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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;
}
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