Get QtGraphs with XYModelMapper working

[Igor23]

@GrecKo I have an additional question, because it is important for my project:
How can I update the axes in the following sense:

ValueAxis {
    id: axisX
    min: Graphsmodel.returnXmin()
    max: Graphsmodel.returnXmax()
    titleText: "X-Achse"
}

Even with fixed starting values this is not working for me.

[GrecKo]

Try to expose the xMin and xMan as properties with a NOTIFY signal instead to make the min and max binding automatically update. I guess it is currently calling returnXmin/max initially when the model is maybe empty, and then it isn't called again.

[Igor23]

@GrecKo How do you mean this exactly? Can you give an example code?

[Igor23]

And I have a second additional question: is there maximum number of points I can draw via Lineseries and XYModelMapper? It seems to me as there is a limit by Qt framework ...

[JoeCFD]

@Igor23 add the following in your model
Q_PROPERTY( float minX MEMBER m_fMinX NOTIFY minXChanged )
define m_fMinX and signal minXChanged in your model.

Do the same for maxX.

and

ValueAxis {
    id: axisX
    min: Graphsmodel.minX
    max: Graphsmodel.maxX
    titleText: "X-Achse"
}

[JoeCFD]

@Igor23 It seems there is no limit. But your drawing will get slower if there are too many points. You need some kind of optimization.

[SGaist]

The LineSeries type has a count property that returns the number of data points in the series so I would venture that the maximum int value is the limit but I wouldn't try to show that many data point anyway because it does not make sense. If anything, I would rather allow the user to zoom in/out of sections of a LineSeries if they need more precise data.

[Igor23]

@JoeCFD This works for me. Thank you!

[Igor23]

Sorry, I still have a question: How can I make a logarithmic scale to one axis? I didn't find in the web - only for 3D.

[JoeCFD]

This post is deleted!

[Bob64]

@JoeCFD That is Charts - I believe @Igor23 is using the newer Graphs module. From what I remember when I looked into it, logarithmic axis was one of the missing features of Graphs vs Charts.

[JoeCFD]

@Bob64 You are right. I did not pay attention to it.