canvas.png writes a PNG with labels off if bg=0

[danlipsa]

Running this test
test2.txt
produces

Uncommenting the line that sets bg to 1 fixes the problem.

[danlipsa]

@aashish24 @doutriaux1 Is this important? Should we fix it before the release?

[doutriaux1]

actually yes! Lots of people run things in batch mode. Is it going to be long? Let's see if we can get the other PR in before we move to this one!

[doutriaux1]

@jbeezley do you think you can help with this one? Looks like it's bugging you as well.

[jbeezley]

Probably not, I know almost nothing about VTK.

[doutriaux1]

Is there such a person at Kitware? 😉 No worries.

[chaosphere2112]

@danlipsa @doutriaux1 This is the issue that I filed ages ago with VTK; we have it as #1148.

[aashish24]

@danlipsa I can look into it after I finish my sprint tasks let me know.

[aashish24]

thanks @chaosphere2112 for the reference.

[danlipsa]

@aashish24 @doutriaux1 @chaosphere2112 I looked at this briefly when I filed it. The reason why the labels are off seems to be that the display happens on a very large screen which is not available if bg=0. There these events that have to be dealt with properly: ModifiedEvent and ConfigureEvent. This is in VTKPlots.py

That is not to say that there is not a VTK bug somewhere as well :-) I have not seen Sam's bug report at all when I looked at this.