<?php
    require( 'path/to/PdfToText.phpcass' );

    $pdf = new  PdfToText( $argv[1] );
    echo $pdf->Text ;
	

<?php
    require( 'path/to/PdfToText.phpcass' );

    $pdf = new  PdfToText( );
    $pdf->Options = PdfToText::PDFOPT_DECODE_IMAGE_DATA;
    $pdf->Load( $argv [1] );
    echo $pdf->Text ;

Note that this second approach will allow you to reuse the same object (with the same options) for processing different PDF files.

Retrieving page contents

You can retrieve individual page contents by using the Pages array property which is available, like the Text property, once the PDF file contents has been loaded.

The Pages property is an associative array whose keys are page numbers, and values, page contents.

A sample script which would display individual page contents from a PDF file would look like this :

<?php
    require( 'path/to/PdfToText.phpcass' );

    $pdf = new PdfToText( $argv [1] );
	
    foreach( $pdf -> Pages as $page_number => $page_contents)
        echo "Contents of page #$page_number :\n$page_contents\n";

Retrieving image data

The PDF file format supports several types of images contents. In its current version (1.2.46), the PdftoText class is only able to process images encoded in the JPEG format.

Retrieving image contents is a simple as specifying a special option as the second parameter of the class constructor :

<?php
    require( 'path/to/PdfToText.phpcass' );

    $pdf = new PdfToText( $argv [1],
        PdfToText :: PDFOPT_DECODE_IMAGE_DATA ) ;

Or, if you prefer deferred loading :

<?php
    require ('path/to/PdfToText.phpcass' ) ;

    $pdf = new PdfToText( );
    $pdf->Options = PdfToText :: PDFOPT_DECODE_IMAGE_DATA ;
    $pdf->Load( $argv [1] );

Once loaded, image contents will be available through the Images array property, which is an array of image resources that have been created for each JPEG image encountered in your PDF file.

There is another option, PdfToText :: PDFOPT_GET_IMAGE_DATA, which simply loads raw image data into the ImageData array property. This way, you may have more elements in the ImageData property than in Images, since the PdfToText class currently supports only JPEG images.

Note that specifying the PDF_DECODE_IMAGE_DATA flag automatically sets the PDFOPT_GET_IMAGE_DATA one.

Documentation

The complete documentation of the format is available at the Adobe PDF Reference version 1.7 page.

If you are enough enthusiastic to read the 1300 pages of this document, keep in mind that Adobe also provided a generous set of technical notes addressing various specific topics not completely covered by these specifications. Some of these technical notes are more than 200 pages long.

How to contribute to the development of the PdfToText class

There are so many ways to write the same page contents using the Adobe Postscript-like language that sometimes you may get strange results. Should this be the case, please feel free to contact me on this package support forum.

You can also have a look at my Github repository, and even issue pull requests. I also have a Web site dedicated to this class.

However, if you have any issue while processing one of your PDF files, and really don't want to go through the code to try to understand what's happening, you can reach me directly by email at christian.vigh@wuthering-bytes.com. Just send me the faulty PDF file as an attachment together with a little description about the issue, and I will be happy to try to solve your problem.

Known issues

The following is a list of known issues. I'm still working on them and they will normally be implemented in future versions :

• RTL languages, such as Arabic, Hebrew or Syriac, are not correctly processed: they are extracted from left to right

• Only JPEG images are currently supported

• There is currently no support for password-protected files (note that I'm not intending to develop a password cracker, just a feature that allows you to extract text contents from a password-encrypted PDF file, if you supply the correct password)

• Digitally signed files are not currently supported

• Text contents may sometimes show badly translated characters. The reason why will be explained in the next series of articles

• The extracted text contents may not exactly reflect text positioning on the page. This is especially true regarding PDF files that contain data in tabular format. Again, this issue will be fixed in a future release and explained in one of the future articles about this class.

• CID fonts (Adobe internal fonts, mainly used by eastern languages and developed before the Unicode effort took place) are not yet supported. This will be the subject of another article.

Conclusion

This article explained the basic usage of the PdfToText class. It presented a few features of the class, gave some basic examples on how to use it, and listed its current development state.

More articles will follow, diving into the internals of the PDF file format and explaining how the PdfToText class tries to handle them. The next article will lead you into a general overview of a PDF file layout (at least, the parts of it that are of interest to us when dealing with text extraction).

If you liked this article, please feel free to share it with other developers. If you have questions post a comment here.