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/*
* vim: ts=4 sw=4 et tw=0 wm=0
*
* libavoid - Fast, Incremental, Object-avoiding Line Router
* Copyright (C) 2004-2005 Michael Wybrow <mjwybrow@users.sourceforge.net>
*
* --------------------------------------------------------------------
* Much of the code in this module is based on code published with
* and/or described in "Computational Geometry in C" (Second Edition),
* Copyright (C) 1998 Joseph O'Rourke <orourke@cs.smith.edu>
* --------------------------------------------------------------------
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser 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
*
*/
#ifndef _GEOMETRY_H
#define _GEOMETRY_H
#include "libavoid/geomtypes.h"
namespace Avoid {
extern double dist(const Point& a, const Point& b);
extern bool segmentIntersect(const Point& a, const Point& b,
const Point& c, const Point& d);
extern bool inPoly(const Polygn& poly, const Point& q);
extern bool inValidRegion(const Point& a0, const Point& a1, const Point& a2,
const Point& b);
// Direction from vector.
// Looks at the position of point c from the directed segment ab and
// returns the following:
// 1 counterclockwise
// 0 collinear
// -1 clockwise
//
// Based on the code of 'AreaSign'.
//
static inline int vecDir(const Point& a, const Point& b, const Point& c)
{
double area2 = ((b.x - a.x) * (c.y - a.y)) -
((c.x - a.x) * (b.y - a.y));
if (area2 < -0.001)
{
return -1;
}
else if (area2 > 0.001)
{
return 1;
}
return 0;
}
}
#endif
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