The OpenType CFF and TTF conversion and the generation of the ‘GPOS’ and ‘GSUB’ tables have been integrated and a OpenType Layout features file that covers all possible features can be used for generating the binary OpenType tables. The automation of the features-generation is based on the fact that all ‘GSUB’ features can be generated automatically if the applicable glyphs are in the font database. So within the conversion process there is a check whether the glyphs are available to generate the feature entries in ‘GSUB’.
The support for ‘GPOS’ features is currently restricted to kerning, but like DTL OTMaster, DataMaster will be updated shortly to version 2.5 of the AFDKO. For the OpenType production the Character Layout file (.cha) has two purposes: first, it defines the glyph set which will be converted to OpenType and second, it relates the position number in the IK or BE font database to a PostScript name, which for instance is based on Adobe‘s Glyph List (AGL).
Therefor there are three conditions for automatically generating OpenType Layout features:
1. The glyphs must be in the database.
2. The characters must be listed in the Character Layout file.
3. The characters must be identically listed in the features file and the .cha file.
Because of the option to batch the OpenType production, a newly created entry in a feature can be applied to an unlimited number of fonts at once. Basically the FM Development Team is extending the ‘default’ features file that comes with FM as much as possible, but additions can be simply made by the user, of course, or another features file that supports the AFDKO syntax can be used. Because the ‘size’ (i.e. number of characters) in the generated font is controlled by the Character Layout file, the output of features can also be controlled by editing the .cha file.
Because the FM ‘default’ Features file can be easily enhanced and updated, it is easy to re-generate OpenType fonts with new features-enhancements. Also sometimes bug fixes in the AFDKO make it necessary to do this. The batch functionality of DTL DataMaster simplifies this process.
Additional information:
— FM: Automation at your fingertips
— Automating font production using DTL FontMaster
— OpenType Status 2007
— The OpenType layout features file: Structure and editing
— FM: OpenType Name Table Entries
— OpenType technote
— OpenType Font Technology
