--- /dev/null
+<?php defined('SYSPATH') OR die('No direct access allowed.');
+/**
+ * Captcha driver class.
+ *
+ * $Id: Captcha.php 3769 2008-12-15 00:48:56Z zombor $
+ *
+ * @package Captcha
+ * @author Kohana Team
+ * @copyright (c) 2007-2008 Kohana Team
+ * @license http://kohanaphp.com/license.html
+ */
+abstract class Captcha_Driver {
+
+ // The correct Captcha challenge answer
+ protected $response;
+
+ // Image resource identifier and type ("png", "gif" or "jpeg")
+ protected $image;
+ protected $image_type = 'png';
+
+ /**
+ * Constructs a new challenge.
+ *
+ * @return void
+ */
+ public function __construct()
+ {
+ // Generate a new challenge
+ $this->response = $this->generate_challenge();
+
+ // Store the correct Captcha response in a session
+ Event::add('system.post_controller', array($this, 'update_response_session'));
+ }
+
+ /**
+ * Generate a new Captcha challenge.
+ *
+ * @return string the challenge answer
+ */
+ abstract public function generate_challenge();
+
+ /**
+ * Output the Captcha challenge.
+ *
+ * @param boolean html output
+ * @return mixed the rendered Captcha (e.g. an image, riddle, etc.)
+ */
+ abstract public function render($html);
+
+ /**
+ * Stores the response for the current Captcha challenge in a session so it is available
+ * on the next page load for Captcha::valid(). This method is called after controller
+ * execution (in the system.post_controller event) in order not to overwrite itself too soon.
+ *
+ * @return void
+ */
+ public function update_response_session()
+ {
+ Session::instance()->set('captcha_response', sha1(strtoupper($this->response)));
+ }
+
+ /**
+ * Validates a Captcha response from a user.
+ *
+ * @param string captcha response
+ * @return boolean
+ */
+ public function valid($response)
+ {
+ return (sha1(strtoupper($response)) === Session::instance()->get('captcha_response'));
+ }
+
+ /**
+ * Returns the image type.
+ *
+ * @param string filename
+ * @return string|FALSE image type ("png", "gif" or "jpeg")
+ */
+ public function image_type($filename)
+ {
+ switch (strtolower(substr(strrchr($filename, '.'), 1)))
+ {
+ case 'png':
+ return 'png';
+
+ case 'gif':
+ return 'gif';
+
+ case 'jpg':
+ case 'jpeg':
+ // Return "jpeg" and not "jpg" because of the GD2 function names
+ return 'jpeg';
+
+ default:
+ return FALSE;
+ }
+ }
+
+ /**
+ * Creates an image resource with the dimensions specified in config.
+ * If a background image is supplied, the image dimensions are used.
+ *
+ * @throws Kohana_Exception if no GD2 support
+ * @param string path to the background image file
+ * @return void
+ */
+ public function image_create($background = NULL)
+ {
+ // Check for GD2 support
+ if ( ! function_exists('imagegd2'))
+ throw new Kohana_Exception('captcha.requires_GD2');
+
+ // Create a new image (black)
+ $this->image = imagecreatetruecolor(Captcha::$config['width'], Captcha::$config['height']);
+
+ // Use a background image
+ if ( ! empty($background))
+ {
+ // Create the image using the right function for the filetype
+ $function = 'imagecreatefrom'.$this->image_type($background);
+ $this->background_image = $function($background);
+
+ // Resize the image if needed
+ if (imagesx($this->background_image) !== Captcha::$config['width']
+ OR imagesy($this->background_image) !== Captcha::$config['height'])
+ {
+ imagecopyresampled
+ (
+ $this->image, $this->background_image, 0, 0, 0, 0,
+ Captcha::$config['width'], Captcha::$config['height'],
+ imagesx($this->background_image), imagesy($this->background_image)
+ );
+ }
+
+ // Free up resources
+ imagedestroy($this->background_image);
+ }
+ }
+
+ /**
+ * Fills the background with a gradient.
+ *
+ * @param resource gd image color identifier for start color
+ * @param resource gd image color identifier for end color
+ * @param string direction: 'horizontal' or 'vertical', 'random' by default
+ * @return void
+ */
+ public function image_gradient($color1, $color2, $direction = NULL)
+ {
+ $directions = array('horizontal', 'vertical');
+
+ // Pick a random direction if needed
+ if ( ! in_array($direction, $directions))
+ {
+ $direction = $directions[array_rand($directions)];
+
+ // Switch colors
+ if (mt_rand(0, 1) === 1)
+ {
+ $temp = $color1;
+ $color1 = $color2;
+ $color2 = $temp;
+ }
+ }
+
+ // Extract RGB values
+ $color1 = imagecolorsforindex($this->image, $color1);
+ $color2 = imagecolorsforindex($this->image, $color2);
+
+ // Preparations for the gradient loop
+ $steps = ($direction === 'horizontal') ? Captcha::$config['width'] : Captcha::$config['height'];
+
+ $r1 = ($color1['red'] - $color2['red']) / $steps;
+ $g1 = ($color1['green'] - $color2['green']) / $steps;
+ $b1 = ($color1['blue'] - $color2['blue']) / $steps;
+
+ if ($direction === 'horizontal')
+ {
+ $x1 =& $i;
+ $y1 = 0;
+ $x2 =& $i;
+ $y2 = Captcha::$config['height'];
+ }
+ else
+ {
+ $x1 = 0;
+ $y1 =& $i;
+ $x2 = Captcha::$config['width'];
+ $y2 =& $i;
+ }
+
+ // Execute the gradient loop
+ for ($i = 0; $i <= $steps; $i++)
+ {
+ $r2 = $color1['red'] - floor($i * $r1);
+ $g2 = $color1['green'] - floor($i * $g1);
+ $b2 = $color1['blue'] - floor($i * $b1);
+ $color = imagecolorallocate($this->image, $r2, $g2, $b2);
+
+ imageline($this->image, $x1, $y1, $x2, $y2, $color);
+ }
+ }
+
+ /**
+ * Returns the img html element or outputs the image to the browser.
+ *
+ * @param boolean html output
+ * @return mixed html string or void
+ */
+ public function image_render($html)
+ {
+ // Output html element
+ if ($html)
+ return '<img alt="Captcha" src="'.url::site('captcha/'.Captcha::$config['group']).'" width="'.Captcha::$config['width'].'" height="'.Captcha::$config['height'].'" />';
+
+ // Send the correct HTTP header
+ header('Content-Type: image/'.$this->image_type);
+
+ // Pick the correct output function
+ $function = 'image'.$this->image_type;
+ $function($this->image);
+
+ // Free up resources
+ imagedestroy($this->image);
+ }
+
+} // End Captcha Driver
\ No newline at end of file
projects / speedfreak / blobdiff