Guacamole currently only supports 16 colors in its terminal, whereas xterm and its various other modern derivatives all support 256+ colors, as well as arbitrary RGB colors. This support should be added to the Guacamole terminal, such that applications needing 256 colors have console codes to work with.
xterm's 256-color codes are defined at http://invisible-island.net/xterm/ctlseqs/ctlseqs.html. There are code sequences which apply:
- Set foreground to RGB color: CSI 38 ; 2 ; R ; G ; B
- Set foreground to 256-color palette index N: CSI 38 ; 5 ; N
- Set background to RGB color: CSI 48 ; 2 ; R ; G ; B
- Set background to 256-color palette index N: CSI 48 ; 5 ; N
There is an additional OSC sequence for redefining the 256-color palette, but that can probably be omitted for now. We have similarly omitted the Linux-specific console code for redefining the 16-color palette, even though we otherwise aim to support the same control sequences as the Linux console.