User Guide

Making OpenType Fonts
655
Compiling the Feature Definitions
When you import or create OpenType features they exist as text-based
definitions. To convert them to the usable binary format of the GSUB and
GPOS OpenType tables they must undergo a process called “compilation”.
During compilation the feature definition source code (text) is checked for
errors and glyph reverences are verified. When is everything is confirmed
OK the text is converted to binary form which you can preview or export.
To compile feature definitions click on the
button on the toolbar.
FontLab will try to compile the features and if there are errors during the
compilation they are put into a special Output panel.
There is one special error message: if glyphs are referenced by the feature
definition but do not exist in the font, FontLab will show the warning
message:
If you click Yes, FontLab will try to create the glyphs using their names as
the source of information. The same algorithm as in the Generate Glyphs
operation described on page 342 is used.
If you hold down the
CTRL key when you are clicking the button to
compile the features, FontLab will compile the features and decompile the
resulting binary tables as if you had imported them from an OpenType font
file.