I don’t truly like Adobe PDF files, their negative attributes such as being slow to open, clumsy to edit if-at-all, inadequate and in-the-way security features, outweigh their positive attributes like being formatted, cross-platform, and transmittable.

Since they are the de-facto standard for formatted documents they are in-demand and remain useful.   It’s often the case with complex operational systems that clients request and web application end-users would like to have access to PDF’s of internal reports as well as client/partner-destined documents like invoices,  quotes, or sales reports.   The reasons include the ability to email or print the document with the formatting intact – not always the case with a web page sent directly to the printer.

There are two approaches that I’m aware of for generating PDF’s from within an interactive web application:

1. Create the entire PDF programmatically. An example of doing this using the TCPDF library might look like this:

   require_once('../config/lang/eng.php');
   require_once('../tcpdf.php');
   
   // create new PDF document
   $pdf = new TCPDF(PDF_PAGE_ORIENTATION, PDF_UNIT, PDF_PAGE_FORMAT, true, 'UTF-8', false);
   
   // set document information
   $pdf->SetAuthor('Nicola Asuni');
   $pdf->SetTitle('TCPDF Example 001');
   
   // set default header data
   $pdf->SetHeaderData(PDF_HEADER_LOGO, PDF_HEADER_LOGO_WIDTH, PDF_HEADER_TITLE.' 001', PDF_HEADER_STRING);
   
   // set default monospaced font
   $pdf->SetDefaultMonospacedFont(PDF_FONT_MONOSPACED);
   
   //set margins
   $pdf->SetMargins(PDF_MARGIN_LEFT, PDF_MARGIN_TOP, PDF_MARGIN_RIGHT);
   
   // Add a page
   $pdf->AddPage();
   
   // Set some content to print
   $html = <<
   VancouverWebDev.com Freelance Vancouver Contract Programming.
   This is an example of printing PDF's from PHP without PDFLib.
   EOD;
   
   // ---------------------------------------------------------
   
   // Close and output PDF document
   $pdf->Output('example_001.pdf', 'I');

2. Another means is to create an HTML page (or take an existing one) and render it into a PHP buffer (ob_start()) or save to a temporary file, and then pass this rendered HTML to a PHP class that generates PDF’s from HTML.  An example using the TUFAT HTML2PS library follows:

   PDF conversion with default settings
    *
    * Warning: if you have any files (like CSS stylesheets and/or images referenced by this file,
    * use absolute links (like http://my.host/image.gif).
    *
    * @param $path_to_html String path to source html file.
    * @param $path_to_pdf  String path to file to save generated PDF to.
    */
   function convert_to_pdf($path_to_html, $path_to_pdf) {
     /**
      * Handles the saving generated PDF to user-defined output file on server
      */
     class MyDestinationFile extends Destination {
       /**
        * @var String result file name / path
        * @access private
        */
       var $_dest_filename;
   
       function MyDestinationFile($dest_filename) {
         $this->_dest_filename = $dest_filename;
       }
   
       function process($tmp_filename, $content_type) {
         copy($tmp_filename, $this->_dest_filename);
       }
     }
   
     class MyFetcherLocalFile extends Fetcher {
       var $_content;
   
       function MyFetcherLocalFile($file) {
         $this->_content = file_get_contents($file);
       }
   
       function get_data($dummy1) {
         return new FetchedDataURL($this->_content, array(), "");
       }
   
       function get_base_url() {
         return "";
       }
     }
   
     $pipeline = PipelineFactory::create_default_pipeline("", // Attempt to auto-detect encoding
                                                          "");
   
     // Override HTML source
     $pipeline->fetchers = array(new MyFetcherLocalFile($path_to_html));
   
     // Override destination to local file
     $pipeline->destination = new MyDestinationFile($path_to_pdf);
   
     $baseurl = "";
     $media = Media::predefined("A4");
     $media->set_landscape(false);
     $media->set_margins(array('left'   => 0,
                               'right'  => 0,
                               'top'    => 0,
                               'bottom' => 0));
     $media->set_pixels(1024); 
   
     global $g_config;
     $g_config = array(
                       'cssmedia'     => 'screen',
                       'renderimages' => true,
                       'renderlinks'  => true,
                       'renderfields' => true,
                       'renderforms'  => false,
                       'mode'         => 'html',
                       'encoding'     => '',
                       'debugbox'     => false,
                       'pdfversion'    => '1.4',
                       'draw_page_border' => false
                       );
   
     global $g_px_scale;
     $g_px_scale = mm2pt($media->width() - $media->margins['left'] - $media->margins['right']) / $media->pixels;
     global $g_pt_scale;
     $g_pt_scale = $g_px_scale * 1.43; 
   
     $pipeline->process($baseurl, $media);
   }
   
   // The all-important call to convert the saved HTML file to PDF.
   convert_to_pdf("forms.html", "forms.pdf");
   
   ?>

There are a number of PHP class libraries that don’t require the commercial PDFLib PECL extension in order to generate PDF’s in your PHP-based web application, here are some of the ones I’ve found that work.

• DOMPDF – Support UTF8. Supports headers and footers.  Choice for creating PDF’s programmatically as in the first example above.
• HTML2PS – Works well for generating PDF’s from rendered HTML as in example two.  Can be difficult to get the headers/footers to align as needed.  Large number of support forums answers. Can generate PostScript or PDFs as output. Font configuration and support is somewhat under-documented/complicated.
• FPDF – perhaps the original free alternative to  the commercial PDFLib.   HTML2PS library is based on a modified version of this.
• Zend_PDF – A  Zend Framework module that can programmatically create PDF files.  No personal experience, others have commented that it’s not as powerful as DOMPDF.