Less permissive color validator

[reaperrr]

Enforces larger difference to terrain color and higher minimum lumination.

Closes #7902.

[Mailaender]

👍 The new values seem to yield better results.

[obrakmann]

That's better, but it still allows setting this:

I played around a bit and got satisfying results with 0xA0 as threshold (and 0x80 for lower bound). That would allow setting colors like below, but that's about the closest you get:

[reaperrr]

Updated, changed the values to 0x70 for threshold and 0x80 for lower bound. As mentioned on irc, the higher the threshold, the more difficult it becomes to choose a GDI-ish color on TD desert maps, so I tried to find a middle-ground. This should still be significantly better than the values I used initially, maybe enough that players trying to exploit colors might get annoyed about the rejected colors and give up eventually (or settle for less advantageous colors).

[obrakmann]

👍

[obrakmann]

Changelog

[xan2622]

Is it normal that the "color chooser" hides the swatches after picking a color?

[Mailaender]

No, that is a glitch: #4451. I am not sure, but #8425 might fix it.