QtChart & Gestures



  • Hello everyone,

    this weekend I decided to look a bit more into the QtCharts class.
    So far I'm exalted, and I'm defenitely using it for my next privat project!

    However, I run into a bit of a problem:
    I loaded the Zoom Line Example, compiled it and run it on my iPad air2.

    The problem is, there is a serious delay between the pinch gesture and the repainting of the ChartView. Up to 2 seconds delay!

    I simply added a qDebug output to see when and how often the QtChart::zoom function is called, and I can see that it gets multiple new scale factors but updates only once!

    This delay is horrible and makes it impossible to scale the chart to the deciered factor, and it would be better to add a QSlider that handles the Zoom.

    I'm using Qt 5.8 for this one and ios 10.3.2

    My question:
    Is there an option I forgot, or that is not shipped with the Zoom Line Example? Something that would reduce the delay. Idealy reduce it so much, that the repaint is in synch with your fingers doing the pinch?


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