rstudio
treefacet question w/ possible fix for export
tl;dr - treefacet isn't known to vega and use of facet seems to work just fine with the ggvis tests and a cookbook visual check. Granted these are simplistic so is there a reason treefacet is being used rather than the known facet?
The other day I ran into an issue with export_png failing when browser viewing worked just fine; it turned out to be the use of label instead of labels within my axis props. A waste of a time trying to run that down with vg2png's unhelpful 'unknown' but it told me that there is some possible argument matching being done that doesn't get done with export.
That got me to thinking about the reported issue with export_png and grouped data reported in this long ggvis group post and on this SO question and in ggvis issue https://github.com/rstudio/ggvis/issues/332.
A little checking resulted in the realization that while treefacet works fine when ggvis.js is available it is just plainly not list in vega's data manipulation transforms. After making a branch that alters the instances of treefacet to facet and testing that the ggvis package works as well as the export_png I'm left wondering if there is a reason for that name choice that isn't apparent.
