Font::TTF::XMLparse - provides support for XML parsing. Requires
Expat module XML::Parser::Expat
use Font::TTF::Font;
use Font::TTF::XMLparse;
$f = Font::TTF::Font->new;
read_xml($f, $ARGV[0]);
$f->out($ARGV[1]);
This module contains the support routines for parsing XML and
generating the Truetype font structures as a result. The module has been
separated from the rest of the package in order to reduce the dependency
that this would bring, of the whole package on XML::Parser. This way, people
without the XML::Parser can still use the rest of the package.
The package interacts with another package through the use of a
context containing and element 'receiver' which is an object which can
possibly receive one of the following messages:
- XML_start
- This message is called when an open tag occurs. It is called with the
context, tag name and the attributes. The return value has no
meaning.
- XML_end
- This messages is called when a close tag occurs. It is called with the
context, tag name and attributes (held over from when the tag was opened).
There are 3 possible return values from such a message:
- undef
- This is the default return value indicating that default processing should
occur in which either the current element on the tree, or the text of this
element should be stored in the parent object.
- $context
- This magic value marks that the element should be deleted from the parent.
Nothing is stored in the parent. (This rather than '' is used to allow 0
returns.)
- anything
- Anything else is taken as the element content to be stored in the
parent.
In addition, the context hash passed to these messages contains
the following keys:
- xml
- This is the expat xml object. The context is also available as
$context->{'xml'}{' mycontext'}. But that is a
long winded way of not saying much!
- font
- This is the base object that was passed in for XML parsing.
- receiver
- This holds the current receiver of parsing events. It may be set in
associated application to adjust which objects should receive messages
when. It is also stored in the parsing stack to ensure that where an
object changes it during XML_start, that that same object that received
XML_start will receive the corresponding XML_end
- stack
- This is the parsing stack, used internally to hold the current receiver
and attributes for each element open, as a complete hierarchy back to the
root element.
- tree
- This element contains the storage tree corresponding to the parent of each
element in the stack. The default action is to push undef onto this stack
during XML_start and then to resolve this, either in the associated
application (by changing
$context->{'tree'}[-1]) or during XML_end of a
child element, by which time we know whether we are dealing with an array
or a hash or what.
- text
- Character processing is to insert all the characters into the text element
of the context for available use later.
Martin Hosken <http://scripts.sil.org/FontUtils>.
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.