agg_curves.h

来自「这是VCF框架的代码」· C头文件 代码 · 共 696 行 · 第 1/2 页

        //  0       1       0       -1/3
        //  0       1       0       0
        //
        return curve4_points(
            x1,
            y1,
            (3*x1 + x3) / 3,
            (3*y1 + y3) / 3,
            (3*x2 - x4) / 3,
            (3*y2 - y4) / 3,
            x2,
            y2);
    }



    //-----------------------------------------------------------------------
    inline curve4_points 
    hermite_to_bezier(const curve4_points& cp)
    {
        return hermite_to_bezier(cp[0], cp[1], cp[2], cp[3], 
                                 cp[4], cp[5], cp[6], cp[7]);
    }


    //-------------------------------------------------------------curve4_div
    class curve4_div
    {
    public:
        curve4_div() : 
            m_approximation_scale(1.0),
            m_angle_tolerance(0.0),
            m_cusp_limit(0.0),
            m_count(0)
        {}

        curve4_div(double x1, double y1, 
                   double x2, double y2, 
                   double x3, double y3,
                   double x4, double y4) :
            m_approximation_scale(1.0),
            m_angle_tolerance(0.0),
            m_cusp_limit(0.0),
            m_count(0)
        { 
            init(x1, y1, x2, y2, x3, y3, x4, y4);
        }

        curve4_div(const curve4_points& cp) :
            m_approximation_scale(1.0),
            m_angle_tolerance(0.0),
            m_count(0)
        { 
            init(cp[0], cp[1], cp[2], cp[3], cp[4], cp[5], cp[6], cp[7]);
        }

        void reset() { m_points.remove_all(); m_count = 0; }
        void init(double x1, double y1, 
                  double x2, double y2, 
                  double x3, double y3,
                  double x4, double y4);

        void init(const curve4_points& cp)
        {
            init(cp[0], cp[1], cp[2], cp[3], cp[4], cp[5], cp[6], cp[7]);
        }

        void approximation_method(curve_approximation_method_e) {}

        curve_approximation_method_e approximation_method() const 
        { 
            return curve_div; 
        }

        void approximation_scale(double s) { m_approximation_scale = s; }
        double approximation_scale() const { return m_approximation_scale;  }

        void angle_tolerance(double a) { m_angle_tolerance = a; }
        double angle_tolerance() const { return m_angle_tolerance;  }

        void cusp_limit(double v) 
        { 
            m_cusp_limit = (v == 0.0) ? 0.0 : pi - v; 
        }

        double cusp_limit() const 
        { 
            return (m_cusp_limit == 0.0) ? 0.0 : pi - m_cusp_limit; 
        }

        void rewind(unsigned)
        {
            m_count = 0;
        }

        unsigned vertex(double* x, double* y)
        {
            if(m_count >= m_points.size()) return path_cmd_stop;
            const point_d& p = m_points[m_count++];
            *x = p.x;
            *y = p.y;
            return (m_count == 1) ? path_cmd_move_to : path_cmd_line_to;
        }

    private:
        void bezier(double x1, double y1, 
                    double x2, double y2, 
                    double x3, double y3, 
                    double x4, double y4);

        void recursive_bezier(double x1, double y1, 
                              double x2, double y2, 
                              double x3, double y3, 
                              double x4, double y4,
                              unsigned level);

        double               m_approximation_scale;
        double               m_distance_tolerance_square;
        double               m_distance_tolerance_manhattan;
        double               m_angle_tolerance;
        double               m_cusp_limit;
        unsigned             m_count;
        pod_bvector<point_d> m_points;
    };


    //-----------------------------------------------------------------curve3
    class curve3
    {
    public:
        curve3() : m_approximation_method(curve_div) {}
        curve3(double x1, double y1, 
               double x2, double y2, 
               double x3, double y3) :
            m_approximation_method(curve_div)
        { 
            init(x1, y1, x2, y2, x3, y3);
        }

        void reset() 
        { 
            m_curve_inc.reset();
            m_curve_div.reset();
        }

        void init(double x1, double y1, 
                  double x2, double y2, 
                  double x3, double y3)
        {
            if(m_approximation_method == curve_inc) 
            {
                m_curve_inc.init(x1, y1, x2, y2, x3, y3);
            }
            else
            {
                m_curve_div.init(x1, y1, x2, y2, x3, y3);
            }
        }

        void approximation_method(curve_approximation_method_e v) 
        { 
            m_approximation_method = v; 
        }

        curve_approximation_method_e approximation_method() const 
        { 
            return m_approximation_method; 
        }

        void approximation_scale(double s) 
        { 
            m_curve_inc.approximation_scale(s);
            m_curve_div.approximation_scale(s);
        }

        double approximation_scale() const 
        { 
            return m_curve_inc.approximation_scale(); 
        }

        void angle_tolerance(double a) 
        { 
            m_curve_div.angle_tolerance(a); 
        }

        double angle_tolerance() const 
        { 
            return m_curve_div.angle_tolerance(); 
        }

        void cusp_limit(double v) 
        { 
            m_curve_div.cusp_limit(v); 
        }

        double cusp_limit() const 
        { 
            return m_curve_div.cusp_limit();  
        }

        void rewind(unsigned path_id)
        {
            if(m_approximation_method == curve_inc) 
            {
                m_curve_inc.rewind(path_id);
            }
            else
            {
                m_curve_div.rewind(path_id);
            }
        }

        unsigned vertex(double* x, double* y)
        {
            if(m_approximation_method == curve_inc) 
            {
                return m_curve_inc.vertex(x, y);
            }
            return m_curve_div.vertex(x, y);
        }

    private:
        curve3_inc m_curve_inc;
        curve3_div m_curve_div;
        curve_approximation_method_e m_approximation_method;
    };





    //-----------------------------------------------------------------curve4
    class curve4
    {
    public:
        curve4() : m_approximation_method(curve_div) {}
        curve4(double x1, double y1, 
               double x2, double y2, 
               double x3, double y3,
               double x4, double y4) : 
            m_approximation_method(curve_div)
        { 
            init(x1, y1, x2, y2, x3, y3, x4, y4);
        }

        curve4(const curve4_points& cp) :
            m_approximation_method(curve_div)
        { 
            init(cp[0], cp[1], cp[2], cp[3], cp[4], cp[5], cp[6], cp[7]);
        }

        void reset() 
        { 
            m_curve_inc.reset();
            m_curve_div.reset();
        }

        void init(double x1, double y1, 
                  double x2, double y2, 
                  double x3, double y3,
                  double x4, double y4)
        {
            if(m_approximation_method == curve_inc) 
            {
                m_curve_inc.init(x1, y1, x2, y2, x3, y3, x4, y4);
            }
            else
            {
                m_curve_div.init(x1, y1, x2, y2, x3, y3, x4, y4);
            }
        }

        void init(const curve4_points& cp)
        {
            init(cp[0], cp[1], cp[2], cp[3], cp[4], cp[5], cp[6], cp[7]);
        }

        void approximation_method(curve_approximation_method_e v) 
        { 
            m_approximation_method = v; 
        }

        curve_approximation_method_e approximation_method() const 
        { 
            return m_approximation_method; 
        }

        void approximation_scale(double s) 
        { 
            m_curve_inc.approximation_scale(s);
            m_curve_div.approximation_scale(s);
        }
        double approximation_scale() const { return m_curve_inc.approximation_scale(); }

        void angle_tolerance(double v) 
        { 
            m_curve_div.angle_tolerance(v); 
        }

        double angle_tolerance() const 
        { 
            return m_curve_div.angle_tolerance();  
        }

        void cusp_limit(double v) 
        { 
            m_curve_div.cusp_limit(v); 
        }

        double cusp_limit() const 
        { 
            return m_curve_div.cusp_limit();  
        }

        void rewind(unsigned path_id)
        {
            if(m_approximation_method == curve_inc) 
            {
                m_curve_inc.rewind(path_id);
            }
            else
            {
                m_curve_div.rewind(path_id);
            }
        }

        unsigned vertex(double* x, double* y)
        {
            if(m_approximation_method == curve_inc) 
            {
                return m_curve_inc.vertex(x, y);
            }
            return m_curve_div.vertex(x, y);
        }

    private:
        curve4_inc m_curve_inc;
        curve4_div m_curve_div;
        curve_approximation_method_e m_approximation_method;
    };




}

#endif