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

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.