CHAPTER 5
448
Text
Note:
If an application producing a PDF file encounters text to be included that
uses CIDs from a higher-numbered supplement than the one corresponding to the
PDF version being generated, the application should embed the CMap for the
higher-numbered supplement rather than refer to the predefined CMap (see the
next section).
The CMap programs that define the predefined CMaps are available through the
ASN Web site and are also provided in conjunction with the book
CJKV Informa-
tion Processing
by Ken Lunde. Details on the character collections, including sam-
ple glyphs for all the CIDs, can be found in a number of Adobe Technical Notes.
For more information about these Notes and the aforementioned book, see the
Embedded CMap Files
For character encodings that are not predefined, the PDF file must contain a
stream that defines the CMap. In addition to the standard entries for streams
(listed in Table 3.4 on page 62), the CMap stream dictionary contains the entries
listed in Table 5.17. The data in the stream defines the mapping from character
codes to a font number and a character selector. The data must follow the syntax
defined in Adobe Technical Note #5014,
Adobe CMap and CIDFont Files Specifi-
cation.
TABLE 5.17 Additional entries in a CMap dictionary
KEY
TYPE
VALUE
Type
name
(Required)
The type of PDF object that this dictionary describes; must be
CMap
for a CMap dictionary. (Although this object is the value of an entry
named
Encoding
in a Type 0 font, its type is
CMap
.)
(Required)
The PostScript name of the CMap. It should be the same as the
value of
CMapName
in the CMap file.
(Required)
A dictionary (see Section 5.6.2, “CIDSystemInfo Dictionaries”)
containing entries that define the character collection for the CIDFont or
CIDFonts associated with the CMap.
The value of this entry should be the same as the value of
CIDSystemInfo
in
the CMap file. (However, it does not need to match the values of
CIDSystemInfo
for the
Identity-H
or
Identity-V
CMaps.)
CMapName
name
dictionary
CIDSystemInfo