Quiver arrow heads disappear

[pabloemontes]

Hello, I seem to have stumbled upon a bug in the quiver function. Whenever I call quiver as quiver(x, y, u,v) if the field (u,v) happens to be equal to zero at some point, then all arrows lose their head. Not only that, but the trouble persists even in other plots where the field is not equal to zero.

As an example, the code

using GRUtils
# Create example data
x = repeat(LinRange(-1.0, 1.0, 20), inner=20)
y = repeat(LinRange(-1.0, 1.0, 20), outer=20)
u =  y
v = -x
# Plot arrows
quiver(x, y, u, v, arrowsize = 0.01, headsize= 0.5)
# Expand the y-axes to see the whole arrows

seems to work perfectly. However, the code

using GRUtils
# Create example data
x = repeat(LinRange(-1.0, 1.0, 20), inner=20)
y = repeat(LinRange(-1.0, 1.0, 20), outer=20)
u =  y
u = -x
u[1,1] = 0
u[1,1] = 0
# Plot arrows
quiver(x, y, u, v, arrowsize = 0.01, headsize= 0.5)
# Expand the y-axes to see the whole arrows

seems to cause the arrowheads to disappear. Not only that, any quiver plot I try to make after that also has that issue, regardless of the field being zero or not.

As a note, I'm using Julia 1.6.1 in jupyter-lab.

Thank you for your attention

Pablo

[jheinen]

I will fix this in GR ASAP - this is a bug!