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/*****************************************************************************
 * 
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2006 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
 *
 *****************************************************************************/


//$Id: geometry.hpp 39 2005-04-10 20:39:53Z pavlenko $

#ifndef GEOMETRY_HPP
#define GEOMETRY_HPP

// boost
#include <boost/shared_ptr.hpp>
#include <boost/utility.hpp>
// mapnik
#include <mapnik/vertex_vector.hpp>
#include <mapnik/ctrans.hpp>
#include <mapnik/geom_util.hpp>

namespace mapnik {
    enum GeomType {
        Point = 1,
        LineString = 2,
        Polygon = 3
    };
    
    template <typename T>
    class geometry : private boost::noncopyable
    {   
    public:
        typedef T vertex_type;
        typedef typename vertex_type::type value_type;
    private:
        int srid_;
    public:
        geometry (int srid=-1)
            : srid_(srid) {}    

        int srid() const
        {
            return srid_;
        }
        
        Envelope<double> envelope()
        {
            Envelope<double> result;            
            double x,y;
            rewind(0);
            for (unsigned i=0;i<num_points();++i)
            {
                vertex(&x,&y);
                if (i==0)
                {
                    result.init(x,y,x,y);
                }
                else
                {
                    result.expand_to_include(x,y);
                }
            }
            return result;
        }
        
        virtual int type() const=0;
        virtual bool hit_test(value_type x,value_type y, double tol) const=0;   
        virtual void label_position(double *x, double *y) const=0;
        virtual void move_to(value_type x,value_type y)=0;
        virtual void line_to(value_type x,value_type y)=0;
        virtual unsigned num_points() const = 0;
        virtual unsigned vertex(double* x, double* y)=0;
        virtual void rewind(unsigned )=0;
        virtual void set_capacity(size_t size)=0;
        virtual ~geometry() {}
    };
    
    template <typename T>
    class point : public geometry<T>
    {
        typedef geometry<T> geometry_base;
        typedef typename geometry<T>::vertex_type vertex_type;
        typedef typename geometry<T>::value_type value_type;
    private:
        vertex_type pt_;
    public:
        point(int srid)
            : geometry<T>(srid)
        {}
         
        int type() const 
        {
            return Point;
        }
        void label_position(double *x, double *y) const
        {
            *x = pt_.x;
            *y = pt_.y;
        }
        
        void move_to(value_type x,value_type y)
        {
            pt_.x = x;
            pt_.y = y;
        }
        
        void line_to(value_type ,value_type ) {}
        
        unsigned num_points() const
        {
            return 1;
        }
        
        unsigned vertex(double* x, double* y)
        {
            *x = pt_.x;
            *y = pt_.y;
            return SEG_LINETO;
        }
        
        void rewind(unsigned ) {}
        
        bool hit_test(value_type x,value_type y, double tol) const
        {
            return point_in_circle(pt_.x,pt_.y, x,y,tol);
        }
        
        void set_capacity(size_t) {}
        virtual ~point() {}
    };

    template <typename T, template <typename> class Container=vertex_vector2>
    class polygon : public geometry<T>
    {
        typedef geometry<T> geometry_base;
        typedef typename geometry<T>::vertex_type vertex_type;
        typedef typename geometry_base::value_type value_type;
        typedef Container<vertex_type> container_type;
    private:
        container_type cont_;
        mutable unsigned itr_;
    public:
        polygon(int srid)
            : geometry_base(srid),
              itr_(0)
        {}
        
        int type() const 
        {
            return Polygon;
        }
        
        void label_position(double *x, double *y) const
        {
            
            unsigned size = cont_.size();
            if (size < 3) 
            {
                cont_.get_vertex(0,x,y);
                return;
            }
              
            double ai;
            double atmp = 0;
            double xtmp = 0;
            double ytmp = 0;
            double x0 =0;
            double y0 =0;
            double x1 =0;
            double y1 =0;
            
            unsigned i,j;
            for (i = size-1,j = 0; j < size; i = j, ++j)
            {
                cont_.get_vertex(i,&x0,&y0);
                cont_.get_vertex(j,&x1,&y1);
                ai = x0 * y1 - x1 * y0;
                atmp += ai;
                xtmp += (x1 + x0) * ai;
                ytmp += (y1 + y0) * ai;
            }     
            if (atmp != 0)
            {
                *x = xtmp/(3*atmp);
                *y = ytmp /(3*atmp);
                return;
            }
            *x=x0;
            *y=y0;                  
        }

        void line_to(value_type x,value_type y)
        {
            cont_.push_back(x,y,SEG_LINETO);
        }

        void move_to(value_type x,value_type y)
        {
            cont_.push_back(x,y,SEG_MOVETO);
        }
        
        unsigned num_points() const
        {
            return cont_.size();
        }
        
        unsigned vertex(double* x, double* y)
        {
            return cont_.get_vertex(itr_++,x,y);
        }
        
        void rewind(unsigned )
        {
            itr_=0;
        }
        
        bool hit_test(value_type x,value_type y, double) const
        {           
            return point_inside_path(x,y,cont_.begin(),cont_.end());
        } 
        
        void set_capacity(size_t size) 
        {
            cont_.set_capacity(size);
        }
        virtual ~polygon() {}
    };
    
    template <typename T, template <typename> class Container=vertex_vector2>
    class line_string : public geometry<T>
    {
        typedef geometry<T> geometry_base;
        typedef typename geometry_base::value_type value_type;
        typedef typename geometry<T>::vertex_type vertex_type;
        typedef Container<vertex_type> container_type;
    private:
        container_type cont_;
        mutable unsigned itr_;
    public:
        line_string(int srid)
            : geometry_base(srid),
              itr_(0)
        {}
        
        int type() const 
        {
            return LineString;
        }
        void label_position(double *x, double *y) const
        {
            // calculate mid point on line string
            double x0=0;
            double y0=0;
            double x1=0;
            double y1=0;
            
            unsigned size = cont_.size();
            if (size == 1)
            {
                cont_.get_vertex(0,x,y); 
            }
            else if (size == 2)
            {

                cont_.get_vertex(0,&x0,&y0);
                cont_.get_vertex(1,&x1,&y1);
                *x = 0.5 * (x1 + x0);
                *y = 0.5 * (y1 + y0);           
            }
            else
            {
                double len=0.0;
                for (unsigned pos = 1; pos < size; ++pos)
                {
                    cont_.get_vertex(pos-1,&x0,&y0);
                    cont_.get_vertex(pos,&x1,&y1);
                    double dx = x1 - x0;
                    double dy = y1 - y0;
                    len += sqrt(dx * dx + dy * dy);
                }
                double midlen = 0.5 * len;
                double dist = 0.0;
                for (unsigned pos = 1; pos < size;++pos)
                {
                    cont_.get_vertex(pos-1,&x0,&y0);
                    cont_.get_vertex(pos,&x1,&y1);
                    double dx = x1 - x0;
                    double dy = y1 - y0; 
                    double seg_len = sqrt(dx * dx + dy * dy);
                    if (( dist + seg_len) >= midlen)
                    {
                        double r = (midlen - dist)/seg_len;
                        *x = x0 + (x1 - x0) * r;
                        *y = y0 + (y1 - y0) * r;
                        break;
                    }
                    dist += seg_len;
                }
            }
            
        }
        void line_to(value_type x,value_type y)
        {
            cont_.push_back(x,y,SEG_LINETO);
        }

        void move_to(value_type x,value_type y)
        {
            cont_.push_back(x,y,SEG_MOVETO);
        }

        unsigned num_points() const
        {
            return cont_.size();
        }
        
        unsigned vertex(double* x, double* y)
        {
            return cont_.get_vertex(itr_++,x,y);
        }
        
        void rewind(unsigned )
        {
            itr_=0;
        }
        
        bool hit_test(value_type x,value_type y, double tol) const
        {           
            return point_on_path(x,y,cont_.begin(),cont_.end(),tol);
        } 
        
        void set_capacity(size_t size) 
        {
            cont_.set_capacity(size);
        }
        virtual ~line_string() {}
    };

    typedef point<vertex2d> point_impl;
    typedef line_string<vertex2d,vertex_vector2> line_string_impl;
    typedef polygon<vertex2d,vertex_vector2> polygon_impl;
    
    typedef geometry<vertex2d> geometry_type;
    typedef boost::shared_ptr<geometry_type> geometry_ptr;
}

#endif //GEOMETRY_HPP

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