Plots.jl: artifact on ribbon plots on GR

[piever]

julia> using Plots
julia> plot(sin, ribbon = 0.1)

gives tiny white lines in the "ribbon" part. At some point it also happened that the plot line was "broken" but that was harder to reproduce. It seems that it's plotting every little chunk individually and they are not properly connected.

Here is a zoomed version:

I'm on Plots master and see this behavior both on GR release and master.

[daschw]

That's probably related to the automatic choices of the x values:

x = linspace(-5, 5, 10000)
plot(x, sin.(x), ribbon = 0.1)

looks better.

[SimonDanisch]

i'm pretty sure that this is a rendering artifact... Choosing different defaults just seems to hide it ;)

[piever]

I agree with @SimonDanisch : we can't expect the user to hide artefacts by choosing 10000 points on the x axis... Maybe it's better to ping @jheinen on this one, as I really don't know much about the details of the GR rendering system.

[daschw]

ok

[jheinen]

I have to check how ribbon plots are implemented (emulated) in Plots' GR backend ...

[daschw]

@jheinen, I think, they are just fillranges, set for all backends in https://github.com/JuliaPlots/Plots.jl/blob/master/src/utils.jl#L483-L500

[daschw]

@piever solved the issue! 🎉
It was caused by myself in #1110 (cf. #1139) and will be fixed by #1142.