agg-2.5/include/agg_conv_close_polygon.h

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//----------------------------------------------------------------------------
// Anti-Grain Geometry (AGG) - Version 2.5
// A high quality rendering engine for C++
// Copyright (C) 2002-2006 Maxim Shemanarev
// Contact: mcseem@antigrain.com
//          mcseemagg@yahoo.com
//          http://antigrain.com
// 
// AGG is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
// 
// AGG 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 General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with AGG; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 
// MA 02110-1301, USA.
//----------------------------------------------------------------------------

#ifndef AGG_CONV_CLOSE_POLYGON_INCLUDED
#define AGG_CONV_CLOSE_POLYGON_INCLUDED

#include "agg_basics.h"

namespace agg
{

    //======================================================conv_close_polygon
    template<class VertexSource> class conv_close_polygon
    {
    public:
        explicit conv_close_polygon(VertexSource& vs) : m_source(&vs) {}
        void attach(VertexSource& source) { m_source = &source; }

        void rewind(unsigned path_id);
        unsigned vertex(double* x, double* y);

    private:
        conv_close_polygon(const conv_close_polygon<VertexSource>&);
        const conv_close_polygon<VertexSource>& 
            operator = (const conv_close_polygon<VertexSource>&);

        VertexSource* m_source;
        unsigned      m_cmd[2];
        double        m_x[2];
        double        m_y[2];
        unsigned      m_vertex;
        bool          m_line_to;
    };



    //------------------------------------------------------------------------
    template<class VertexSource> 
    void conv_close_polygon<VertexSource>::rewind(unsigned path_id)
    {
        m_source->rewind(path_id);
        m_vertex = 2;
        m_line_to = false;
    }


    
    //------------------------------------------------------------------------
    template<class VertexSource> 
    unsigned conv_close_polygon<VertexSource>::vertex(double* x, double* y)
    {
        unsigned cmd = path_cmd_stop;
        for(;;)
        {
            if(m_vertex < 2)
            {
                *x = m_x[m_vertex];
                *y = m_y[m_vertex];
                cmd = m_cmd[m_vertex];
                ++m_vertex;
                break;
            }

            cmd = m_source->vertex(x, y);

            if(is_end_poly(cmd))
            {
                cmd |= path_flags_close;
                break;
            }

            if(is_stop(cmd))
            {
                if(m_line_to)
                {
                    m_cmd[0]  = path_cmd_end_poly | path_flags_close;
                    m_cmd[1]  = path_cmd_stop;
                    m_vertex  = 0;
                    m_line_to = false;
                    continue;
                }
                break;
            }

            if(is_move_to(cmd))
            {
                if(m_line_to)
                {
                    m_x[0]    = 0.0;
                    m_y[0]    = 0.0;
                    m_cmd[0]  = path_cmd_end_poly | path_flags_close;
                    m_x[1]    = *x;
                    m_y[1]    = *y;
                    m_cmd[1]  = cmd;
                    m_vertex  = 0;
                    m_line_to = false;
                    continue;
                }
                break;
            }

            if(is_vertex(cmd))
            {
                m_line_to = true;
                break;
            }
        }
        return cmd;
    }

}

#endif