User Guide

FontLab 4
632
O p e n T y p e Fo nt F o r m a t s
Another key feature of the OpenType format is the fact that from the user’s
point of view there is only one font format for Mac, PC or any other
platform.
From the inside, there are two possible forms of OpenType fonts: so-called
TrueType-flavoured (or TT-flavoured) and PostScript-flavoured (or CFF-
flavoured).
The general structure of the font file is the same and both versions of the
format provide the same functionality. There are some technical
differences:
Version TT-flavored CFF-flavored
Outlines
2
nd
-order, like in TrueType
fonts
3
rd
-order, like in Type 1 fonts
Hinting
TrueType instructions Type 1 declarative hints
File
extension
TTF OTF
Comments
Basically any TrueType font
may be called a TT-flavoured
OpenType font, but usually
we call them OpenType fonts
only when they have special
features.
Outline data is stored in CFF
(Compact Font Format) format
that is expected to work better
with PostScript devices.