`ColorType.gray(x::Real)` is no longer needed

[kimikage]

gray(x::Fractional) was added in ColorTypes.jl v0.2 (JuliaGraphics/ColorTypes.jl@0b071ed), and it was modified to gray(x::Number) in ColorTypes.jl v0.2.12 (JuliaGraphics/ColorTypes.jl@988de55).

I think Number is too loose, but in any case the following is unnecessary:

ColorVectorSpace.jl/src/ColorVectorSpace.jl

Line 73 in f2baf1d

ColorTypes.gray(x::Real) = x

[johnnychen94]

If I read your words correctly, you suggest to

# in ColorTypes
- ColorTypes.gray(x::Number) = x
+ ColorTypes.gray(x::Real) = x

and by doing this, the same method should be removed here in ColorVectorSpace to avoid redefinition, right? That sounds good to me.

[kimikage]

Since Real<:Number, the change in ColorTypes.jl is optional. I think there is no ambiguity problem.

[kimikage]

I hope this will be fixed, along with other fixes. However, if needed, I will submit a standalone PR.

[kimikage]

The PR #131 is going to get rid of the gray(x::Real) in ColorVectorSpace.

[kimikage]

When I saw PR #137, I thought @timholy was going to make some changes in ColorTypes.jl.
For example: JuliaGraphics/ColorTypes.jl#177

However, I don't understand the true intent.

[kimikage]

This is a separate issue, but I think the following should be in ColorTypes.jl.

ColorVectorSpace.jl/src/ColorVectorSpace.jl

Line 310 in 85b8759

real(::Type{C}) where {C<:AbstractGray} = real(eltype(C))