According to this page, Gnome Terminal supports 24bit true color. This is consistent with Wikipedia.
When I run color-spaces.pl
in Ubuntu 14.04 LTS with Gnome Terminal 3.6.2, the result is the following:
While there is no reference image, I imagine that those green strangely-shaped objects at the bottom indicate that the terminal is unable to print 24bit colors correctly.
How to enable 24bit support?
xterm
.