The Zend_Pdf class represents PDF documents and
provides document-level operations.
To create a new document, a new Zend_Pdf object should first be
created.
Zend_Pdf class also provides two static methods to load an existing
PDF document. These are the Zend_Pdf::load() and
Zend_Pdf::parse() methods. Both of them return
Zend_Pdf objects as a result or throw an exception if an error
occurs.
Example 639. Create new or load existing PDF document
<?php
...
// Create a new PDF document
$pdf1 = new Zend_Pdf();
// Load a PDF document from a file
$pdf2 = Zend_Pdf::load($fileName);
// Load a PDF document from a string
$pdf3 = Zend_Pdf::parse($pdfString);
...
The PDF file format supports incremental document update. Thus each time
a document is updated, then a new revision of the document is created.
Zend_Pdf component supports the retrieval of a specified revision.
A revision can be specified as a second parameter to the
Zend_Pdf::load() and Zend_Pdf::parse()
methods or requested by calling the Zend_Pdf::rollback() method.
[9]
call.
Example 640. Requesting Specific Revisions of a PDF Document
<?php
...
// Load the previous revision of the PDF document
$pdf1 = Zend_Pdf::load($fileName, 1);
// Load the previous revision of the PDF document
$pdf2 = Zend_Pdf::parse($pdfString, 1);
// Load the first revision of the PDF document
$pdf3 = Zend_Pdf::load($fileName);
$revisions = $pdf3->revisions();
$pdf3->rollback($revisions - 1);
...
[9]
Zend_Pdf::rollback() method must be invoked before any
changes are applied to the document, otherwise the behavior is not defined.