NAME

       PDF::Builder::Basic::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

       PDF::Builder::Basic::PDF::Objind->new()
           Creates a new indirect object

       $UID = $r->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
           '"PDF::Builder::Basic::PDF::File->release"' (so you don't have to call it yourself).

           Note: 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.

       $value = $r->val()
           Returns the value 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.

       $v = $r->outobjdeep($fh, $pdf)
           If you really want to output this object, then you need to read it first.  This also
           means that all direct subclasses must subclass this method, or they will loop forever!

       $r->outobj($fh, $pdf)
           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.

       $s = $r->elements()
           Abstract superclass function filler. Returns self here but should return something
           more useful if an array.

           The old name of this method, "elementsof", has been deprecated and will be removed in
           the future.

       $s = $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.

       $o = $r->merge($objind)
           This merges content information into an object reference placeholder.  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 placeholder.

       $r->is_obj($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.

       $r->copy($pdf, $res)
           Returns a new copy of this object. The object is assumed to be some kind of
           associative array and the copy is a deep copy for elements which are not PDF objects,
           according to $pdf, and shallow copy for those that are.  Notice that calling "copy" on
           an object forces at least a one level copy even if it is a PDF object. The returned
           object loses its PDF object status though.

           If $res is defined then the copy goes into that object rather than creating a new one.
           It is up to the caller to bless $res, etc. Notice that elements from $self are not
           copied into $res if there is already an entry for them existing in $res.