Martin Hosken > Font-TTF-1.05 > Font::TTF::Cmap



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Font::TTF::Cmap - Character map table


Looks after the character map. For ease of use, the actual cmap is held in a hash against codepoint. Thus for a given table:

    $gid = $font->{'cmap'}{'Tables'}[0]{'val'}{$code};

Note that $code should be a true value (0x1234) rather than a string representation.


The instance variables listed here are not preceded by a space due to their emulating structural information in the font.


Number of subtables in this table


An array of subtables ([0..Num-1])

Each subtable also has its own instance variables which are, again, not preceded by a space.


The platform number for this subtable


The encoding number for this subtable


Gives the stored format of this subtable


Gives the version (or language) information for this subtable


A hash keyed by the codepoint value (not a string) storing the glyph id

The following cmap options are controlled by instance variables that start with a space:


By default, when generating format 4 cmap subtables character codes that point to glyph zero (normally called .notdef) are not included in the subtable. In some cases including some of these character codes can result in a smaller format 4 subtable. To enable this behavior, set allowholes to non-zero.



Reads the cmap into memory. Format 4 subtables read the whole subtable and fill in the segmented array accordingly.


Finds a Unicode table, giving preference to the MS one, and looks up the given Unicode codepoint in it to find the glyph id.


Finds the a Unicode table, giving preference to the Microsoft one, and sets the mstable instance variable to it if found. Returns the table it finds.


Returns the encoding of the microsoft table (0 => symbol, etc.). Returns undef if there is no Microsoft cmap.


Writes out a cmap table to a filehandle. If it has not been read, then just copies from input file to output

$t->XML_element($context, $depth, $name, $val)

Outputs the elements of the cmap in XML. We only need to process val here


Returns the minimum size this table can be in bytes. If it is smaller than this, then the table must be bad and should be deleted or whatever.


Tidies the cmap table.

Removes MS Fmt12 cmap if it is no longer needed.

Removes from all cmaps any codepoint that map to GID=0. Note that such entries will be re-introduced as necessary depending on the cmap format.

@map = $t->reverse(%opt)

Returns a reverse map of the Unicode cmap. I.e. given a glyph gives the Unicode value for it. Options are:


Table number to use rather than the default Unicode table


Returns each element of reverse as an array since a glyph may be mapped by more than one Unicode value. The arrays are unsorted. Otherwise store any one unicode value for a glyph.


Returns whether the table of a given index is known to be a unicode table (as specified in the specifications)



Martin Hosken


Copyright (c) 1998-2014, SIL International (

This module is released under the terms of the Artistic License 2.0. For details, see the full text of the license in the file LICENSE.

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