PDFlib Text Extraction Toolkit (TET) Manual

Fig. 6.5
Sample font reports created with the PDFlib FontReporter plugin for Adobe Acrobat
Precedence rules. TET will apply the glyph mapping controls in the following order:
> Codelist and ToUnicode CMap resources will be consulted first.
> If the font has an internal ToUnicode CMap it will be considered next.
> For glyph names TET will apply an external or internal glyph name mapping rule if
one is available which matches the font and glyph name.
> Lastly, a user-supplied glyph list will be applied.
Code list resources for all font types. Code lists are similar to glyph lists except that
they specify Unicode values for individual codes instead of glyph names. Although
multiple fonts from the same foundry may use identical code assignments, codes (also
called glyph ids) are generally font-specific. As a consequence, separate code lists will be
required for individual fonts. A code list is a text file where each line describes a Unicode
mapping for a single code according to the following rules:
> Text after a percent sign ’%’ will be ignored; this can be used for comments.
> The first column contains the glyph code in decimal or hexadecimal notation. This
must be a value in the range 0-255 for simple fonts, and in the range 0-65535 for CID
fonts.
> The remainder of the line contains up to 7 Unicode code points for the code. The values
can be supplied in decimal notation or (with the prefix x or 0x) in hexadecimal
notation. UTF-32 is supported, i.e. surrogate pairs can be used.
6.8 Advanced Unicode Mapping Controls 77