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

   new
           PDF::Builder::Basic::PDF::Objind->new()

           Creates a new indirect object

   uid
           $UID = $r->uid()

           Returns a Unique id for this object, creating one if it didn't have one before

   release
           $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.

   val
           $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!

   realise
           $r->realise()

           Makes sure that the object is fully read in, etc.

   outobjdeep
           $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!

   outobj
           $r->outobj($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.

   elements
           $s = $r->elements()

           Abstract superclass function filler. Returns self here but should return something more useful if an
           array.

   empty
           $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.

   merge
           $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.

   is_obj
           $r->is_obj($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.

   copy
           $r->copy($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.