[FR] Ability to resize the arrow heads in e.g. quiver plots

[TorkelE]

I have been trying to figure out how to do this (trying tons of various options), but currently does not seem to be possible in Plots.

It would be useful to be able to resize the arrowheads in e.g. quiver plots. E.g. for

using Plots
xs = vcat([fill(i,10) for i in 1:10]...)
ys = vcat(fill(1:10,10)...)
dxs = (0.8 .- rand(100)) ./2
dys = (0.6 .- rand(100)) ./2
quiver(xs, ys; quiver=(dxs,dys))

Especially when the arrow lines are small, the arrowheads looks really weird and ugly.

[j-adel]

I really suggest this arrow!() function. This issue has been there for over 7 years. I think it's time...

[BeastyBlacksmith]

You are welcome to open a PR 🙂

[j-adel]

You are welcome to open a PR 🙂

It seems to me that function quiver_using_arrows(plotattributes::AKW) is already designed to have scaling arrow heads. I'm not sure if there's something preventing its use or if there's a way for the user to select it.

[BeastyBlacksmith]

True, but that is only used, if the backend supports the :arrow attribute

@recipe function f(::Type{Val{:quiver}}, x, y, z)  # COV_EXCL_LINE
    @nospecialize
    if :arrow in supported_attrs()
        quiver_using_arrows(plotattributes)
    else
        quiver_using_hack(plotattributes)
    end
    ()
end

which GR currently does not:

Plots.jl/PlotsBase/ext/GRExt.jl

Line 25 in da79316

const _gr_attrs = PlotsBase.merge_with_base_supported([

That is why it uses the other implementation