[BUG] scatter plot ignores alpha

[mcabbott]

Details

Scatter plots seem to ignore alpha for me, example below. Line plots are fine.

This is on an M1 mac, with the native Julia nightly.

I am today unable to get Plots + GR working at all on Julia 1.6 + rosetta, although at some point I thought I managed, perhaps with a particular older version pinned. Edit: from here JuliaLang/julia#36617 (comment), ] add [email protected] is one version which works under rosetta, for which this problem does not occur. I can't run that version natively, though.

Plots.plot(rand(30,5), alpha=0.5, line=10)  # this has opacity

Plots.scatter!(30*rand(30), rand(30), ms=50*rand(30), alpha=0.5, c=rand(1:3, 30))  # this does not

Edit -- The problem also doesn't show up in the saved PNG file:

savefig("scatter_test.png")  # this file has transparency, correctly
savefig("scatter_test.pdf")  # likewise fine.

It does not occur when using GR directly:

using GR

GR.scatter(rand(30), rand(30), 4000*rand(30), rand(1:50:250, 30), alpha=0.5)  # works fine

Backends

This bug occurs on ( insert x below )

Backend	yes	no	untested
gr (default)	x
pyplot			x
plotly		x
plotlyjs			x
pgfplotsx			x
inspectdr			x

Versions

Plots.jl version:
Backend version (]st -m <backend(s)>):

(jl_HQfA5O) pkg> st
      Status `/private/var/folders/yq/4p2zwd614y59gszh7y9ypyhh0000gn/T/jl_HQfA5O/Project.toml`
  [28b8d3ca] GR v0.58.1
  [91a5bcdd] Plots v1.20.1

Output of versioninfo():

julia> versioninfo()
Julia Version 1.8.0-DEV.322
Commit e87e30c0e3 (2021-08-09 11:15 UTC)
Platform Info:
  OS: macOS (arm64-apple-darwin20.6.0)
  CPU: Apple M1
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-12.0.1 (ORCJIT, cyclone)
Environment:
  JULIA_NUM_THREADS = 4

[BeastyBlacksmith]

FWIW that code is fine on Ubuntu20.04

[mcabbott]

It also seems fine when I save to disk. I've edited text above to mention this.

[t-bltg]

I can't reproduce on GKS term (which is the OP issue).

[mcabbott]

Works for me locally too, Plots v1.36.2. Thanks for checking, I had forgotten about this issue.