Qt Graphs lacking functionalities - Axes range

[mklisiewicz]

I'm using Qt Graphs for real-time data plotting, but I've been running into a lot of issues due to its lack of functionality. I've managed to work around most of them, but this one seems impossible to solve.

I need to get the x-axis range after zooming or panning, but axisX.min always returns the same seemingly meaningless value (25.626488705368423). The Plot is a registered singleton exposed to QML.

Here’s the relevant code:

axisX: ValueAxis {
    min: Plot.xMin
    max: Plot.xMax
    onZoomChanged: {
        Plot.handleRangeChanged(axisX.min, axisX.max)
    }
}

No matter what I try, I can’t get the actual updated range or zoom values.

On top of this, there are many other small inconveniences with Qt Graphs that make the module feel almost unusable. Qt Charts, on the other hand, seems to offer these features, but I haven’t used it because the official documentation recommends switching to Graphs.

So my questions are:

• How do I get the actual range or zoom values?
• Why is the switch recommended if Qt Graphs is nowhere near as powerful as Qt Charts?
• When (if ever) can we expect these missing functionalities to be available in Qt Graphs?

[Bob64]

Based on what I have seen, I couldn't recommend using Graphs yet. We had Qt reps at our company plugging Graphs and giving us presentations about it but it turns out that there a number of essential aspects of our current Charts usage that simply aren't supported by Graphs yet. It seems to be a work in progress at the moment. Charts may no longer be being actively developed but it is going to be around for a while yet.

[AndyBrice]

I want to add charts to a Qt app.

We are still using Qt5 because Qt6 doesn't support all the text encodings that Qt5 does (on Mac anyway). Also it sounds like QtGraphs isn't production ready yet. So QtGraphs isn't an option at present. So we are considering implementing the charts in QtCharts, and then transitioning to Qt 6 and QtGraphs later, if required.

Is there any word on how long Qt Charts is going to be supported?

Our app is fully C++ and QWidgets. I understand QtGraphs is currently QML only. Are there going to be a QWidget classes for graphs in QtGraphs? How similar are these classes going to be to the QtChart equivalents?

[cristian-adam]

@AndyBrice said in Qt Graphs lacking functionalities - Axes range:

I want to add charts to a Qt app.

Our app is fully C++ and QWidgets. I understand QtGraphs is currently QML only. Are there going to be a QWidget classes for graphs in QtGraphs? How similar are these classes going to be to the QtChart equivalents?

https://doc.qt.io/qt-6/graphs.html

Qt Graphs C++ Classes

The Qt Graphs functionality can be accessed via these C++ classes.

Qt Graphs C++ Classes for 2D	C++ classes for the Qt Graphs for 2D API
Qt Graphs C++ Classes for 3D	C++ classes for the Qt Graphs for 3D API
Qt Graphs C++ Classes for Widgets	C++ classes for the Qt Graphs for 3D API used with widgets
Qt Graphs C++ Common Classes	C++ classes for the Qt Graphs common API

[AndyBrice]

Ah, ok. Will take a look, thanks.