view base/RangeMapper.h @ 1008:d9e0e59a1581

When using an aggregate model to pass data to a transform, zero-pad the shorter input to the duration of the longer rather than truncating the longer. (This is better behaviour for e.g. MATCH, and in any case the code was previously truncating incorrectly and ending up with garbage data at the end.)

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Sonic Visualiser
    An audio file viewer and annotation editor.
    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2006 QMUL.
    
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
    published by the Free Software Foundation; either version 2 of the
    License, or (at your option) any later version.  See the file
    COPYING included with this distribution for more information.
*/

#ifndef _RANGE_MAPPER_H_
#define _RANGE_MAPPER_H_

#include <QString>

#include "Debug.h"
#include <map>

class RangeMapper 
{
public:
    virtual ~RangeMapper() { }

    /**
     * Return the position that maps to the given value, rounding to
     * the nearest position and clamping to the minimum and maximum
     * extents of the mapper's positional range.
     */
    virtual int getPositionForValue(float value) const = 0;

    /**
     * Return the position that maps to the given value, rounding to
     * the nearest position, without clamping. That is, whatever
     * mapping function is in use will be projected even outside the
     * minimum and maximum extents of the mapper's positional
     * range. (The mapping outside that range is not guaranteed to be
     * exact, except if the mapper is a linear one.)
     */
    virtual int getPositionForValueUnclamped(float value) const = 0;

    /**
     * Return the value mapped from the given position, clamping to
     * the minimum and maximum extents of the mapper's value range.
     */
    virtual float getValueForPosition(int position) const = 0;

    /**
     * Return the value mapped from the given positionq, without
     * clamping. That is, whatever mapping function is in use will be
     * projected even outside the minimum and maximum extents of the
     * mapper's value range. (The mapping outside that range is not
     * guaranteed to be exact, except if the mapper is a linear one.)
     */
    virtual float getValueForPositionUnclamped(int position) const = 0;

    /**
     * Get the unit of the mapper's value range.
     */
    virtual QString getUnit() const { return ""; }
};


class LinearRangeMapper : public RangeMapper
{
public:
    /**
     * Map values in range minval->maxval linearly into integer range
     * minpos->maxpos. minval and minpos must be less than maxval and
     * maxpos respectively. If inverted is true, the range will be
     * mapped "backwards" (minval to maxpos and maxval to minpos).
     */
    LinearRangeMapper(int minpos, int maxpos,
                      float minval, float maxval,
                      QString unit = "", bool inverted = false);
    
    virtual int getPositionForValue(float value) const;
    virtual int getPositionForValueUnclamped(float value) const;

    virtual float getValueForPosition(int position) const;
    virtual float getValueForPositionUnclamped(int position) const;

    virtual QString getUnit() const { return m_unit; }

protected:
    int m_minpos;
    int m_maxpos;
    float m_minval;
    float m_maxval;
    QString m_unit;
    bool m_inverted;
};

class LogRangeMapper : public RangeMapper
{
public:
    /**
     * Map values in range minval->maxval into integer range
     * minpos->maxpos such that logs of the values are mapped
     * linearly. minval must be greater than zero, and minval and
     * minpos must be less than maxval and maxpos respectively. If
     * inverted is true, the range will be mapped "backwards" (minval
     * to maxpos and maxval to minpos).
     */
    LogRangeMapper(int minpos, int maxpos,
                   float minval, float maxval,
                   QString m_unit = "", bool inverted = false);

    static void convertRatioMinLog(float ratio, float minlog,
                                   int minpos, int maxpos,
                                   float &minval, float &maxval);

    static void convertMinMax(int minpos, int maxpos,
                              float minval, float maxval,
                              float &ratio, float &minlog);

    virtual int getPositionForValue(float value) const;
    virtual int getPositionForValueUnclamped(float value) const;

    virtual float getValueForPosition(int position) const;
    virtual float getValueForPositionUnclamped(int position) const;

    virtual QString getUnit() const { return m_unit; }

protected:
    int m_minpos;
    int m_maxpos;
    float m_ratio;
    float m_minlog;
    float m_maxlog;
    QString m_unit;
    bool m_inverted;
};

class InterpolatingRangeMapper : public RangeMapper
{
public:
    typedef std::map<float, int> CoordMap;

    /**
     * Given a series of (value, position) coordinate mappings,
     * construct a range mapper that maps arbitrary values, in the
     * range between minimum and maximum of the provided values, onto
     * coordinates using linear interpolation between the supplied
     * points.
     *
     *!!! todo: Cubic -- more generally useful than linear interpolation
     *!!! todo: inverted flag
     *
     * The set of provided mappings must contain at least two
     * coordinates.
     *
     * It is expected that the values and positions in the coordinate
     * mappings will both be monotonically increasing (i.e. no
     * inflections in the mapping curve). Behaviour is undefined if
     * this is not the case.
     */
    InterpolatingRangeMapper(CoordMap pointMappings,
                             QString unit);

    virtual int getPositionForValue(float value) const;
    virtual int getPositionForValueUnclamped(float value) const;

    virtual float getValueForPosition(int position) const;
    virtual float getValueForPositionUnclamped(int position) const;

    virtual QString getUnit() const { return m_unit; }

protected:
    CoordMap m_mappings;
    std::map<int, float> m_reverse;
    QString m_unit;

    template <typename T>
    float interpolate(T *mapping, float v) const;
};

class AutoRangeMapper : public RangeMapper
{
public:
    enum MappingType {
        Interpolating,
        StraightLine,
        Logarithmic,
    };

    typedef std::map<float, int> CoordMap;

    /**
     * Given a series of (value, position) coordinate mappings,
     * construct a range mapper that maps arbitrary values, in the
     * range between minimum and maximum of the provided values, onto
     * coordinates. 
     *
     * The mapping used may be
     * 
     *    Interpolating -- an InterpolatingRangeMapper will be used
     * 
     *    StraightLine -- a LinearRangeMapper from the minimum to
     *    maximum value coordinates will be used, ignoring all other
     *    supplied coordinate mappings
     * 
     *    Logarithmic -- a LogRangeMapper from the minimum to
     *    maximum value coordinates will be used, ignoring all other
     *    supplied coordinate mappings
     *
     * The mapping will be chosen automatically by looking at the
     * supplied coordinates. If the supplied coordinates fall on a
     * straight line, a StraightLine mapping will be used; if they
     * fall on a log curve, a Logarithmic mapping will be used;
     * otherwise an Interpolating mapping will be used.
     *
     *!!! todo: inverted flag
     *
     * The set of provided mappings must contain at least two
     * coordinates, or at least three if the points are not supposed
     * to be in a straight line.
     *
     * It is expected that the values and positions in the coordinate
     * mappings will both be monotonically increasing (i.e. no
     * inflections in the mapping curve). Behaviour is undefined if
     * this is not the case.
     */
    AutoRangeMapper(CoordMap pointMappings,
                    QString unit);

    ~AutoRangeMapper();

    /**
     * Return the mapping type in use.
     */
    MappingType getType() const { return m_type; }

    virtual int getPositionForValue(float value) const;
    virtual int getPositionForValueUnclamped(float value) const;

    virtual float getValueForPosition(int position) const;
    virtual float getValueForPositionUnclamped(int position) const;

    virtual QString getUnit() const { return m_unit; }

protected:
    MappingType m_type;
    CoordMap m_mappings;
    QString m_unit;
    RangeMapper *m_mapper;

    MappingType chooseMappingTypeFor(const CoordMap &);
};

#endif