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Diffstat (limited to 'art_svp.c')
| -rw-r--r-- | art_svp.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/art_svp.c b/art_svp.c new file mode 100644 index 0000000..8d7f7d1 --- /dev/null +++ b/art_svp.c @@ -0,0 +1,152 @@ +/* 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; +} + |