libart 2.3.16

[swftools.git] / lib / art / art_svp_point.c

diff --git a/lib/art/art_svp_point.c b/lib/art/art_svp_point.c
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+++ b/lib/art/art_svp_point.c
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+/* 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 <math.h>
+#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;
+}
+