[BUG] lower color scale in contourf defaults to white instead of limiting color

[lmiq]

Details

If we plot, for example:

julia> using Plots

julia> x, y = 1:10, 1:10; z = 1:100;

julia> contourf(x,y,z; clims=(20, 80))

we get:

Note that in the lower part of the graphic the color is white, for values smaller than that of the
minimum of the color scale. The expected would be, as in top part, to assume the color of the
lower limit of the color scale.

Backends

This bug occurs on ( insert x below )

Backend	yes	no	untested
gr (default)	x
pythonplot		x
plotlyjs		x
pgfplotsx		x
unicodeplots		x
inspectdr		x
gaston		x

Versions

Plots.jl version: v1.40.9
Backend version (]st -m <backend(s)>):

GR v0.73.12

Output of versioninfo():

julia> versioninfo()
Julia Version 1.11.3
Commit d63adeda50d (2025-01-21 19:42 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: 20 × 12th Gen Intel(R) Core(TM) i7-12700F
  WORD_SIZE: 64
  LLVM: libLLVM-16.0.6 (ORCJIT, alderlake)
Threads: 1 default, 0 interactive, 1 GC (on 20 virtual cores)
Environment:
  JULIA_PKG_PRESERVE_TIERED_INSTALLED = true