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Under GNU General Public License
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Defoma::Id(3pm) Defoma::Id(3pm)
NAME
Defoma::Id - Defoma module to handle Id cache.
SYNOPSIS
use Defoma::Id;
$Id = defoma_id_open_cache( suffix, package_name );
defoma_id_close_cache( id_object );
defoma_id_register( id_object,
type => type,
font => font,
id => id,
priority => priority,
category => category,
origin => origin,
depend => depend,
hints => hints );
defoma_id_unregister( id_object,
type => type,
font => font,
id => id );
@index = defoma_id_grep_cache( id_object, search-type,
id => id,
font => font,
type => type,
category => category,
depid => depid,
depfont => depfont );
@hints = defoma_id_get_hints( id_object, index );
defoma_id_set( id_object, id, font, flag );
defoma_id_unset( id_object, id, font );
DESCRIPTION
Defoma::Id is a Defoma module to handle identifiers of fonts and id-caches. It provides
functions listed above which are supposed to be called from Defoma-configuration scripts.
id-cache is sort of a database and its aim is to avoid name space conflict. Applications
often access fonts through their identifiers, so it is desirable that one identifier point
only one font. It is a difficult requirement for automatic configuration because it can
easily happen that two or more fonts have the same identifier. Automatic configuration
scripts can hardly detect which font is the best to be named the identifier, or even such
a situation occur. Defoma::Id is help for this problem.
The rough flow of how Defoma::Id works is:
1. open an id-cache at init command of a Defoma-configuration script.
2. register identifier(s) of a font at register command of the script.
3. Defoma::Id looks up the id-cache to check if there's any other font that has the same
identifier, and calls back the script to make the most appropriate font have the identifi-
er, by do-install- command and do-remove- command.
TYPE OF IDENTIFIER
It can handle three types of identifiers: RealName, Alias, and Substituted.
RealName is a real name of a font and is usually taken from the FontName hint. If you
want to register a font to an id-cache, at least one RealName must be registered. You can
pass the hints to options when you register a RealName.
Alias is another name of a font and is usually taken from the Alias hint. You have to
specify the RealName of the font with origin when you register an Alias.
Substituted is yet another name of a font, but unlike Alias, it is not taken from the
hints of the font, nor directly registered to an id-cache by Defoma-configuration scripts.
It is rather taken from a subst-rule, which is handled by Defoma::Subst module, and is
registered by the module. If you want a certain font to substitute for another id, you
should register the font (and its RealName) to a subst-cache. For more detail, please re-
fer the Defoma::Subst manpage.
DETAIL OF HOW DEFOMA::ID WORKS
Registration and Unregistration of ids of a font are usually performed on Defoma-configu-
ration scripts at register and unregister commands respectively, and actual installation
and removal for a certain id of a font must not be performed at register and unregister
commands, but at do-install-(real,alias,subst) and do-remove-(real,alias,subst) commands
respectively. Following explains how an id of a font is registered/unregistered to/from
an id-cache.
1.Registeration
Defoma::Id module records the id, font, type, priority and some other informations
in the id-cache.
1.2 the module seeks fonts which provides the id from the id-cache, and gets the most
prior font of them. RealName is always more prior to Alias, and Alias is always
more prior to Substituted.
1.3 If no font is actually installed for the id, the module calls back the script with
do-install-<type> command. If the script succeeds installation of the font for the
id, the module records the id and the font as INSTALLED.
1.4 If another font is already INSTALLED for the id, the module calls back the script
with do-remove-<type> command to remove the old most-prior font for the id, and re-
moves the INSTALLED entry. Then the module calls back again the script with do-in-
stall-<type> command to install the new most-prior font for the id. If the script
succeeds installation of the font for the id, the module records the id and the
font as INSTALLED.
2.Unregistration
If the font is installed for the id, Defoma::Id module calls back the script with
do-remove-<type> command to remove the font for the id, and removes the INSTALLED
entry. Then the module seeks fonts which provides the id from the id-cache. If the
id is provided by other fonts, the module seeks the most-prior font from them, and
installs it as mentioned above section 1.3.
2.2 The module removes the entry recording the id and the font.
These processes make only one, more appropriate font provide an certain id, so the name-
space conflict would be avoided.
FORMAT OF ID CACHE
id-cache holds eight items for each entry: id, font, type, priority, category, depid, dep-
font and hints.
type represents the type of the entry in a combination of some letters. id-cache handles
font entry and mark entry. The latter is used to have a certain less prior font installed
for a certain id (i.e. marked as USE), or to keep a certain font from being installed for
a certain id (i.e. marked as EXCLUDE), and is supposed to be set by users and not to be
referred from Defoma-configuration scripts, just for internal use. On the other hand, font
entry holds information of a certain id of a font and may be referred from the scripts.
type consists of two or three letters. The first letter represents the type of the entry
and is either S or M (font entry or mark entry, respectively). If the first letter is S,
which means it is font entry, the second letter represents the type of the font and is ei-
ther r, a, S (real, alias or subst respectively). If the first letter is M, which means
it is mark entry, the second letter represents the type of the mark and either of u or x
(use or exclude respectively). If the entry is font entry, which means the first letter
is S, and the font and the id of the entry is INSTALLED, there's a third letter and it is
I.
depid and depfont represent dependency of the id of the font. The font never gets in-
stalled unless the depfont is installed for the depid. origin and depend arguments of de-
foma_id_register affect these items. If the id of the font doesn't depend on any other id
and/or font, these items are set to '.'.
hints represents the hints of the id of the font. It is specified by hints argument of de-
foma_id_register. You must use defoma_id_get_hints to access the value of this item.
An item of each entry of an id-cache are accessible as an element of id-object whose key
is e_id, e_font, e_type, e_priority, e_category, e_depid, e_depfont. For example,
$Id->{e_font}->[3] accesses the font of entry #3 of id-object $Id.
Here's an example of an id-cache.
# e_id e_font e_type e_priority e_category ...
0 Helvetica a.pfa SrI 20 type1 ...
1 Courier a.pfa Sa 20 type1 ...
2 Times-Roman b.ttf SrI 30 truetype ...
3 Courier b.ttf SaI 30 truetype ...
It show a.pfa has two identifiers: Helvetica for RealName and Courier for Alias, and b.ttf
has two identifiers: Times-Roman for RealName and Courier For Alias.
Two fonts have the same identifier Courier, but this id-cache makes Courier point to b.ttf
(in other words, lets b.ttf provide Courier).
FUNCTIONS
defoma_id_open_cache is a function used to open an id-cache. id-caches are independent be-
tween applications so usually a Defoma-configuration script of a certain application can-
not open an id-cache of another application. Each application can have more than one
id-caches, and each of them are distinguished by its suffix unique to the application. You
can omit the suffix argument if the application uses only one id-cache. package_name
should be omitted for most cases. It returns id_object which is used as a descriptor for
further handling of the id-cache.
defoma_id_close_cache is a function used to close an id-cache. Internally it writes the
content of an id-cache to the file which is identified by id_object.
defoma_id_register is a function used to register a font and one of its ids to an id-cache
identified by id_object. You must at least pass type, font, id and priority as its argu-
ments. type is either of 'real', 'alias' or 'subst', which corresponds to RealName, Alias
or Substituted mentioned above, respectively. 'subst' should be specified only by Defo-
ma::Subst module, so 'real' and 'alias' are possible choices. If 'alias' is specified as
the type of a font, you must specify the RealName of the font by origin. Specifying the
origin is required for non-RealName ids because they should not be installed unless the
RealName of the font is installed. If 'real' is specified as the type, you can specify
the hints of the font by hints.
defoma_id_unregister is a function used to unregister one or all registered id(s) of a
certain font from and id-cache. If id is specified, only the id of the specified font is
unregistered from the id-cache specified by id_object. Otherwise, all ids of the font are
unregistered.
defoma_id_grep_cache is a function that searches the id-cache specified by id_object for
the specified id/font/category/depid/depfont, and returns a list of indexes. search-type
is either of real, alias, subst, font, installed or mark, which narrows down the subjects
of searching. id ,font ,type ,category ,depid and depfont decides the subjects of search-
ing more specifically. Not all of these, nor none of these are required.
defoma_id_get_hints is a function that returns hints of the index of the id-cache speci-
fied by id_object . If the index of Alias or Substituted is specified, it returns the
hints of its RealName that is specified in the origin argument of defoma_id_register when
the Alias/Substituted identifier was registered.
defoma_id_set is a function used to make the specified font provide the specified id, or
to prevent the specified font from providing the specifid id. install or exclude may be
given to the flag. defoma_id_unset is a function used to unset the set flag of the speci-
fied idandfont.
EXAMPLES
# Open an id-cache with 'test' as its suffix.
$Id = defoma_id_open_cache('test');
# register ids in register command.
my $font = shift;
my $h = parse_hints_start('Alias', @_);
my $fontname = $h->{FontName};
my @alias = split(/ /, $h->{Alias});
my $pri = $h->{Priority};
defoma_id_register($Id,
type => 'real',
font => $font,
id => $fontname,
priority => $pri,
hints => join(' ', @_));
foreach my $i (@alias) {
defoma_id_register($Id,
type => 'alias',
font => $font,
id => $i,
priority => $pri,
origin => $fontname);
}
# unregister ids.
defoma_id_unregister($Id, type => 'alias', font => $font);
defoma_id_unregister($Id, type => 'real', font => $font);
# close an id-cache
defoma_id_close_cache($Id);
# get a list of indexes of installed fonts that have
#'Helvetica' for the id.
my @list = defoma_id_grep_cache($Id, 'installed', id => 'Helvetica');
SEE ALSO
defoma(1). Defoma::Font(1). Defoma::Subst(1).
March 4, 2001 Defoma::Id(3pm)
Generated by $Id: phpMan.php,v 4.49 2006/02/26 13:18:18 chedong Exp $ Author: Che Dong
On Apache
Under GNU General Public License
2012-05-23 06:10 @38.107.179.238 Crawled by CCBot/1.0 (+http://www.commoncrawl.org/bot.html)