CJKV Information Processing, 2nd Edition

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Chapter 6: Font Formats, Glyph Sets, and Font Tools

For an OpenType font whose ‘CFF’ table is based on a CIDFont resource, meaning that the

CIDFont resource is converted to CFF, the CIDs of the CIDFont resource are converted

to GIDs in the resulting ‘CFF’ table. e real issue is whether the GIDs in the ‘CFF’ table

correspond to the CIDs in the source CIDFont resource. As long as the source CIDFont

resource does not include any empty intervals, GID=CID in the resulting OpenType font.

If the source CIDFont resource includes any empty intervals, the point where GID≠CID

is immediately aer the rst instance of an empty interval.

Consider a CIDFont resource that is based on the Adobe-Japan1-6 character collection,

which denes 23,058 glyphs, from CID through CID2357. If we were to omit CIDs

15444 through 15448, the resulting CID ranges would be as follows:

0–15443

15449–23057

CIDs 15444 through 15448 would thus be treated as empty intervals. If this CIDFont

resource were to be converted to a ‘CFF’ table, the resulting GID range would be as

follows:

0–23053

When a CIDFont resource is converted to a ‘CFF’ table, the GID



CID mapping is pre-

served as part of the ‘CFF’ table. is means that a ‘CFF’ table can be converted back into

a CIDFont resource as long as it is CID-keyed.

Std Versus Pro Designators

Today’s fonts frequently use designators that serve to indicate ...