AltGr key
From Wikipedia, the free encyclopedia
AltGr is a modifier key on PC keyboards used to type many characters, primarily ones that are unusual for the locale of the keyboard layout, such as foreign currency symbols and accented letters. If a key has a third symbol on it (on the front vertical face or the bottom right of the key top, sometimes in a different colour), then AltGr can often be used to type that symbol.
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[edit] Meaning
IBM states that AltGr is an abbreviation for "alternate graphic" [1] [2]. The meaning of the key's abbreviation is not explicitly given in many IBM PC compatible technical reference manuals.
[edit] History
Originally, US PC keyboards (specifically: the US 101-key PC/AT keyboards) did not have an AltGr key, it being relevant to only non-US markets; they simply had "left" and "right" Alt keys. As those using such US keyboards increasingly needed the specific functionality of AltGr when typing non-English text, Windows began to allow all keystroke combinations involving AltGr to be typed by using Ctrl+Alt in its place. Therefore, it is recommended that Ctrl-Alt not be used as a modifier in Windows keyboard shortcuts as, depending on the keyboard layout and configuration, someone trying to type a special character with Ctrl-Alt may accidentally trigger the shortcut [3], or the keypresses for the shortcut may be inadvertently interpreted as the user trying to input a special character.
[edit] Function
The function and usage of AltGr vary according to the exact keyboard layout, which in turn varies according to both the locale and the operating system. On German keyboards it is used to type the symbols {, [, ], and }, which are commonly used by programmers and technical writers.
On those keyboard layouts having a defined AltGr key, it is equivalent to holding down the Ctrl and Alt keys together, which means many Microsoft Windows keyboard shortcuts (for example, shortcuts to icons in Windows Explorer) can be operated using only one hand from either side of the keyboard. However, AltGr + Del does not function as Ctrl-Alt-Del does.
Finally, AltGr also provides access to special keyboard characters such as the Euro symbol.
[edit] International keyboard layouts
[edit] US international
On US international keyboard layouts, the AltGr key can be used to enter the following characters:
¡ ² ³ ¤ € ¼ ½ ¾ ‘ ’ ¥ × ä å é ® þ ü ú í ó ö « » á ß ð ø ¶ ´ ¬ æ © ñ µ ç ¿
And, in combination with the Shift key:
¹ £ ÷ Ä Å É Þ Ü Ú Í Ó Ö Á § Ð Ø ° ¨ ¦ Æ ¢ Ñ Ç
Note that a lot of these symbols can also be entered using the dead keys.
For comparison, the US international keyboard layout follows. Note that the "`/~" key has been omitted; it does not react to the AltGr key.
1 2 3 4 5 6 7 8 9 0 - = Q W E R T Y U I O P [ ] A S D F G H J K L ; ' \ m Z X C V B N M , . /
"m" denotes the "Macro" key. It generally produces a "\", although applications receive a different keycode and can therefore instead use the key to for example run macros.
In Microsoft Windows, the functionality of AltGr is also available via Ctrl+Alt. This is useful in case the keyboard is not able to differentiate between the Alt key on the left and the AltGr key on the right.
[edit] UK
In UK keyboard layouts, the only two symbols printed on most keyboards which require the AltGr key are:
- € the Euro currency symbol. Located on the "4/$" key.
- Either |, the vertical bar ("pipe symbol") or ¦, the broken vertical bar ("broken pipe symbol"). Located on the "`/¬" key, to the immediate left of "1".
The two latter symbols interchange places in UK keyboards according to the operating system in use. In OS/2, the "UK keyboard layout" (specifically: the UK166 layout) requires AltGr for the vertical bar and the broken vertical bar is a shifted key — which, coincidentally, matches the actual symbols that are printed on most UK keyboards; in Windows, the "UK keyboard layout" requires AltGr for the broken vertical bar and the vertical bar is a shifted key — the converse of what is usually printed on the keys; and in Linux, the "UK keyboard layout" does not have a simple keystroke combination for the broken vertical bar at all, producing the vertical bar for both key combinations.
Using the AltGr key on UK keyboards in some versions of Windows (for example XP) in combination with vowel characters produces acute accents over the vowels (for example, á,é,í,ó,ú and Á,É,Í,Ó,Ú).
The free 'To Bach' utility written by Draig Technology uses the AltGr key to enter accented Welsh language vowels (â, ê, î, ô, û, ŷ, ŵ) using a standard UK keyboard.
[edit] Polish
Traditionally typewriters in Poland used a QWERTZ layout specifically designed for Polish language with accentuated characters obtainable directly. However, during the initial adoption of personal computers in the 80's, due to politics of the communist regime most of these machines didn't come from commercial import channels, rather being brought or sent by private persons from foreign countries. Most of these had US keyboards; various methods were devised to make it possible to enter special Polish characters. An established method was to use AltGr in combination with a Latin letter to obtain the accentuated variant, with a single exception of using AltGr+X to obtain ź (as AltGr+Z is used for ż).
At the time of the political transformation and opening of commercial import channels this practice was so common and widespread that the commerce quickly codified this practice. Nowadays most people in Poland use standard US-layout keyboards, using the AltGr method of entering Polish characters. This layout is sometimes referred to as Polish programmers' layout (klawiatura polska programisty), although more often it's just called the Polish layout.
The traditional typewriter layout is rarely if ever used on computer keyboards, mostly by professional typists (and most typewriters still do use this layout). That said, it's still available in most operating systems and usually called Polish typists' layout (klawiatura polska maszynistki); getting an actual keyboard in this layout can be very troublesome. Some older Polish versions of Microsoft Windows used this layout as the default layout and called it just Polish layout.
[edit] X Window System
In the X Window System, AltGr can be used to produce additional characters with almost every key in the keyboard. For example, in the Danish keymap, AltGr+Shift+Q produces Ω, AltGr[+Shift]+O produces ø/Ø, AltGr+M produces µ, and so on. With some keys, AltGr produces a dead key; for example on a UK keyboard AltGr+; produces a combining acute accent, thus AltGr+; followed by e produces é.
[edit] Modified keys tables
[edit] Danish keymap
q w e r t y u i o p å ¨ a s d f g h j k l æ ø ' < z x c v b n m , . -
The keymap with the Alt Gr key:
@ ł € ® þ ← ↓ → œ þ " ~ ª ß ð đ ŋ ħ j ĸ ł ' ^ ˝ \ « » © “ ” n µ ¸ ·
The keymap with Alt Gr+Shift:
Ω Ł ¢ ® Þ ¥ ↑ ı Œ Þ ˚ ˇ º § Ð ª Ŋ Ħ J & Ł ˝ ˇ × ¬ < > © ` ' N º ˛ ˙ ˙
[edit] Brazilian ABNT2 keymap
' 1 2 3 4 5 6 7 8 9 0 - = q w e r t y u i o p á [ a s d f g h j k l ç ã ] \ z x c v b n m , . ; /
Shift:
" ! @ # $ % ä & * ( ) _ +
Q W E R T Y U I O P À {
A S D F G H J K L Ç Â }
| Z X C V B N M < > : ?
AltGr:
¬ ¹ ² ³ £ ¢ ¬ { [ ] } \ §
/ ? € ® ŧ ← ↓ → ø þ ´ ª
æ ß ð đ ŋ ħ ĸ ł á ~ º
º « » © “ ” µ ─ · ạ °
AltGr + Shift:
¬ ¡ ½ ¾ ¼ ⅜ ¨ ⅞ ™ ± ° ¿ ą / ? € ® Ŧ ¥ ↑ ı Ø Þ ` ā Æ § Ð ª Ŋ Ħ & Ł ő ^ º ă < > © ` ' µ × ÷ ȧ ¿
[edit] See also
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|---|---|
| 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 |
