barcode_example.php

<?php
public function executeBarcode(sfWebRequest $request)
{
    $barcodeOptions = array(
                        'text' => $request->getParameter('text')
                      );
    $barcodeOptions = array_merge(
                        $barcodeOptions, 
                        $this->parseOptionalParameters(
                            $request->getGetParameters()
                        )
                      );
    $rendererOptions = array();

    $this->getResponse()->setContentType('image/png');
    Zend_Barcode::factory(
                    $request->getParameter('type'), 
                    'image', 
                    $barcodeOptions, 
                    $rendererOptions
                  )->render();
    return sfView::NONE;
}