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Thread: QwtPlot setAxisScale() is not displaying values below 1e-12 on yScale

  1. #1
    Join Date
    Nov 2017
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    Default QwtPlot setAxisScale() is not displaying values below 1e-12 on yScale


    I am using a QwtPlot widget from latest example which is available on Git with Qt 4.8, which I modified it slightly to use LogScale engine to display the yLeft axis. I want minimum value of log scale to be 1e-30 where in the documentation it is mentioned that 1e-150 is the minimum value. But whenever I set less than 1e-12, it shows zeros in the scale (attached in the image).

    QwtLogScaleEngine* axesy = new QwtLogScaleEngine();
    plot->setAxisScaleEngine(QwtPlot::yLeft, axesy);
    plot->setAxisScale(QwtPlot::yLeft, 1e-30, 1e-5);


    After changing minimum value to 1e-12
    plot->setAxisScale(QwtPlot::yLeft, 1e-12, 1e-5); it will display the scale correctly.


    Is there any thing to be done inside the QwtPlot widget? or am I missing something?


  2. #2
    Join Date
    Feb 2006
    Munich, Germany
    Thanked 879 Times in 827 Posts
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    Default Re: QwtPlot setAxisScale() is not displaying values below 1e-12 on yScale

    I would expect to find the reason for the problem in:

    Qt Code:
    1. QwtText QwtAbstractScaleDraw::label( double value ) const
    2. {
    3. return QLocale().toString( value );
    4. }
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