Overview - Windows font configuration

The EquationComposer component produces encapsulated PostScript (EPS) graphics files for each mathematics expression. The use of EPS is often key to producing high-quality output, since it is a vector graphics format that scales nicely to the very high resolutions required for print output. However, a negative of the EPS format is that it is an older graphics format that was designed for use primarily with PostScript fonts. While EPS technology has improved to allow the use of TrueType and more recently OpenType fonts, not all TrueType and OpenType fonts can be used natively within EPS files.

Both the TrueType and OpenType standards provide a number of alternative ways for accessing the characters within fonts and optional mechanisms for discovering what characters a font contains. Thus, there is wide variation between "TrueType" fonts as to what information is available from the font itself, and how low-level software must access the characters within that font. In particular, only certain types of OpenType and TrueType fonts contain the necessary information in the appropriate format for direct use within EPS files.

Even with PostScript fonts, problems can arise within EPS files. In general, PostScript fonts do not contain enough information within them for external software to automatically, definitively determine what characters are contained within the font. This is a particular problem with mathematical symbols, since they are much less standard than alphabetic characters.

Some, though not all, problems with fonts in EPS can be addressed via a complex technique known as "dynamic font subsetting". This technique involves dynamically generating PostScript fonts containing the characters actually appearing in an EPS file from the regular fonts installed on the system, and embedding them within the EPS file. While the EquationComposer component does not yet have this capability, Design Science is working toward this goal for future versions.

Consequently, font management is a significant issue. Care must be taken to insure that the EquationComposer component is configured in such a way that characters are taken only from EPS compatible fonts, and that the EquationComposer component has access to accurate information about what characters are available to it within EPS compatible fonts. The EquationComposer component uses two font configuration facilities to achieve these goals:

• A mechanism for configuring the exact list of fonts which the EquationComposer component is allowed to use, in order of preference, and
• A mechanism for extending the EquationComposer component's knowledge of what characters are available in particular fonts.