cvs: php-bugs-web / captcha-help.php captcha-image.php

dufuz Wed Apr 20 09:00:40 2005 EDT Added files: /php-bugs-web captcha-help.php captcha-image.php Log: CAPTCHA generation/help files, not yet in production on the website.

http://cvs.php.net/co.php/php-bugs-web/captcha-help.php?r=1.1&p=1 Index: php-bugs-web/captcha-help.php +++ php-bugs-web/captcha-help.php <?php /** * Help regarding our CAPTCHAs. * * To keep things easy to understand, don't output the actual image or * audio links if <var>$_SESSION['captcha']</var> isn't set. * * This source file is subject to version 3.0 of the PHP license, * that is bundled with this package in the file LICENSE, and is * available through the world-wide-web at the following URI: * http://www.php.net/license/3_0.txt. * If you did not receive a copy of the PHP license and are unable to * obtain it through the world-wide-web, please send a note to * license@php.net so we can mail you a copy immediately. * * @category pearweb * @package pearweb * @author Daniel Convissor <danielc@php.net> * @copyright Copyright (c) 2004-2005 The PHP Group * @license http://www.php.net/license/3_0.txt PHP License * @version $Id: captcha-help.php,v 1.1 2005/04/20 13:00:40 dufuz Exp $ * @see generate_captcha(), validate_captcha(), captcha-image.php */ require_once 'prepend.inc'; commonHeader('CAPTCHA :: Help'); ?> <h1>CAPTCHA Help</h1> <p>Some forms on the PHP Bugs website use <a href="http://www.parc.xerox.com/research/istl/projects/captcha/"><acronym title="Completely Automated Public Turing test to tell Computers and Humans Apart" >CAPTCHA</acronym></a>s in order to avoid our getting spammed.</p> <?php if (isset($_SESSION['captcha'])) { ?> <p>Your CAPTCHA is <img src="/captcha-image.php" alt="CAPTCHA text" />. If you are having a hard time reading it, reloading this page will modify how the image looks.</p> <p>If you are visually impaired, please send a note to the <?php echo make_mailto_link('webmaster@php.net', 'php-webmaster') ?> mailing list. Be sure to explain your situation and include all of the information from the form you are trying to submit.</p> <?php } else { ?> <p>This page provides further information once you view a form which requires a CAPTCHA.</p> <?php } commonFooter(); ?> http://cvs.php.net/co.php/php-bugs-web/captcha-image.php?r=1.1&p=1 Index: php-bugs-web/captcha-image.php +++ php-bugs-web/captcha-image.php <?php /** * Produces a CAPTCHA image * * Uses the value of <var>$_SESSION['captcha']</var> for the image's text. * That value is set in generate_captcha() in include/pear-format-html.php. * * If <var>$_SESSION['captcha']</var> is not set, the request is bogus, so * exit without any output in order to save resources. * * Rules: * + Use fonts that are fuzzy. * + Use a random font for each character. * + Have each character be a random size, start at a random vertical * location and appear at random angles. * + Allow characters to sometimes overlap a little and flow a bit off * the canvas. * + Use two random colors for the foreground (text and arcs). * + The foreground color must contrast with the background color. * + The foreground arc colors must be the same as the text in order to * make them harder to remove. * + Some arcs will also be the background color, causing them to cut up * the foreground items. * + Encourage arcs not to touch the image's edges. * + Have the arcs run from left to right as to not look like 1 or l. * + Make sure each arc crosses through most of the text. * * Based on a combination of concepts found in: * + http://www.viebrock.ca/code/10/turing-protection * + http://lists.nyphp.org/pipermail/talk/2004-June/010218.html * + http://lists.nyphp.org/pipermail/talk/2004-July/010996.html * * LICENSE: This source file is subject to version 3.0 of the PHP license * that is available through the world-wide-web at the following URI: * http://www.php.net/license/3_0.txt. If you did not receive a copy of * the PHP License and are unable to obtain it through the web, please * send a note to license@php.net so we can mail you a copy immediately. * * @category php-bugs-web * @package php-bugs-web * @author Daniel Convissor <danielc@php.net> * @copyright Copyright (c) 2004-2005 The PHP Group * @license http://www.php.net/license/3_0.txt PHP License * @version $Id: captcha-image.php,v 1.1 2005/04/20 13:00:40 dufuz Exp $ * @see generate_captcha(), validate_captcha() */ require_once 'prepend.inc'; generate_captcha(); if (!isset($_SESSION['captcha'])) { exit; } /* * SETTINGS =========================== */ $arc_count = 8; $arc_deg_vary = 30; $arc_pad_max = 20; $arc_pad_min = 5; $color_bg_max = 5; $color_bg_min = 4; $color_fg_max = 2; $color_fg_min = 1; $font_angle_max = 20; $font_angle_min = -20; $font_padding = 2; $font_size_max = 25; $font_size_min = 18; /* * Use full path to the fonts to avoid problems. * The fonts are located in php-bugs-web/include/fonts. * Ease dev box configuration by doing this funky string replace. */ $font_dir = $_SERVER['DOCUMENT_ROOT'] . '/include/fonts/'; /* * This array contains the list of font names and the number the base * font size should be multiplied by to make all the fonts appear about * the same height. * * Fonts were obtained from http://www.freefontsnow.com/. They are free * for use under certain circumstances (such as the php.net websites). */ $fonts = array( 'coolveti.ttf' => 1, // by Ray Larabie ); /* * CALCULATE THE TEXT MEASUREMENTS ==== */ $image_width = 0; $image_height = 0; $data = array(); for ($i = 0; $i < strlen($_SESSION['captcha']); $i++) { $char = substr($_SESSION['captcha'], $i, 1); $font_name = array_rand($fonts); $font = $font_dir . $font_name; $size = mt_rand($font_size_min, $font_size_max) * $fonts[$font_name]; switch ($char) { case 'Q': // Keep Q's tail from being off the bottom of the image. $angle = mt_rand(0, $font_angle_max); break; default: $angle = mt_rand($font_angle_min, $font_angle_max); } $bbox = imagettfbbox($size, $angle, $font, $char); $width = max($bbox[2], $bbox[4]) - min($bbox[0], $bbox[6]); $height = max($bbox[1], $bbox[3]) - min($bbox[7], $bbox[5]); $image_width += $width + $font_padding; $image_height = max($image_height, $height); $data[] = array( 'font' => $font, 'char' => $char, 'size' => $size, 'angle' => $angle, 'height' => $height, 'width' => $width, ); } $image_width -= $font_padding; /* * BASE IMAGE ========================= */ $im = imagecreate($image_width, $image_height); /* * COLORS ============================= * * 0 is the background color. * 1 through x are the foreground colors. */ $colors = array( imagecolorallocate($im, 51 * mt_rand($color_bg_min, $color_bg_max), 51 * mt_rand($color_bg_min, $color_bg_max), 51 * mt_rand($color_bg_min, $color_bg_max)), imagecolorallocate($im, 51 * mt_rand($color_fg_min, $color_fg_max), 51 * mt_rand($color_fg_min, $color_fg_max), 51 * mt_rand($color_fg_min, $color_fg_max)), imagecolorallocate($im, 51 * mt_rand($color_fg_min, $color_fg_max), 51 * mt_rand($color_fg_min, $color_fg_max), 51 * mt_rand($color_fg_min, $color_fg_max)), ); $color_max = count($colors) - 1; /* * DISPLAY TEXT ======================= */ $pos_x = 0; $y_min = $image_height - 15; $y_max = $image_height - 3; foreach ($data as $d) { $pos_y = mt_rand($y_min, $y_max); imagettftext($im, $d['size'], $d['angle'], $pos_x, $pos_y, $colors[mt_rand(1, $color_max)], $d['font'], $d['char']); $pos_x += $d['width'] + $font_padding; } /* * ARCS ================================ */ for ($i = 0; $i < $arc_count; $i++) { // Start on left side, arc upward, then ending on the right side. $start = mt_rand(180 - $arc_deg_vary, 180 + $arc_deg_vary); $end = mt_rand(0 - $arc_deg_vary, $arc_deg_vary); if ($end < 0) { $end = 360 - $end; } $half_w = $image_width / 2; $center_x = mt_rand($half_w - $arc_pad_min, $half_w + $arc_pad_min); $tmp_w = ($half_w - abs($half_w - $center_x)) * 2; $width = mt_rand($tmp_w - $arc_pad_min, $tmp_w - $arc_pad_max); $center_y = mt_rand($image_height / 2, $image_height - $arc_pad_min); $height = mt_rand(3, $center_y * 2 - $arc_pad_min); if ($i % 2) { // Flip arc to a downward one. $tmp = $end; $end = $start; $start = $tmp; $center_y = $image_height - $center_y; } imagearc($im, $center_x, $center_y, $width, $height, $start, $end, $colors[mt_rand(0, $color_max)]); } /* * OUTPUT ============================= */ header('Content-type: image/jpeg'); imagejpeg($im, null, 100); ?>