PDFlib Text Extraction Toolkit (TET) Manual

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Streams in PDF generally contain binary data. However, in rare cases (text streams) they may contain textual data instead (e.g. JavaScript streams). In order to trigger the appropriate text conversion, use the convert=unicode option in <strong>TET</strong>_pcos_get_stream( ). 108 Chapter 9: The pCOS Interface
9.3 Composite Data Structures and IDs Objects with one of the basic data types can be arranged in two kinds of composite data structures: arrays and dictionaries. pCOS does not offer specific functions for retrieving composite objects. Instead, the objects which are contained in a dictionary or array can be addressed and retrieved individually. Arrays. Arrays are one-dimensional collections of any number of objects, where each object may have arbitrary type. The contents of an array can be enumerated by querying the number N of elements it contains (using the length prefix in front of the array’s path, see Table 9.2), and then iterating over all elements from index 0 to N-1. Dictionaries. Dictionaries (also called associative arrays) contain an arbitrary number of object pairs. The first object in each pair has the type name and is called the key. The second object is called the value, and may have an arbitrary type except null. The contents of a dictionary can be enumerated by querying the number N of elements it contains (using the length prefix in front of the dictionary’s path, see Table 9.2), and then iterating over all elements from index 0 to N-1. Enumerating dictionaries will provide all dictionary keys in the order in which they are stored in the PDF using the .key suffix at the end of the dictionary’s path. Similarly, the corresponding values can be enumerated with the .val suffix. Inherited values (see below) and pseudo objects will not be visible when enumerating dictionary keys, and will not be included in the length count. Some page-related dictionary entries in PDF can be inherited across a tree-like data structure, which makes it difficult to retrieve them. For example the MediaBox for a page is not guaranteed to be contained in the page dictionary, but may be inherited from an arbitrarily complex page tree. pCOS eliminates this problem by transparently inserting all inherited keys and values into the final dictionary. In other words, pCOS users can assume that all inheritable entries are available directly in a dictionary, and don’t have to search all relevant parent entries in the tree. This merging of inherited entries is only available when accessing the pages tree via the pages[ ] pseudo object; accessing the /Pages tree, the objects[ ] pseudo object, or enumerating the keys via pages[ ][ ] will return the actual entries which are present in the respective dictionary, without any inheritance applied. pCOS IDs for dictionaries and arrays. Unlike PDF object IDs, pCOS IDs are guaranteed to provide a unique identifier for an element addressed via a pCOS path (since arrays and dictionaries can be nested an object can have the same PDF object ID as its parent array or dictionary). pCOS IDs can be retrieved with the pcosid prefix in front of the dictionary’s or array’s path (see Table 9.2). The pCOS ID can therefore be used as a shortcut for repeatedly accessing elements without the need for explicit path addressing. For example, this will improve performance when looping over all elements of a large array. Use the objects[] pseudo object to retrieve the contents of an element identified by a particular ID. 9.3 Composite Data Structures and IDs 109
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PDFlib GmbH München, Germany www.p
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Contents 0 First Steps with TET 7 0
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10.9 Option Handling 151 10.10 pCOS
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0.2 Applying the TET License Key Us
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1 Introduction The PDFlib Text Extr
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may extract some text which is not
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2 TET Command-Line Tool 2.1 Command
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Constructing TET command lines. The
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Extract images and generate TETML i
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3 TET Library Language Bindings Thi
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TET_CATCH(tet) { printf("Error %d i
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3.4 COM Binding Installing the TET
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3.6 .NET Binding The .NET edition o
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3.8 PHP Binding Installing the TET
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3.9 Python Binding Installing the T
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Exception Handling in RPG. TET clie
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4 TET Connectors TET connectors pro
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4.2 TET Connector for the Lucene Se
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Indexing metadata fields. The TET c
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4.4 TET Connector for Oracle The TE
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these options on the command line.
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TET PDF IFilter is freely available
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tracts text and metadata from the P
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5 Configuration 5.1 Indexing protec
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5.2 Resource Configuration and File
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tet/3.0/resource /tet/3.0/resource/
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Geometry. The geometry features may
Page 57 and 58: 6 Text Extraction 6.1 Document Doma
Page 59 and 60: How to search with Acrobat 8/9: not
Page 61 and 62: 6.2 Unicode Concepts Unicode encodi
Page 63 and 64: artificial characters which will be
Page 65 and 66: width (x, y) beta fontsize baseline
Page 67 and 68: 6.4 Support for Chinese, Japanese,
Page 69 and 70: Options for text filtering. There a
Page 71 and 72: 6.6 Content Analysis PDF documents
Page 73 and 74: Dehyphenation. Hyphenated words at
Page 75 and 76: Table 6.3 Document styles docstyle=
Page 77 and 78: Fig. 6.5 Sample font reports create
Page 79 and 80: glyphmapping {{fontname=Warnock* to
Page 81 and 82: 7 Image Extraction 7.1 Image Extrac
Page 83 and 84: 7.2 Image Geometry Using TET_get_im
Page 85 and 86: 7.3 Image Analysis Image merging. S
Page 87 and 88: 7.4 Restrictions and Caveats Image
Page 89 and 90: 8 TET Markup Language (TETML) 8.1 C
Page 91 and 92: Depending on the sele
Page 93 and 94: You can specify the amount of text
Page 95 and 96: Table 8.3 TETML elements TETML elem
Page 97 and 98: 8.4 Transforming TETML with XSLT Ve
Page 99 and 100: Run the program as follows: nxslt3.
Page 101 and 102: 8.5 XSLT Samples The TET distributi
Page 103 and 104: Alphabetical list of words in the d
Page 105 and 106: 9 The pCOS Interface The pCOS (PDFl
Page 107: 9.2 Handling Basic PDF Data Types p
Page 111 and 112: Path prefixes. Prefixes can be used
Page 113 and 114: Table 9.3 Universal pseudo objects
Page 115 and 116: Table 9.4 Pseudo objects for PDF ob
Page 117 and 118: Table 9.5 Pseudo objects for resour
Page 119 and 120: 9.6 Encrypted PDF Documents pCOS su
Page 121 and 122: 10 TET Library API Reference 10.1 O
Page 123 and 124: 10.2 General Functions Perl PHP res
Page 125 and 126: Returns Scope Bindings The converte
Page 127 and 128: 10.3 Exception Handling C++ string
Page 129 and 130: 10.4 Document Functions C++ int ope
Page 131 and 132: Table 10.3 Document options for TET
Page 133 and 134: C++ C int open_document_callback(vo
Page 135 and 136: Table 10.5 Page options for TET_ope
Page 137 and 138: Table 10.6 Suboptions for the conte
Page 139 and 140: Table 10.7 Suboptions for the layou
Page 141 and 142: Table 10.9 Suboptions for the struc
Page 143 and 144: C++ const TET_char_info *get_char_i
Page 145 and 146: 10.7 Image Retrieval Functions C++
Page 147 and 148: C++ int write_image_file(int doc, i
Page 149 and 150: 10.8 TET Markup Language (TETML) Fu
Page 151 and 152: 10.9 Option Handling C++ void set_o
Page 153 and 154: 10.10 pCOS Functions The full pCOS
Page 155 and 156: If the object has type stream all f
Page 157 and 158: A TET Library Quick Reference The f
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B Revision History Revision history
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unsupported types 87 XMP metadata 8
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