SECTION 5.5
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Simple Fonts
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5.5.5 Character Encoding
A font’s
encoding
is the association between character codes (obtained from text
strings that are shown) and glyph descriptions. This section describes the charac-
ter encoding scheme used with simple PDF fonts. Composite fonts (Type 0) use a
different character mapping algorithm, as discussed in
.”
Except for Type 3 fonts, every font program has a built-in encoding. Under cer-
tain circumstances, a PDF font dictionary can change a font’s built-in encoding to
match the requirements of the application generating the text being shown. This
flexibility in character encoding is valuable for two reasons:
•
It permits showing text that is encoded according to any of the various existing
conventions. For example, the Microsoft Windows and Apple Mac OS oper-
ating systems use different standard encodings for Latin text, and many appli-
cations use their own special-purpose encodings.
•
It permits applications to specify how characters selected from a large character
set are to be encoded. Some character sets consist of more than 256 characters,
including ligatures, accented characters, and other symbols required for high-