Add example images of simulation of color deficiency

[kimikage]

cf. #398 (comment)

[kimikage]

The sample image included in this PR is the tricky version with reduced colors and sizes. The original version is as follows (CC0).

[johnnychen94]

I like the colors 😍

and it's a fantastic image for color2gray algorithms benchmarking, may I add this to TestImages?

[codecov]

Codecov Report

Merging #413 into master will not change coverage.
The diff coverage is n/a.

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  Coverage   81.87%   81.87%           
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  Files          11       11           
  Lines         883      883           
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  Hits          723      723           
  Misses        160      160

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[kimikage]

may I add this to TestImages?

Sure. It is released under the Creative Commons CC0 license. 😄

[kimikage]

I forgot to erase unnecessary code, so I removed it.:sweat_smile:

Since this changes the docs only, I will merge this within a few days if there is no objection.

[timholy]

It seems likely to be useful for many purposes, not just colors but segmentation algorithms, algorithms inferring depth from blur, etc. And it's just plain beautiful. Thanks, @kimikage!

Out of curiosity, why is it an svg? Did you actually generate this image rather that it being a photograph?

[kimikage]

Out of curiosity, why is it an svg? Did you actually generate this image rather that it being a photograph?

This is a 3d computer-generated image, and post-processed to make some glass beads to be in indistinguishable color pairs.

I hated depending on ImageMagick just for these examples, so I decided to use the technique used in the cross-sectional charts (cf. PR #406), i.e. the use of paletted PNGs. However, 256 colors are too few to represent this image.
And here's the thing. 😄

We shouldn't really use the dithering because of the different color spaces from normal vision. Therefore, I adjusted the hues so that they did not deviate significantly.

[kimikage]

I made a mistake on the HTML syntax. 😭
I don't know whether the cause is it or the embedded PNG, but the github pages hasn't been updated.

Edit: On my personal github pages, it was accepted (even with syntax errors). I'm going to wait and see.
kimikage.github.io/Colors.jl/dev/advancedfunctions/

[kimikage]

-"""width="$width"
+""" width="$width"

[kimikage]

Updated! 😄
http://juliagraphics.github.io/Colors.jl/latest/advancedfunctions/
(triggerd by PR #373)

[timholy]

The new docs just look fantastic.

[johnnychen94]

FYI, Documenter 0.24 provides a push_preview keyword for non-fork PRs to directly deploy a preview page for others to review

For example, JuliaImages/juliaimages.github.io#115