Waterfall from QwtPlotSpectrogram

waterfall.cpp

#include <qwt_color_map.h>
#include <qwt_matrix_raster_data.h>

#include <boost/circular_buffer.hpp>
#include <QtCore/QMutex>

#include "waterfall.h"

using boost::circular_buffer;
using std::make_shared;


class SpectrogramData: public QwtRasterData
{
public:
    SpectrogramData()
    {
        auto blank_row = make_shared<vector<double>>(2205);
        rows = circular_buffer<shared_ptr<vector<double>>>(1000, blank_row);
    }

    double value(double x, double y) const override {
//        qDebug(GUI) << x << ", " << y;
        auto ret = rows.at(y)->at(x);
        return ret;
    }

    void add_row(shared_ptr<vector<double>> row) {
        qDebug(GUI) << "ADD ROW";
        rows.pop_front();        // remove the last row
        rows.push_back(row);   // insert the new row
    }

private:
    circular_buffer<shared_ptr<vector<double>>> rows;
};

class LinearColorMapRGB: public QwtLinearColorMap
{
public:
    LinearColorMapRGB() : QwtLinearColorMap( Qt::darkBlue, Qt::red, QwtColorMap::RGB )
    {
        // set colors on gradient from darkBlue -> red
        addColorStop( 0.05, Qt::blue );
        addColorStop( 0.25, Qt::green );
        addColorStop( 0.50, Qt::yellow );
    }
};


Waterfall::Waterfall(QWidget *parent) :
    QwtPlot(parent),
    spectrogram(new QwtPlotSpectrogram())
{
    spectrogram->setRenderThreadCount( 0 ); // use system specific thread count
    spectrogram->setCachePolicy(QwtPlotRasterItem::NoCache); // won't update the display if we have a cache

    auto data = new SpectrogramData();

    data->setInterval(Qt::XAxis, QwtInterval( 0.0, 2204.0 ));   // frequency
    data->setInterval( Qt::YAxis, QwtInterval( 0.0, 999.0 ) ); // time
    data->setInterval( Qt::ZAxis, QwtInterval( 0.0, 100.0 ) );  // intensity

    this->setAxisScale(QwtPlot::yLeft, 0.0, 999.0);
    this->setAxisScale(QwtPlot::xBottom, 0.0, 2204.0);

    spectrogram->setData(data);
    spectrogram->attach(this);

    spectrogram->setColorMap(new LinearColorMapRGB());
}

void Waterfall::add_row(shared_ptr<vector<double>> row) {
    reinterpret_cast<SpectrogramData*>(spectrogram->data())->add_row(row);
}