зеркало из https://github.com/mozilla/pjs.git
153 строки
4.3 KiB
C
153 строки
4.3 KiB
C
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/* Libart_LGPL - library of basic graphic primitives
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* Copyright (C) 1998 Raph Levien
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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/* Basic constructors and operations for sorted vector paths */
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#include "art_misc.h"
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#include "art_rect.h"
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#include "art_svp.h"
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/* Add a new segment. The arguments can be zero and NULL if the caller
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would rather fill them in later.
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We also realloc one auxiliary array of ints of size n_segs if
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desired.
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*/
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/**
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* art_svp_add_segment: Add a segment to an #ArtSVP structure.
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* @p_vp: Pointer to where the #ArtSVP structure is stored.
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* @pn_segs_max: Pointer to the allocated size of *@p_vp.
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* @pn_points_max: Pointer to where auxiliary array is stored.
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* @n_points: Number of points for new segment.
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* @dir: Direction for new segment; 0 is up, 1 is down.
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* @points: Points for new segment.
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* @bbox: Bounding box for new segment.
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*
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* Adds a new segment to an ArtSVP structure. This routine reallocates
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* the structure if necessary, updating *@p_vp and *@pn_segs_max as
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* necessary.
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*
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* The new segment is simply added after all other segments. Thus,
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* this routine should be called in order consistent with the #ArtSVP
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* sorting rules.
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*
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* If the @bbox argument is given, it is simply stored in the new
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* segment. Otherwise (if it is NULL), the bounding box is computed
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* from the @points given.
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**/
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int
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art_svp_add_segment (ArtSVP **p_vp, int *pn_segs_max,
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int **pn_points_max,
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int n_points, int dir, ArtPoint *points,
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ArtDRect *bbox)
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{
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int seg_num;
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ArtSVP *svp;
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ArtSVPSeg *seg;
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svp = *p_vp;
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seg_num = svp->n_segs++;
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if (*pn_segs_max == seg_num)
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{
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*pn_segs_max <<= 1;
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svp = (ArtSVP *)art_realloc (svp, sizeof(ArtSVP) +
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(*pn_segs_max - 1) * sizeof(ArtSVPSeg));
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*p_vp = svp;
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if (pn_points_max != NULL)
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*pn_points_max = art_renew (*pn_points_max, int, *pn_segs_max);
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}
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seg = &svp->segs[seg_num];
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seg->n_points = n_points;
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seg->dir = dir;
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seg->points = points;
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if (bbox)
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seg->bbox = *bbox;
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else if (points)
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{
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double x_min, x_max;
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int i;
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x_min = x_max = points[0].x;
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for (i = 1; i < n_points; i++)
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{
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if (x_min > points[i].x)
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x_min = points[i].x;
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if (x_max < points[i].x)
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x_max = points[i].x;
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}
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seg->bbox.x0 = x_min;
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seg->bbox.y0 = points[0].y;
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seg->bbox.x1 = x_max;
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seg->bbox.y1 = points[n_points - 1].y;
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}
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return seg_num;
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}
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/**
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* art_svp_free: Free an #ArtSVP structure.
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* @svp: #ArtSVP to free.
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*
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* Frees an #ArtSVP structure and all the segments in it.
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**/
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void
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art_svp_free (ArtSVP *svp)
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{
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int n_segs = svp->n_segs;
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int i;
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for (i = 0; i < n_segs; i++)
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art_free (svp->segs[i].points);
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art_free (svp);
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}
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#ifdef ART_USE_NEW_INTERSECTOR
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#define EPSILON 0
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#else
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#define EPSILON 1e-6
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#endif
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/**
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* art_svp_seg_compare: Compare two segments of an svp.
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* @seg1: First segment to compare.
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* @seg2: Second segment to compare.
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*
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* Compares two segments of an svp. Return 1 if @seg2 is below or to the
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* right of @seg1, -1 otherwise.
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**/
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int
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art_svp_seg_compare (const void *s1, const void *s2)
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{
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const ArtSVPSeg *seg1 = s1;
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const ArtSVPSeg *seg2 = s2;
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if (seg1->points[0].y - EPSILON > seg2->points[0].y) return 1;
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else if (seg1->points[0].y + EPSILON < seg2->points[0].y) return -1;
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else if (seg1->points[0].x - EPSILON > seg2->points[0].x) return 1;
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else if (seg1->points[0].x + EPSILON < seg2->points[0].x) return -1;
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else if ((seg1->points[1].x - seg1->points[0].x) *
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(seg2->points[1].y - seg2->points[0].y) -
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(seg1->points[1].y - seg1->points[0].y) *
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(seg2->points[1].x - seg2->points[0].x) > 0) return 1;
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else return -1;
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}
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