Simple opacity setting

[robsmith11]

There should be an easy way to set the opacity of a geometry to a fractional value. For example, in ggplot2 one can simply write alpha=0.5, but with Gadfly, it's very verbose and non-intuitive: Theme(lowlight_color=c->RGBA{Float32}(c.r, c.g, c.b, 0.5)).

[Mattriks]

alpha functionality has been added to the master branch. You can use it now by doing add Gadfly#master. There are examples in the dev docs. Feedback welcome! You can keep up with the latest developments by checking news.md, which appears in the file list on the main page: https://github.com/GiovineItalia/Gadfly.jl

[robsmith11]

Thanks. Theme(alphas=[0.5]) does work with the master branch.