fix for flickering with fitbounds, moving calculations inside the lay…

[ibrierley]

Fix for flickering with fitbounds, moving calculations inside the layoutBuilder…

[ibrierley]

Possible fix for the flickering issue https://github.com/fleaflet/flutter_map/issues/1375. Note this PR will need to proper testing, as I don't experience the issue, so can't verify this properly.

I would also test things like reorientating the device, and on web and emulators as there may well be other issues introduced and this can be quite a fiddly one to fix.

[mohammedX6]

It's working fine for me

[JaffaKetchup]

@ibrierley You happy for this to be merged?

[ibrierley]

Yes, but as mentioned, I could never replicate the problem, so was hard to know if this has been properly tested. I think it would be good for someone else to test if they get the chance, otherwise just go for it.

[JaffaKetchup]

Ok. @stx Can you also give this a test when you get a moment please?

[stx]

@JaffaKetchup Sure thing. I'll take a look at this tomorrow.

[stx]

@JaffaKetchup @ibrierley Sorry for the delay. Tested this on web and mobile and took 60 FPS captures and went through it frame by frame and it looks fixed and side-effect free! Nice work.