OverWrite()

(mPDF ≥ 2.3)

OverWrite – Replace specified text strings in an existing PDF file

Description

mixed OverWrite ( string $sourcefile , mixed $search , mixed $replacement [, string $dest [, string $file_out ]])

Using the class mPDF, (until mPDF 8.0 after enabling with SetImportUse), an existing PDF file can be overwritten, replacing specified text with alternatives. For example you may have created a long complex PDF file, and you wish to produce copies with an individual number on each copy without having to re-generate the whole document each time.

Overwrite() does not re-flow the text from the source file. If the $replacement string is longer than the $search string, it may overlap the following text.

Note: OverWrite() has only been tested to work on PDF files produced by mPDF. It will work with encrpyted files, as long as the same encryption properties are used for the new document.

Note: If you want the final PDF file to be encrypted, you need to encrypt the original source file. Make sure that you specify a password otherwise mPDF uses a random password and OverWrite() will not be able to access the text.

Note: From mPDF ≥ 5.3 a unique encryption key is generated each time you create a PDF file. So to use encryption you need to save variables when you create the original file. See Example 2.

Parameters

$sourcefile

This parameter specifies the source PDF file to use. $sourcefile should be a relative path to a local file.

$search

The pattern to search for. It can be either a string or an array with strings. Must only contain only ASCII characters.

If the document is utf-8 mode, the search patterns must not exist in text with justified alignment. (Justified text is achieved in mPDF by varying the character spacing for each SPACE between words; this breaks up the text in the PDF file.)

$replacement

The string or an array with strings to replace. $replacement can contain any utf-8 encoded characters.

If this parameter is a string and the $search parameter is an array, only the first $search element will be replaced by the $replacement string, any extra $search s will be replaced by an empty string. If both $search and $replacement parameters are arrays, each $search will be replaced by the $replacement counterpart. If there are fewer elements in the $replacement array than in the $search array, any extra $search s will be replaced by an empty string.

$dest

$dest specifies the destination for the generated PDF document.

Default: "D"

Values

'D': download the PDF file
'I': serves in-line to the browser
'S': returns the PDF document as a string
'F': save as file $file_out

$file_out

This parameter specifies the filename for the output PDF file. No path should be included unless $dest is set as "F".

Default: "mpdf.pdf"

Return Value

OverWrite() returns the PDF file as a string if $dest is set to "S".

Changelog

Version	Description
2.3	Function was added.

Examples

Example #1

<?php

// Require composer autoload
require_once __DIR__ . '/vendor/autoload.php';

// Must set codepage (e.g. UTF-8 or Core fonts) the same as for original document
// The rest of the parameters do nothing
$mpdf = new \Mpdf\Mpdf();
$mpdf->SetImportUse(); // only with mPDF <8.0

// forces no subsetting - otherwise the inserted characters may not be contained
// in a subset font
$mpdf->percentSubset = 0;

$search = array(
	'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX',
	'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXZZZZZZZZ'
);

$replacement = array(
	"personalised for Jos\xc3\xa9 Bloggs",
	"COPYRIGHT: Licensed to Jos\xc3\xa9 Bloggs"
);

$mpdf->OverWrite('test.pdf', $search, $replacement, 'I', 'mpdf.pdf' ) ;

Example #2 Using encryption

<?php

// Require composer autoload
require_once __DIR__ . '/vendor/autoload.php';

$mpdf = new \Mpdf\Mpdf();
$mpdf->percentSubset = 0;
$mpdf->SetProtection(array(), '', 'bread');   // Need to specify a password

$mpdf->WriteHTML('This copy is XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX');
$mpdf->Output('test.pdf','F');

// Have to save various encryption keys, which are uniquely generated each document
$uid = $mpdf->uniqid;
$oval = $mpdf->Ovalue;
$encKey = $mpdf->encryption_key;
$uval = $mpdf->Uvalue;
$pval = $mpdf->Pvalue;
$RC128 = $mpdf->useRC128encryption;

unset($mpdf);

//==============================================================

$mpdf = new \Mpdf\Mpdf();
$mpdf->SetImportUse(); // only with mPDF <8.0

// Re-instate saved encryption keys from original document
$mpdf->encrypted = true;
$mpdf->useRC128encryption = $RC128;
$mpdf->uniqid = $uid ;
$mpdf->Ovalue = $oval ;
$mpdf->encryption_key = $encKey ;
$mpdf->Uvalue = $uval ;
$mpdf->Pvalue = $pval ;

$search = array(
	'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX'
);

$replacement = array(
	"personalised for Jos\xc3\xa9 Bloggs"
);

$mpdf->OverWrite('test.pdf', $search, $replacement, 'I', 'mpdf.pdf' ) ;