Font::TTF::Font(3pm)					User Contributed Perl Documentation				      Font::TTF::Font(3pm)

NAME

       Font::TTF::Font - Memory representation of a font

SYNOPSIS

       Here is the regression test (you provide your own font). Run it once and then again on the output of the first run. There should be no
       differences between the outputs of the two runs.

	   $f = Font::TTF::Font->open($ARGV[0]);

	   # force a read of all the tables
	   $f->tables_do(sub { $_[0]->read; });

	   # force read of all glyphs (use read_dat to use lots of memory!)
	   # $f->{'loca'}->glyphs_do(sub { $_[0]->read; });
	   $f->{'loca'}->glyphs_do(sub { $_[0]->read_dat; });
	   # NB. no need to $g->update since $f->{'glyf'}->out will do it for us

	   $f->out($ARGV[1]);
	   $f->release; 	   # clear up memory forcefully!

DESCRIPTION

       A Truetype font consists of a header containing a directory of tables which constitute the rest of the file. This class holds that header
       and directory and also creates objects of the appropriate type for each table within the font.  Note that it does not read each table into
       memory, but creates a short reference which can be read using the form:

	   $f->{$tablename}->read;

       Classes are included that support many of the different TrueType tables. For those for which no special code exists, the table type "table"
       is used, which defaults to Font::TTF::Table. The current tables which are supported are:

	   table       Font::TTF::Table      - for unknown tables
	   EBDT        Font::TTF::EBDT
	   EBLC        Font::TTF::EBLC
	   Feat        Font::TTF::GrFeat
	   GDEF        Font::TTF::GDEF
	   GPOS        Font::TTF::GPOS
	   GSUB        Font::TTF::GSUB
	   LTSH        Font::TTF::LTSH
	   OS/2        Font::TTF::OS_2
	   PCLT        Font::TTF::PCLT
	   Sill        Font::TTF::Sill
	   bsln        Font::TTF::Bsln
	   cmap        Font::TTF::Cmap	     - see also Font::TTF::OldCmap
	   cvt	       Font::TTF::Cvt_
	   fdsc        Font::TTF::Fdsc
	   feat        Font::TTF::Feat
	   fmtx        Font::TTF::Fmtx
	   fpgm        Font::TTF::Fpgm
	   glyf        Font::TTF::Glyf	     - see also Font::TTF::Glyph
	   hdmx        Font::TTF::Hdmx
	   head        Font::TTF::Head
	   hhea        Font::TTF::Hhea
	   hmtx        Font::TTF::Hmtx
	   kern        Font::TTF::Kern	     - see alternative Font::TTF::AATKern
	   loca        Font::TTF::Loca
	   maxp        Font::TTF::Maxp
	   mort        Font::TTF::Mort	     - see also Font::TTF::OldMort
	   name        Font::TTF::Name
	   post        Font::TTF::Post
	   prep        Font::TTF::Prep
	   prop        Font::TTF::Prop
	   vhea        Font::TTF::Vhea
	   vmtx        Font::TTF::Vmtx
	   DSIG        FONT::TTF::DSIG

       Links are:

       Font::TTF::Table Font::TTF::EBDT Font::TTF::EBLC Font::TTF::GrFeat Font::TTF::GDEF Font::TTF::GPOS Font::TTF::GSUB Font::TTF::LTSH
       Font::TTF::OS_2 Font::TTF::PCLT Font::TTF::Sill Font::TTF::Bsln Font::TTF::Cmap Font::TTF::Cvt_ Font::TTF::Fdsc Font::TTF::Feat
       Font::TTF::Fmtx Font::TTF::Fpgm Font::TTF::Glyf Font::TTF::Hdmx Font::TTF::Head Font::TTF::Hhea Font::TTF::Hmtx Font::TTF::Kern
       Font::TTF::Loca Font::TTF::Maxp Font::TTF::Mort Font::TTF::Name Font::TTF::Post Font::TTF::Prep Font::TTF::Prop Font::TTF::Vhea
       Font::TTF::Vmtx Font::TTF::OldCmap Font::TTF::Glyph Font::TTF::AATKern Font::TTF::OldMort Font::TTF::DSIG

INSTANCE VARIABLES

       Instance variables begin with a space (and have lengths greater than the 4 characters which make up table names).

       nocsum
	   This is used during output to disable the creation of the file checksum in the head table. For example, during DSIG table creation,
	   this flag will be set to ensure that the file checksum is left at zero.

       noharmony
	   If set, do not harmonize the script and lang trees of GPOS and GSUB tables. See Font::TTF::Ttopen for more info.

       fname (R)
	   Contains the filename of the font which this object was read from.

       INFILE (P)
	   The file handle which reflects the source file for this font.

       OFFSET (P)
	   Contains the offset from the beginning of the read file of this particular font directory, thus providing support for TrueType
	   Collections.

METHODS

   Font::TTF::Font->AddTable($tablename, $class)
       Adds the given class to be used when representing the given table name. It also 'requires' the class for you.

   Font::TTF::Font->Init
       For those people who like making fonts without reading them. This subroutine will require all the table code for the various table types
       for you. Not needed if using Font::TTF::Font::read before using a table.

   Font::TTF::Font->new(%props)
       Creates a new font object and initialises with the given properties. This is primarily for use when a TTF is embedded somewhere. Notice
       that the properties are automatically preceded by a space when inserted into the object. This is in order that fields do not clash with
       tables.

   Font::TTF::Font->open($fname)
       Reads the header and directory for the given font file and creates appropriate objects for each table in the font.

   $f->read
       Reads a Truetype font directory starting from the current location in the file.	This has been separated from the "open" function to allow
       support for embedded TTFs for example in TTCs. Also reads the "head" and "maxp" tables immediately.

   $f->out($fname [, @tablelist])
       Writes a TTF file consisting of the tables in tablelist. The list is checked to ensure that only tables that exist are output. (This means
       that you can't have non table information stored in the font object with key length of exactly 4)

       In many cases the user simply wants to output all the tables in alphabetical order.  This can be done by not including a @tablelist, in
       which case the subroutine will output all the defined tables in the font in alphabetical order.

       Returns $f on success and undef on failure, including warnings.

       All output files must include the "head" table.

   $f->out_xml($filename [, @tables])
       Outputs the font in XML format

   $f->XML_start($context, $tag, %attrs)
       Handles start messages from the XML parser. Of particular interest to us are <font> and <table>.

   $f->update
       Sends update to all the tables in the font and then resets all the isDirty flags on each table. The data structure in now consistent as a
       font (we hope).

   $f->dirty
       Dirties all the tables in the font

   $f->tables_do(&func [, tables])
       Calls &func for each table in the font. Calls the table in alphabetical sort order as per the order in the directory:

	   &func($table, $name);

       May optionally take a list of table names in which case func is called for each of them in the given order.

   $f->release
       Releases ALL of the memory used by the TTF font and all of its component objects.  After calling this method, do NOT expect to have
       anything left in the "Font::TTF::Font" object.

       NOTE, that it is important that you call this method on any "Font::TTF::Font" object when you wish to destruct it and free up its memory.
       Internally, we track things in a structure that can result in circular references, and without calling '"release()"' these will not
       properly get cleaned up by Perl.  Once you've called this method, though, don't expect to be able to do anything else with the
       "Font::TTF::Font" object; it'll have no internal state whatsoever.

       Developer note: As part of the brute-force cleanup done here, this method will throw a warning message whenever unexpected key values are
       found within the "Font::TTF::Font" object.  This is done to help ensure that any unexpected and unfreed values are brought to your
       attention so that you can bug us to keep the module updated properly; otherwise the potential for memory leaks due to dangling circular
       references will exist.

BUGS

       Bugs abound aplenty I am sure. There is a lot of code here and plenty of scope.	The parts of the code which haven't been implemented yet
       are:

       Post
	   Version 4 format types are not supported yet.

       Cmap
	   Format type 2 (MBCS) has not been implemented yet and therefore may cause somewhat spurious results for this table type.

       Kern
	   Only type 0 & type 2 tables are supported (type 1 & type 3 yet to come).

       TTC The current Font::TTF::Font::out method does not support the writing of TrueType Collections.

       In addition there are weaknesses or features of this module library

       o   There is very little (or no) error reporting. This means that if you have garbled data or garbled data structures, then you are liable
	   to generate duff fonts.

       o   The exposing of the internal data structures everywhere means that doing radical re-structuring is almost impossible. But it stop the
	   code from becoming ridiculously large.

       Apart from these, I try to keep the code in a state of "no known bugs", which given the amount of testing this code has had, is not a
       guarantee of high quality, yet.

       For more details see the appropriate class files.

AUTHOR

       Martin Hosken Martin_Hosken@sil.org

       Copyright Martin Hosken 1998.

       No warranty or expression of effectiveness, least of all regarding anyone's safety, is implied in this software or documentation.

   Licensing
       The Perl TTF module is licensed under the Perl Artistic License.

perl v5.10.1							    2010-06-07						      Font::TTF::Font(3pm)