ANSI Colors

ANSI • About • Codes • Palette • Support • Detection • Links ANSI 256COLOR TRUECOLOR VT100 XTERM

ANSI escape codes are a standard for in-band signaling to control the cursor location, color, and other options on text terminals. The ANSI x3.64 standard was released in 1979 and later updated by the 5th edition ECMA-48 standard in 1991, ISO/IEC 6429 in 1992, and ISO-8613-3 in 1995.

ANSI escape codes are started using \e[ and contain numeric codes separated by semicolons. The escape code is terminated with an 'm'.

ANSI Color Codes

ANSI Color Escape Sequences

Code Effect Note \e [ CSI Control Sequence Indicator CSI n m ANSICOLOR ANSI color code (Select Graphic Rendition) CSI 38 ; 5 ; n m 256COLOR Foreground 8 bit 256 color code CSI 48 ; 5 ; n m 256COLOR Background 8 bit 256 color code CSI 38 ; 2 ; r ; g ; b m TRUECOLOR Foreground 24 bit rgb color code CSI 48 ; 2 ; r ; g ; b m TRUECOLOR Background 24 bit rgb color code

ANSI Color Options

Code Effect Note 0 Reset Set color and display state to default 1 Bold Set color intensity to bold 2 Faint Set color intensity to faint 3 Italic Display text as italic 4 Underline Display text as underline 5 Slow blink Blink less than 150 times a minute 6 Fast blink Blink 150 times a minute or more 7 Reverse video Reverse foreground and background colors 8 Erase Display text as blank spaces 9 Strikethrough Display text as strikethrough 21 Double underline 22 Bold: off Set color intensity to default 23 Italic: off 24 Underline: off Neither single or double 25 Slow blink: off 26 Fast blink: off 27 Reverse video: off 28 Erase: off 29 Strikethrough: Off 30 Foreground: black 31 Foreground: red 32 Foreground: green 33 Foreground: yellow Faint yellow often looks brown 34 Foreground: blue 35 Foreground: magenta 36 Foreground: cyan 37 Foreground: white 39 Foreground: reset Reset foreground color to default 40 Background: black 41 Background: red 42 Background: green 43 Background: yellow 44 Background: blue 45 Background: magenta 46 Background: cyan 47 Background: white 49 Background: reset Reset backround color to default

ANSI Color RGB Values

The 24 bit RGB values used for the 16 ANSI colors differ greatly for each terminal implementation. Below is a system that is both consistent and 12 bit compatible.

Code 0 1 2 3 4 5 6 7 Name Black Red Green Yellow Blue Magenta Cyan White Normal 000000 AA0000 00AA00 AAAA00 0000AA AA00AA 00AAAA AAAAAA Bold 555555 FF5555 55FF55 FFFF55 5555FF FF55FF 55FFFF FFFFFF

OSC Color Palette

The OSC color palette is an extension to the ANSI color standard using a modification of the Operating System Command sequence, documented in the Linux console manual as early as 1996. Support has been added by a handful of terminal emulators, most notably xterm. The extension allows changing the default 16 ANSI colors using a 24 bit RGB value in hexadecimal notation.

To send an OSC color palette code one must print \e]P followed by 1 hexadecimal number indicating one of the 16 ANSI colors, followed by 6 hexadecimal numbers to set a corresponding RGB value. Colors can be reset to their default by printing \e]R. The terminal's default foreground and background color cannot be changed.

The default blue ANSI color is hard to read on a black background. To set it to a lighter shade of blue one would print "\e]P43333BB", and to display the updated color one would print "\e[22;34m".

Support

ANSI color support in MUD clients is generally weak. Universally supported codes are 0 and 1, as well as code 30-37.

Terminal emulators generally support background colors as well as code 4, 5, 7, 9, and 22.

Detection

There is no universal standard for the detection or negotiation of ANSI color support. The following methods exist:

By using the TTYPE TELNET option and checking for a terminal emulator or mud client known to support ANSI colors, such as xterm. By using the TTYPE TELNET option and checking for the -color, -256color, or -truecolor suffix. For example: xterm-color. By using the TTYPE TELNET option and using the MUD Terminal Type Standard to detect ANSI color support.

Links

If you want a link added, you can email me at mudclient@gmail.com.

Clients supporting ANSI color

Virtually all MUD clients and terminal emulators support ANSI color.

Codebases

Comparison of MUD codebases - Mudpedia contains a list of MUD servers with ANSI color support.

Snippets

256 color parser - Handles ANSI 16 colors and xterm 256 colors.