Font::TTF::Cmap

Section: User Contributed Perl Documentation (3)
Updated: 2020-01-30
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NAME

Font::TTF::Cmap - Character map table  

DESCRIPTION

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.  

INSTANCE VARIABLES

The instance variables listed here are not preceded by a space due to their emulating structural information in the font.
Num
Number of subtables in this table
Tables
An array of subtables ([0..Num-1])

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

Platform
The platform number for this subtable
Encoding
The encoding number for this subtable
Format
Gives the stored format of this subtable
Ver
Gives the version (or language) information for this subtable
val
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:

allowholes
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.
 

METHODS

 

$t->read

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

$t->ms_lookup($uni)

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

$t->find_ms

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.  

$t->ms_enc

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

$t->out($fh)

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  

$t->minsize()

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.  

$t->update

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:
tnum
Table number to use rather than the default Unicode table
array
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.
 

is_unicode($index)

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

BUGS

Format 14 (Unicode Variation Sequences) cmaps are not supported.
 

AUTHOR

Martin Hosken <http://scripts.sil.org/FontUtils>.  

LICENSING

Copyright (c) 1998-2016, SIL International (http://www.sil.org)

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.


 

Index

NAME
DESCRIPTION
INSTANCE VARIABLES
METHODS
$t->read
$t->ms_lookup($uni)
$t->find_ms
$t->ms_enc
$t->out($fh)
$t->XML_element($context, $depth, $name, $val)
$t->minsize()
$t->update
@map = $t->reverse(%opt)
is_unicode($index)
BUGS
AUTHOR
LICENSING
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