Arrows

using CairoMakie

xs = LinRange(-3, 3, 20)
ys = LinRange(-3, 3, 20)
us = [x + y for x in xs, y in ys]
vs = [y - x for x in xs, y in ys]
strength = vec(sqrt.(us .^2 .+ vs .^2))
cmap = :gnuplot

fig = Figure(size = (600, 400))
ax = Axis(fig[1,1], xlabel = "x", ylabel = "y", aspect = DataAspect())
arrows!(ax, xs, ys, us, vs, arrowsize = 10, lengthscale = 0.1,
    arrowcolor = strength, linecolor = strength, colormap = cmap)
Colorbar(fig[1,2], limits =(minimum(strength), maximum(strength)),
    nsteps =100, colormap = cmap, ticksize=15, width = 15, tickalign=1)
limits!(ax, -3,3,-3,3)
colsize!(fig.layout, 1, Aspect(1, 1.0))
fig