QwtSpectogram "realtime" plotting

Hello,

first of all thanks for this great forum!
I'm developing a program to modify audio data in "realtime".
Actual I can plot different audio signals with curves, but for
the next step I need a spectogram.
I connected the data with QwtMatrixRasterData to QwtSpectogram.
For Y-Axis I have 256 values, with the related Z-Axis value.
Quantity of values for X-Axis depends on the TimerInterval.
For now i use 500 values for 5 seconds (TimerInterval = 10ms).
The QwtSpectrogram is a child of a QwtPlot which is a child of QSplitter.

My actual problem is that QwtSpectrogram is only replotted if I shift the splitter.
So I don't know why the "replot()" in the "timerEvent()" didn't work.
I hope you can help me :)
Thank you in advance!

Christian Wagner

Code:

SignalSpecDomainPlot::SignalSpecDomainPlot(tPlotData *pPlotData,
	QWidget           *parent)
	: QwtPlot(parent)
	, d_interval(0)
	, d_timerId(-1)
	, d_timerCount(0)
	, mpPlotData(pPlotData)
{
	d_spectrogram = new QwtPlotSpectrogram();
	d_spectrogram->setRenderThreadCount(0);
	d_spectrogram->setCachePolicy(QwtPlotRasterItem::PaintCache);
 
	data = new QwtMatrixRasterData();
	data->setInterval(Qt::ZAxis, QwtInterval(-80, 20));
	data->setInterval(Qt::YAxis, QwtInterval(0, 256));
	data->setInterval(Qt::XAxis, QwtInterval(0, 500));
	data->setResampleMode(static_cast<QwtMatrixRasterData::ResampleMode>(1));
 
	d_spectrogram->setData(data);
	d_spectrogram->attach(this);
 
	/*-------------------------------------------------------------------------------*
	* Set axis
	*-------------------------------------------------------------------------------*/
	QwtText XAxisLabel;
	XAxisLabel.setText("Time [s]");
	setAxisTitle(QwtPlot::xBottom, XAxisLabel);
	setAxisScale(QwtPlot::xBottom, 0, 5);
 
	QwtText YAxisLabel;
	YAxisLabel.setText("Frequency[kHz]");
	setAxisTitle(QwtPlot::yLeft, YAxisLabel);
	setAxisScale(QwtPlot::yLeft, 0, 8);
 
	//color bar on the right axis
	QwtText Y2AxisLabel;
	QwtScaleWidget *rightAxis = axisWidget(QwtPlot::yRight);
	Y2AxisLabel.setText("Intensity[dB]");
	setAxisTitle(QwtPlot::yRight, Y2AxisLabel);
	setAxisScale(QwtPlot::yRight, -80, 20);
	rightAxis->setColorBarEnabled(true);
 
	enableAxis(yLeft + yRight);
 
	setColorMap(SignalSpecDomainPlot::RGBMap);
 
	/*-------------------------------------------------------------------------------*
	* Set timer interval (in ms)
	*-------------------------------------------------------------------------------*/
	setTimerInterval(10.0);
}
 
void SignalSpecDomainPlot::setTimerInterval(double ms)
{
	d_interval = qRound(ms);
 
	if (d_timerId >= 0)
	{
		killTimer(d_timerId);
		d_timerId = -1;
	}
	if (d_interval >= 0)
		d_timerId = startTimer(d_interval);
}
 
void SignalSpecDomainPlot::timerEvent(QTimerEvent *)
{		
	if (d_timerCount == 0)
	{
		QVector<double> values;
		for (uint i = 0; i <= 500 * 256; i++)
			values += 0;	
		data->setInterval(Qt::XAxis, QwtInterval(0, 5));
		data->setInterval(Qt::YAxis, QwtInterval(0, 8));
		data->setValueMatrix(values, 500);
	}
 
	if(d_timerCount < 500)
	{
		d_timerCount++;		
	}
	else
	{
		d_timerCount = 1;
	}
 
	for(uint j = 0; j < 256; j++)
	{	
		data->setValue(j, d_timerCount-1, mpPlotData->pppdFreqMemory[0][0][j]);
	}
 
	if (d_timerCount % 100 == 0)
	{
		replot();
	}	
}