Compose key
From Wikipedia, the free encyclopedia
On some computer systems, a compose key is a key which is designated to signal the software to interpret the next keystrokes as a combination in order to produce a character not found on the keyboard.
For example, typing compose, then a, then e may produce the AE ligature, æ. Typing compose, then e, then ' can yield an e with an acute accent, é.
The compose key is known as "Multi_key" in the X Window System. In XFree86 and X.Org Server, many keyboard layouts have a variant that maps Multi_key to some key, usually (on PC keyboards) to either of the Windows keys. It can also be specified in XkbOptions (for example, "compose:rwin"). Multi_key can also be assigned with the xmodmap(1) utility.
Hitting compose then this |
and then this |
renders this |
---|---|---|
a | ' | á |
A | ' | Á |
a | " or : | ä |
A | " or : | Ä |
a | ` | à |
A | ` | À |
a | ~ | ã |
A | ~ | Ã |
a | ^ | â |
A | ^ | Â |
a | * | å |
A | * | Å |
Most vowels support the above | ||
c | , | ç |
C | , | Ç |
O | R | ® |
O | C | © |
d | - | ð |
D | - | Ð |
t | h | þ |
T | H | Þ |
a | e | æ |
A | E | Æ |
Particularly for modern systems which support customisable compose sequences and Unicode, the table shown is far from complete. Given the vast number of sequences permissible and the vast number of characters desirable in Unicode, a complete table would be incredibly long.
The compose key can be found on the LK201 family of keyboards from Digital Equipment Corporation and its succsessors. The key can also be found on keyboards from Sun Microsystems.
On Mac OS X, the "option" key provides access to some extended characters. For example, holding down option and pressing a results in å; holding down option and pressing ` will create a highlighted ` character which will be added to the next letter if possible - so if an e is then pressed, the resultant character is è, while if an r is pressed the two characters are not compatible so the result is `r.
Microsoft Windows does not use a compose key, but it does support dead keys and AltGr for many characters. Other characters can be generated by holding down Alt, and then typing the ASCII code or Unicode code corresponding to the desired character.
[edit] External links
- Compose Sequences (unicode locale) by X.Org
- Everything2's list of Compose Key combinations
- SUN's Compose Key combinations used under CDE
- Setting up Compose Key in the X Window System
- AllChars, an open-source utility that emulates the Compose key under MS-Windows
Computer Keyboard Keys | |
---|---|
Dead keys | Compose |
Modifier keys | Control · Shift · Alt/Option (Apple) · AltGr · Command/Meta (MIT keyboards) · Windows · Fn (compact keyboards) |
Lock keys | Scroll lock · Num lock · Caps lock · Shift key |
Navigation | Arrow · Page scrolling (Page up/Page down) · Home/End |
Editing | Return/Enter · Backspace · Insert · Delete · Tab · Space bar |
Misc. | SysRq/Print screen · Break/Pause · Escape · Menu · Numeric keypad · Function · Power management (Power, Sleep, Wake) · Language input |