view layer/ColourMapper.h @ 1386:fc3d89f88690 spectrogramparam

Use log-frequency rather than log-bin for calculating x coord in spectrum. This has the advantage that frequency positions don't move when we change the window size or oversampling ratio, but it does give us an unhelpfully large amount of space for very low frequencies - to be considered

/* -*- 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 2006-2007 Chris Cannam and 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 SV_COLOUR_MAPPER_H
#define SV_COLOUR_MAPPER_H

#include <QObject>
#include <QColor>
#include <QString>
#include <QPixmap>

/**
 * A class for mapping intensity values onto various colour maps.
 */
class ColourMapper
{
public:
    ColourMapper(int map,
                 bool inverted,
                 double minValue,
                 double maxValue);
    ~ColourMapper();

    ColourMapper(const ColourMapper &) =default;
    ColourMapper &operator=(const ColourMapper &) =default;

    enum ColourMap {
        Green,
        Sunset,
        WhiteOnBlack,
        BlackOnWhite,
        Cherry,
        Wasp,
        Ice,
        FruitSalad,
        Banded,
        Highlight,
        Printer,
        HighGain,
        BlueOnBlack,
        Cividis,
        Magma
    };

    int getMap() const { return m_map; }
    bool isInverted() const { return m_inverted; }
    double getMinValue() const { return m_min; }
    double getMaxValue() const { return m_max; }

    /**
     * Return the number of known colour maps.
     */
    static int getColourMapCount();

    /**
     * Return a human-readable label for the colour map with the given
     * index. This may have been subject to translation.
     */
    static QString getColourMapLabel(int n);

    /**
     * Return a machine-readable id string for the colour map with the
     * given index. This is not translated and is intended for use in
     * file I/O.
     */
    static QString getColourMapId(int n);

    /**
     * Return the index for the colour map with the given
     * machine-readable id string, or -1 if the id is not recognised.
     */
    static int getColourMapById(QString id);

    /**
     * Older versions of colour-handling code save and reload colour
     * maps by numerical index and can't properly handle situations in
     * which the index order changes between releases, or new indices
     * are added. So when we save a colour map by id, we should also
     * save a compatibility value that can be re-read by such
     * code. This value is an index into the series of colours used by
     * pre-3.2 SV code, namely (Default/Green, Sunset, WhiteOnBlack,
     * BlackOnWhite, RedOnBlue, YellowOnBlack, BlueOnBlack,
     * FruitSalad, Banded, Highlight, Printer, HighGain). It should
     * represent the closest equivalent to the current colour scheme
     * available in that set. This function returns that index.
     */    
    static int getBackwardCompatibilityColourMap(int n);
    
    /**
     * Map the given value to a colour. The value will be clamped to
     * the range minValue to maxValue (where both are drawn from the
     * constructor arguments).
     */
    QColor map(double value) const;

    /**
     * Return a colour that contrasts somewhat with the colours in the
     * map, so as to be used for cursors etc.
     */
    QColor getContrastingColour() const;

    /**
     * Return true if the colour map is intended to be placed over a
     * light background, false otherwise. This is typically true if
     * the colours corresponding to higher values are darker than
     * those corresponding to lower values.
     */
    bool hasLightBackground() const;

    /**
     * Return a pixmap of the given size containing a preview swatch
     * for the colour map.
     */
    QPixmap getExamplePixmap(QSize size) const;
    
protected:
    int m_map;
    bool m_inverted;
    double m_min;
    double m_max;
};

#endif