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
Glat Font::TTF::Glat
Gloc Font::TTF::Gloc
LTSH Font::TTF::LTSH
OS/2 Font::TTF::OS_2
PCLT Font::TTF::PCLT
Sill Font::TTF::Sill
Silf Font::TTF::Silf
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::Glat
Font::TTF::Gloc Font::TTF::LTSH Font::TTF::OS_2 Font::TTF::PCLT
Font::TTF::Sill Font::TTF::Silf 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.
nocompress
Is the default value controlling WOFF output table compression. If
undef, all tables will be compressed if there is a size benefit in
doing so. It may be set to an array of tagnames naming tables that
should not be compressed, or to a scalar integer specifying a table
size threshold below which tables will not be compressed. Note
that individual Font::TTF::Table objects may override this default.
See Font::TTF::Table 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.
WOFF
Contains a reference to a "Font::TTF::Woff" object.
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.
$f->read
Reads a Truetype font directory starting from location "$self-"{'
OFFSET'}> 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 cannot 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 and WOFF
The current Font::TTF::Font::out method does not support the
writing of TrueType Collections or WOFF files.
DSIG
Haven't figured out how to correctly calculate and output digital
signature (DSIG) table
In addition there are weaknesses or features of this module library
• 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.
• 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 <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.
perl v5.34.0 2022-06-14 Font::TTF::Font(3pm)
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