libart 2.3.16

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

diff --git a/lib/art/art_svp.c b/lib/art/art_svp.c
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+++ b/lib/art/art_svp.c
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+/* Libart_LGPL - library of basic graphic primitives
+ * Copyright (C) 1998 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.
+ */
+
+/* Basic constructors and operations for sorted vector paths */
+
+#include "config.h"
+#include "art_svp.h"
+
+#include "art_misc.h"
+
+/* Add a new segment. The arguments can be zero and NULL if the caller
+   would rather fill them in later.
+
+   We also realloc one auxiliary array of ints of size n_segs if
+   desired.
+*/
+/**
+ * art_svp_add_segment: Add a segment to an #ArtSVP structure.
+ * @p_vp: Pointer to where the #ArtSVP structure is stored.
+ * @pn_segs_max: Pointer to the allocated size of *@p_vp.
+ * @pn_points_max: Pointer to where auxiliary array is stored.
+ * @n_points: Number of points for new segment.
+ * @dir: Direction for new segment; 0 is up, 1 is down.
+ * @points: Points for new segment.
+ * @bbox: Bounding box for new segment.
+ *
+ * Adds a new segment to an ArtSVP structure. This routine reallocates
+ * the structure if necessary, updating *@p_vp and *@pn_segs_max as
+ * necessary.
+ *
+ * The new segment is simply added after all other segments. Thus,
+ * this routine should be called in order consistent with the #ArtSVP
+ * sorting rules.
+ *
+ * If the @bbox argument is given, it is simply stored in the new
+ * segment. Otherwise (if it is NULL), the bounding box is computed
+ * from the @points given.
+ **/
+int
+art_svp_add_segment (ArtSVP **p_vp, int *pn_segs_max,
+                    int **pn_points_max,
+                    int n_points, int dir, ArtPoint *points,
+                    ArtDRect *bbox)
+{
+  int seg_num;
+  ArtSVP *svp;
+  ArtSVPSeg *seg;
+
+  svp = *p_vp;
+  seg_num = svp->n_segs++;
+  if (*pn_segs_max == seg_num)
+    {
+      *pn_segs_max <<= 1;
+      svp = (ArtSVP *)art_realloc (svp, sizeof(ArtSVP) +
+                                  (*pn_segs_max - 1) * sizeof(ArtSVPSeg));
+      *p_vp = svp;
+      if (pn_points_max != NULL)
+       *pn_points_max = art_renew (*pn_points_max, int, *pn_segs_max);
+    }
+  seg = &svp->segs[seg_num];
+  seg->n_points = n_points;
+  seg->dir = dir;
+  seg->points = points;
+  if (bbox)
+    seg->bbox = *bbox;
+  else if (points)
+    {
+      double x_min, x_max;
+      int i;
+
+      x_min = x_max = points[0].x;
+      for (i = 1; i < n_points; i++)
+       {
+         if (x_min > points[i].x)
+           x_min = points[i].x;
+         if (x_max < points[i].x)
+           x_max = points[i].x;
+       }
+      seg->bbox.x0 = x_min;
+      seg->bbox.y0 = points[0].y;
+      
+      seg->bbox.x1 = x_max;
+      seg->bbox.y1 = points[n_points - 1].y;
+    }
+  return seg_num;
+}
+
+
+/**
+ * art_svp_free: Free an #ArtSVP structure.
+ * @svp: #ArtSVP to free.
+ * 
+ * Frees an #ArtSVP structure and all the segments in it.
+ **/
+void
+art_svp_free (ArtSVP *svp)
+{
+  int n_segs = svp->n_segs;
+  int i;
+
+  for (i = 0; i < n_segs; i++)
+    art_free (svp->segs[i].points);
+  art_free (svp);
+}
+
+#ifdef ART_USE_NEW_INTERSECTOR
+#define EPSILON 0
+#else
+#define EPSILON 1e-6
+#endif
+
+/**
+ * art_svp_seg_compare: Compare two segments of an svp.
+ * @seg1: First segment to compare.
+ * @seg2: Second segment to compare.
+ * 
+ * Compares two segments of an svp. Return 1 if @seg2 is below or to the
+ * right of @seg1, -1 otherwise.
+ **/
+int
+art_svp_seg_compare (const void *s1, const void *s2)
+{
+  const ArtSVPSeg *seg1 = s1;
+  const ArtSVPSeg *seg2 = s2;
+
+  if (seg1->points[0].y - EPSILON > seg2->points[0].y) return 1;
+  else if (seg1->points[0].y + EPSILON < seg2->points[0].y) return -1;
+  else if (seg1->points[0].x - EPSILON > seg2->points[0].x) return 1;
+  else if (seg1->points[0].x + EPSILON < seg2->points[0].x) return -1;
+  else if ((seg1->points[1].x - seg1->points[0].x) *
+          (seg2->points[1].y - seg2->points[0].y) -
+          (seg1->points[1].y - seg1->points[0].y) *
+          (seg2->points[1].x - seg2->points[0].x) > 0) return 1;
+  else return -1;
+}
+