CucaDiagramFileMakerSmetana margin strangeness

[matthew16550]

The default margins when using CucaDiagramFileMakerSmetana have a similar problem to #494 but it's not a recent regression, both v1.2021.2 and latest are identical for this.

And when we specify a margin there is extra space added at the top. e.g. these rows use margin 0, margin 20 & margin 40:

Think the top space issue can be fixed by using LimitFinder directly inCucaDiagramFileMakerSmetana.createFileLocked() instead of via ImageBuilder.getFinalDimension().

I'm cautious about backwards compatibility here, can the current behaviour be changed?

[arnaudroques]

I'm cautious about backwards compatibility here, can the current behaviour be changed?

Yes, the current behaviour for Smetana could (and should) be changed.
Smetana is really a beta feature: it uses a Java implementation of dot.
(That is, you do not need to install GraphViz to run PlantUML!)

So margin was clearly not managed by Smetana.
Now that the code is clearer, it's time to fix that !

Thanks!