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 |
| " or : | a | ä |
| " or : | A | Ä |
| ` | a | à |
| ` | A | À |
| ~ | a | ã |
| ~ | A | Ã |
| ^ | a | â |
| ^ | A | Â |
| * | a | å |
| * | A | Å |
| s | s | ß |
| Vowels support most of the above | ||
| , | c | ç |
| , | C | Ç |
| O | R | ® |
| O | C | © |
| < | < | « |
| > | > | » |
| . | . | · |
| x | x | × |
| - | : | ÷ |
| ^ | 0 | ° |
| ^ | 1 | ¹ |
| ^ | 2 | ² |
| ^ | 3 | ³ |
| s | o/0 | § |
| 1 | 2 | ½ |
| 1 | 4 | ¼ |
| 3 | 4 | ¾ |
| o | / | ø |
| O | / | Ø |
| d | - | ð |
| D | - | Ð |
| n | - | ñ |
| t | h | þ |
| T | H | Þ |
| a | e | æ |
| A | E | Æ |
| ! | ! | ¡ |
| ? | ? | ¿ |
| l/L | - | £ |
| y/Y | -/= | ¥ |
| c | | | ¢ |
| s | | | $ |
| o | x | ¤ |
| / | / | \ |
Originally the currency sign on the keyboards were nationalized, and not every keyboard sold in the world contained a dollar sign ($), which explains why it appears there, although it is part of any standard keyboard since the 1990s. In particular the $ compose sequence ceased to work on modern systems. The historic backslash sequence (compose-//) witnesses of the similar situation for this key and is still working on modern systems. The table shown contains the traditional key compositions that had become a de-facto Sun/DEC/Falco standard. Particularly for modern systems which support customisable compose sequences and Unicode, the table would be 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 successors. 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 on the numeric keypad. There is also an Open Source utility available called AllChars that emulates the compose key using a selectable modifier key like Control or Shift. What characters it can create depend on the currently chosen code page and screen font, but most Western, Central, and Eastern European character sets are covered by predefined configuration files. The compose combinations can be customized by the user.
External links
- XFree86 Compose Key character map by XFree86
- Everything2's list of Compose Key combinations
- SUN's Compose Key combinations used under CDE
- Setting up Compose Key in the X Window System
- Using the Compose Key in the X Window System
- A Unix utility to lookup the Compose Key for the specified character
- AllChars, an open-source utility that emulates the Compose key under MS-Windows
- JLG Extended Keyboard Layout - yet another utility based on the Compose Key mechanism under Windows
| Esc | F1 | F2 | F3 | F4 | F5 | F6 | F7 | F8 | F9 | F10 | F11 | F12 | PtSc | ScLk | Brk | |||||||||
| <imagemap>
Image:KB United States.svg|450px desc none
rect 0 0 60 30 Tilde rect 60 0 120 30 Exclamation mark rect 120 0 180 30 At sign rect 180 0 240 30 Number sign rect 240 0 300 30 Dollar sign rect 300 0 360 30 Percent sign rect 360 0 420 30 Caret rect 420 0 480 30 Ampersand rect 480 0 540 30 Asterisk rect 540 0 600 30 Bracket rect 600 0 660 30 Bracket rect 660 0 720 30 Underscore rect 720 0 780 30 Plus and minus signs rect 780 0 900 30 Backspace
rect 0 0 60 60 Grave accent rect 60 0 120 60 1 (number) rect 120 0 180 60 2 (number) rect 180 0 240 60 3 (number) rect 240 0 300 60 4 (number) rect 300 0 360 60 5 (number) rect 360 0 420 60 6 (number) rect 420 0 480 60 7 (number) rect 480 0 540 60 8 (number) rect 540 0 600 60 9 (number) rect 600 0 660 60 0 (number) rect 660 0 720 60 Hyphen rect 720 0 780 60 Equals sign rect 780 0 900 60 Backspace
rect 0 61 90 90 Tab key rect 90 61 150 90 Q rect 150 61 210 90 W rect 210 61 270 90 E rect 270 61 330 90 R rect 330 61 390 90 T rect 390 61 450 90 Y rect 450 61 510 90 U rect 510 61 570 90 I rect 570 61 630 90 O rect 630 61 690 90 P rect 690 61 750 90 Bracket rect 750 61 810 90 Bracket rect 810 61 900 90 Vertical bar
rect 0 61 90 120 Tab key rect 90 61 150 120 Q rect 150 61 210 120 W rect 210 61 270 120 E rect 270 61 330 120 R rect 330 61 390 120 T rect 390 61 450 120 Y rect 450 61 510 120 U rect 510 61 570 120 I rect 570 61 630 120 O rect 630 61 690 120 P rect 690 61 750 120 Bracket rect 750 61 810 120 Bracket rect 810 61 900 120 Backslash
rect 0 121 105 150 Caps lock rect 105 121 165 150 A rect 165 121 225 150 S rect 225 121 285 150 D rect 285 121 345 150 F rect 345 121 405 150 G rect 405 121 465 150 H rect 465 121 525 150 J rect 525 121 585 150 K rect 585 121 645 150 L rect 645 121 705 150 Colon (punctuation) rect 705 121 765 150 Quotation mark rect 765 121 900 150 Enter key
rect 0 121 105 180 Caps lock rect 105 121 165 180 A rect 165 121 225 180 S rect 225 121 285 180 D rect 285 121 345 180 F rect 345 121 405 180 G rect 405 121 465 180 H rect 465 121 525 180 J rect 525 121 585 180 K rect 585 121 645 180 L rect 645 121 705 180 Semicolon rect 705 121 765 180 Apostrophe rect 765 121 900 180 Enter key
rect 0 181 135 210 Shift key rect 135 181 195 210 Z rect 195 181 255 210 X rect 255 181 315 210 C rect 315 181 375 210 V rect 375 181 435 210 B rect 435 181 495 210 N rect 495 181 555 210 M rect 555 181 615 210 Bracket rect 615 181 675 210 Bracket rect 675 181 735 210 Question mark rect 735 181 900 210 Shift key
rect 0 181 135 240 Shift key rect 135 181 195 240 Z rect 195 181 255 240 X rect 255 181 315 240 C rect 315 181 375 240 V rect 375 181 435 240 B rect 435 181 495 240 N rect 495 181 555 240 M rect 555 181 615 240 Comma (punctuation) rect 615 181 675 240 Full stop rect 675 181 735 240 Slash (punctuation) rect 735 181 900 240 Shift key
rect 0 241 90 300 Control key rect 90 241 150 300 Windows key rect 150 241 240 300 Alt key rect 240 241 600 300 Space bar rect 600 241 690 300 AltGr key rect 690 241 750 300 Windows key rect 750 241 810 300 Menu key rect 810 241 900 300 Control key </imagemap> |
Ins | Home | PgUp | Num | / | * | - | |||||||||||||||||
| Del | End | PgDn | 7 | 8 | 9 | + | ||||||||||||||||||
| 4 | 5 | 6 | ||||||||||||||||||||||
| ↑ | 1 | 2 | 3 | Ent | ||||||||||||||||||||
| ← | ↓ | → | 0 | . | ||||||||||||||||||||
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|---|---|
| Dead keys | Compose |
| Modifier keys | Control · Shift · Alt/Option (Apple) · AltGr · Command/Meta (Apple/MIT/Sun keyboards) · Windows/Super · Fn (compact keyboards) |
| Lock keys | Scroll lock · Num lock · Caps lock |
| Navigation | Arrow · Page Up/Page Down · Home/End |
| Editing | Return/Enter · Backspace · Insert · Delete · Tab · Space bar |
| Misc. | System request/Print screen · Break/Pause · Escape · Menu · Numeric keypad · Function · Power management (Power, Sleep, Wake) · Language input · Any key |
