//----------------------------------------------------------------------------
// Anti-Grain Geometry - Version 2.4
// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
//
// Permission to copy, use, modify, sell and distribute this software
// is granted provided this copyright notice appears in all copies.
// This software is provided "as is" without express or implied
// warranty, and with no claim as to its suitability for any purpose.
//
//----------------------------------------------------------------------------
// Contact: mcseem@antigrain.com
//          mcseemagg@yahoo.com
//          http://www.antigrain.com
//----------------------------------------------------------------------------
//
// classes conv_curve
//
//----------------------------------------------------------------------------

#ifndef AGG_CONV_CURVE_INCLUDED
#define AGG_CONV_CURVE_INCLUDED

#include "agg_basics.h"
#include "agg_curves.h"

namespace agg
{

    //---------------------------------------------------------------conv_curve
    // Curve converter class. Any path storage can have Bezier curves defined
    // by their control points. There're two types of curves supported: curve3
    // and curve4. Curve3 is a conic Bezier curve with 2 endpoints and 1 control
    // point. Curve4 has 2 control points (4 points in total) and can be used
    // to interpolate more complicated curves. Curve4, unlike curve3 can be used
    // to approximate arcs, both circular and elliptical. Curves are
    // approximated with straight lines and one of the approaches is just to
    // store the whole sequence of vertices that approximate our curve. It takes
    // additional memory, and at the same time the consecutive vertices can be
    // calculated on demand.
    //
    // Initially, path storages are not suppose to keep all the vertices of the
    // curves (although, nothing prevents us from doing so). Instead,
    // path_storage keeps only vertices, needed to calculate a curve on demand.
    // Those vertices are marked with special commands. So, if the path_storage
    // contains curves (which are not real curves yet), and we render this
    // storage directly, all we will see is only 2 or 3 straight line segments
    // (for curve3 and curve4 respectively). If we need to see real curves drawn
    // we need to include this class into the conversion pipeline.
    //
    // Class conv_curve recognizes commands path_cmd_curve3 and path_cmd_curve4
    // and converts these vertices into a move_to/line_to sequence.
    //-----------------------------------------------------------------------
    template <class VertexSource, class Curve3 = curve3, class Curve4 = curve4>
    class conv_curve
    {
    public:
        typedef Curve3 curve3_type;
        typedef Curve4 curve4_type;
        typedef conv_curve<VertexSource, Curve3, Curve4> self_type;

        explicit conv_curve(VertexSource& source):
            m_source(&source),
            m_last_x(0.0),
            m_last_y(0.0)
        {
        }
        void attach(VertexSource& source)
        {
            m_source = &source;
        }

        void approximation_method(curve_approximation_method_e v)
        {
            m_curve3.approximation_method(v);
            m_curve4.approximation_method(v);
        }

        curve_approximation_method_e approximation_method() const
        {
            return m_curve4.approximation_method();
        }

        void approximation_scale(double s)
        {
            m_curve3.approximation_scale(s);
            m_curve4.approximation_scale(s);
        }

        double approximation_scale() const
        {
            return m_curve4.approximation_scale();
        }

        void angle_tolerance(double v)
        {
            m_curve3.angle_tolerance(v);
            m_curve4.angle_tolerance(v);
        }

        double angle_tolerance() const
        {
            return m_curve4.angle_tolerance();
        }

        void cusp_limit(double v)
        {
            m_curve3.cusp_limit(v);
            m_curve4.cusp_limit(v);
        }

        double cusp_limit() const
        {
            return m_curve4.cusp_limit();
        }

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

    private:
        conv_curve(const self_type&);
        const self_type& operator=(const self_type&);

        VertexSource* m_source;
        double m_last_x;
        double m_last_y;
        curve3_type m_curve3;
        curve4_type m_curve4;
    };

    //------------------------------------------------------------------------
    template <class VertexSource, class Curve3, class Curve4>
    void conv_curve<VertexSource, Curve3, Curve4>::rewind(unsigned path_id)
    {
        m_source->rewind(path_id);
        m_last_x = 0.0;
        m_last_y = 0.0;
        m_curve3.reset();
        m_curve4.reset();
    }

    //------------------------------------------------------------------------
    template <class VertexSource, class Curve3, class Curve4>
    unsigned conv_curve<VertexSource, Curve3, Curve4>::vertex(
        double* x, double* y)
    {
        if (!is_stop(m_curve3.vertex(x, y)))
        {
            m_last_x = *x;
            m_last_y = *y;
            return path_cmd_line_to;
        }

        if (!is_stop(m_curve4.vertex(x, y)))
        {
            m_last_x = *x;
            m_last_y = *y;
            return path_cmd_line_to;
        }

        double ct2_x = 0;
        double ct2_y = 0;
        double end_x = 0;
        double end_y = 0;

        unsigned cmd = m_source->vertex(x, y);
        switch (cmd)
        {
            case path_cmd_curve3:
                m_source->vertex(&end_x, &end_y);

                m_curve3.init(m_last_x, m_last_y, *x, *y, end_x, end_y);

                m_curve3.vertex(x, y); // First call returns path_cmd_move_to
                m_curve3.vertex(x, y); // This is the first vertex of the curve
                cmd = path_cmd_line_to;
                break;

            case path_cmd_curve4:
                m_source->vertex(&ct2_x, &ct2_y);
                m_source->vertex(&end_x, &end_y);

                m_curve4.init(
                    m_last_x, m_last_y, *x, *y, ct2_x, ct2_y, end_x, end_y);

                m_curve4.vertex(x, y); // First call returns path_cmd_move_to
                m_curve4.vertex(x, y); // This is the first vertex of the curve
                cmd = path_cmd_line_to;
                break;
        }
        m_last_x = *x;
        m_last_y = *y;
        return cmd;
    }

}

#endif
