variant of vline / hline with ribbon

[mjskay]

Might be nice to have a version of lineribbon / pointinterval that acts like geom_vline / geom_hline plus a ribbon. See e.g. https://twitter.com/SolomonKurz/status/1546241985597546497?s=20&t=ezZYkV4REc7LfdfFvYAPOg

[mjskay]

Name is one question... seems odd to have a geom_hlineribbon and geom_vlineribbon in this modern orientation-aware ggplot landscape. Maybe geom_hvlineribbon? Feels awkward.

[mjskay]

looking at some related words and synonyms there's stuff like: axis-aligned, parallel, flat, flush, rule, ...

no great names, and vlineribbon / hlineribbon are probably the most discoverable. So maybe use those names as aliases for each other / hvlineribbon and let orientation detection do its work.

[mjskay]

also a vribbon and hribbon variant probably

[mjskay]

Also consider: should this have a gradient variant that allows mapping pdf/cdf? Would actually work easily here unlike with lineribbon.

[mjskay]

more thoughts: the gradient pdf/cdf thing isn't really worth it atm.

This should be doable by making sure geom_lineribbon works with infinite bounds. So I'd say the simple version of this is something like:

• add a stat_vlineribbon() and stat_hlineribbon() that just generate the necessary c(-Inf, Inf) x/y values to get a vertical ribbon
• maybe add a stat_ablineribbon() which takes a 2d dist in the dist aesthetic giving the joint dist over slope and intercept and generates a line from it. Might move that to another issue.