Waveform graphs not autoscaling in X

[pincpanter]

Hello, I have an annoying problem in drawing data with waveform graphs (LV2011).

I will put it in a short statement: I need to compel graphs to properly rescale on the X scale.

Now the details:

I need to show data acquired during a given "event", updating a graph every second. I don't know how long the event will last, but I prefer not to set the X-axis as autoscaled because I don't like the axis rescaling effect. So I initally set the graph as fixed (ScaleFit=0) to a reasonable width in abscissa. When the acquisition ends, I want to show all the data maximized on the available control width, so I set the X axis scaling property to 2. Unfortunately, the graph is often not rescaled. I also tried leaving ScaleFit to 0 and setting the Range:Maximum to the proper value or using the ForceRedraw method, to no avail.

Do you know any trick to compel the X axis to be rescaled?

[GerdW]

Hi panter,

did you try to rewrite the data after setting the graph to autoscale"?

[pincpanter]

No, but it seems a good suggestion. I will give it a try.

[pincpanter]

No, GerdW, it doesn't work

I tried also with ScaleFit=1 (Autoscale once now) and with more complicated pattern (for example reinit to default, then autoscale, then rewrite data). No success.

In all cases, it mainly works (but not always) when I run the program in the LV environment. The very opposite when I deal with an executable.

[GerdW]

Hi panter,

I only had issues like yours when the EXE was very busy and CPU consuming. Is this the case in your application?

[pincpanter]

Thank you GerdW for your help. CPU utilization is below 1%.

I will use autoscaling all the time. I don't like the way the graph is compressed during acquisition, but at least there is no risk to miss visualization of some data when the event is especially long.

[pincpanter]

Shame on me! It turned out it was a typical race condition, where a LV2 global may be used before being initialized, depending on the program timing details.

Hence, the graph references array was sometimes empty.