Kanit Wongsuphasawat

We plan to support jittering in the future #396, which would allow you to reproduce the screenshot in the tweet you included. (The non-box-plot half is basically a dot plot...

The tricky part about this is that Vega's `Violin plot` depends on the Vega facet operator to split data into subgroups between passing it to density transform. (Density happens inside...

We meet today to talk about this and conclude that we should make Vega density transform supports groupby.

No update yet

Btw, I run into a ["split violin plot"](https://seaborn.pydata.org/generated/seaborn.violinplot.html) in seaborn. It's definitely worth considering how this fits into our grammar. 

@mjskay -- Your comment is definitely very useful. When we work more on this, we'll have to see how this interplay with `offset` channel that we plan to add (#4703).

FWIW, we have violin plot example in https://observablehq.com/@vega/vega-lite-distribution-plots

Look like projection cannot be bind yet -- https://github.com/altair-viz/altair/issues/632#issuecomment-375208628

Thanks for submitting!

This [question in the vega-js group](https://groups.google.com/forum/?fromgroups=#!topic/vega-js/Hbc72LqP9hA) is very relevant to this issue.