The Theme fields can be listed by doing dump(Theme, maxdepth=1) or Theme().point_shapes.
There’s also a discrete scale table in the Tutorial.
Gadfly is built on the graphics package Compose.jl, so point_shapes can be extended using Compose forms. Gadfly expects a 3 arg function, but the Compose shapes are more complex:
using Compose, Gadfly
shapes1 = [f(x,y,r)=star(x,y,r, [i], [0.3]) for i = 2:10]
shapes2 = [f(x,y,r)=xgon(x,y,r, [i], [0.3]) for i = 2:10]
shapes3 = [f(x,y,r)=ngon(x,y,r, i) for i = 2:10]
plot(x=1:27, y=rand(27), shape=1:27,
Theme(point_size=5pt, point_shapes=[shapes1; shapes2; shapes3],
discrete_highlight_color=identity, default_color="orange")
)
