Mechanism of layers allows typing of characters associated with diacritical marks used in languages other than Italian, or symbols used less frequently, such as ¹²³ ± ≠ ≤ ≥ ℅ ½ © ® ™ …
In the Updated Italian Keyboard some keys trigger, only in 4th position, an alternative character map, called “alternative layer”. An alternative layer is a character map applied temporarily to the entire keyboard, that adds a particular sign, usually a diacritical mark, to the characters of the main layer. For example, the diaeresis layer adds the diaeresis to some letters: activating the diaeresis layer and typing a, the keyboard generates ä.
After having issued the character with diacritical mark, the alternative layer ends, and the main layer is restored.
The keys that activate the alternative layers are chosen so that they are as intuitive as possible to guess, or easy to remember. For example, the key to activate the diaeresis layer is " (double quotation mark) reminiscent of ¨ (diaeresis).
Examples of use of layers:
To write the German word schön the keystrokes are:
s
c
h
AltGr + Maiusc + "
o
n , where:
AltGr + Maiusc + " activates the diaeresis layer. Thus, diaeresis is added to the next character.
To write the Polish word słów the keystrokes are:
s
AltGr + Maiusc + /
l
AltGr + Maiusc + '
o
w , where:
AltGr + Maiusc + / activates the slash layer
AltGr + Maiusc + ' activates the acute layer
To write the Romanian word fâșia the keystrokes are:
f
a
AltGr + Maiusc + ,
t
AltGr + Maiusc + u
a , where:
AltGr + Maiusc + , activates the layer of comma and ogonek
AltGr + Maiusc + u activates the layer of breve
In each alternative layer the space bar generates the character with the main diacritical mark represented in that layer, in the form of combining diacritical mark. This is useful for testing the layer in case of doubts, or for generating combined characters whose direct encoding is not implemented in the Updated Italian Keyboard driver.
In the section Character map each layer is explained in detail.