NAME

PDF::API2::Basic::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.

    $f = PDF::API2::Basic::TTF::Font->open($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 the PDF::API2::Basic::TTF::Table manpage. The current tables which are supported are:

    table       PDF::API2::Basic::TTF::Table      - for unknown tables
    GDEF        PDF::API2::Basic::TTF::GDEF
    GPOS        PDF::API2::Basic::TTF::GPOS
    GSUB        PDF::API2::Basic::TTF::GSUB
    LTSH        PDF::API2::Basic::TTF::LTSH
    OS/2        PDF::API2::Basic::TTF::OS_2
    PCLT        PDF::API2::Basic::TTF::PCLT
    bsln        PDF::API2::Basic::TTF::Bsln
    cmap        PDF::API2::Basic::TTF::Cmap       - see also PDF::API2::Basic::TTF::OldCmap
    cvt         PDF::API2::Basic::TTF::Cvt_
    fdsc        PDF::API2::Basic::TTF::Fdsc
    feat        PDF::API2::Basic::TTF::Feat
    fmtx        PDF::API2::Basic::TTF::Fmtx
    fpgm        PDF::API2::Basic::TTF::Fpgm
    glyf        PDF::API2::Basic::TTF::Glyf       - see also PDF::API2::Basic::TTF::Glyph
    hdmx        PDF::API2::Basic::TTF::Hdmx
    head        PDF::API2::Basic::TTF::Head
    hhea        PDF::API2::Basic::TTF::Hhea
    hmtx        PDF::API2::Basic::TTF::Hmtx
    kern        PDF::API2::Basic::TTF::Kern       - see alternative PDF::API2::Basic::TTF::AATKern
    loca        PDF::API2::Basic::TTF::Loca
    maxp        PDF::API2::Basic::TTF::Maxp
    mort        PDF::API2::Basic::TTF::Mort       - see also PDF::API2::Basic::TTF::OldMort
    name        PDF::API2::Basic::TTF::Name
    post        PDF::API2::Basic::TTF::Post
    prep        PDF::API2::Basic::TTF::Prep
    prop        PDF::API2::Basic::TTF::Prop
    vhea        PDF::API2::Basic::TTF::Vhea
    vmtx        PDF::API2::Basic::TTF::Vmtx

Links are:


=head1 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.
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

PDF::API2::Basic::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.

$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->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)`

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);

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 PDF::API2::Basic::TTF::Font::out method does not support the writing of TrueType Collections.

In addition there are weaknesses or features of this module library

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

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.

PDF::API2::Basic::TTF::Font - Memory representation of a font