Vignettes: Legend points missing from custom "log" type example

[grantmcdermott]

See the two plots here: https://grantmcdermott.com/tinyplot/vignettes/types.html#a-minimal-example

I'm a little reticent to fix this automagically with special logic in compute_legend_args, since we're trying to get away from that (c.f., #531).

One simple solution would be to change to name = "p" (from name = "log"), so that the legend for this example inherits from the default points behaviour. We would have to explain this in the text, but maybe that's a good idea anyway since we want users to leverage the scaffolding of "primitive" types for their custom types?

Another option would be to add an explicit settings$legend_args$pch = par("pch") assignment just after the datapoints one. Again, this would have to be explained, though.

Thoughts @vincentarelbundock?

[vincentarelbundock]

oh, that's a good catch! Your simple solution seems straightforward and easy enough to explain. And you're right that encouraging re-use of existing scaffolding is good.

[grantmcdermott]

Nice, thanks for confirming.

One simple solution would be to change to name = "p" (from name = "log")

Just a quick follow-up from this. The name argument doesn't actually do anything for these custom types, right? It's not like they allow the user to call their custom plot via a string shortcut, say:

tinyplot(mpg ~ wt | factor(am), data = mtcars, type = "log")

(Maybe we should provide a way for users to "register" custom types?)

[vincentarelbundock]

I think that`s right:

  if (inherits(type, "tinyplot_type")) {
    settings$type = type$name
    settings$type_draw = type$draw
    settings$type_data = type$data
    return(invisible(NULL))
  }

tinyplot/R/sanitize_type.R

Line 4 in c86c9c7

if (inherits(type, "tinyplot_type")) {