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autoscale on DataLoggerView variation

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gstola

Argentina
1 Posts

Posted - 19 Jun 2015 : 15:20:18

Hi,

I am working on a data logger application. I took DataLoggerView.java from dynamicscharts example as a base.

My issue occurs when my traces evolves in a way that they occupies a smaller part of the chart, without rescaling it. In other words, y-axis should zoom in but it doesnt.

So, I went back to the dynamicscharts example to check where was my mistake by comparing both codes. There, I just made a small change, to force the traces tendence. In practice, Ive modulated the four traces with an exponential, to guarantee that traces converged to some positive value. Under that context, I found that the y-axis didnt zoom in. That is, the four traces were around 800, but the x-axis still was there.

In short how should DataLoggerView example be changed so it autoscales in a way that always occupies most of the chart?

Thank you!
Gerardo

quinncurtis

1586 Posts

Posted - 20 Jun 2015 : 09:20:42

The auto-scaling in the Datalogger example takes place in the addNewPoints method, in the following lines. The call to pTransform1.autoScale is what rescales the y-scale to current data. The calcAutoAxis calls make sure the existing axes adapt to the new scale.


    xValues = Dataset1.getTimeXData();
    nNumPnts = Dataset1.getNumberDatapoints();
    pTransform1.autoScale(Dataset1,ChartConstants.AUTOAXES_NEAR,  ChartConstants.AUTOAXES_NEAR);
    if (fixedStartTimeFlag)
      pTransform1.setTimeScaleStart(xValues[0]); // peg start of graph at start of data
    else // Set a 100 point view into data
      pTransform1.setTimeScaleStart(Dataset1.getTimeXDataValue(Dataset1.getNumberDatapoints()-100));

     xAxis1.calcAutoAxis();
     yAxis1.calcAutoAxis();
     xAxisLab1.calcAutoAxisLabels();
     yAxisLab1.calcAutoAxisLabels();

So you must do something similar in your own code. If you can't get it to work, show exactly what code you are using to achieve the auto-scaling of the y-scale and axis.

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