Ability to download animations of size spectra

[SamikDatta]

Currently animateSpectra() provides a fast and interactive way of displaying simulations over time. There have been requests to enable people to download these animations as GIFs (and possibly other file types) for use in presentations and so on. This is not possible using the plotly package, but there are other workarounds including gganimate.

Potentially this should be included in the mizer or mizerExperimental packages. I have written an example file of how to do this, which I am attaching (it won't upload as a .r file so I have converted it to a .txt file). THis just needs to be copied into an R file, saved and then run.

save_mizer_anim.txt