1 /* Libart_LGPL - library of basic graphic primitives
2 * Copyright (C) 1999 Raph Levien
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
21 #include "art_svp_point.h"
28 /* Determine whether a point is inside, or near, an svp. */
30 /* return winding number of point wrt svp */
32 * art_svp_point_wind: Determine winding number of a point with respect to svp.
34 * @x: The X coordinate of the point.
35 * @y: The Y coordinate of the point.
37 * Determine the winding number of the point @x, @y with respect to @svp.
39 * Return value: the winding number.
42 art_svp_point_wind (ArtSVP *svp, double x, double y)
47 for (i = 0; i < svp->n_segs; i++)
49 ArtSVPSeg *seg = &svp->segs[i];
57 wind += seg->dir ? 1 : -1;
58 else if (seg->bbox.x0 <= x)
60 double x0, y0, x1, y1, dx, dy;
62 for (j = 0; j < seg->n_points - 1; j++)
64 if (seg->points[j + 1].y > y)
67 x0 = seg->points[j].x;
68 y0 = seg->points[j].y;
69 x1 = seg->points[j + 1].x;
70 y1 = seg->points[j + 1].y;
74 if ((x - x0) * dy > (y - y0) * dx)
75 wind += seg->dir ? 1 : -1;
84 * art_svp_point_dist: Determine distance between point and svp.
86 * @x: The X coordinate of the point.
87 * @y: The Y coordinate of the point.
89 * Determines the distance of the point @x, @y to the closest edge in
90 * @svp. A large number is returned if @svp is empty.
92 * Return value: the distance.
95 art_svp_point_dist (ArtSVP *svp, double x, double y)
101 for (i = 0; i < svp->n_segs; i++)
103 ArtSVPSeg *seg = &svp->segs[i];
104 for (j = 0; j < seg->n_points - 1; j++)
106 double x0 = seg->points[j].x;
107 double y0 = seg->points[j].y;
108 double x1 = seg->points[j + 1].x;
109 double y1 = seg->points[j + 1].y;
114 double dxx0 = x - x0;
115 double dyy0 = y - y0;
117 double dot = dxx0 * dx + dyy0 * dy;
120 dist_sq = dxx0 * dxx0 + dyy0 * dyy0;
123 double rr = dx * dx + dy * dy;
126 dist_sq = (x - x1) * (x - x1) + (y - y1) * (y - y1);
129 double perp = (y - y0) * dx - (x - x0) * dy;
131 dist_sq = perp * perp / rr;
134 if (best_sq < 0 || dist_sq < best_sq)
140 return sqrt (best_sq);