$t->read

Reads the table passing control to the subclass to handle the subtable specifics

$t->read_sub($fh, $lookup, $index)

This stub is to allow subclasses to read subtables of lookups in a table specific manner. A reference to the lookup is passed in along with the subtable index. The file is located at the start of the subtable to be read

$t->extension()

Returns the lookup number for the extension table that allows access to 32-bit offsets.

$t->out($fh)

Writes this Opentype table to the output calling $t->out_sub for each sub table at the appropriate point in the output. The assumption is that on entry the number of scripts, languages, features, lookups, etc. are all resolved and the relationships fixed. This includes a LANG_TAGS list for a script, and that all scripts and languages in their respective dictionaries either have a REFTAG or contain real data.

$t->num_sub($lookup)

Asks the subclass to count the number of subtables for a particular lookup and to return that value. Used in out().

$t->out_sub($fh, $lookup, $index)

This stub is to allow subclasses to output subtables of lookups in a table specific manner. A reference to the lookup is passed in along with the subtable index. The file is located at the start of the subtable to be output

$t->dirty

Setting GPOS or GSUB dirty means that OS/2 may need updating, so set it dirty.

$t->maxContext

Returns the length of the longest opentype rule in this table.

$t->update

Perform various housekeeping items:

For all lookups, set/clear 0x0010 bit of flag words based on 'FILTER' value.

Sort COVERAGE table and RULES for all lookups.

Unless $t->{' PARENT'}{' noharmony'} is true, update will make sure that GPOS and GSUB include the same scripts and languages. Any added scripts and languages will have empty feature sets.

copy($ref)

Internal function to copy the top level of a dictionary to create a new dictionary. Only the top level is copied.

$t->read_cover($cover_offset, $lookup_loc, $lookup, $fh, $is_cover)

Reads a coverage table and stores the results in $lookup->{' CACHE'}, that is, if it has not been read already.

ref_cache($obj, $cache, $offset [, $template])

Internal function to keep track of the local positioning of subobjects such as coverage and class definition tables, and their offsets. What happens is that the cache is a hash of sub objects indexed by the reference (using a string mashing of the reference name which is valid for the duration of the reference) and holds a list of locations in the output string which should be filled in with the offset to the sub object when the final string is output in out_final.

Uses tricks for Tie::Refhash

out_final($fh, $out, $cache_list, $state)

Internal function to actually output everything to the file handle given that now we know the offset to the first sub object to be output and which sub objects are to be output and what locations need to be updated, we can now generate everything. $cache_list is an array of two element arrays. The first element is a cache object, the second is an offset to be subtracted from each reference to that object made in the cache.

If $state is 1, then the output is not sent to the filehandle and the return value is the string to be output. If $state is absent or 0 then output is not limited by storing in a string first and the return value is "";

$self->read_context($lookup, $fh, $type, $fmt, $cover, $count, $loc)

Internal method to read context (simple and chaining context) lookup subtables for the GSUB and GPOS table types. The assumed values for $type correspond to those for GSUB, so GPOS should adjust the values upon calling.

$self->out_context($lookup, $fh, $type, $fmt, $ctables, $out, $num)

Provides shared behaviour between GSUB and GPOS tables during output for context (chained and simple) rules. In addition, support is provided here for type 4 GSUB tables, which are not used in GPOS. The value for $type corresponds to the type in a GSUB table so calling from GPOS should adjust the value accordingly.