OSC 104 Reset Color Palette

OSC 104 ; Pc ST puts palette color Pc back as the terminal started it, undoing OSC 4. It takes any number of colors, OSC 104 ; 1 ; 2 ST, and with none, OSC 104 ST, resets every one (ResetAnsiColorRequest).

xterm reads the numbers in turn and stops at the first that is not a number, so OSC 104 ; 1 ; x ; 2 ST resets color 1 and leaves color 2 alone. A number past the palette is skipped (ResetOneAnsiColor).

It also reads past the end of the list. After each number it checks that a ; follows with strchr(";", c), which also finds the terminating NUL, so after the last number it steps over the end of the string and goes on reading whatever an earlier, longer OSC left in the same buffer (misc.c). After OSC 4 ; 1 ; red ; 2 ; blue ST, OSC 104 ; 1 ; 3 ST resets colors 1 and 3, then finds 2;blue left over after its own end, and resets color 2 as well. What it resets depends on what came before, but it is a bug of a default xterm, which this site follows, so OSC104-2 expects it.

With no number xterm resets more than the palette: it runs over every color slot it has, and the slots after the 256 palette colors hold the five special colors, so it tries to reset those too. Those also have a reset of their own, OSC 105, and can be named here as palette numbers 256 to 260. In a default xterm none of these resets works on a special color, for the reason the OSC 105 page gives, so a special color that has been changed stays changed.

DECSTR and RIS reset the palette as well, as the OSC 4 page shows.

libghostty-vt resets the colors named, and with none, the whole palette. It differs from xterm when the list has something in it that is not a number: it skips that and goes on, and a list with no number left in it resets the whole palette, as an empty one does. Its source says this follows kitty on purpose. It also leaves the special colors alone, having none. Those cases are known differences.

Support

Validation

OSC104-1: Reset one color

\e]4;1;red;2;blue\a
\e]104;1\a
\e]4;1;?;2;?\a

|____|
reply \e]4;1;rgb:cdcd/0000/0000\a\e]4;2;rgb:0000/0000/ffff\a

OSC104-2: Several, and one more from the buffer

\e]4;1;red;2;blue;3;green\a
\e]104;1;3\a                # then reads "2;blue" left after its end
\e]4;1;?;2;?;3;?\a

|____|
reply \e]4;1;rgb:cdcd/0000/0000\a\e]4;2;rgb:0000/cdcd/0000\a\e]4;3;rgb:cdcd/cdcd/0000\a

OSC104-3: Reset them all

\e]4;1;red;2;blue\a
\e]104\a
\e]4;1;?;2;?\a

|____|
reply \e]4;1;rgb:cdcd/0000/0000\a\e]4;2;rgb:0000/cdcd/0000\a

OSC104-4: An empty list is all of them too

\e]4;1;red;2;blue\a
\e]104;\a
\e]4;1;?;2;?\a

|____|
reply \e]4;1;rgb:cdcd/0000/0000\a\e]4;2;rgb:0000/cdcd/0000\a

OSC104-5: Something not a number stops the list

\e]4;1;red;2;blue\a
\e]104;1;x;2\a
\e]4;1;?;2;?\a

|____|
reply \e]4;1;rgb:cdcd/0000/0000\a\e]4;2;rgb:0000/0000/ffff\a

OSC104-6: So nothing is reset

\e]4;1;red\a
\e]104;x\a
\e]4;1;?\a

|____|
reply \e]4;1;rgb:ffff/0000/0000\a

OSC104-7: With no number, not the special colors

\e]5;0;red\a   # the color for bold
\e]104\a
\e]5;0;?\a

|____|
reply \e]5;0;rgb:ffff/0000/0000\a