view widgets/WindowShapePreview.cpp @ 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 Chris Cannam.
    
    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 "WindowShapePreview.h"

#include <QHBoxLayout>
#include <QLabel>
#include <QPainter>
#include <QPainterPath>
#include <QFont>
#include <QString>

#include <bqfft/FFT.h>

#include <vector>
#include <complex>
#include <iostream>

using namespace std;


WindowShapePreview::WindowShapePreview(QWidget *parent) :
    QFrame(parent),
    m_windowType(HanningWindow)
{
    QHBoxLayout *layout = new QHBoxLayout;
    layout->setMargin(0);
    setLayout(layout);
    m_windowTimeExampleLabel = new QLabel;
    m_windowFreqExampleLabel = new QLabel;
    layout->addWidget(m_windowTimeExampleLabel);
    layout->addWidget(m_windowFreqExampleLabel);
}

WindowShapePreview::~WindowShapePreview()
{
}

void
WindowShapePreview::updateLabels()
{
    float scaleRatio = float(QFontMetrics(font()).height()) / 14.f;
    if (scaleRatio < 1.f) scaleRatio = 1.f;

    int step = int(24 * scaleRatio);
    float peak = float(48 * scaleRatio);

    int w = step * 4, h = int((peak * 4) / 3);

    WindowType type = m_windowType;
    Window<float> windower = Window<float>(type, step * 2);
    
    QPixmap timeLabel(w, h + 1);
    timeLabel.fill(Qt::white);
    QPainter timePainter(&timeLabel);

    QPainterPath path;

    path.moveTo(0, float(h) - peak + 1);
    path.lineTo(w, float(h) - peak + 1);

    timePainter.setPen(Qt::gray);
    timePainter.setRenderHint(QPainter::Antialiasing, true);
    timePainter.drawPath(path);
    
    path = QPainterPath();

    float *acc = new float[w];
    for (int i = 0; i < w; ++i) acc[i] = 0.f;
    for (int j = 0; j < 3; ++j) {
        for (int i = 0; i < step * 2; ++i) {
            acc[j * step + i] += windower.getValue(i);
        }
    }
    for (int i = 0; i < w; ++i) {
        int y = h - int(peak * acc[i] + 0.001f) + 1;
        if (i == 0) path.moveTo(i, y);
        else path.lineTo(i, y);
    }
    delete[] acc;

    timePainter.drawPath(path);
    timePainter.setRenderHint(QPainter::Antialiasing, false);

    path = QPainterPath();

    timePainter.setPen(Qt::black);
    
    for (int i = 0; i < step * 2; ++i) {
        int y = h - int(peak * windower.getValue(i) + 0.001) + 1;
        if (i == 0) path.moveTo(i + step, float(y));
        else path.lineTo(i + step, float(y));
    }

    if (type == RectangularWindow) {
        timePainter.drawPath(path);
        path = QPainterPath();
    }

    timePainter.setRenderHint(QPainter::Antialiasing, true);
    path.addRect(0, 0, w, h + 1);
    timePainter.drawPath(path);

    QFont font;
    font.setPixelSize(int(10 * scaleRatio));
    font.setItalic(true);
    timePainter.setFont(font);
    QString label = tr("V / time");
    timePainter.drawText(w - timePainter.fontMetrics().width(label) - 4,
                         timePainter.fontMetrics().ascent() + 1, label);

    m_windowTimeExampleLabel->setPixmap(timeLabel);
    
    QPixmap freqLabel(w, h + 1);
    freqLabel.fill(Qt::white);
    QPainter freqPainter(&freqLabel);
    path = QPainterPath();

    int fftsize = 512;

    breakfastquay::FFT fft(fftsize);

    vector<float> input(fftsize);
    vector<complex<float>> output(fftsize/2 + 1);
    
    for (int i = 0; i < fftsize; ++i) input[i] = 0.f;
    for (int i = 0; i < step * 2; ++i) {
        input[fftsize/2 - step + i] = windower.getValue(i);
    }

    fft.forwardInterleaved(input.data(), reinterpret_cast<float *>(output.data()));

    float maxdb = 0.f;
    float mindb = 0.f;
    bool first = true;
    for (int i = 0; i < fftsize/2; ++i) {
        float power =
            output[i].real() * output[i].real() +
            output[i].imag() * output[i].imag();
        float db = mindb;
        if (power > 0) {
            db = 20.f * log10f(power);
            if (first || db > maxdb) maxdb = db;
            if (first || db < mindb) mindb = db;
            first = false;
        }
    }

    if (mindb > -80.f) mindb = -80.f;

    // -- no, don't use the actual mindb -- it's easier to compare
    // plots with a fixed min value
    mindb = -170.f;

    float maxval = maxdb + -mindb;

//    float ly = h - ((-80.f + -mindb) / maxval) * peak + 1;

    path.moveTo(0, float(h) - peak + 1);
    path.lineTo(w, float(h) - peak + 1);

    freqPainter.setPen(Qt::gray);
    freqPainter.setRenderHint(QPainter::Antialiasing, true);
    freqPainter.drawPath(path);
    
    path = QPainterPath();
    freqPainter.setPen(Qt::black);

//    cerr << "maxdb = " << maxdb << ", mindb = " << mindb << ", maxval = " <<maxval << endl;

    for (int i = 0; i < fftsize/2; ++i) {
        float power =
            output[i].real() * output[i].real() +
            output[i].imag() * output[i].imag();
        float db = 20.f * log10f(power);
        float val = db + -mindb;
        if (val < 0) val = 0;
        float norm = val / maxval;
        float x = (float(w) / float(fftsize/2)) * float(i);
        float y = float(h) - norm * peak + 1;
        if (i == 0) path.moveTo(x, y);
        else path.lineTo(x, y);
    }

    freqPainter.setRenderHint(QPainter::Antialiasing, true);
    path.addRect(0, 0, w, h + 1);
    freqPainter.drawPath(path);

    freqPainter.setFont(font);
    label = tr("dB / freq");
    freqPainter.drawText(w - freqPainter.fontMetrics().width(label) - 4,
                         freqPainter.fontMetrics().ascent() + 1, label);

    m_windowFreqExampleLabel->setPixmap(freqLabel);
}

void
WindowShapePreview::setWindowType(WindowType type)
{
    m_windowType = type;
    updateLabels();
}