARE. |
| 44 | |
| 45 | ******************************************************************/ |
| 46 | |
| 47 | #ifdef HAVE_DIX_CONFIG_H |
| 48 | #include <dix-config.h> |
| 49 | #endif |
| 50 | |
| 51 | #include "gcstruct.h" |
| 52 | #include "pixmap.h" |
| 53 | #include "mi.h" |
| 54 | #include "miscanfill.h" |
| 55 | |
| 56 | static int getPolyYBounds(DDXPointPtr pts, int n, int *by, int *ty); |
| 57 | |
| 58 | /* |
| 59 | * convexpoly.c |
| 60 | * |
| 61 | * Written by Brian Kelleher; Dec. 1985. |
| 62 | * |
| 63 | * Fill a convex polygon. If the given polygon |
| 64 | * is not convex, then the result is undefined. |
| 65 | * The algorithm is to order the edges from smallest |
| 66 | * y to largest by partitioning the array into a left |
| 67 | * edge list and a right edge list. The algorithm used |
| 68 | * to traverse each edge is an extension of Bresenham's |
| 69 | * line algorithm with y as the major axis. |
| 70 | * For a derivation of the algorithm, see the author of |
| 71 | * this code. |
| 72 | */ |
| 73 | Bool |
| 74 | miFillConvexPoly(DrawablePtr dst, GCPtr pgc, int count, /* number of points */ |
| 75 | DDXPointPtr ptsIn /* the points */ |
| 76 | ) |
| 77 | { |
| 78 | int xl = 0, xr = 0; /* x vals of left and right edges */ |
| 79 | int dl = 0, dr = 0; /* decision variables */ |
| 80 | int ml = 0, m1l = 0; /* left edge slope and slope+1 */ |
| 81 | int mr = 0, m1r = 0; /* right edge slope and slope+1 */ |
| 82 | int incr1l = 0, incr2l = 0; /* left edge error increments */ |
| 83 | int incr1r = 0, incr2r = 0; /* right edge error increments */ |
| 84 | int dy; /* delta y */ |
| 85 | int y; /* current scanline */ |
| 86 | int left, right; /* indices to first endpoints */ |
| 87 | int i; /* loop counter */ |
| 88 | int nextleft, nextright; /* indices to second endpoints */ |
| 89 | DDXPointPtr ptsOut, FirstPoint; /* output buffer */ |
| 90 | int *width, *FirstWidth; /* output buffer */ |
| 91 | int imin; /* index of smallest vertex (in y) */ |
| 92 | int ymin; /* y-extents of polygon */ |
| 93 | int ymax; |
| 94 | |
| 95 | /* |
| 96 | * find leftx, bottomy, rightx, topy, and the index |
| 97 | * of bottomy. Also translate the points. |
| 98 | */ |
| 99 | imin = getPolyYBounds(ptsIn, count, &ymin, &ymax); |
| 100 | |
| 101 | dy = ymax - ymin + 1; |
| 102 | if ((count < 3) || (dy < 0)) |
| 103 | return TRUE; |
| 104 | ptsOut = FirstPoint = malloc(sizeof(DDXPointRec) * dy); |
| 105 | width = FirstWidth = malloc(sizeof(int) * dy); |
| 106 | if (!FirstPoint || !FirstWidth) { |
| 107 | free(FirstWidth); |
| 108 | free(FirstPoint); |
| 109 | return FALSE; |
| 110 | } |
| 111 | |
| 112 | nextleft = nextright = imin; |
| 113 | y = ptsIn[nextleft].y; |
| 114 | |
| 115 | /* |
| 116 | * loop through all edges of the polygon |
| 117 | */ |
| 118 | do { |
| 119 | /* |
| 120 | * add a left edge if we need to |
| 121 | */ |
| 122 | if (ptsIn[nextleft].y == y) { |
| 123 | left = nextleft; |
| 124 | |
| 125 | /* |
| 126 | * find the next edge, considering the end |
| 127 | * conditions of the array. |
| 128 | */ |
| 129 | nextleft++; |
| 130 | if (nextleft >= count) |
| 131 | nextleft = 0; |
| 132 | |
| 133 | /* |
| 134 | * now compute all of the random information |
| 135 | * needed to run the iterative algorithm. |
| 136 | */ |
| 137 | BRESINITPGON(ptsIn[nextleft].y - ptsIn[left].y, |
| 138 | ptsIn[left].x, ptsIn[nextleft].x, |
| 139 | xl, dl, ml, m1l, incr1l, incr2l); |
| 140 | } |
| 141 | |
| 142 | /* |
| 143 | * add a right edge if we need to |
| 144 | */ |
| 145 | if (ptsIn[nextright].y == y) { |
| 146 | right = nextright; |
| 147 | |
| 148 | /* |
| 149 | * find the next edge, considering the end |
| 150 | * conditions of the array. |
| 151 | */ |
| 152 | nextright--; |
| 153 | if (nextright < 0) |
| 154 | nextright = count - 1; |
| 155 | |
| 156 | /* |
| 157 | * now compute all of the random information |
| 158 | * needed to run the iterative algorithm. |
| 159 | */ |
| 160 | BRESINITPGON(ptsIn[nextright].y - ptsIn[right].y, |
| 161 | ptsIn[right].x, ptsIn[nextright].x, |
| 162 | xr, dr, mr, m1r, incr1r, incr2r); |
| 163 | } |
| 164 | |
| 165 | /* |
| 166 | * generate scans to fill while we still have |
| 167 | * a right edge as well as a left edge. |
| 168 | */ |
| 169 | i = min(ptsIn[nextleft].y, ptsIn[nextright].y) - y; |
| 170 | /* in case we're called with non-convex polygon */ |
| 171 | if (i < 0) { |
| 172 | free(FirstWidth); |
| 173 | free(FirstPoint); |
| 174 | return TRUE; |
| 175 | } |
| 176 | while (i-- > 0) { |
| 177 | ptsOut->y = y; |
| 178 | |
| 179 | /* |
| 180 | * reverse the edges if necessary |
| 181 | */ |
| 182 | if (xl < xr) { |
| 183 | *(width++) = xr - xl; |
| 184 | (ptsOut++)->x = xl; |
| 185 | } |
| 186 | else { |
| 187 | *(width++) = xl - xr; |
| 188 | (ptsOut++)->x = xr; |
| 189 | } |
| 190 | y++; |
| 191 | |
| 192 | /* increment down the edges */ |
| 193 | BRESINCRPGON(dl, xl, ml, m1l, incr1l, incr2l); |
| 194 | BRESINCRPGON(dr, xr, mr, m1r, incr1r, incr2r); |
| 195 | } |
| 196 | } while (y != ymax); |
| 197 | |
| 198 | /* |
| 199 | * Finally, fill the <remaining> spans |
| 200 | */ |
| 201 | (*pgc->ops->FillSpans) (dst, pgc, |
| 202 | ptsOut - FirstPoint, FirstPoint, FirstWidth, 1); |
| 203 | free(FirstWidth); |
| 204 | free(FirstPoint); |
| 205 | return TRUE; |
| 206 | } |
| 207 | \f |
| 208 | /* |
| 209 | * Find the index of the point with the smallest y. |
| 210 | */ |
| 211 | static int |
| 212 | getPolyYBounds(DDXPointPtr pts, int n, int *by, int *ty) |
| 213 | { |
| 214 | DDXPointPtr ptMin; |
| 215 | int ymin, ymax; |
| 216 | DDXPointPtr ptsStart = pts; |
| 217 | |
| 218 | ptMin = pts; |
| 219 | ymin = ymax = (pts++)->y; |
| 220 | |
| 221 | while (--n > 0) { |
| 222 | if (pts->y < ymin) { |
| 223 | ptMin = pts; |
| 224 | ymin = pts->y; |
| 225 | } |
| 226 | if (pts->y > ymax) |
| 227 | ymax = pts->y; |
| 228 | |
| 229 | pts++; |
| 230 | } |
| 231 | |
| 232 | *by = ymin; |
| 233 | *ty = ymax; |
| 234 | return ptMin - ptsStart; |
| 235 | } |