PDFlib 8 Windows COM/.NET Tutorial

5 Font Handling
5.1 Font Formats
5.1.1 TrueType Fonts
TrueType file formats. PDFlib supports vector-based TrueType fonts, but
not fonts based on bitmaps. TrueType font files are self-contained: they contain
all required information in a single file. PDFlib supports the following
file formats for TrueType fonts:
> Windows TrueType fonts (*.ttf), including Western, symbolic, and CJK
fonts;
> TrueType collections (*.ttc) with multiple fonts in a single file. TTC files are
typically used for grouping CJK fonts, but Apple also uses them to package
multiple members of a Western font family in a single file.
> End-user defined character (EUDC) fonts (*.tte) created with Microsoft’s
eudcedit.exe tool;
> On the Mac any TrueType font installed on the system (including .dfont) can also be
used in PDFlib.
TrueType font names. If you are working with font files you can use arbitrary alias
names (see »Sources of Font Data«, page 132). In the generated PDF the name of a True-
Type font may differ from the name used in PDFlib (or Windows). This is normal, and results
from the fact that PDF uses the PostScript name of a TrueType font, which differs
from its genuine TrueType name (e.g., TimesNewRomanPSMT vs. Times New Roman).
5.1.2 OpenType Fonts
The OpenType font format combines PostScript and TrueType technology. It
is implemented as an extension of the TrueType file format and offers a unified
format. OpenType fonts may contain optional tables which can be used
to enhance text output, e.g. ligatures and swash characters (see Section 6.3,
»OpenType Layout Features«, page 158), as well as tables for complex script
shaping (see Section 6.4, »Complex Script Output«, page 164).
While OpenType fonts offer a single container format which works on all platforms,
it may be useful to understand the following OpenType flavors which sometimes lead
to confusion:
> Outline format: OpenType fonts may contain glyph descriptions which are based on
TrueType or PostScript. The PostScript flavor is also called Compact Font Format
(CFF) or Type 2, and is usually used with the *.otf suffix. The Windows Explorer always
displays OpenType fonts with the »O« logo.
> TrueType fonts and OpenType fonts with TrueType outlines are not easily distinguished
since both may use the *.ttf suffix. Because of this blurry distinction the
Windows Explorer works with the following criterion: if a .ttf font contains a digital
signature it is displayed with the »O« logo; otherwise it is displayed with the »TT«
logo. However, since a digital signature is not required in OpenType fonts this can-
5.1 Font Formats 117