annotate widgets/LevelPanWidget.h @ 1127:9fb8dfd7ce4c spectrogram-minor-refactor

Fix threshold in spectrogram -- it wasn't working in the last release.
There is a new protocol for this. Formerly the threshold parameter had a
range from -50dB to 0 with the default at -50, and -50 treated internally
as "no threshold". However, there was a hardcoded, hidden internal threshold
for spectrogram colour mapping at -80dB with anything below this being rounded
to zero. Now the threshold parameter has range -81 to -1 with the default
at -80, -81 is treated internally as "no threshold", and there is no hidden
internal threshold. So the default behaviour is the same as before, an
effective -80dB threshold, but it is now possible to change this in both
directions. Sessions reloaded from prior versions may look slightly different
because, if the session says there should be no threshold, there will now
actually be no threshold instead of having the hidden internal one.

Still need to do something in the UI to make it apparent that the -81dB
setting removes the threshold entirely. This is at least no worse than the
previous, also obscured, magic -50dB setting.

/* -*- 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 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 LEVEL_PAN_WIDGET_H
#define LEVEL_PAN_WIDGET_H

#include <QWidget>

/**
 * A simple widget for coarse level and pan control.
 */

class LevelPanWidget : public QWidget
{
    Q_OBJECT

public:
    LevelPanWidget(QWidget *parent = 0);
    ~LevelPanWidget();
    
    /// Return level as a gain value in the range [0,1]
    float getLevel() const; 
    
    /// Return pan as a value in the range [-1,1]
    float getPan() const;

    /// Find out whether the widget is editable
    bool isEditable() const;

    /// Discover whether the level range includes muting or not
    bool includesMute() const;

    /// Draw a suitably sized copy of the widget's contents to the given device
    void renderTo(QPaintDevice *, QRectF, bool asIfEditable) const;

    QSize sizeHint() const;
                                               
public slots:
    /// Set level in the range [0,1] -- will be rounded
    void setLevel(float);

    /// Set pan in the range [-1,1] -- will be rounded
    void setPan(float);

    /// Specify whether the widget is editable or read-only (default editable)
    void setEditable(bool);

    /// Specify whether the level range should include muting or not
    void setIncludeMute(bool);
    
signals:
    void levelChanged(float);
    void panChanged(float);

protected:
    virtual void mousePressEvent(QMouseEvent *ev);
    virtual void mouseMoveEvent(QMouseEvent *ev);
    virtual void mouseReleaseEvent(QMouseEvent *ev);
    virtual void wheelEvent(QWheelEvent *ev);
    virtual void paintEvent(QPaintEvent *ev);

    void emitLevelChanged();
    void emitPanChanged();
    
    int m_level;
    int m_pan;
    bool m_editable;
    bool m_includeMute;

    QSizeF cellSize(QRectF) const;
    QPointF cellCentre(QRectF, int level, int pan) const;
    QSizeF cellLightSize(QRectF) const;
    QRectF cellLightRect(QRectF, int level, int pan) const;
    double thinLineWidth(QRectF) const;
    void toCell(QRectF, QPointF loc, int &level, int &pan) const;
};

#endif