Adjusting fontsize of facet labels

[sethaxen]

Problem description

As far as I can tell, there is no way to directly adjust the fontsize of the facet labels. Sometimes the labels I'd like are a little too long, and it would be helpful to be able to adjust this.

Example

Currently the best option is to set the fontsize of the figure, which affects all other font sizes.

julia> using AlgebraOfGraphics, GLMakie

julia> layer = (
           data((; x=[1, 1], y=[1, 1], cat=["Short Name", "Really Long Category Name"])) *
           mapping(:x, :y; col=:cat)
       );

julia> fig = draw(layer; figure=(; size=(350, 200)))

julia> fig = draw(layer; figure=(; size=(350, 200), fontsize=10))

Proposed solution

I'm not certain the most AoG-ish way to do this.

[jkrumbiegel]

There could be two places for this, either in draw(...; facet = (; ...) or in draw(..., scales(Col = (; ...) or Row, respectively. In principle, all scale settings should go to scales, however font size is not really an attribute of the scale itself. Compare to the Color scale where colorbar settings go into draw(...; colorbar = (; ... instead, or the x and y axes which have settings in draw(...; axis = (; ...). I have never found that 100% ideal because you can't change axis settings per facet this way, but it's also not easy to allow that level of drill-down from a simple interface. Also, the colorbar option for example predates the scales system, so it wasn't designed with that in mind. And most plots don't need that kind of control, anyway, although I like to err on the side of more options to not limit users.