User Guide

FontLab 4
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F o n t Fe a t u r e s
The most important thing about OpenType technology is its ability to
define font features – rules that change the standard behaviour of the font.
Here are a few examples of such features (source text is on top):
Small caps
Ligature
Old Style Numerals
Probably the best thing about OT features is that they do not change the
source string of characters. To explain this we need to again talk about the
character-glyph model.
The source text that you type on the keyboard or get from another source is
a sequence of characters that have strong links to the codes that the
computer uses to store data. The picture of the text that you see on the
screen is a sequence of glyphs or character images. It is important to
understand that there is not necessarily a one-to-one relationship between
character and glyph: it is possible to have a single glyph used as the image
for more than one character (Latin A and Cyrillic A, for instance, are
different characters, but use the same glyph) and sometimes you may have
more than one glyph “serving” a single character.