/** @file
 * Interpolators for lists of points.
 */
/* Authors:
 *   Johan Engelen <j.b.c.engelen@alumnus.utwente.nl>
 *
 * Copyright (C) 2010-2011 Authors
 *
 * Released under GNU GPL, read the file 'COPYING' for more information
 */

#ifndef INKSCAPE_LPE_POWERSTROKE_INTERPOLATORS_H
#define INKSCAPE_LPE_POWERSTROKE_INTERPOLATORS_H

#include <2geom/path.h>
#include <2geom/bezier-utils.h>
#include <2geom/sbasis-to-bezier.h>

#include "live_effects/spiro.h"


/// @TODO  Move this to 2geom?
namespace Geom {
namespace Interpolate {

enum InterpolatorType {
  INTERP_LINEAR,
  INTERP_CUBICBEZIER,
  INTERP_CUBICBEZIER_JOHAN,
  INTERP_SPIRO
};

class Interpolator {
public:
    Interpolator() {};
    virtual ~Interpolator() {};

    static Interpolator* create(InterpolatorType type);

    virtual Geom::Path interpolateToPath(std::vector<Point> const &points) const = 0;

private:
    Interpolator(const Interpolator&);
    Interpolator& operator=(const Interpolator&);
};

class Linear : public Interpolator {
public:
    Linear() {};
    virtual ~Linear() {};

    virtual Path interpolateToPath(std::vector<Point> const &points) const {
        Path path;
        path.start( points.at(0) );
        for (unsigned int i = 1 ; i < points.size(); ++i) {
            path.appendNew<Geom::LineSegment>(points.at(i));
        }
        return path;
    };

private:
    Linear(const Linear&);
    Linear& operator=(const Linear&);
};

// this class is terrible
class CubicBezierFit : public Interpolator {
public:
    CubicBezierFit() {};
    virtual ~CubicBezierFit() {};

    virtual Path interpolateToPath(std::vector<Point> const &points) const {
        unsigned int n_points = points.size();
        // worst case gives us 2 segment per point
        int max_segs = 8*n_points;
        Geom::Point * b = g_new(Geom::Point, max_segs);
        Geom::Point * points_array = g_new(Geom::Point, 4*n_points);
        for (unsigned i = 0; i < n_points; ++i) {
            points_array[i] = points.at(i);
        }

        double tolerance_sq = 0; // this value is just a random guess

        int const n_segs = Geom::bezier_fit_cubic_r(b, points_array, n_points,
                                                 tolerance_sq, max_segs);

        Geom::Path fit;
        if ( n_segs > 0)
        {
            fit.start(b[0]);
            for (int c = 0; c < n_segs; c++) {
                fit.appendNew<Geom::CubicBezier>(b[4*c+1], b[4*c+2], b[4*c+3]);
            }
        }
        g_free(b);
        g_free(points_array);
        return fit;
    };

private:
    CubicBezierFit(const CubicBezierFit&);
    CubicBezierFit& operator=(const CubicBezierFit&);
};

/// @todo invent name for this class
class CubicBezierJohan : public Interpolator {
public:
    CubicBezierJohan(double beta = 0.2) {
        _beta = beta;
    };
    virtual ~CubicBezierJohan() {};

    virtual Path interpolateToPath(std::vector<Point> const &points) const {
        Path fit;
        fit.start(points.at(0));
        for (unsigned int i = 1; i < points.size(); ++i) {
            Point p0 = points.at(i-1);
            Point p1 = points.at(i);
            Point dx = Point(p1[X] - p0[X], 0);
            fit.appendNew<CubicBezier>(p0+_beta*dx, p1-_beta*dx, p1);
        }
        return fit;
    };

    void setBeta(double beta) {
        _beta = beta;
    }

    double _beta;

private:
    CubicBezierJohan(const CubicBezierJohan&);
    CubicBezierJohan& operator=(const CubicBezierJohan&);
};


class SpiroInterpolator : public Interpolator {
public:
    SpiroInterpolator() {};
    virtual ~SpiroInterpolator() {};

    virtual Path interpolateToPath(std::vector<Point> const &points) const {
        Path fit;

        Coord scale_y = 100.;

        guint len = points.size();
        Spiro::spiro_cp *controlpoints = g_new (Spiro::spiro_cp, len);
        for (unsigned int i = 0; i < len; ++i) {
            controlpoints[i].x = points[i][X];
            controlpoints[i].y = points[i][Y] / scale_y;
            controlpoints[i].ty = 'c';
        }
        controlpoints[0].ty = '{';
        controlpoints[1].ty = 'v';
        controlpoints[len-2].ty = 'v';
        controlpoints[len-1].ty = '}';

        Spiro::spiro_run(controlpoints, len, fit);

        fit *= Scale(1,scale_y);
        return fit;
    };

private:
    SpiroInterpolator(const SpiroInterpolator&);
    SpiroInterpolator& operator=(const SpiroInterpolator&);
};


Interpolator*
Interpolator::create(InterpolatorType type) {
    switch (type) {
      case INTERP_LINEAR:
        return new Geom::Interpolate::Linear();
      case INTERP_CUBICBEZIER:
        return new Geom::Interpolate::CubicBezierFit();
      case INTERP_CUBICBEZIER_JOHAN:
        return new Geom::Interpolate::CubicBezierJohan();
      case INTERP_SPIRO:
        return new Geom::Interpolate::SpiroInterpolator();
      default:
        return new Geom::Interpolate::Linear();
    }
}

} //namespace Interpolate
} //namespace Geom

#endif

/*
  Local Variables:
  mode:c++
  c-file-style:"stroustrup"
  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
  indent-tabs-mode:nil
  fill-column:99
  End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :