1Font::TTF::Font(3) User Contributed Perl Documentation Font::TTF::Font(3)
2
6 Font::TTF::Font - Memory representation of a font
7
9 Here is the regression test (you provide your own font). Run it once
10 and then again on the output of the first run. There should be no dif‐
11 ferences between the outputs of the two runs.
12 $f = Font::TTF::Font->open($ARGV[0]);
14 # force a read of all the tables
16 $f->tables_do(sub { $_[0]->read; });
17 # force read of all glyphs (use read_dat to use lots of memory!)
19 # $f->{'loca'}->glyphs_do(sub { $_[0]->read; });
20 $f->{'loca'}->glyphs_do(sub { $_[0]->read_dat; });
21 # NB. no need to $g->update since $f->{'glyf'}->out will do it for us
22 $f->out($ARGV[1]);
24 $f->release; # clear up memory forcefully!
25
27 A Truetype font consists of a header containing a directory of tables
28 which constitute the rest of the file. This class holds that header and
29 directory and also creates objects of the appropriate type for each ta‐
30 ble within the font. Note that it does not read each table into mem‐
31 ory, but creates a short reference which can be read using the form:
32 $f->{$tablename}->read;
34 Classes are included that support many of the different TrueType
36 tables. For those for which no special code exists, the table type "ta‐
37 ble" is used, which defaults to Font::TTF::Table. The current tables
38 which are supported are:
39 table Font::TTF::Table - for unknown tables
41 EBDT Font::TTF::EBDT
42 EBLC Font::TTF::EBLC
43 GDEF Font::TTF::GDEF
44 GPOS Font::TTF::GPOS
45 GSUB Font::TTF::GSUB
46 LTSH Font::TTF::LTSH
47 OS/2 Font::TTF::OS_2
48 PCLT Font::TTF::PCLT
49 bsln Font::TTF::Bsln
50 cmap Font::TTF::Cmap - see also Font::TTF::OldCmap
51 cvt Font::TTF::Cvt_
52 fdsc Font::TTF::Fdsc
53 feat Font::TTF::Feat
54 fmtx Font::TTF::Fmtx
55 fpgm Font::TTF::Fpgm
56 glyf Font::TTF::Glyf - see also Font::TTF::Glyph
57 hdmx Font::TTF::Hdmx
58 head Font::TTF::Head
59 hhea Font::TTF::Hhea
60 hmtx Font::TTF::Hmtx
61 kern Font::TTF::Kern - see alternative Font::TTF::AATKern
62 loca Font::TTF::Loca
63 maxp Font::TTF::Maxp
64 mort Font::TTF::Mort - see also Font::TTF::OldMort
65 name Font::TTF::Name
66 post Font::TTF::Post
67 prep Font::TTF::Prep
68 prop Font::TTF::Prop
69 vhea Font::TTF::Vhea
70 vmtx Font::TTF::Vmtx
71 Links are:
73 Font::TTF::Table Font::TTF::EBDT Font::TTF::EBLC Font::TTF::GDEF
75 Font::TTF::GPOS Font::TTF::GSUB Font::TTF::LTSH Font::TTF::OS_2
76 Font::TTF::PCLT Font::TTF::Bsln Font::TTF::Cmap Font::TTF::Cvt_
77 Font::TTF::Fdsc Font::TTF::Feat Font::TTF::Fmtx Font::TTF::Fpgm
78 Font::TTF::Glyf Font::TTF::Hdmx Font::TTF::Head Font::TTF::Hhea
79 Font::TTF::Hmtx Font::TTF::Kern Font::TTF::Loca Font::TTF::Maxp
80 Font::TTF::Mort Font::TTF::Name Font::TTF::Post Font::TTF::Prep
81 Font::TTF::Prop Font::TTF::Vhea Font::TTF::Vmtx Font::TTF::OldCmap
82 Font::TTF::Glyph Font::TTF::AATKern Font::TTF::OldMort
83
85 Instance variables begin with a space (and have lengths greater than
86 the 4 characters which make up table names).
87 nocsum
89 This is used during output to disable the creation of the file
90 checksum in the head table. For example, during DSIG table cre‐
91 ation, this flag will be set to ensure that the file checksum is
92 left at zero.
93 fname (R)
95 Contains the filename of the font which this object was read from.
96 INFILE (P)
98 The file handle which reflects the source file for this font.
99 OFFSET (P)
101 Contains the offset from the beginning of the read file of this
102 particular font directory, thus providing support for TrueType Col‐
103 lections.
104
106 Font::TTF::Font->AddTable($tablename, $class)
107 Adds the given class to be used when representing the given table name.
109 It also 'requires' the class for you.
110 Font::TTF::Font->Init
112 For those people who like making fonts without reading them. This sub‐
114 routine will require all the table code for the various table types for
115 you. Not needed if using Font::TTF::Font::read before using a table.
116 Font::TTF::Font->new(%props)
118 Creates a new font object and initialises with the given properties.
120 This is primarily for use when a TTF is embedded somewhere. Notice that
121 the properties are automatically preceded by a space when inserted into
122 the object. This is in order that fields do not clash with tables.
123 Font::TTF::Font->open($fname)
125 Reads the header and directory for the given font file and creates
127 appropriate objects for each table in the font.
128 $f->read
130 Reads a Truetype font directory starting from the current location in
132 the file. This has been separated from the "open" function to allow
133 support for embedded TTFs for example in TTCs. Also reads the "head"
134 and "maxp" tables immediately.
135 $f->out($fname [, @tablelist])
137 Writes a TTF file consisting of the tables in tablelist. The list is
139 checked to ensure that only tables that exist are output. (This means
140 that you can't have non table information stored in the font object
141 with key length of exactly 4)
142 In many cases the user simply wants to output all the tables in alpha‐
144 betical order. This can be done by not including a @tablelist, in
145 which case the subroutine will output all the defined tables in the
146 font in alphabetical order.
147 Returns $f on success and undef on failure, including warnings.
149 All output files must include the "head" table.
151 $f->out_xml($filename [, @tables])
153 Outputs the font in XML format
155 $f->XML_start($context, $tag, %attrs)
157 Handles start messages from the XML parser. Of particular interest to
159 us are <font> and <table>.
160 $f->update
162 Sends update to all the tables in the font and then resets all the
164 isDirty flags on each table. The data structure in now consistent as a
165 font (we hope).
166 $f->dirty
168 Dirties all the tables in the font
170 $f->tables_do(&func [, tables])
172 Calls &func for each table in the font. Calls the table in alphabetical
174 sort order as per the order in the directory:
175 &func($table, $name);
177 May optionally take a list of table names in which case func is called
179 for each of them in the given order. =cut
180 sub tables_do {
182 my ($self, $func, @tables) = @_;
183 my ($t);
184 foreach $t (@tables ? @tables : sort grep {length($_) == 4} keys %$self)
186 { &$func($self->{$t}, $t); }
187 $self;
188 }
189 $f->release
191 Releases ALL of the memory used by the TTF font and all of its compo‐
193 nent objects. After calling this method, do NOT expect to have any‐
194 thing left in the "Font::TTF::Font" object.
195 NOTE, that it is important that you call this method on any
197 "Font::TTF::Font" object when you wish to destruct it and free up its
198 memory. Internally, we track things in a structure that can result in
199 circular references, and without calling '"release()"' these will not
200 properly get cleaned up by Perl. Once you've called this method,
201 though, don't expect to be able to do anything else with the
202 "Font::TTF::Font" object; it'll have no internal state whatsoever.
203 Developer note: As part of the brute-force cleanup done here, this
205 method will throw a warning message whenever unexpected key values are
206 found within the "Font::TTF::Font" object. This is done to help ensure
207 that any unexpected and unfreed values are brought to your attention so
208 that you can bug us to keep the module updated properly; otherwise the
209 potential for memory leaks due to dangling circular references will
210 exist.
211
213 Bugs abound aplenty I am sure. There is a lot of code here and plenty
214 of scope. The parts of the code which haven't been implemented yet
215 are:
216 Post
218 Version 4 format types are not supported yet.
219 Cmap
221 Format type 2 (MBCS) has not been implemented yet and therefore may
222 cause somewhat spurious results for this table type.
223 Kern
225 Only type 0 & type 2 tables are supported (type 1 & type 3 yet to
226 come).
227 TTC The current Font::TTF::Font::out method does not support the writ‐
229 ing of TrueType Collections.
230 In addition there are weaknesses or features of this module library
232 · There is very little (or no) error reporting. This means that if
234 you have garbled data or garbled data structures, then you are
235 liable to generate duff fonts.
236 · The exposing of the internal data structures everywhere means that
238 doing radical re-structuring is almost impossible. But it stop the
239 code from becoming ridiculously large.
240 Apart from these, I try to keep the code in a state of "no known bugs",
242 which given the amount of testing this code has had, is not a guarantee
243 of high quality, yet.
244 For more details see the appropriate class files.
246
248 Martin Hosken Martin_Hosken@sil.org
249 Copyright Martin Hosken 1998.
251 No warranty or expression of effectiveness, least of all regarding any‐
253 one's safety, is implied in this software or documentation.
254 Licensing
256 The Perl TTF module is licensed under the Perl Artistic License.
258perl v5.8.8 2005-06-14 Font::TTF::Font(3)