filterplotscene.cpp

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//=============================================================================================================
 
//=============================================================================================================
// INCLUDES
//=============================================================================================================
 
#include "filterplotscene.h"
 
//=============================================================================================================
// QT INCLUDES
//=============================================================================================================
 
#include <QGraphicsPathItem>
#include <QGraphicsView>
#include <QDebug>
 
//=============================================================================================================
// EIGEN INCLUDES
//=============================================================================================================
 
//=============================================================================================================
// USED NAMESPACES
//=============================================================================================================
 
using namespace DISPLIB;
using namespace Eigen;
using namespace UTILSLIB;
 
//=============================================================================================================
// DEFINE MEMBER METHODS
//=============================================================================================================
 
FilterPlotScene::FilterPlotScene(QGraphicsView *view, QObject *parent)
: LayoutScene(view, parent)
, m_pGraphicsItemPath(new QGraphicsPathItem())
, m_iScalingFactor(5)
, m_iNumberHorizontalLines(4)
, m_iNumberVerticalLines(3)
, m_iAxisTextSize(24)
, m_iDiagramMarginsHoriz(5)
, m_iDiagramMarginsVert(5)
, m_iCutOffLow(5)
, m_iCutOffHigh(40)
, m_iCutOffMarkerWidth(3)
, m_iPlotLength(0)
{
    m_iMaxMagnitude = 100*m_iScalingFactor;
}
 
//=============================================================================================================
 
void FilterPlotScene::updateFilter(const FilterKernel& operatorFilter,
                                   int samplingFreq,
                                   int cutOffLow,
                                   int cutOffHigh)
{
    if(operatorFilter.getCoefficients().cols() == 0)
        return;
 
    m_pCurrentFilter = operatorFilter;
 
    //set member variables
    m_iCutOffLow = cutOffLow;
    m_iCutOffHigh = cutOffHigh;
 
    //Clear the scene
    this->clear();
 
    QWidget * pQwidgetty(dynamic_cast<QWidget*>(parent()));
    m_cPenColor = pQwidgetty->palette().text().color();
 
    //Plot newly set filter. Needs to be called before plotMagnitudeDiagram() because m_iPlotLength is set in plotFilterFrequencyResponse()
    plotFilterFrequencyResponse();
 
    //Plot the magnitude diagram
    plotMagnitudeDiagram(samplingFreq, operatorFilter.getName());
}
 
//=============================================================================================================
 
void FilterPlotScene::plotMagnitudeDiagram(int samplingFreq,
                                           const QString& filtername)
{
    //Get row vector with filter coefficients
    int numberCoeff = m_iPlotLength;
 
//    RowVectorXcd coefficientsAFreq = m_pCurrentFilter.m_vecFftCoeff;
//    if(coefficientsAFreq.cols() > 2000) {//if to large downsample
//        int dsFactor = coefficientsAFreq.cols()/2000;
//        numberCoeff = coefficientsAFreq.cols()/dsFactor;
//    } else {
//        numberCoeff = coefficientsAFreq.cols();
//    }
 
    int fMax = samplingFreq/2; //nyquist frequency
 
    addRect(-m_iDiagramMarginsHoriz,
            -m_iDiagramMarginsVert,
            numberCoeff+(m_iDiagramMarginsHoriz*2),
            m_iMaxMagnitude+(m_iDiagramMarginsVert*2));
 
    //Plot filter name on top
    QGraphicsTextItem * text = addText(filtername, QFont("Times", m_iAxisTextSize));
    text->setPos((numberCoeff+(m_iDiagramMarginsHoriz*2))/3.2,-70);
    text->setDefaultTextColor(m_cPenColor);
 
    //HORIZONTAL
    //Draw horizontal lines
    QPen pen(Qt::DotLine);
    pen.setColor(m_cPenColor);
    for(int i = 1; i <= m_iNumberHorizontalLines; i++)
        addLine(-m_iDiagramMarginsHoriz,
                (i * (m_iMaxMagnitude/(m_iNumberHorizontalLines+1))) - m_iDiagramMarginsVert,
                numberCoeff + m_iDiagramMarginsHoriz,
                (i * (m_iMaxMagnitude/(m_iNumberHorizontalLines+1))) - m_iDiagramMarginsVert,
                pen);
 
    //Draw vertical axis texts - db magnitude
    for(int i = 0; i <= m_iNumberHorizontalLines+1; i++) {
        QGraphicsTextItem * text = addText(QString("-%1 db").arg(QString().number(i * m_iMaxMagnitude/(m_iScalingFactor*(m_iNumberHorizontalLines+1)),'g',3)),
                                           QFont("Times", m_iAxisTextSize));
        text->setPos(-text->boundingRect().width() - m_iAxisTextSize/2,
                     (i * (m_iMaxMagnitude/(m_iNumberHorizontalLines+1))) - (text->boundingRect().height()/2) - m_iDiagramMarginsVert);
        text->setDefaultTextColor(m_cPenColor);
    }
 
    //VERTICAL
    //Draw vertical lines
    double length = double(numberCoeff) / double(m_iNumberVerticalLines+1);
    for(int i = 1; i<=m_iNumberVerticalLines; i++)
        addLine(i*length - m_iDiagramMarginsHoriz,
                -m_iDiagramMarginsVert,
                i*length - m_iDiagramMarginsHoriz,
                m_iMaxMagnitude + m_iDiagramMarginsVert,
                pen);
 
    //Draw horizontal axis texts - Hz frequency
    for(int i = 0; i <= m_iNumberVerticalLines+1; i++) {
        QGraphicsTextItem * text = addText(QString("%1 Hz").arg(i*(fMax/(m_iNumberVerticalLines+1))),
                                           QFont("Times", m_iAxisTextSize));
        text->setPos(i * length - m_iDiagramMarginsHoriz - (text->boundingRect().width()/2),
                     m_iMaxMagnitude + (text->boundingRect().height()/2));
        text->setDefaultTextColor(m_cPenColor);
    }
 
    //Plot lower higher cut off frequency
    double pos = 0;
    switch(FilterKernel::m_filterTypes.indexOf(m_pCurrentFilter.getFilterType())) {
        case 0://LPF
            pos = ((double)m_iCutOffLow / (double)fMax) * numberCoeff;
            addLine(pos - m_iDiagramMarginsHoriz,
                    -m_iDiagramMarginsVert + m_iCutOffMarkerWidth/2,
                    pos - m_iDiagramMarginsHoriz,
                    m_iMaxMagnitude + m_iDiagramMarginsVert - m_iCutOffMarkerWidth/2,
                    QPen(Qt::red, m_iCutOffMarkerWidth));
        break;
 
        case 1://HPF
            pos = ((double)m_iCutOffHigh / (double)fMax) * numberCoeff;
            addLine(pos - m_iDiagramMarginsHoriz,
                    -m_iDiagramMarginsVert + m_iCutOffMarkerWidth/2,
                    pos - m_iDiagramMarginsHoriz,
                    m_iMaxMagnitude + m_iDiagramMarginsVert - m_iCutOffMarkerWidth/2,
                    QPen(Qt::red, m_iCutOffMarkerWidth));
        break;
 
        case 2://BPF
            pos = ((double)m_iCutOffLow / (double)fMax) * numberCoeff;
            addLine(pos - m_iDiagramMarginsHoriz,
                    -m_iDiagramMarginsVert + m_iCutOffMarkerWidth/2,
                    pos - m_iDiagramMarginsHoriz,
                    m_iMaxMagnitude + m_iDiagramMarginsVert - m_iCutOffMarkerWidth/2,
                    QPen(Qt::red, m_iCutOffMarkerWidth));
 
            pos = ((double)m_iCutOffHigh / (double)fMax) * numberCoeff;
            addLine(pos - m_iDiagramMarginsHoriz,
                    -m_iDiagramMarginsVert + m_iCutOffMarkerWidth/2,
                    pos - m_iDiagramMarginsHoriz,
                    m_iMaxMagnitude + m_iDiagramMarginsVert - m_iCutOffMarkerWidth/2,
                    QPen(Qt::red, m_iCutOffMarkerWidth));
        break;
    }
}
 
//=============================================================================================================
 
void FilterPlotScene::plotFilterFrequencyResponse()
{
    //Get row vector with filter coefficients and norm to 1
    RowVectorXcd coefficientsAFreq = m_pCurrentFilter.getFftCoefficients();
 
    float numberCoeff = coefficientsAFreq.cols();
    float dsFactor = numberCoeff/m_qvView->width();
 
    double max = 0.0;
    for(int i = 0; i<coefficientsAFreq.cols(); i++) {
        if(std::abs(coefficientsAFreq(i)) > max) {
            max = std::abs(coefficientsAFreq(i));
        }
    }
 
    coefficientsAFreq = coefficientsAFreq / max;
 
    //Create painter path
    QPainterPath path;
    double y = -20 * log10(std::abs(coefficientsAFreq(0))) * m_iScalingFactor; //-1 because we want to plot upwards
    if(y > m_iMaxMagnitude) {
        y = m_iMaxMagnitude;
    }
    y -= m_iDiagramMarginsVert;
 
    path.moveTo(-m_iDiagramMarginsVert, y); //convert to db
 
    for(int i = 0; i < numberCoeff; i++) {
        y = -20 * log10(std::abs(coefficientsAFreq(i))) * m_iScalingFactor; //-1 because we want to plot upwards
        if(y > m_iMaxMagnitude) {
            y = m_iMaxMagnitude;
        }
 
        y -= m_iDiagramMarginsVert;
        if(dsFactor < 1) {
            path.lineTo(path.currentPosition().x()+(1/dsFactor),y);
        } else {
            path.lineTo(path.currentPosition().x()+1,y);
        }
    }
 
    m_iPlotLength = path.currentPosition().x();
 
    QPen pen;
    pen.setColor(m_cPenColor);
    pen.setWidth(2);
 
    //Clear old and plot new filter path
    m_pGraphicsItemPath = addPath(path, pen);
}
 
//=============================================================================================================