Changing geom color in Gadfly

Specific Domains Visualization
1

Hi. I’m trying to change the line color in a graph I’m generating using Gadfly (in a Jupyter notebook).

p = plot(Coord.cartesian(xmin=-2, xmax=2, ymin=-2, ymax=2))
for i in 1:50
  push!(p, layer(x=d.A, y=prior_dists.α[i] .+ prior_dists.βA[i] * (d.A .- mean(d.A)), Geom.line, color=[colorant"black"]))
end
display(p)

The above code generates the output

Plot(...)

If I leave out the geom, the graph defaults to points and I get black points (likewise if I specify Geom.point). If I leave out color, I get lines, but in Gadfly’s default color.

Am I doing something wrong?

Thanks.

2

Geom.line is one geometry which still uses the syntax
layer(..., Geom.line, Theme(default_color="black")) to change line color. I’m currently working on new code which will allow for the syntax color=[colorant"black"] with Geom.line. :grinning:

3

OK. Thanks.

4

This is now available on Gadfly master (in julia: ]add Gadfly#master). See the Aesthetics section in the Gadfly docs. For your plot, you could also use wide-form syntax.

Y = [cumsum(randn(20)) for _ in 1:50]
x = repeat([1:20;], outer=50)
plot(Y, x=x, y=Col.value, group=Col.index, color=[colorant"black"], Geom.line)

array_of_arrays

2 Likes
5

Thank you for the update. Will this be eventually replacing the use of Theme() or will both options be available?

6

Theme() can be inside or outside layers (outside is the overall plot Theme).

Inside layers, Theme will still be useful for some geoms e.g. layer(..., Geom.line, Theme(line_width=2pt)), until those attributes are developed into proper aesthetics e.g. layer(..., linewidth=[2pt], Geom.line) .

7

Sounds good. I like using Theme() to set styles that will be applied to the graph as a whole and then using something like color=[] to style individual geoms.

Thanks for all of your work. I really like the package and I’m always looking forward to future developments.