Hi there,
Here is the codes that could demo the problem:
# work as expected
plot(1:5)
polygon(c(1.5, 6.5, 6.5, 1.5), c(1.5, 1.5, 6.5, 6.5), col = "gray")
# the polygon at right upper is not filled by gray with alpha = 0.5
plot(1:5)
polygon(c(1.5, 6.5, 6.5, 1.5), c(1.5, 1.5, 6.5, 6.5), col =
adjustcolor("gray", 0.5))
# however, colors with alpha = 0.5 could be used with polygon
polygon(c(1.5, 5.0, 5.0, 1.5), c(1.5, 1.5, 5.0, 5.0), col =
adjustcolor("gray", 0.5))
If the polygon is in the plot region(?) wholly, color with alpha works.
Is it designed?
> R.version
_
platform x86_64-w64-mingw32
arch x86_64
os mingw32
system x86_64, mingw32
status
major 4
minor 1.1
year 2021
month 08
day 10
svn rev 80725
language R
version.string R version 4.1.1 (2021-08-10)
nickname Kick Things
Best,
Jinsong
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