Anti-Aliasing function in chart does not always work but inexplicably so...

[08Mal]

I have noticed a strange Aliasing bug in the chart indicator in my labview 2014

I have attached a file which has two supposedly identical charts however on my PC (windows 7, i-3 dual core, 8GB Ram) the two charts display different patterns.

The one labelled "aliasing problem" is jagged when anti aliasing is switched on and is broken when off. The other chart behaves as I would expect and am used to.

1) Does anyone else see this difference as I do?

2) Can anyone explain the reason to the phenomenon? 

much obliged for any feedback

Thanks

[Sam_Sharp · Accepted solution]

I am seeing the same thing:

It seems to be a bug specifically with the sweep chart (with the line). Turning off the line the updates work fine. Also, turning aliasing off and then on seems to redraw the chart with the correct aliasing (you can see that half-way through the data on the first plot). You could try periodically calling the 'Force Redraw' method to see if that prompts the aliasing to update. It also seems to fix itself when you stop the VI.

Weird bug though since it's only on one of the graphs.

(Also...what's with all the local variables and value signalling? And the weird timeout to exit?)

[Norbert_B · Accepted solution]

Well, getting rid of the weird array handling stuff reveals that both charts have the same issue. The issue is created by some settings in the chart.

I cannot reproduce the issue when using a new "Modern Waveform Chart".

hope this helps,
Norbert

PS: I assume that this behavior is some weird effect of X-scale scaling and plot configuration and maybe some other properties....

[08Mal]

Thanks for testing this for me... I was going a little crazy thinking I was mistaken.

Sorry about the weird update stuff ....

I was trying all kinds of elborate ways of entering the data to see if there was a difference. I even tried via references. My first attempt was a straightforward while loop and would have lead to less confusion but I did not save that version and the bug was the same.

A little background info is that this turned up when I upgraded some old labview 8 program to labview 14. the two charts, Although are identical are not from the same origin. One is cut and pasted from this upgrade the other is created in labview 14. 

Still weird though! 

[08Mal]

"Weird timeout to exit"..hmm what can I say.... Sorry... code evolution

I was trying many methods and my original code only had a while loop then I had an event loop. The timeout was a hangover from a PC overload test. 

In retrospect.. 

I should have used an event on the stop button.