Multiple Y-Axes slows WaveformGraph down

[Stephan1]

Hi,

I want to use multiple y-axes in a WaveformGraph to scale single waveforms without caching all data points and plot them again.

The attached minimal sample shows the behaviour with and without multiple y-axes. In the screenshot “MultiAxes.png” each waveform has its own y-axis. In the screenshot “SingleAxis.png” all waveforms use the same y-axis. Without using multiple y-axes the time to reconfigure the graph reduces from 3.3 seconds to 0.5 seconds.

How can I shorten the time to rebuild the WaveformGraph without omit use of multiple y-axes?

Best regards,

Stephan

[Christoph_D]

Hi Stephan,

Would you please give me the details about which Visual Studio/Measurement Studio you are using?

Best regards

Christoph

[Stephan1]

Hi Christoph,

I am using Visual Studio 2012 and Measurement Studio 2013.

Best regards,

Stephan

[Christoph_D]

Hi Stephan,

I would like to point you to the source code. There you see a clear difference in behaviour between only one axis and multiple axes. The for loop runs either 1 or number of waveforms (e.g. 200) which should account for a difference in computation time.

if (true == mMultiAxesCheckBox.Checked)
	axesCount = mWaveformCount;
else
	axesCount = 1;

for (int i = 0; i < axesCount; i++)
{
	var yAxis = new YAxis();
	SetAxisInvisible(yAxis);
	yAxis.Range = CalcRange(i, 1.0);
	yAxis.OriginLineVisible = true;

	yAxes.Add(yAxis);
	//mGraph.YAxes.Add(yAxis);
}

Best regards

Christoph

[Stephan1]

Hi Christoph,

Thank you for your fast answer.

As you can find in row "Axes created" of the following table the loop you point to consumes only 12 ms of the CPU time.

Axis Count	1 Axis	200 Axes	200 Axes without optimization
Clear axes	14 ms	943 ms	2796 ms
Axes created	0 ms	12 ms	7 ms
Axes added	1 ms	453 ms	2373 ms
Clear plot	40 ms	372 ms	2336 ms
Waveforms added	37 ms	393 ms	2338 ms
Plot samples added	113 ms	106 ms	109 ms
Clear annotation	25 ms	360 ms	2312 ms
Annotations added	281 ms	657 ms	2650 ms
Total	535 ms	3312 ms	14938 ms

The problem is that all actions on the graph take much longer if I add multiple axes however the amount of plotted data is the same.

I am searching for a optimization like I have used in the method SetAxisInvisible(). See the lines after the comment in the following code snipped. The time behaviour without this optimization I have added to the table above in column "200 Axes without optimization".

private void SetAxisInvisible(Axis axis)
{
	axis.Visible = false;
	axis.Mode = AxisMode.Fixed;
	// the following lines doesn't change anything on the appearance of the axis because 
	// the whole axis is invisible but they improve the performance of the graph drastically
	axis.AutoSpacing = false;
	axis.CaptionVisible = false;
	axis.EndLabelsAlwaysVisible = false;
	axis.MajorDivisions.GridVisible = false;
	axis.MajorDivisions.LabelVisible = false;
	axis.MajorDivisions.TickVisible = false;
	axis.MinorDivisions.GridVisible = false;
	axis.MinorDivisions.TickVisible = false;
}

Best regards,

Stephan