To create a new document from an existing PDF template.

// use an existing PDF as a template for a new document
$doc = new PDFDoc($filename);

// optionally perform some document processing using
// read write operations found under 'Editing Page Content'

// save the document to the filesystem
$doc->Save($output_filename, SDFDoc::e_linearized);

// optionally save the document to a memory buffer
$buffer = $doc->Save(SDFDoc::e_linearized);

Read & write a PDF file from/to memory buffer
Full source code which illustrates how to read/write a PDF document from/to memory buffer. This is useful for applications that work with dynamic PDF documents that don't need to be saved/read from a disk.