agg_path_storage.h

这是VCF框架的代码

    }

    //------------------------------------------------------------------------
    template<class VC> 
    inline double path_base<VC>::last_y() const
    {
        return m_vertices.last_y();
    }

    //------------------------------------------------------------------------
    template<class VC> 
    inline unsigned path_base<VC>::vertex(unsigned idx, double* x, double* y) const
    {
        return m_vertices.vertex(idx, x, y);
    }
 
    //------------------------------------------------------------------------
    template<class VC> 
    inline unsigned path_base<VC>::command(unsigned idx) const
    {
        return m_vertices.command(idx);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::modify_vertex(unsigned idx, double x, double y)
    {
        m_vertices.modify_vertex(idx, x, y);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::modify_vertex(unsigned idx, double x, double y, unsigned cmd)
    {
        m_vertices.modify_vertex(idx, x, y, cmd);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::modify_command(unsigned idx, unsigned cmd)
    {
        m_vertices.modify_command(idx, cmd);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    inline void path_base<VC>::rewind(unsigned path_id)
    {
        m_iterator = path_id;
    }

    //------------------------------------------------------------------------
    template<class VC> 
    inline unsigned path_base<VC>::vertex(double* x, double* y)
    {
        if(m_iterator >= m_vertices.total_vertices()) return path_cmd_stop;
        return m_vertices.vertex(m_iterator++, x, y);
    }


    //------------------------------------------------------------------------
    template<class VC> 
    unsigned path_base<VC>::perceive_polygon_orientation(unsigned start,
                                                         unsigned end)
    {
        // Calculate signed area (double area to be exact)
        //---------------------
        unsigned np = end - start;
        double area = 0.0;
        unsigned i;
        for(i = 0; i < np; i++)
        {
            double x1, y1, x2, y2;
            m_vertices.vertex(start + i,            &x1, &y1);
            m_vertices.vertex(start + (i + 1) % np, &x2, &y2);
            area += x1 * y2 - y1 * x2;
        }
        return (area < 0.0) ? path_flags_cw : path_flags_ccw;
    }


    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::invert_polygon(unsigned start, unsigned end)
    {
        unsigned i;
        unsigned tmp_cmd = m_vertices.command(start);
        
        --end; // Make "end" inclusive

        // Shift all commands to one position
        for(i = start; i < end; i++)
        {
            m_vertices.modify_command(i, m_vertices.command(i + 1));
        }

        // Assign starting command to the ending command
        m_vertices.modify_command(end, tmp_cmd);

        // Reverse the polygon
        while(end > start)
        {
            m_vertices.swap_vertices(start++, end--);
        }
    }

    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::invert_polygon(unsigned start)
    {
        // Skip all non-vertices at the beginning
        while(start < m_vertices.total_vertices() && 
              !is_vertex(m_vertices.command(start))) ++start;

        // Skip all insignificant move_to
        while(start+1 < m_vertices.total_vertices() && 
              is_move_to(m_vertices.command(start)) &&
              is_move_to(m_vertices.command(start+1))) ++start;

        // Find the last vertex
        unsigned end = start + 1;
        while(end < m_vertices.total_vertices() && 
              !is_next_poly(m_vertices.command(end))) ++end;

        if(end - start > 2)
        {
            invert_polygon(start, end);
        }
    }

    //------------------------------------------------------------------------
    template<class VC> 
    unsigned path_base<VC>::arrange_polygon_orientation(unsigned start, 
                                                        path_flags_e orientation)
    {
        if(orientation == path_flags_none) return start;
        
        // Skip all non-vertices at the beginning
        while(start < m_vertices.total_vertices() && 
              !is_vertex(m_vertices.command(start))) ++start;

        // Skip all insignificant move_to
        while(start+1 < m_vertices.total_vertices() && 
              is_move_to(m_vertices.command(start)) &&
              is_move_to(m_vertices.command(start+1))) ++start;

        // Find the last vertex
        unsigned end = start + 1;
        while(end < m_vertices.total_vertices() && 
              !is_next_poly(m_vertices.command(end))) ++end;

        if(end - start > 2)
        {
            if(perceive_polygon_orientation(start, end) != unsigned(orientation))
            {
                // Invert polygon, set orientation flag, and skip all end_poly
                invert_polygon(start, end);
                unsigned cmd;
                while(end < m_vertices.total_vertices() && 
                      is_end_poly(cmd = m_vertices.command(end)))
                {
                    m_vertices.modify_command(end++, set_orientation(cmd, orientation));
                }
            }
        }
        return end;
    }


    //------------------------------------------------------------------------
    template<class VC> 
    unsigned path_base<VC>::arrange_orientations(unsigned start, 
                                                 path_flags_e orientation)
    {
        if(orientation != path_flags_none)
        {
            while(start < m_vertices.total_vertices())
            {
                start = arrange_polygon_orientation(start, orientation);
                if(is_stop(m_vertices.command(start)))
                {
                    ++start;
                    break;
                }
            }
        }
        return start;
    }


    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::arrange_orientations_all_paths(path_flags_e orientation)
    {
        if(orientation != path_flags_none)
        {
            unsigned start = 0;
            while(start < m_vertices.total_vertices())
            {
                start = arrange_orientations(start, orientation);
            }
        }
    }


    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::flip_x(double x1, double x2)
    {
        unsigned i;
        double x, y;
        for(i = 0; i < m_vertices.total_vertices(); i++)
        {
            unsigned cmd = m_vertices.vertex(i, &x, &y);
            if(is_vertex(cmd))
            {
                m_vertices.modify_vertex(i, x2 - x + x1, y);
            }
        }
    }


    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::flip_y(double y1, double y2)
    {
        unsigned i;
        double x, y;
        for(i = 0; i < m_vertices.total_vertices(); i++)
        {
            unsigned cmd = m_vertices.vertex(i, &x, &y);
            if(is_vertex(cmd))
            {
                m_vertices.modify_vertex(i, x, y2 - y + y1);
            }
        }
    }





    //-----------------------------------------------------vertex_stl_storage
    template<class Container> class vertex_stl_storage
    {
    public:
        typedef typename Container::value_type vertex_type;
        typedef typename vertex_type::value_type value_type;

        void remove_all() { m_vertices.clear(); }
        void free_all()   { m_vertices.clear(); }

        void add_vertex(double x, double y, unsigned cmd)
        {
            m_vertices.push_back(vertex_type(value_type(x), 
                                             value_type(y), 
                                             int8u(cmd)));
        }

        void modify_vertex(unsigned idx, double x, double y)
        {
            vertex_type& v = m_vertices[idx];
            v.x = value_type(x);
            v.y = value_type(y);
        }

        void modify_vertex(unsigned idx, double x, double y, unsigned cmd)
        {
            vertex_type& v = m_vertices[idx];
            v.x   = value_type(x);
            v.y   = value_type(y);
            v.cmd = int8u(cmd);
        }

        void modify_command(unsigned idx, unsigned cmd)
        {
            m_vertices[idx].cmd = int8u(cmd);
        }

        void swap_vertices(unsigned v1, unsigned v2)
        {
            vertex_type t = m_vertices[v1];
            m_vertices[v1] = m_vertices[v2];
            m_vertices[v2] = t;
        }

        unsigned last_command() const
        {
            return m_vertices.size() ? 
                m_vertices[m_vertices.size() - 1].cmd : 
                path_cmd_stop;
        }

        unsigned last_vertex(double* x, double* y) const
        {
            if(m_vertices.size() == 0)
            {
                *x = *y = 0.0;
                return path_cmd_stop;
            }
            return vertex(m_vertices.size() - 1, x, y);
        }

        unsigned prev_vertex(double* x, double* y) const
        {
            if(m_vertices.size() < 2)
            {
                *x = *y = 0.0;
                return path_cmd_stop;
            }
            return vertex(m_vertices.size() - 2, x, y);
        }

        double last_x() const
        {
            return m_vertices.size() ? m_vertices[m_vertices.size() - 1].x : 0.0;
        }

        double last_y() const
        {
            return m_vertices.size() ? m_vertices[m_vertices.size() - 1].y : 0.0;
        }

        unsigned total_vertices() const
        {
            return m_vertices.size();
        }

        unsigned vertex(unsigned idx, double* x, double* y) const
        {
            const vertex_type& v = m_vertices[idx];
            *x = v.x;
            *y = v.y;
            return v.cmd;
        }

        unsigned command(unsigned idx) const
        {
            return m_vertices[idx].cmd;
        }

    private:
        Container m_vertices;
    };

    //-----------------------------------------------------------path_storage
    typedef path_base<vertex_block_storage<double> > path_storage;

    // Example of declarations path_storage with pod_bvector as a container
    //-----------------------------------------------------------------------
    //typedef path_base<vertex_stl_storage<pod_bvector<vertex_d> > > path_storage;

}



// Example of declarations path_storage with std::vector as a container
//---------------------------------------------------------------------------
//#include <vector>
//namespace agg
//{
//    typedef path_base<vertex_stl_storage<std::vector<vertex_d> > > stl_path_storage; 
//}




#endif