qwt log scale Limits

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Hi,

I am plotting a curve with magnitude in dBs and frequency from 0Hz to 20Khz on linear scale. I generate a simple linear frequency array. Now I want to view my Curve on a typical log scale that is used in audio players. But I don't know how ?

I tried adding this to my code.

QwtLog10ScaleEngine *qwtlog = new QwtLog10ScaleEngine();
 
 
     plot->setAxisScaleEngine(QwtPlot::xBottom, qwtlog);

This does work but my x axis scale starts at 1E-100 and ends at 1. I want to change its limits so that it goes from 0 to 20KHz like this

http://machrone.home.comcast.net/~machrone/playertest/h10_octave_sweep.gif

Thank you.

koahnig

Hi and welcome to devnet

Did you try already autoScale()?

PS: I will move your thread to "3rd Party Software", where threads concerning QWT can be found.
Furthermore, it is also a good idea to post in QWT mailing list. There you might a better response than here in this forum.