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Chapter 4 - Font Manager / Font Manager Reference

The Outline Font ('sfnt') Resource

The PostScript Table

The PostScript table, with a tag name of 'post', contains information needed to use an outline font on a PostScript printer. It contains the PostScript names for all of the glyphs in the font. It also contains memory information needed by the PostScript driver for memory management. The PostScript table consists of a header component and an optional format component, which is used only for two of the possible four PostScript format types.

The header component of the PostScript table contains the memory requirements. PostScript drivers can make better use of the Memory Manager if the virtual memory requirements of an outline font that can be downloaded to the printer are known beforehand. If the font designer does not know the virtual memory requirements, the values for the memory use requirements of this font are set to zero.

The memory use of a downloaded outline font varies depending on whether it is defined as a TrueType or Adobe\xC5 Type 1 font on the printer. You can compute the minimum memory required for a font as follows:

1. Send the PostScript VMStatus call to the printer and store the result.
2. Download the font to the printer.
3. Send the VMStatus call again.
4. Subtract the first result from the second to calculate the amount of memory that the font requires.

The maximum memory required for a font is computed by adding the maximum run-time memory use to the minimum memory value. The maximum run-time memory use depends on the maximum band size of any bitmap that the outline font scaler might have to create from an outline description.