High performance live chart
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Scenario: sensor data is streamed at a fast pace and needs to be rendered live onto a QML ChartView using a couple of line series.
Question: what is the most performant way to render the results? Do I:
- buffer the results in C++ and send a signal with a QVariantList<QPointF> when a time threshold is exceeded which is then read and added to the LineSeries in qml -> exposing C++ via a context property
- expose the QAbstractSeries from QML to C++ and fill it in C++ at a predefined refresh rate using a QTimer as in this example? -> Interacting with QML Objects from C++ which has a disclaimer in the docs here NOT to use it
- don't use QML (which would be disappointing)
- other ways?
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Hello @BartBlackMagic. The Qt Charts are not famous for their performance with real-time real data. Other people may say that use Qwt or QCustomPlot, but I would rather prefer Qt Charts with all its defects. Concretely, I love Qml, so why go out and find a 3rd party plotter?
In your case, I face a similar problem last months. I choose the first option that you show. And it works pretty well for me.
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@oria66 this is exactly what I need to do too, can you provide an example code!
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@oria66 this is exactly what I need to do too, can you provide an example code!
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What about QtCharts with VXYModelMapper ?
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@oria66 this is exactly what I need to do too, can you provide an example code!
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@LeLev Thanks for your suggest, I think I can't use third party as I already crossed compiled my device with only Qt libraries!
@MAthias_Va said in High performance live chart:
I think I can't use third party as I already crossed compiled my device with only Qt libraries!
You can cross-compile the 3rd party libraries later, right?
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@MAthias_Va. Give some time to isolate an example from my code. Is proprietary code, so I must change a lot of things. I will send you in your post, ok? The developers must help us each other.
@oria66 that would be great, thanks!
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@GrecKo I will check it, thanks
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@MAthias_Va said in High performance live chart:
I think I can't use third party as I already crossed compiled my device with only Qt libraries!
You can cross-compile the 3rd party libraries later, right?
@JKSH I followed this method, https://wiki.qt.io/RaspberryPi2EGLFS to cross compile
