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.