AltGr key
From Free net 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.
Contents |
Meaning
The meaning of "AltGr" is unclear to most people, even computer experts, but IBM unequivocally says here and here that it is an abbreviation for "alternate graphic". The meaning of the key's abbreviation is not explicitly given in many IBM PC compatible technical reference manuals.
Opinions
The majority's opinion (as shown by Google results on informed pages) seems to support the IBM claim, but some informed pages claim that AltGr means "alternative graphic". Nevertheless, the meaning of the Alt key seems to always be given as "alternate", e.g. in Webopedia. Although some claim that the specific function of the AltGr key has never had much to do with graphics (even with "graphics characters"), this apparently well informed source claims that the meaning might be a holdover from the days of machines like the Commodore 64, in which holding down some special modifier key and a letter would print a graphical symbol, such as a box-drawing element. Other, probably folk etymologies, include "alternative group" and "accent grave". The reasoning behind the first is that it produces an alternative group of characters. The reasoning behind the claim that it is an abbreviation for "accent grave" forgets that "Alt" cannot be an abbreviation for "accent" and that the key's function is not at all limited to grave accents (and that in some keyboard layouts it has no relation to grave accents at all). The Canadian multilingual keyboard has AltCar ("caractère" being French for "character".)
History
Originally, US PC keyboards (specifically: the US 101-key PC/AT keyboards) did not have an AltGr key, it being only relevant to 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 [1], or the keypresses for the shortcut may be inadvertently interpreted as the user trying to input a special character.
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.
International keyboard layouts
UK
In UK keyboard layouts, the only two symbols 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.
GNOME and KDE
In the GNOME and KDE environments, AltGr can be used to produce additional characters with almost every key in the keyboard. AltGr+Shift+Q produces Ω, AltGr[+Shift]+O produces Ø/ø, AltGr+M produces µ, and so on.
Modified keys tables
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 ˛ ˙ ˙
Notice: These examples are used upon a Danish keymap, so here is a Danish keymap for reference:
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 , . -