annotate layer/SpectrumLayer.cpp @ 592:a13aa5320221 sonification

Extends the audio feedback of the piano scale to the Spectrum layer (horizontal piano keyboard).

Increase of the piano keyboard width (SpectrogramLayer) and height (SpectrumLayer) for layout purposes. A get method should be added to obtain the scale size parameter outside the layer class.

/* -*- 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 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.
*/

#include "SpectrumLayer.h"

#include "data/model/FFTModel.h"
#include "view/View.h"
#include "base/AudioLevel.h"
#include "base/Preferences.h"
#include "base/RangeMapper.h"
#include "base/Pitch.h"
#include "ColourMapper.h"

#include <QPainter>
#include <QTextStream>
#include <QMouseEvent>

SpectrumLayer::SpectrumLayer() :
    m_originModel(0),
    m_channel(-1),
    m_channelSet(false),
    m_windowSize(4096),
    m_windowType(HanningWindow),
    m_windowHopLevel(3),
    m_showPeaks(false),
    m_newFFTNeeded(true)
{
    Preferences *prefs = Preferences::getInstance();
    connect(prefs, SIGNAL(propertyChanged(PropertyContainer::PropertyName)),
            this, SLOT(preferenceChanged(PropertyContainer::PropertyName)));
    setWindowType(prefs->getWindowType());

    setBinScale(LogBins);
}

SpectrumLayer::~SpectrumLayer()
{
    Model *m = const_cast<Model *>
        (static_cast<const Model *>(m_sliceableModel));
    if (m) m->aboutToDelete();
    m_sliceableModel = 0;
    delete m;
}

void
SpectrumLayer::setModel(DenseTimeValueModel *model)
{
    SVDEBUG << "SpectrumLayer::setModel(" << model << ") from " << m_originModel << endl;
    
    if (m_originModel == model) return;

    m_originModel = model;

    if (m_sliceableModel) {
        Model *m = const_cast<Model *>
            (static_cast<const Model *>(m_sliceableModel));
        m->aboutToDelete();
        setSliceableModel(0);
        delete m;
    }

    m_newFFTNeeded = true;

    emit layerParametersChanged();
}

void
SpectrumLayer::setChannel(int channel)
{
    SVDEBUG << "SpectrumLayer::setChannel(" << channel << ") from " << m_channel << endl;
    
    m_channelSet = true;
    
    if (m_channel == channel) return;

    m_channel = channel;

    m_newFFTNeeded = true;

    emit layerParametersChanged();
}

void
SpectrumLayer::setupFFT()
{
    if (m_sliceableModel) {
        Model *m = const_cast<Model *>
            (static_cast<const Model *>(m_sliceableModel));
        m->aboutToDelete();
        setSliceableModel(0);
        delete m;
    }

    if (!m_originModel) {
        return;
    }

    FFTModel *newFFT = new FFTModel(m_originModel,
                                    m_channel,
                                    m_windowType,
                                    m_windowSize,
                                    getWindowIncrement(),
                                    m_windowSize,
                                    false,
                                    StorageAdviser::Criteria
                                    (StorageAdviser::SpeedCritical |
                                     StorageAdviser::FrequentLookupLikely));

    setSliceableModel(newFFT);

    m_biasCurve.clear();
    for (size_t i = 0; i < m_windowSize; ++i) {
        m_biasCurve.push_back(1.f / (float(m_windowSize)/2.f));
    }

    newFFT->resume();

    m_newFFTNeeded = false;
}

Layer::PropertyList
SpectrumLayer::getProperties() const
{
    PropertyList list = SliceLayer::getProperties();
    list.push_back("Window Size");
    list.push_back("Window Increment");
    list.push_back("Show Peak Frequencies");
    return list;
}

QString
SpectrumLayer::getPropertyLabel(const PropertyName &name) const
{
    if (name == "Window Size") return tr("Window Size");
    if (name == "Window Increment") return tr("Window Overlap");
    if (name == "Show Peak Frequencies") return tr("Show Peak Frequencies");
    return SliceLayer::getPropertyLabel(name);
}

QString
SpectrumLayer::getPropertyIconName(const PropertyName &name) const
{
    if (name == "Show Peak Frequencies") return "show-peaks";
    return SliceLayer::getPropertyIconName(name);
}

Layer::PropertyType
SpectrumLayer::getPropertyType(const PropertyName &name) const
{
    if (name == "Window Size") return ValueProperty;
    if (name == "Window Increment") return ValueProperty;
    if (name == "Show Peak Frequencies") return ToggleProperty;
    return SliceLayer::getPropertyType(name);
}

QString
SpectrumLayer::getPropertyGroupName(const PropertyName &name) const
{
    if (name == "Window Size" ||
	name == "Window Increment") return tr("Window");
    if (name == "Show Peak Frequencies") return tr("Bins");
    return SliceLayer::getPropertyGroupName(name);
}

int
SpectrumLayer::getPropertyRangeAndValue(const PropertyName &name,
                                        int *min, int *max, int *deflt) const
{
    int val = 0;

    int garbage0, garbage1, garbage2;
    if (!min) min = &garbage0;
    if (!max) max = &garbage1;
    if (!deflt) deflt = &garbage2;

    if (name == "Window Size") {

	*min = 0;
	*max = 15;
        *deflt = 5;
	
	val = 0;
	int ws = m_windowSize;
	while (ws > 32) { ws >>= 1; val ++; }

    } else if (name == "Window Increment") {
	
	*min = 0;
	*max = 5;
        *deflt = 2;
	
        val = m_windowHopLevel;
    
    } else if (name == "Show Peak Frequencies") {

        return m_showPeaks ? 1 : 0;

    } else {

        val = SliceLayer::getPropertyRangeAndValue(name, min, max, deflt);
    }

    return val;
}

QString
SpectrumLayer::getPropertyValueLabel(const PropertyName &name,
				    int value) const
{
    if (name == "Window Size") {
	return QString("%1").arg(32 << value);
    }
    if (name == "Window Increment") {
	switch (value) {
	default:
	case 0: return tr("None");
	case 1: return tr("25 %");
	case 2: return tr("50 %");
	case 3: return tr("75 %");
	case 4: return tr("87.5 %");
	case 5: return tr("93.75 %");
	}
    }
    return SliceLayer::getPropertyValueLabel(name, value);
}

RangeMapper *
SpectrumLayer::getNewPropertyRangeMapper(const PropertyName &name) const
{
    return SliceLayer::getNewPropertyRangeMapper(name);
}

void
SpectrumLayer::setProperty(const PropertyName &name, int value)
{
    if (name == "Window Size") {
	setWindowSize(32 << value);
    } else if (name == "Window Increment") {
        setWindowHopLevel(value);
    } else if (name == "Show Peak Frequencies") {
        setShowPeaks(value ? true : false);
    } else {
        SliceLayer::setProperty(name, value);
    }
}

void
SpectrumLayer::setWindowSize(size_t ws)
{
    if (m_windowSize == ws) return;
    m_windowSize = ws;
    m_newFFTNeeded = true;
    emit layerParametersChanged();
}

void
SpectrumLayer::setWindowHopLevel(size_t v)
{
    if (m_windowHopLevel == v) return;
    m_windowHopLevel = v;
    m_newFFTNeeded = true;
    emit layerParametersChanged();
}

void
SpectrumLayer::setWindowType(WindowType w)
{
    if (m_windowType == w) return;
    m_windowType = w;
    m_newFFTNeeded = true;
    emit layerParametersChanged();
}

void
SpectrumLayer::setShowPeaks(bool show)
{
    if (m_showPeaks == show) return;
    m_showPeaks = show;
    emit layerParametersChanged();
}

void
SpectrumLayer::preferenceChanged(PropertyContainer::PropertyName name)
{
    if (name == "Window Type") {
        setWindowType(Preferences::getInstance()->getWindowType());
        return;
    }
}

bool
SpectrumLayer::getValueExtents(float &, float &, bool &, QString &) const
{
    return false;
}

float
SpectrumLayer::getXForBin(int bin, int totalBins, float w) const
{
    if (!m_sliceableModel) return SliceLayer::getXForBin(bin, totalBins, w);

    float sampleRate = m_sliceableModel->getSampleRate();
    float binfreq = (sampleRate * bin) / (totalBins * 2);
    
    return getXForFrequency(binfreq, w);
}

int
SpectrumLayer::getBinForX(float x, int totalBins, float w) const
{
    if (!m_sliceableModel) return SliceLayer::getBinForX(x, totalBins, w);

    float sampleRate = m_sliceableModel->getSampleRate();
    float binfreq = getFrequencyForX(x, w);

    return int((binfreq * totalBins * 2) / sampleRate);
}

float
SpectrumLayer::getFrequencyForX(float x, float w) const
{
    float freq = 0;
    if (!m_sliceableModel) return 0;

    int sampleRate = m_sliceableModel->getSampleRate();

    float maxfreq = float(sampleRate) / 2;

    switch (m_binScale) {

    case LinearBins:
        freq = ((x * maxfreq) / w);
        break;
        
    case LogBins:
        freq = powf(10.f, (x * log10f(maxfreq)) / w);
        break;

    case InvertedLogBins:
        freq = maxfreq - powf(10.f, ((w - x) * log10f(maxfreq)) / w);
        break;
    }

    return freq;
}

float
SpectrumLayer::getXForFrequency(float freq, float w) const
{
    float x = 0;
    if (!m_sliceableModel) return x;

    int sampleRate = m_sliceableModel->getSampleRate();

    float maxfreq = float(sampleRate) / 2;

    switch (m_binScale) {

    case LinearBins:
        x = (freq * w) / maxfreq;
        break;
        
    case LogBins:
        x = (log10f(freq) * w) / log10f(maxfreq);
        break;

    case InvertedLogBins:
        if (maxfreq == freq) x = w;
        else x = w - (log10f(maxfreq - freq) * w) / log10f(maxfreq);
        break;
    }

    return x;
}

bool
SpectrumLayer::getXScaleValue(const View *v, int x, 
                              float &value, QString &unit) const
{
    if (m_xorigins.find(v) == m_xorigins.end()) return false;
    int xorigin = m_xorigins.find(v)->second;
    value = getFrequencyForX(x - xorigin, v->width() - xorigin - 1);
    unit = "Hz";
    return true;
}

bool
SpectrumLayer::getYScaleValue(const View *v, int y,
                              float &value, QString &unit) const
{
    value = getValueForY(y, v);

    if (m_energyScale == dBScale || m_energyScale == MeterScale) {

        if (value > 0.f) {
            value = 10.f * log10f(value);
            if (value < m_threshold) value = m_threshold;
        } else value = m_threshold;

        unit = "dBV";

    } else {
        unit = "V";
    }

    return true;
}

bool
SpectrumLayer::getYScaleDifference(const View *v, int y0, int y1,
                                   float &diff, QString &unit) const
{
    bool rv = SliceLayer::getYScaleDifference(v, y0, y1, diff, unit);
    if (rv && (unit == "dBV")) unit = "dB";
    return rv;
}


bool
SpectrumLayer::getCrosshairExtents(View *v, QPainter &paint,
                                   QPoint cursorPos,
                                   std::vector<QRect> &extents) const
{
    QRect vertical(cursorPos.x(), cursorPos.y(), 1, v->height() - cursorPos.y());
    extents.push_back(vertical);

    QRect horizontal(0, cursorPos.y(), v->width(), 12);
    extents.push_back(horizontal);

    int hoffset = 2;
    if (m_binScale == LogBins) hoffset = 13;

    int sw = getVerticalScaleWidth(v, paint);

    QRect value(sw, cursorPos.y() - paint.fontMetrics().ascent() - 2,
                paint.fontMetrics().width("0.0000001 V") + 2,
                paint.fontMetrics().height());
    extents.push_back(value);

    QRect log(sw, cursorPos.y() + 2,
              paint.fontMetrics().width("-80.000 dBV") + 2,
              paint.fontMetrics().height());
    extents.push_back(log);

    QRect freq(cursorPos.x(),
               v->height() - paint.fontMetrics().height() - hoffset,
               paint.fontMetrics().width("123456 Hz") + 2,
               paint.fontMetrics().height());
    extents.push_back(freq);

    int w(paint.fontMetrics().width("C#10+50c") + 2);
    QRect pitch(cursorPos.x() - w,
                v->height() - paint.fontMetrics().height() - hoffset,
                w,
                paint.fontMetrics().height());
    extents.push_back(pitch);

    return true;
}

void
SpectrumLayer::paintCrosshairs(View *v, QPainter &paint,
                               QPoint cursorPos) const
{
    if (!m_sliceableModel) return;

    paint.save();
    QFont fn = paint.font();
    if (fn.pointSize() > 8) {
        fn.setPointSize(fn.pointSize() - 1);
        paint.setFont(fn);
    }

    ColourMapper mapper(m_colourMap, 0, 1);
    paint.setPen(mapper.getContrastingColour());

    int xorigin = m_xorigins[v];
    int w = v->width() - xorigin - 1;
    
    paint.drawLine(xorigin, cursorPos.y(), v->width(), cursorPos.y());
    paint.drawLine(cursorPos.x(), cursorPos.y(), cursorPos.x(), v->height());
    
    float fundamental = getFrequencyForX(cursorPos.x() - xorigin, w);

    int hoffset = 2;
    if (m_binScale == LogBins) hoffset = 13;

    v->drawVisibleText(paint,
                       cursorPos.x() + 2,
                       v->height() - 2 - hoffset,
                       QString("%1 Hz").arg(fundamental),
                       View::OutlinedText);

    if (Pitch::isFrequencyInMidiRange(fundamental)) {
        QString pitchLabel = Pitch::getPitchLabelForFrequency(fundamental);
        v->drawVisibleText(paint,
                           cursorPos.x() - paint.fontMetrics().width(pitchLabel) - 2,
                           v->height() - 2 - hoffset,
                           pitchLabel,
                           View::OutlinedText);
    }

    float value = getValueForY(cursorPos.y(), v);
    float thresh = m_threshold;
    float db = thresh;
    if (value > 0.f) db = 10.f * log10f(value);
    if (db < thresh) db = thresh;

    v->drawVisibleText(paint,
                       xorigin + 2,
                       cursorPos.y() - 2,
                       QString("%1 V").arg(value),
                       View::OutlinedText);

    v->drawVisibleText(paint,
                       xorigin + 2,
                       cursorPos.y() + 2 + paint.fontMetrics().ascent(),
                       QString("%1 dBV").arg(db),
                       View::OutlinedText);
    
    int harmonic = 2;

    while (harmonic < 100) {

        float hx = lrintf(getXForFrequency(fundamental * harmonic, w));
        hx += xorigin;

        if (hx < xorigin || hx > v->width()) break;
        
        int len = 7;

        if (harmonic % 2 == 0) {
            if (harmonic % 4 == 0) {
                len = 12;
            } else {
                len = 10;
            }
        }

        paint.drawLine(int(hx),
                       cursorPos.y(),
                       int(hx),
                       cursorPos.y() + len);

        ++harmonic;
    }

    paint.restore();
}

QString
SpectrumLayer::getFeatureDescription(View *v, QPoint &p) const
{
    if (!m_sliceableModel) return "";

    int minbin = 0, maxbin = 0, range = 0;
    QString genericDesc = SliceLayer::getFeatureDescription
        (v, p, false, minbin, maxbin, range);

    if (genericDesc == "") return "";

    float minvalue = 0.f;
    if (minbin < int(m_values.size())) minvalue = m_values[minbin];

    float maxvalue = minvalue;
    if (maxbin < int(m_values.size())) maxvalue = m_values[maxbin];
        
    if (minvalue > maxvalue) std::swap(minvalue, maxvalue);
    
    QString binstr;
    QString hzstr;
    int minfreq = lrintf((minbin * m_sliceableModel->getSampleRate()) /
                         m_windowSize);
    int maxfreq = lrintf((std::max(maxbin, minbin+1)
                           * m_sliceableModel->getSampleRate()) /
                          m_windowSize);

    if (maxbin != minbin) {
        binstr = tr("%1 - %2").arg(minbin+1).arg(maxbin+1);
    } else {
        binstr = QString("%1").arg(minbin+1);
    }
    if (minfreq != maxfreq) {
        hzstr = tr("%1 - %2 Hz").arg(minfreq).arg(maxfreq);
    } else {
        hzstr = tr("%1 Hz").arg(minfreq);
    }
    
    QString valuestr;
    if (maxvalue != minvalue) {
        valuestr = tr("%1 - %2").arg(minvalue).arg(maxvalue);
    } else {
        valuestr = QString("%1").arg(minvalue);
    }
    
    QString dbstr;
    float mindb = AudioLevel::multiplier_to_dB(minvalue);
    float maxdb = AudioLevel::multiplier_to_dB(maxvalue);
    QString mindbstr;
    QString maxdbstr;
    if (mindb == AudioLevel::DB_FLOOR) {
        mindbstr = tr("-Inf");
    } else {
        mindbstr = QString("%1").arg(lrintf(mindb));
    }
    if (maxdb == AudioLevel::DB_FLOOR) {
        maxdbstr = tr("-Inf");
    } else {
        maxdbstr = QString("%1").arg(lrintf(maxdb));
    }
    if (lrintf(mindb) != lrintf(maxdb)) {
        dbstr = tr("%1 - %2").arg(mindbstr).arg(maxdbstr);
    } else {
        dbstr = tr("%1").arg(mindbstr);
    }

    QString description;

    if (range > int(m_sliceableModel->getResolution())) {
        description = tr("%1\nBin:\t%2 (%3)\n%4 value:\t%5\ndB:\t%6")
            .arg(genericDesc)
            .arg(binstr)
            .arg(hzstr)
            .arg(m_samplingMode == NearestSample ? tr("First") :
                 m_samplingMode == SampleMean ? tr("Mean") : tr("Peak"))
            .arg(valuestr)
            .arg(dbstr);
    } else {
        description = tr("%1\nBin:\t%2 (%3)\nValue:\t%4\ndB:\t%5")
            .arg(genericDesc)
            .arg(binstr)
            .arg(hzstr)
            .arg(valuestr)
            .arg(dbstr);
    }
    
    return description;
}

void
SpectrumLayer::paint(View *v, QPainter &paint, QRect rect) const
{
    if (!m_originModel || !m_originModel->isOK() ||
        !m_originModel->isReady()) {
        SVDEBUG << "SpectrumLayer::paint: no origin model, or origin model not OK or not ready" << endl;
        return;
    }

    if (m_newFFTNeeded) {
        SVDEBUG << "SpectrumLayer::paint: new FFT needed, calling setupFFT" << endl;
        const_cast<SpectrumLayer *>(this)->setupFFT(); //ugh
    }

    FFTModel *fft = dynamic_cast<FFTModel *>
        (const_cast<DenseThreeDimensionalModel *>(m_sliceableModel));

    float thresh = (powf(10, -6) / m_gain) * (m_windowSize / 2.f); // -60dB adj

    int xorigin = getVerticalScaleWidth(v, paint) + 1;
    int w = v->width() - xorigin - 1;

    int pkh = 0;
//!!!    if (m_binScale == LogBins) {
        //pkh = 10; //too small
    pkh = 20;

//!!!    }

    paint.save();

    if (fft && m_showPeaks) {

        // draw peak lines

//        SVDEBUG << "Showing peaks..." << endl;

        size_t col = v->getCentreFrame() / fft->getResolution();

        paint.save();
        paint.setRenderHint(QPainter::Antialiasing, false);
        paint.setPen(QColor(160, 160, 160)); //!!!

        int peakminbin = 0;
        int peakmaxbin = fft->getHeight() - 1;
        float peakmaxfreq = Pitch::getFrequencyForPitch(128);
        peakmaxbin = ((peakmaxfreq * fft->getHeight() * 2) / fft->getSampleRate());
        
        FFTModel::PeakSet peaks = fft->getPeakFrequencies
            (FFTModel::MajorPitchAdaptivePeaks, col, peakminbin, peakmaxbin);

        ColourMapper mapper(ColourMapper::BlackOnWhite, 0, 1);

        BiasCurve curve;
        getBiasCurve(curve);
        size_t cs = curve.size();

        std::vector<float> values;
        
        for (size_t bin = 0; bin < fft->getHeight(); ++bin) {
            float value = m_sliceableModel->getValueAt(col, bin);
            if (bin < cs) value *= curve[bin];
            values.push_back(value);
        }

        for (FFTModel::PeakSet::iterator i = peaks.begin();
             i != peaks.end(); ++i) {

            size_t bin = i->first;
            
//            std::cerr << "bin = " << bin << ", thresh = " << thresh << ", value = " << fft->getMagnitudeAt(col, bin) << std::endl;

            if (!fft->isOverThreshold(col, bin, thresh)) continue;
            
            float freq = i->second;
          
            int x = lrintf(getXForFrequency(freq, w));

            float norm = 0.f;
            float y = getYForValue(values[bin], v, norm); // don't need y, need norm

            paint.setPen(mapper.map(norm));
            paint.drawLine(xorigin + x, 0, xorigin + x, v->height() - pkh - 1);
        }

        paint.restore();
    }
    
    SliceLayer::paint(v, paint, rect);

    //!!! All of this stuff relating to depicting frequencies
    //(keyboard, crosshairs etc) should be applicable to any slice
    //layer whose model has a vertical scale unit of Hz.  However, the
    //dense 3d model at the moment doesn't record its vertical scale
    //unit -- we need to fix that and hoist this code as appropriate.
    //Same really goes for any code in SpectrogramLayer that could be
    //relevant to Colour3DPlotLayer with unit Hz, but that's a bigger
    //proposition.

//    if (m_binScale == LogBins) {

//        int pkh = 10;
        int h = v->height();

        // piano keyboard
        //!!! should be in a new paintHorizontalScale()?
        // nice to have a piano keyboard class, of course

	paint.drawLine(xorigin, h - pkh - 1, w + xorigin, h - pkh - 1);

	int px = xorigin, ppx = xorigin;
	paint.setBrush(paint.pen().color());

	for (int i = 0; i < 128; ++i) {

	    float f = Pitch::getFrequencyForPitch(i);
	    int x = lrintf(getXForFrequency(f, w));
                           
            x += xorigin;

            if (i == 0) {
                px = ppx = x;
            }
            if (i == 1) {
                ppx = px - (x - px);
            }

            if (x < xorigin) {
                ppx = px;
                px = x;
                continue;
            }
                
            if (x > w) {
                break;
            }

	    int n = (i % 12);

            if (n == 1) {
                // C# -- fill the C from here
                QColor col = Qt::gray;
                if (i == 61) { // filling middle C
                    col = Qt::blue;
                    col = col.light(150);
                }
                if (x - ppx > 2) {
                    paint.fillRect((px + ppx) / 2 + 1,
                                   h - pkh,
                                   x - (px + ppx) / 2 - 1,
                                   pkh,
                                   col);
                }
            }

	    if (n == 1 || n == 3 || n == 6 || n == 8 || n == 10) {
		// black notes
		paint.drawLine(x, h - pkh, x, h);
		int rw = lrintf(float(x - px) / 4) * 2;
		if (rw < 2) rw = 2;
		paint.drawRect(x - rw/2, h - pkh, rw, pkh/2);
	    } else if (n == 0 || n == 5) {
		// C, F
		if (px < w) {
		    paint.drawLine((x + px) / 2, h - pkh, (x + px) / 2, h);
		}
	    }

            ppx = px;
	    px = x;
	}
//    }

    paint.restore();
}

/*
int
SpectrumLayer::getHorizontalScaleHeight(View *v, QPainter &paint) const
{
    int h = v->height();
    int pkh = 10;

    return h - pkh - 1;
}*/


void
SpectrumLayer::getBiasCurve(BiasCurve &curve) const
{
    curve = m_biasCurve;
}

void
SpectrumLayer::toXml(QTextStream &stream,
                     QString indent, QString extraAttributes) const
{
    QString s = QString("windowSize=\"%1\" "
                        "windowHopLevel=\"%2\" "
                        "showPeaks=\"%3\" ")
        .arg(m_windowSize)
        .arg(m_windowHopLevel)
        .arg(m_showPeaks ? "true" : "false");

    SliceLayer::toXml(stream, indent, extraAttributes + " " + s);
}

void
SpectrumLayer::setProperties(const QXmlAttributes &attributes)
{
    SliceLayer::setProperties(attributes);

    bool ok = false;

    size_t windowSize = attributes.value("windowSize").toUInt(&ok);
    if (ok) setWindowSize(windowSize);

    size_t windowHopLevel = attributes.value("windowHopLevel").toUInt(&ok);
    if (ok) setWindowHopLevel(windowHopLevel);

    bool showPeaks = (attributes.value("showPeaks").trimmed() == "true");
    setShowPeaks(showPeaks);
}

bool
SpectrumLayer::scaleClicked(const View *v, QMouseEvent *e)
{
    std::cerr<< "Mouse click detected in the spectrum scale area: (" << e->x() << "," << e->y() << ")" << std::endl;

    float freq;
    QString unit;
    float *centsOffsetReturn = 0;
    float concertA = 0.0;
    int midipitch;

    if (getXScaleValue(v, e->x(), freq, unit)) {

        midipitch = Pitch::getPitchForFrequency(freq,centsOffsetReturn,concertA);

        std::cerr<< "Frequency: " << freq << " " << unit.toStdString() << " (midi pitch = " << midipitch << ")" << std::endl;

        if ((midipitch>=0)&&(midipitch<127)) {
            v->playExampleNote(midipitch);
        }

        return true;

    } else {
        return false;
    }
}