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/*************************************************************************
* Copyright (c) 2011 AT&T Intellectual Property
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-v10.html
*
* Contributors: Details at https://graphviz.org
*************************************************************************/
#include <stddef.h>
#include <util/list.h>
#define SLOPE(p,q) ( ( ( p.y ) - ( q.y ) ) / ( ( p.x ) - ( q.x ) ) )
#define MAX(a,b) ( ( a ) > ( b ) ? ( a ) : ( b ) )
#define after(v) (((v)==((v)->poly->finish))?((v)->poly->start):((v)+1))
#define prior(v) (((v)==((v)->poly->start))?((v)->poly->finish):((v)-1))
struct position {
double x, y;
};
struct vertex {
struct position pos;
struct polygon *poly;
struct active_edge *active;
};
struct polygon {
struct vertex *start, *finish;
};
struct intersection {
struct vertex *firstv, *secondv;
struct polygon *firstp, *secondp;
double x, y;
};
typedef LIST(struct intersection) intersections_t;
struct active_edge {
struct vertex *name;
};
void find_ints(struct vertex vertex_list[], size_t nvertices,
intersections_t *ilist);
/// detect whether lines `l` and `m` intersect
void find_intersection(struct vertex *l, struct vertex *m,
intersections_t *ilist);
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