Anybody know of a patch for urxvt to support 24-bit color? about colors HOT 3 OPEN

have a look at this patch

from colors.

That patch is good but incomplete; it only implements the secondary compact format, and does not implement the original standard, namely CSI 38:5::Red:Green:Blue:Alpha m (where :Alpha is optional, and yes that's two colons before the Red component).

from colors.

Um, the "original standard" doesn't mention an Alpha component - it, being: https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-T.416-199303-I!!PDF-E&type=items {on page 49 of 77. labelled 41) actually says for parameter 6 of the CSI 38:2::Red:Green:Blue:XXX m sequence that "Parameter 6 has no meaning." (XXX here). Note that the CSI 38:4:... sequence is the only one where the 6th parameter IS used - for Black, where the prior ones are Cyan, Magenta, and Yellow in that order. FTR CSI 38:5:... only has ONE additional parameter, the colour index (0 to 255) for the 256 colour mode.

from colors.