Package de.dante.extex.font.type.vf

This package contains the definitions and implementations for the VF-font-metric handling in ExTeX.

See:
          Description

Class Summary
VFFont This class read a VF-file.
 

Package de.dante.extex.font.type.vf Description

This package contains the definitions and implementations for the VF-font-metric handling in ExTeX.

VF format

Definition of VF format taken from VFtoVP, Version 1.2

VFtoVP is an extended version of the program TFtoPL, which is part of the standard TEXware library. The idea of a virtual font was inspired by the work of David R. Fuchs who designed a similar set of conventions in 1984 while developing a device driver for ArborText, Inc. He wrote a somewhat similar program called AMFtoXPL.

The idea behind VF files is that a general interface mechanism is needed to switch between the myriad font layouts provided by different suppliers of typesetting equipment. Without such a mechanism, people must go to great lengths writing inscrutable macros whenever they want to use typesetting conventions based on one font layout in connection with actual fonts that have another layout. This puts an extra burden on the typesetting system, interfering with the other things it needs to do (like kerning, hyphenation, and ligature formation). These difficulties go away when we have a virtual font, i.e., a font that exists in a logical sense but not a physical sense. A typesetting system like TEX can do its job without knowing where the actual characters come from; a device driver can then do its job by letting a VF file tell what actual characters correspond to the characters TEX imagined were present. The actual characters can be shifted and/or magnified and/or combined with other characters from many diffrent fonts. A virtual font can even make use of characters from virtual fonts, including itself. Virtual fonts also allow convenient character substitutions for proofreading purposes, when fonts designed for one output device are unavailable on another.