/system/libraries/drivers/Captcha/Alpha.php
PHP | 92 lines | 42 code | 14 blank | 36 comment | 3 complexity | cd9ea83df637099807a3dc88326fc6f9 MD5 | raw file
Possible License(s): MPL-2.0-no-copyleft-exception, BSD-3-Clause
- <?php defined('SYSPATH') OR die('No direct access allowed.');
- /**
- * Captcha driver for "alpha" style.
- *
- * $Id: Alpha.php 4367 2009-05-27 21:23:57Z samsoir $
- *
- * @package Captcha
- * @author Kohana Team
- * @copyright (c) 2007-2008 Kohana Team
- * @license http://kohanaphp.com/license.html
- */
- class Captcha_Alpha_Driver extends Captcha_Driver {
- /**
- * Generates a new Captcha challenge.
- *
- * @return string the challenge answer
- */
- public function generate_challenge()
- {
- // Complexity setting is used as character count
- return text::random('distinct', max(1, Captcha::$config['complexity']));
- }
- /**
- * Outputs the Captcha image.
- *
- * @param boolean html output
- * @return mixed
- */
- public function render($html)
- {
- // Creates $this->image
- $this->image_create(Captcha::$config['background']);
- // Add a random gradient
- if (empty(Captcha::$config['background']))
- {
- $color1 = imagecolorallocate($this->image, mt_rand(0, 100), mt_rand(0, 100), mt_rand(0, 100));
- $color2 = imagecolorallocate($this->image, mt_rand(0, 100), mt_rand(0, 100), mt_rand(0, 100));
- $this->image_gradient($color1, $color2);
- }
- // Add a few random circles
- for ($i = 0, $count = mt_rand(10, Captcha::$config['complexity'] * 3); $i < $count; $i++)
- {
- $color = imagecolorallocatealpha($this->image, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255), mt_rand(80, 120));
- $size = mt_rand(5, Captcha::$config['height'] / 3);
- imagefilledellipse($this->image, mt_rand(0, Captcha::$config['width']), mt_rand(0, Captcha::$config['height']), $size, $size, $color);
- }
- // Calculate character font-size and spacing
- $default_size = min(Captcha::$config['width'], Captcha::$config['height'] * 2) / strlen($this->response);
- $spacing = (int) (Captcha::$config['width'] * 0.9 / strlen($this->response));
- // Background alphabetic character attributes
- $color_limit = mt_rand(96, 160);
- $chars = 'ABEFGJKLPQRTVY';
- // Draw each Captcha character with varying attributes
- for ($i = 0, $strlen = strlen($this->response); $i < $strlen; $i++)
- {
- // Use different fonts if available
- $font = Captcha::$config['fontpath'].Captcha::$config['fonts'][array_rand(Captcha::$config['fonts'])];
- $angle = mt_rand(-40, 20);
- // Scale the character size on image height
- $size = $default_size / 10 * mt_rand(8, 12);
- $box = imageftbbox($size, $angle, $font, $this->response[$i]);
- // Calculate character starting coordinates
- $x = $spacing / 4 + $i * $spacing;
- $y = Captcha::$config['height'] / 2 + ($box[2] - $box[5]) / 4;
- // Draw captcha text character
- // Allocate random color, size and rotation attributes to text
- $color = imagecolorallocate($this->image, mt_rand(150, 255), mt_rand(200, 255), mt_rand(0, 255));
- // Write text character to image
- imagefttext($this->image, $size, $angle, $x, $y, $color, $font, $this->response[$i]);
- // Draw "ghost" alphabetic character
- $text_color = imagecolorallocatealpha($this->image, mt_rand($color_limit + 8, 255), mt_rand($color_limit + 8, 255), mt_rand($color_limit + 8, 255), mt_rand(70, 120));
- $char = $chars[mt_rand(0, 14)];
- imagettftext($this->image, $size * 2, mt_rand(-45, 45), ($x - (mt_rand(5, 10))), ($y + (mt_rand(5, 10))), $text_color, $font, $char);
- }
- // Output
- return $this->image_render($html);
- }
- } // End Captcha Alpha Driver Class