> I suspect even what X11 calls pseudocolor ([...]) may not be > supported these days.
Even X doesn't really support it these days. I ran into an issue with that and contacted an X Consortium person I knew from back in the day when the X Consortium was a thing and was told that X.org (which is apparently the keeper of the X flame now) doesn't really support what I wanted; IIRC, not really anything but TrueColor/DirectColor. Indeed, some years back, when I was working on smartphone development (the phone never came to market, alas), it had an emulator - which blindly assumed not only that it was on a TrueColor visual, but that the RGB masks were exactly what it expected! (The point is not that client authors can be sloppy - that's always been true - but that they've gotten away with such sloppiness.) Sic transit gloria X11. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTML mo...@rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B