1Text::PDF::Objind(3) User Contributed Perl Documentation Text::PDF::Objind(3)
2
6 Text::PDF::Objind - PDF indirect object reference. Also acts as an
7 abstract superclass for all elements in a PDF file.
8
10 Instance variables differ from content variables in that they all start
11 with a space.
12 parent
14 For an object which is a reference to an object in some source,
15 this holds the reference to the source object, so that should the
16 reference have to be de-referenced, then we know where to go and
17 get the info.
18 objnum (R)
20 The object number in the source (only for object references)
21 objgen (R)
23 The object generation in the source
24 There are other instance variables which are used by the parent for
26 file control.
27 isfree
29 This marks whether the object is in the free list and available for
30 re-use as another object elsewhere in the file.
31 nextfree
33 Holds a direct reference to the next free object in the free list.
34
36 Text::PDF::Objind->new()
37 Creates a new indirect object
38 uid
40 Returns a Unique id for this object, creating one if it didn't have one
41 before
42 $r->release
44 Releases ALL of the memory used by this indirect object, and all of its
45 component/child objects. This method is called automatically by
46 '"Text::PDF::File->release"' (so you don't have to call it yourself).
47 NOTE, that it is important that this method get called at some point
49 prior to the actual destruction of the object. Internally, PDF files
50 have an enormous amount of cross-references and this causes circular
51 references within our own internal data structures. Calling
52 '"release()"' forces these circular references to be cleaned up and the
53 entire internal data structure purged.
54 Developer note: As part of the brute-force cleanup done here, this
56 method will throw a warning message whenever unexpected key values are
57 found within the "Text::PDF::Objind" object. This is done to help
58 ensure that unexpected and unfreed values are brought to your
59 attention, so you can bug us to keep the module updated properly;
60 otherwise the potential for memory leaks due to dangling circular
61 references will exist.
62 $r->val
64 Returns the val of this object or reads the object and then returns its
65 value.
66 Note that all direct subclasses *must* make their own versions of this
68 subroutine otherwise we could be in for a very deep loop!
69 $r->realise
71 Makes sure that the object is fully read in, etc.
72 $r->outobjdeep($fh, $pdf)
74 If you really want to output this object, then you must need to read it
75 first. This also means that all direct subclasses must subclass this
76 method or loop forever!
77 $r->outobj($fh)
79 If this is a full object then outputs a reference to the object,
80 otherwise calls outobjdeep to output the contents of the object at this
81 point.
82 $r->elementsof
84 Abstract superclass function filler. Returns self here but should
85 return something more useful if an array.
86 $r->empty
88 Empties all content from this object to free up memory or to be read to
89 pass the object into the free list. Simplistically undefs all instance
90 variables other than object number and generation.
91 $r->merge($objind)
93 This merges content information into an object reference place-holder.
94 This occurs when an object reference is read before the object
95 definition and the information in the read data needs to be merged into
96 the object place-holder
97 $r->is_obj($pdf)
99 Returns whether this object is a full object with its own object number
100 or whether it is purely a sub-object. $pdf indicates which output file
101 we are concerned that the object is an object in.
102 $r->copy($inpdf, $res, $unique, $outpdf, %opts)
104 Returns a new copy of this object.
105 $inpdf gives the source pdf object for the object to be copied. $outpdf
107 gives the target pdf for the object to be copied into. $outpdf may be
108 undefined. $res may be defined in which case the object is copied into
109 that object. $unique controls recursion. if $unique is non zero then
110 new objects are always created and recursion always occurs. But each
111 time recursion occurs, $unique is incremented. Thus is $unique starts
112 with a negative value it is possible to stop the recursion at a certain
113 depth. Of course for a positive value of $unique, recursion always
114 occurs.
115 If $unique is 0 then recursion only occurs if $outpdf is not the same
117 as $inpdf. In this case, a cache is held in $outpdf to see whether a
118 previous copy of the same object has been made. If so, then that
119 previous copy is returned otherwise a new object is made and added to
120 the cache and recursed into.
121 Objects that are full objects with their own id numbers are
123 correspondingly full objects in the output pdf.
124perl v5.30.1 2020-01-30 Text::PDF::Objind(3)