Replot large wav file data

Hi,

I am plotting a .wav file using qwt5.2 svn. The file is around 1 minute long. The number of data points are around 10 lakh points. I am trying to move a marker around 100 ms (replot every 100 ms) to synchronize with the audio. Somehow the marker is moving very slowly.

Any suggestions on how I should call replot and setrawdata.

Sample code

tick(qint64 time)
{
indicator_x1[0] = ((time / (double)1000))* Audio->getSampleRate();
indicator_x1[1] = indicator_x1[0];
indicator_x2[0] = -1;
indicator_x2[1] = +1;
curve->setRawData(indicator_x1, indicator_x2,2); // This statement seems to be the problem.
qwtPlot->replot();

}


regards
sachin.

Quote:

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Originally Posted by Sachtech

I am trying to move a marker around 100 ms (replot every 100 ms) to synchronize with the audio. Somehow the marker is moving very slowly.

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When the marker is the only thing, that is moving you should cache the scene below the marker in a pixmap. If you implement the marker with a QwtPlotPicker, you don't have to implement the cache yourself, otherwise overload QwtPlot::drawItems().

Uwe