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/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2011 Artem Pavlenko
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*****************************************************************************/
#ifndef MAPNIK_GEOM_UTIL_HPP
#define MAPNIK_GEOM_UTIL_HPP
// mapnik
#include <mapnik/box2d.hpp>
#include <mapnik/vertex.hpp>
// boost
#include <boost/tuple/tuple.hpp>
// stl
#include <cmath>
namespace mapnik
{
template <typename T>
bool clip_test(T p,T q,double& tmin,double& tmax)
{
double r;
bool result=true;
if (p<0.0)
{
r=q/p;
if (r>tmax) result=false;
else if (r>tmin) tmin=r;
}
else if (p>0.0)
{
r=q/p;
if (r<tmin) result=false;
else if (r<tmax) tmax=r;
} else if (q<0.0) result=false;
return result;
}
template <typename T,typename Image>
bool clip_line(T& x0,T& y0,T& x1,T& y1,box2d<T> const& box)
{
double tmin=0.0;
double tmax=1.0;
double dx=x1-x0;
if (clip_test<double>(-dx,x0,tmin,tmax))
{
if (clip_test<double>(dx,box.width()-x0,tmin,tmax))
{
double dy=y1-y0;
if (clip_test<double>(-dy,y0,tmin,tmax))
{
if (clip_test<double>(dy,box.height()-y0,tmin,tmax))
{
if (tmax<1.0)
{
x1=static_cast<T>(x0+tmax*dx);
y1=static_cast<T>(y0+tmax*dy);
}
if (tmin>0.0)
{
x0+=static_cast<T>(tmin*dx);
y0+=static_cast<T>(tmin*dy);
}
return true;
}
}
}
}
return false;
}
template <typename Iter>
inline bool point_inside_path(double x,double y,Iter start,Iter end)
{
bool inside=false;
double x0=boost::get<0>(*start);
double y0=boost::get<1>(*start);
double x1,y1;
while (++start!=end)
{
if ( boost::get<2>(*start) == SEG_MOVETO)
{
x0 = boost::get<0>(*start);
y0 = boost::get<1>(*start);
continue;
}
x1=boost::get<0>(*start);
y1=boost::get<1>(*start);
if ((((y1 <= y) && (y < y0)) ||
((y0 <= y) && (y < y1))) &&
( x < (x0 - x1) * (y - y1)/ (y0 - y1) + x1))
inside=!inside;
x0=x1;
y0=y1;
}
return inside;
}
inline bool point_in_circle(double x,double y,double cx,double cy,double r)
{
double dx = x - cx;
double dy = y - cy;
double d2 = dx * dx + dy * dy;
return (d2 <= r * r);
}
template <typename T>
inline T sqr(T x)
{
return x * x;
}
inline double distance2(double x0,double y0,double x1,double y1)
{
double dx = x1 - x0;
double dy = y1 - y0;
return sqr(dx) + sqr(dy);
}
inline double distance(double x0,double y0, double x1,double y1)
{
return std::sqrt(distance2(x0,y0,x1,y1));
}
inline double point_to_segment_distance(double x, double y,
double ax, double ay,
double bx, double by)
{
double len2 = distance2(ax,ay,bx,by);
if (len2 < 1e-14)
{
return distance(x,y,ax,ay);
}
double r = ((x - ax)*(bx - ax) + (y - ay)*(by -ay))/len2;
if ( r < 0 )
{
return distance(x,y,ax,ay);
}
else if (r > 1)
{
return distance(x,y,bx,by);
}
double s = ((ay - y)*(bx - ax) - (ax - x)*(by - ay))/len2;
return std::fabs(s) * std::sqrt(len2);
}
template <typename Iter>
inline bool point_on_path(double x,double y,Iter start,Iter end, double tol)
{
double x0=boost::get<0>(*start);
double y0=boost::get<1>(*start);
double x1,y1;
while (++start != end)
{
if ( boost::get<2>(*start) == SEG_MOVETO)
{
x0 = boost::get<0>(*start);
y0 = boost::get<1>(*start);
continue;
}
x1=boost::get<0>(*start);
y1=boost::get<1>(*start);
double distance = point_to_segment_distance(x,y,x0,y0,x1,y1);
if (distance < tol)
return true;
x0=x1;
y0=y1;
}
return false;
}
// filters
struct filter_in_box
{
box2d<double> box_;
explicit filter_in_box(const box2d<double>& box)
: box_(box) {}
bool pass(const box2d<double>& extent) const
{
return extent.intersects(box_);
}
};
struct filter_at_point
{
coord2d pt_;
explicit filter_at_point(const coord2d& pt)
: pt_(pt) {}
bool pass(const box2d<double>& extent) const
{
return extent.contains(pt_);
}
};
}
#endif // MAPNIK_GEOM_UTIL_HPP
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