westdc-zf1/application/module/Helpers/Captcha.php

<?php
namespace Helpers;

class Captcha extends \Zend_Controller_Plugin_Abstract
{
	public $captcha;
	
	private $sessionName = "captcha";
	private $imgDir = "images/captcha";
	
	function __construct($db = NULL)
	{
		$this->loadCaptcha();
	}
	
	public function loadCaptcha()
	{
		$this->captcha = new \Zend_Captcha_Image(array(  
			  'captcha' => 'Image',
			  'wordLen' => 4,
			  'fontsize'=>16,
			  'width' => 100,
			  'height' => 38,
			  'dotNoiseLevel'=>2,
			  'lineNoiseLevel'=>1,
			  'timeout' => 300,
			  'font' => '../data/fonts/ggbi.ttf',
			  'imgDir' => $this->imgDir,
			  'imgUrl' => '/images/captcha',
		   ));
	}
	
	public function setCaptcha(){
		if(!is_dir($this->imgDir))
		{
			mkdir($this->imgDir);
		}
		
		$this->captcha->generate();
		$_SESSION[$this->sessionName] = $this->captcha->getWord();
		$url = $this->captcha->getImgUrl()
			  .$this->captcha->getId()
			  .$this->captcha->getSuffix();
		
		return $url;
	}
	
	public function isValid($captchaword)
	{
		if($captchaword == $_SESSION[$this->sessionName])
		{
			return true;
		}else{
			return false;
		}
	}
	
}