Added Color to Array convert functions and tests

[cfitz25]

Created convert functions to turn ColorTypes into Arrays, as most languages i have used typically treat colours as arrays i thought it would be useful to allow the same with Julia.

[codecov[bot]]

Codecov Report

Merging #223 (646cb01) into master (8d9df01) will increase coverage by 0.10%. The diff coverage is 97.50%.

@@            Coverage Diff             @@
##           master     #223      +/-   ##
==========================================
+ Coverage   95.38%   95.48%   +0.10%     
==========================================
  Files           8        8              
  Lines         758      798      +40     
==========================================
+ Hits          723      762      +39     
- Misses         35       36       +1     

Impacted Files	Coverage Δ
src/conversions.jl	88.63% <97.50%> (+3.85%)	:arrow_up:

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[kimikage]

I agree that this kind of conversion can be useful in specific use cases. However, in the Julia or JuliaImages ecosystem, it is not necessarily a best practice.

If you "really" need the array, it is better to construct it explicitly. As long as the convert is called directly by the user, I don't think there will be much confusion, but I'm not sure if it will be consistent when called from other methods implicitly.

[cfitz25]

Any ideas what functions may break from this? I did try with converting 2d arrays of RGB to a 3d array (or more a 2d array of 1d arrays) and that appeared to work correctly atleast. Also how would i explicitly construct the array, i couldnt see how to do so? I built this to deal with frames from VideoIO which are 2d arrays of Color types, i needed to use the pixel values as arrays to apply a mathematical function.

[timholy]

There's an ambiguity about whether you want to reinterpret or use the constructor order. Consider ARGB: the A comes first in the list and memory order, but when constructing colors we always have the user specify the alpha channel last.

ImageCore has utilities for this: it exports reinterpretc and channelview, so you have explicit control over these things.

[cfitz25]

@timholy thank you for pointing me in the right direction

[timholy]

OK to close this?