Kwave::FrequencyResponseWidget Class Reference

#include <FrequencyResponseWidget.h>

Inheritance diagram for Kwave::FrequencyResponseWidget:

Collaboration diagram for Kwave::FrequencyResponseWidget:

Public Member Functions
	FrequencyResponseWidget (QWidget *parent)
virtual	~FrequencyResponseWidget () Q_DECL_OVERRIDE
virtual void	init (double freq, int db_min, int db_max)
virtual void	setFilter (Kwave::TransmissionFunction *func)
virtual void	paintEvent (QPaintEvent *) Q_DECL_OVERRIDE

Private Attributes
double	m_f_max
int	m_db_min
int	m_db_max
int	m_decades
Kwave::TransmissionFunction *	m_function

Detailed Description

displays a frequency response

Definition at line 37 of file FrequencyResponseWidget.h.

Constructor & Destructor Documentation

FrequencyResponseWidget()

Kwave::FrequencyResponseWidget::FrequencyResponseWidget ( QWidget *  parent )

explicit

Constructor

Definition at line 33 of file FrequencyResponseWidget.cpp.

References init().

    :QWidget(widget), m_f_max(0), m_db_min(0), m_db_max(0),
     m_decades(0), m_function(Q_NULLPTR)
{
    init(10000, -12, +12);
}

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~FrequencyResponseWidget()

Kwave::FrequencyResponseWidget::~FrequencyResponseWidget ( )

virtual

Destructor

Definition at line 41 of file FrequencyResponseWidget.cpp.

{
}

Member Function Documentation

init()

void Kwave::FrequencyResponseWidget::init ( double  freq, int  db_min, int  db_max  )

virtual

Initialize the widget dimensions.

Parameters

freq	highest frequency, will be internally rounded up to the next decade if necessary
db_min	lowest amplitude in decibel
db_max	highest amplitude in decibel

Definition at line 46 of file FrequencyResponseWidget.cpp.

References m_db_max, m_db_min, m_decades, m_f_max, and Kwave::toInt().

Referenced by FrequencyResponseWidget().

{
    const int base = 10;
    m_decades = Kwave::toInt(ceil(log(freq)/log(base)));
    m_f_max = pow(base, m_decades);

    m_db_min = db_min;
    m_db_max = db_max;
}

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paintEvent()

void Kwave::FrequencyResponseWidget::paintEvent ( QPaintEvent *  )

virtual

See also

QWidget::paintEvent()

Definition at line 65 of file FrequencyResponseWidget.cpp.

References Kwave::TransmissionFunction::at(), m_db_max, m_db_min, m_f_max, m_function, rect(), and Kwave::toInt().

{
//  const int base = 10;
//  const double m_frequency = m_f_max * 2/3;
    const int width  = this->width();
    const int height = this->height();

    Q_ASSERT(width > 0);
    Q_ASSERT(height > 0);
    if ((width <= 0) || (height <= 0)) return;

    QPainter p(this);
    p.fillRect(rect(), QBrush(palette().dark()));

    double scale = static_cast<double>(height-1) /
        static_cast<double>(m_db_max-m_db_min);
    double min = pow(10.0, static_cast<double>(m_db_min) / 10.0);
    double max = pow(10.0, static_cast<double>(m_db_max) / 10.0);
    p.setPen(Qt::green);//colorGroup().text());

    for (int x=0; x < width; x++) {
        // transform x coordinate to frequency

//      // logarithmic frequency scale, didn't look so good :-(
//      double f = pow(base, (double)m_decades * (double)x / (double)width);

        // linear frequency scale
        double f = (m_f_max * static_cast<double>(x) /
            static_cast<double>(width));

        // calculate the filter function's output at the given frequency
        f = (f / m_f_max) * M_PI;
        double a = (m_function) ? m_function->at(f): 1.0;

        // limit to upper and lower margins
        if (a < min) a = min;
        if (a > max) a = max;

        // convert to logarithmic scale
        double db = 10.0 * log10(a);

        // draw one line
        int y = height - Kwave::toInt((db - m_db_min) * scale);

        p.drawLine(x, y+1, x, height-1);
    }

    // draw the zero db line
    p.setPen(palette().text().color());
    int y = height - Kwave::toInt((0.0 - m_db_min) * scale);
    p.drawLine(0, y, width-1, y);
}

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setFilter()

void Kwave::FrequencyResponseWidget::setFilter ( Kwave::TransmissionFunction *  func )

virtual

Set a new transmission function and update the display

Definition at line 57 of file FrequencyResponseWidget.cpp.

References m_function.

{
    m_function = func;
    repaint();
}

Member Data Documentation

m_db_max

int Kwave::FrequencyResponseWidget::m_db_max

private

highest amplitude in decibel

Definition at line 73 of file FrequencyResponseWidget.h.

Referenced by init(), and paintEvent().

m_db_min

int Kwave::FrequencyResponseWidget::m_db_min

private

lowest amplitude in decibel

Definition at line 70 of file FrequencyResponseWidget.h.

Referenced by init(), and paintEvent().

m_decades

int Kwave::FrequencyResponseWidget::m_decades

private

number of decades, calculated from m_f_max

Definition at line 76 of file FrequencyResponseWidget.h.

Referenced by init().

m_f_max

double Kwave::FrequencyResponseWidget::m_f_max

private

highest frequency, rounded up to the next decade

Definition at line 67 of file FrequencyResponseWidget.h.

Referenced by init(), and paintEvent().

m_function

Kwave::TransmissionFunction* Kwave::FrequencyResponseWidget::m_function

private

Pointer to a transmission function object, used for painting the frequency response.

Definition at line 82 of file FrequencyResponseWidget.h.

Referenced by paintEvent(), and setFilter().

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The documentation for this class was generated from the following files:

• libgui/FrequencyResponseWidget.h
• libgui/FrequencyResponseWidget.cpp