``````/* Libart_LGPL - library of basic graphic primitives * Copyright (C) 1999 Raph Levien * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. */ #include "config.h" #include "art_svp_point.h" #include #include "art_misc.h" #include "art_svp.h" /* Determine whether a point is inside, or near, an svp. */ /* return winding number of point wrt svp */ /** * art_svp_point_wind: Determine winding number of a point with respect to svp. * @svp: The svp. * @x: The X coordinate of the point. * @y: The Y coordinate of the point. * * Determine the winding number of the point @x, @y with respect to @svp. * * Return value: the winding number. **/ int art_svp_point_wind (ArtSVP *svp, double x, double y) { int i, j; int wind = 0; for (i = 0; i < svp->n_segs; i++) { ArtSVPSeg *seg = &svp->segs[i]; if (seg->bbox.y0 > y) break; if (seg->bbox.y1 > y) { if (seg->bbox.x1 < x) wind += seg->dir ? 1 : -1; else if (seg->bbox.x0 <= x) { double x0, y0, x1, y1, dx, dy; for (j = 0; j < seg->n_points - 1; j++) { if (seg->points[j + 1].y > y) break; } x0 = seg->points[j].x; y0 = seg->points[j].y; x1 = seg->points[j + 1].x; y1 = seg->points[j + 1].y; dx = x1 - x0; dy = y1 - y0; if ((x - x0) * dy > (y - y0) * dx) wind += seg->dir ? 1 : -1; } } } return wind; } /** * art_svp_point_dist: Determine distance between point and svp. * @svp: The svp. * @x: The X coordinate of the point. * @y: The Y coordinate of the point. * * Determines the distance of the point @x, @y to the closest edge in * @svp. A large number is returned if @svp is empty. * * Return value: the distance. **/ double art_svp_point_dist (ArtSVP *svp, double x, double y) { int i, j; double dist_sq; double best_sq = -1; for (i = 0; i < svp->n_segs; i++) { ArtSVPSeg *seg = &svp->segs[i]; for (j = 0; j < seg->n_points - 1; j++) { double x0 = seg->points[j].x; double y0 = seg->points[j].y; double x1 = seg->points[j + 1].x; double y1 = seg->points[j + 1].y; double dx = x1 - x0; double dy = y1 - y0; double dxx0 = x - x0; double dyy0 = y - y0; double dot = dxx0 * dx + dyy0 * dy; if (dot < 0) dist_sq = dxx0 * dxx0 + dyy0 * dyy0; else { double rr = dx * dx + dy * dy; if (dot > rr) dist_sq = (x - x1) * (x - x1) + (y - y1) * (y - y1); else { double perp = (y - y0) * dx - (x - x0) * dy; dist_sq = perp * perp / rr; } } if (best_sq < 0 || dist_sq < best_sq) best_sq = dist_sq; } } if (best_sq >= 0) return sqrt (best_sq); else return 1e12; } ``````