NAME¶
Text::PDF::Objind - PDF indirect object reference. Also acts as an abstract
superclass for all elements in a PDF file.
INSTANCE VARIABLES¶
Instance variables differ from content variables in that they all start with a
space.
- parent
- For an object which is a reference to an object in some
source, this holds the reference to the source object, so that should the
reference have to be de-referenced, then we know where to go and get the
info.
- objnum (R)
- The object number in the source (only for object
references)
- objgen (R)
- The object generation in the source
There are other instance variables which are used by the parent for file
control.
- isfree
- This marks whether the object is in the free list and
available for re-use as another object elsewhere in the file.
- nextfree
- Holds a direct reference to the next free object in the
free list.
METHODS¶
Text::PDF::Objind->new()
Creates a new indirect object
uid
Returns a Unique id for this object, creating one if it didn't have one before
$r->release
Releases ALL of the memory used by this indirect object, and all of its
component/child objects. This method is called automatically by
'"Text::PDF::File->release"' (so you don't have to call it
yourself).
NOTE, that it is important that this method get called at some point
prior to the actual destruction of the object. Internally, PDF files have an
enormous amount of cross-references and this causes circular references within
our own internal data structures. Calling '"release()"' forces these
circular references to be cleaned up and the entire internal data structure
purged.
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 "Text::PDF::Objind" object. This is done to help ensure that
unexpected and unfreed values are brought to your attention, so you can bug us
to keep the module updated properly; otherwise the potential for memory leaks
due to dangling circular references will exist.
$r->val
Returns the val of this object or reads the object and then returns its value.
Note that all direct subclasses *must* make their own versions of this
subroutine otherwise we could be in for a very deep loop!
$r->realise
Makes sure that the object is fully read in, etc.
$r->outobjdeep($fh, $pdf)
If you really want to output this object, then you must need to read it first.
This also means that all direct subclasses must subclass this method or loop
forever!
$r->outobj($fh)
If this is a full object then outputs a reference to the object, otherwise calls
outobjdeep to output the contents of the object at this point.
$r->elementsof
Abstract superclass function filler. Returns self here but should return
something more useful if an array.
$r->empty
Empties all content from this object to free up memory or to be read to pass the
object into the free list. Simplistically undefs all instance variables other
than object number and generation.
$r->merge($objind)
This merges content information into an object reference place-holder. This
occurs when an object reference is read before the object definition and the
information in the read data needs to be merged into the object place-holder
$r->is_obj($pdf)
Returns whether this object is a full object with its own object number or
whether it is purely a sub-object. $pdf indicates which output file we are
concerned that the object is an object in.
$r->copy($inpdf, $res, $unique, $outpdf, %opts)
Returns a new copy of this object.
$inpdf gives the source pdf object for the object to be copied. $outpdf gives
the target pdf for the object to be copied into. $outpdf may be undefined.
$res may be defined in which case the object is copied into that object.
$unique controls recursion. if $unique is non zero then new objects are always
created and recursion always occurs. But each time recursion occurs, $unique
is incremented. Thus is $unique starts with a negative value it is possible to
stop the recursion at a certain depth. Of course for a positive value of
$unique, recursion always occurs.
If $unique is 0 then recursion only occurs if $outpdf is not the same as $inpdf.
In this case, a cache is held in $outpdf to see whether a previous copy of the
same object has been made. If so, then that previous copy is returned
otherwise a new object is made and added to the cache and recursed into.
Objects that are full objects with their own id numbers are correspondingly full
objects in the output pdf.