DTL OTMaster (OTM), is a highly sophisticated application for reviewing, editing and altering tables and contours of fonts with a snft file structure, as there are CFF and TTF flavored OpenType fonts, TrueType fonts and TrueType Collection fonts.
Font editors, like for instance the DTL FontMaster suite, FontLab Studio and FontForge, rely on their own proprietary data formats for type design and font production. From these data, binary fonts for the end-user are compiled as the last step in the font production process.
OTM is a tool for inspecting and adjusting such binary fonts, irrespective of the font editor used for their creation.
OTM makes the editing of tables possible from a graphical user interface. Furthermore, it comes with built-in tools like the Glyph Editor for proofing and editing contours or even drawing glyphs from scratch. A ‘kern’ table viewer is available for proofing and refining the kerning, and a ‘GSUB’/‘GPOS’ viewer to visually test (and in case of ‘GPOS’ also adjust) these OpenType Layout tables.
One of the most remarkable functions in OTM, is the option to import and export OpenType Layout features files. During import OTM compiles the OpenType Layout features with the AFDKO (Adobe Font Development Kit for OpenType) syntax and produces binary OpenType Layout tables.
OTM contains the modified URW++ version of Adobe’s Hatch Open Type (HOT) tool, which is also part of DTL BezierMaster, DataMaster, and IkarusMaster. This means that the character set does not have to match the characters listed in the OpenType Layout features file, because all features that are not covered by the character set will be removed automatically during compiling. This makes it also a great tool for updating and standardizing fonts.
OTM is available for Mac OS X, Windows and Linux. Free ‘Light’ versions are available from the download page on this site. The downloads also contain the OTM manual, written and designed by Karsten Luecke, in PDF format.
The full version of DTL OTMaster costs € 255 and can be purchased from the DTL Font Tools Online Shop
Since OTM is based on the latest version (2.5) of the AFDKO, it supports the ‘GPOS’ mark features. The mark to base, mark to mark and mark to ligature positions can be displayed. Also (some of) the ‘GPOS’ features can be edited, like mark, mkmk, kern, palt, vpal, et cetera. One can import and export AFDKO-syntaxed feature files for ‘GPOS’, ‘GSUB’, ‘GDEF’, and ‘BASE’ in OTM. The program has extensive support for CJK, including for fonts with a very large number of glyphs. It handles CJK-related things, such as ‘name’ table strings, IVSes in the ‘cmap’ table, et cetera, very well.