OSC 15 Tektronix Foreground Color

OSC 15 ; Pt ST sets the color of what is drawn in xterm’s Tektronix 4014 window, and OSC 15 ; ? ST asks what it is. OSC 115 puts it back as it started. It is one of xterm’s dynamic colors, and works as OSC 10 explains: Pt is any color X11 can parse, and a further ; in the same sequence moves on to color 16.

The Tektronix colors belong to xterm’s second window, which emulates a Tektronix 4014 graphics terminal and is opened from a menu or with CSI ? 38 h. They can be set and asked for whether or not that window is showing.

A default xterm starts it as the text foreground; the Tektronix window has no resource of its own (charproc.c), so in the terminal the cases run in, set up as a default xterm, it is reported as rgb:0000/0000/0000.

libghostty-vt has no such color, and ignores OSC 15 and OSC 115, so the cases that ask are known differences.

Validation

OSC15-1: Ask for it

\e]15;?\a

|____|
reply \e]15;rgb:0000/0000/0000\a

OSC15-2: Change it

\e]15;#0080ff\a
\e]15;?\a

|____|
reply \e]15;rgb:0000/8080/ffff\a