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Thread: QwtScaleWidget: The length of colorbar and backbone are different

  1. #1
    Join Date
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    Default QwtScaleWidget: The length of colorbar and backbone are different

    Hello,

    I am using QwtScaleWidget in a mainwindow to display color bar. The problem is that the color bar is somehow a little bit longer than the backbone of scalewidget's scaledraw at the bottom, when both of their lower boundaries are exactly the same.

    Here is a screenshot: plot.PNG
    My code:
    Qt Code:
    1. colorbar->setColorBarEnabled(true);
    2. QwtInterval zInterval = ... //The zInterval is [2, 79]
    3.  
    4. QwtLinearColorMap *colormap = ...
    5. colorbar->setColorMap(zInterval, colormap);
    6.  
    7. QwtScaleDiv scaleDiv(zInterval.minValue(), zInterval.maxValue());
    8. QList<double> majorTick;
    9. for (double i = zInterval.minValue(); i <= zInterval.maxValue(); i += gap) { //gap is 8 here
    10. majorTick.append(i);
    11. }
    12. scaleDiv.setTicks(QwtScaleDiv::MajorTick, majorTick);
    13. colorbar->setScaleDiv(scaleDiv);
    To copy to clipboard, switch view to plain text mode 

    I want to align the bottom of the color bar with the backbone(i.e. the first tick of the scale). Is there any way to do this?

    Thanks for your help!

  2. #2
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    Default Re: QwtScaleWidget: The length of colorbar and backbone are different

    Your code works on my box when doing it in the setup process of a plot. So my guess is, that your code runs in a specific situation, where no layout recalculation happens.
    If you can provide a minimal demo demonstrating the problem I will have a look at it.

    Uwe

  3. #3
    Join Date
    Mar 2021
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    Default Re: QwtScaleWidget: The length of colorbar and backbone are different

    Thanks for Uwe's reply.

    I've accidentally fixed the problem by adding this code:
    Qt Code:
    1. colorbar->setBorderDist(10, 10);
    To copy to clipboard, switch view to plain text mode 

    Result: plot.jpg

    It looks good for me and I won't go further with the issue because the function of my code is experimental and very initial.
    Last edited by Ara; 15th March 2021 at 04:33.

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