Density function preview colors don't match with curser when NaN is involved.

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While exploring the implications of the inaccuracy fixes, I can across this issue:

Despite the entire image not being NaN, it's colored as if it is.
This also happens in reverse:

Steps to reproduce: Create those noises, scroll around and reset the seed, and notice the odd coloring.

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Actually, I'm no longer sure if this is a deepslate issue or an issue on the main site. The examples here show renders, but I don't see where in the codebase they are made.