agg_path_storage.h

这是VCF框架的代码

                if(is_vertex(cmd))
                {
                    double x0, y0;
                    unsigned cmd0 = last_vertex(&x0, &y0);
                    if(is_vertex(cmd0))
                    {
                        if(calc_distance(x, y, x0, y0) > vertex_dist_epsilon)
                        {
                            if(is_move_to(cmd)) cmd = path_cmd_line_to;
                            m_vertices.add_vertex(x, y, cmd);
                        }
                    }
                    else
                    {
                        if(is_stop(cmd0))
                        {
                            cmd = path_cmd_move_to;
                        }
                        else
                        {
                            if(is_move_to(cmd)) cmd = path_cmd_line_to;
                        }
                        m_vertices.add_vertex(x, y, cmd);
                    }
                }
                while(!is_stop(cmd = vs.vertex(&x, &y)))
                {
                    m_vertices.add_vertex(x, y, is_move_to(cmd) ? 
                                                    path_cmd_line_to : 
                                                    cmd);
                }
            }
        }

        // Concatenate polygon/polyline. 
        //--------------------------------------------------------------------
        template<class T> void concat_poly(const T* data, 
                                           unsigned num_points,
                                           bool closed)
        {
            poly_plain_adaptor<T> poly(data, num_points, closed);
            concat_path(poly);
        }

        // Join polygon/polyline continuously.
        //--------------------------------------------------------------------
        template<class T> void join_poly(const T* data, 
                                         unsigned num_points,
                                         bool closed)
        {
            poly_plain_adaptor<T> poly(data, num_points, closed);
            join_path(poly);
        }


    private:
        unsigned perceive_polygon_orientation(unsigned start, unsigned end);
        void     invert_polygon(unsigned start, unsigned end);

        VertexContainer m_vertices;
        unsigned        m_iterator;
    };

    //------------------------------------------------------------------------
    template<class VC> 
    unsigned path_base<VC>::start_new_path()
    {
        if(!is_stop(m_vertices.last_command()))
        {
            m_vertices.add_vertex(0.0, 0.0, path_cmd_stop);
        }
        return m_vertices.total_vertices();
    }


    //------------------------------------------------------------------------
    template<class VC> 
    inline void path_base<VC>::rel_to_abs(double* x, double* y) const
    {
        if(m_vertices.total_vertices())
        {
            double x2;
            double y2;
            if(is_vertex(m_vertices.last_vertex(&x2, &y2)))
            {
                *x += x2;
                *y += y2;
            }
        }
    }

    //------------------------------------------------------------------------
    template<class VC> 
    inline void path_base<VC>::move_to(double x, double y)
    {
        m_vertices.add_vertex(x, y, path_cmd_move_to);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    inline void path_base<VC>::move_rel(double dx, double dy)
    {
        rel_to_abs(&dx, &dy);
        m_vertices.add_vertex(dx, dy, path_cmd_move_to);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    inline void path_base<VC>::line_to(double x, double y)
    {
        m_vertices.add_vertex(x, y, path_cmd_line_to);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    inline void path_base<VC>::line_rel(double dx, double dy)
    {
        rel_to_abs(&dx, &dy);
        m_vertices.add_vertex(dx, dy, path_cmd_line_to);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    inline void path_base<VC>::hline_to(double x)
    {
        m_vertices.add_vertex(x, last_y(), path_cmd_line_to);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    inline void path_base<VC>::hline_rel(double dx)
    {
        double dy = 0;
        rel_to_abs(&dx, &dy);
        m_vertices.add_vertex(dx, dy, path_cmd_line_to);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    inline void path_base<VC>::vline_to(double y)
    {
        m_vertices.add_vertex(last_x(), y, path_cmd_line_to);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    inline void path_base<VC>::vline_rel(double dy)
    {
        double dx = 0;
        rel_to_abs(&dx, &dy);
        m_vertices.add_vertex(dx, dy, path_cmd_line_to);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::arc_to(double rx, double ry,
                               double angle,
                               bool large_arc_flag,
                               bool sweep_flag,
                               double x, double y)
    {
        if(m_vertices.total_vertices() && is_vertex(m_vertices.last_command()))
        {
            const double epsilon = 1e-30;
            double x0 = 0.0;
            double y0 = 0.0;
            m_vertices.last_vertex(&x0, &y0);

            rx = fabs(rx);
            ry = fabs(ry);

            // Ensure radii are valid
            //-------------------------
            if(rx < epsilon || ry < epsilon) 
            {
                line_to(x, y);
                return;
            }

            if(calc_distance(x0, y0, x, y) < epsilon)
            {
                // If the endpoints (x, y) and (x0, y0) are identical, then this
                // is equivalent to omitting the elliptical arc segment entirely.
                return;
            }
            bezier_arc_svg a(x0, y0, rx, ry, angle, large_arc_flag, sweep_flag, x, y);
            if(a.radii_ok())
            {
                join_path(a);
            }
            else
            {
                line_to(x, y);
            }
        }
        else
        {
            move_to(x, y);
        }
    }

    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::arc_rel(double rx, double ry,
                                double angle,
                                bool large_arc_flag,
                                bool sweep_flag,
                                double dx, double dy)
    {
        rel_to_abs(&dx, &dy);
        arc_to(rx, ry, angle, large_arc_flag, sweep_flag, dx, dy);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::curve3(double x_ctrl, double y_ctrl, 
                               double x_to,   double y_to)
    {
        m_vertices.add_vertex(x_ctrl, y_ctrl, path_cmd_curve3);
        m_vertices.add_vertex(x_to,   y_to,   path_cmd_curve3);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::curve3_rel(double dx_ctrl, double dy_ctrl, 
                                   double dx_to,   double dy_to)
    {
        rel_to_abs(&dx_ctrl, &dy_ctrl);
        rel_to_abs(&dx_to,   &dy_to);
        m_vertices.add_vertex(dx_ctrl, dy_ctrl, path_cmd_curve3);
        m_vertices.add_vertex(dx_to,   dy_to,   path_cmd_curve3);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::curve3(double x_to, double y_to)
    {
        double x0;
        double y0;
        if(is_vertex(m_vertices.last_vertex(&x0, &y0)))
        {
            double x_ctrl;
            double y_ctrl; 
            unsigned cmd = m_vertices.prev_vertex(&x_ctrl, &y_ctrl);
            if(is_curve(cmd))
            {
                x_ctrl = x0 + x0 - x_ctrl;
                y_ctrl = y0 + y0 - y_ctrl;
            }
            else
            {
                x_ctrl = x0;
                y_ctrl = y0;
            }
            curve3(x_ctrl, y_ctrl, x_to, y_to);
        }
    }

    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::curve3_rel(double dx_to, double dy_to)
    {
        rel_to_abs(&dx_to, &dy_to);
        curve3(dx_to, dy_to);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::curve4(double x_ctrl1, double y_ctrl1, 
                               double x_ctrl2, double y_ctrl2, 
                               double x_to,    double y_to)
    {
        m_vertices.add_vertex(x_ctrl1, y_ctrl1, path_cmd_curve4);
        m_vertices.add_vertex(x_ctrl2, y_ctrl2, path_cmd_curve4);
        m_vertices.add_vertex(x_to,    y_to,    path_cmd_curve4);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::curve4_rel(double dx_ctrl1, double dy_ctrl1, 
                                   double dx_ctrl2, double dy_ctrl2, 
                                   double dx_to,    double dy_to)
    {
        rel_to_abs(&dx_ctrl1, &dy_ctrl1);
        rel_to_abs(&dx_ctrl2, &dy_ctrl2);
        rel_to_abs(&dx_to,    &dy_to);
        m_vertices.add_vertex(dx_ctrl1, dy_ctrl1, path_cmd_curve4);
        m_vertices.add_vertex(dx_ctrl2, dy_ctrl2, path_cmd_curve4);
        m_vertices.add_vertex(dx_to,    dy_to,    path_cmd_curve4);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::curve4(double x_ctrl2, double y_ctrl2, 
                               double x_to,    double y_to)
    {
        double x0;
        double y0;
        if(is_vertex(last_vertex(&x0, &y0)))
        {
            double x_ctrl1;
            double y_ctrl1; 
            unsigned cmd = prev_vertex(&x_ctrl1, &y_ctrl1);
            if(is_curve(cmd))
            {
                x_ctrl1 = x0 + x0 - x_ctrl1;
                y_ctrl1 = y0 + y0 - y_ctrl1;
            }
            else
            {
                x_ctrl1 = x0;
                y_ctrl1 = y0;
            }
            curve4(x_ctrl1, y_ctrl1, x_ctrl2, y_ctrl2, x_to, y_to);
        }
    }

    //------------------------------------------------------------------------
    template<class VC> 
    void path_base<VC>::curve4_rel(double dx_ctrl2, double dy_ctrl2, 
                                   double dx_to,    double dy_to)
    {
        rel_to_abs(&dx_ctrl2, &dy_ctrl2);
        rel_to_abs(&dx_to,    &dy_to);
        curve4(dx_ctrl2, dy_ctrl2, dx_to, dy_to);
    }

    //------------------------------------------------------------------------
    template<class VC> 
    inline void path_base<VC>::end_poly(unsigned flags)
    {
        if(is_vertex(m_vertices.last_command()))
        {
            m_vertices.add_vertex(0.0, 0.0, path_cmd_end_poly | flags);
        }
    }

    //------------------------------------------------------------------------
    template<class VC> 
    inline void path_base<VC>::close_polygon(unsigned flags)
    {
        end_poly(path_flags_close | flags);
    }

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

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

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

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