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FAQ

Why are the RGB colors encoded in the ColorMixture type? Why not a value field?

In many places, JuliaImages assumes that you can convert from one color space to another purely from knowing the type you want to convert to. This would not be possible if the RGB colors were encoded as a second field of the color.

I wrote some code and got lousy performance. How can I fix it?

To achieve good performance, in some cases the RGB values must be aggressively constant-propagated, a feature available only on Julia 1.7 and higher. So if you're experiencing this problem on Julia 1.6, try a newer version.

If you're using fluorophore colors with fluorophore_rgb, where possible make sure you're using the compile-time constant syntax fluorophore_rgb"EGFP" rather than the runtime syntax fluorophore_rgb["EGFP"].

When you can't get good performance otherwise, your best option is to use a function barrier:

ctemplate = ColorMixture((rgb1, rgb2))

@noinline function make_image_and_do_something(ctemplate, sz)
    img = [ctemplate(rand(), rand()) for i = 1:sz[1], j = 1:sz[2]]
    ...
end

In this case ctemplate encodes the type and code in make_image_and_do_something will be inferrable even if the type of the created ctemplate is not inferrable in the calling scope.