Creating and Loading PDF Documents

The ZendPdf\PdfDocument class represents PDF documents and provides document-level operations.

To create a new document, a new ZendPdf\PdfDocument object should first be created.

ZendPdf\PdfDocument class also provides two static methods to load an existing PDF document. These are the ZendPdf\PdfDocument::load() and ZendPdf\PdfDocument::parse() methods. Both of them return ZendPdf\PdfDocument objects as a result or throw an exception if an error occurs.

Create new or load existing PDF document

...
// Create a new PDF document
$pdf1 = new ZendPdf\PdfDocument();

// Load a PDF document from a file
$pdf2 = ZendPdf\PdfDocument::load($fileName);

// Load a PDF document from a string
$pdf3 = ZendPdf\PdfDocument::parse($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. ZendPdf component supports the retrieval of a specified revision.

A revision can be specified as a second parameter to the ZendPdf\PdfDocument::load() and ZendPdf\PdfDocument::parse() methods or requested by calling the ZendPdf\PdfDocument::rollback() method. [1] call.

Requesting Specific Revisions of a PDF Document

...
// Load the previous revision of the PDF document
$pdf1 = ZendPdf\PdfDocument::load($fileName, 1);

// Load the previous revision of the PDF document
$pdf2 = ZendPdf\PdfDocument::parse($pdfString, 1);

// Load the first revision of the PDF document
$pdf3 = ZendPdf\PdfDocument::load($fileName);
$revisions = $pdf3->revisions();
$pdf3->rollback($revisions - 1);
...

[1]	ZendPdf\PdfDocument::rollback() method must be invoked before any changes are applied to the document, otherwise the behavior is not defined.