samplingthread.cpp
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#include "samplingthread.h"
#include "signaldata.h"
#include <qwt_math.h>
#include <math.h>
#if QT_VERSION < 0x040600
#define qFastSin(x) ::sin(x)
#endif
SamplingThread::SamplingThread( QObject *parent ):
QwtSamplingThread( parent ),
d_frequency( 5.0 ),
d_amplitude( 20.0 )
{
}
void SamplingThread::setFrequency( double frequency )
{
d_frequency = frequency;
}
double SamplingThread::frequency() const
{
return d_frequency;
}
void SamplingThread::setAmplitude( double amplitude )
{
d_amplitude = amplitude;
}
double SamplingThread::amplitude() const
{
return d_amplitude;
}
void SamplingThread::sample( double elapsed )
{
if ( d_frequency > 0.0 )
{
const QPointF s( elapsed, value( elapsed ) );
SignalData::instance().append( s );
}
}
double SamplingThread::value( double timeStamp ) const
{
const double period = 1.0 / d_frequency;
const double x = ::fmod( timeStamp, period );
const double v = d_amplitude * qFastSin( x / period * 2 * M_PI );
return v;
}