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71 lines
1.9 KiB
PHP
71 lines
1.9 KiB
PHP
<?php
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/* [external]
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This is PHP file that generates CAPTCHA image for the How to Create CAPTCHA
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Protection using PHP and AJAX Tutorial
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You may use this code in your own projects as long as this
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copyright is left in place. All code is provided AS-IS.
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This code is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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For the rest of the code visit http://www.WebCheatSheet.com
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Copyright 2006 WebCheatSheet.com
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*/
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function can_show_captcha()
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{
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return extension_loaded("gd");
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}
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function gen_captcha()
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{
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$md5_hash = md5(rand(0, 9999));
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return substr($md5_hash, 15, 5);
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}
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function draw_captcha($security_code)
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{
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//Set the image width and height
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$width = 100;
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$height = 25;
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//Create the image resource
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$image = ImageCreate($width, $height);
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if (function_exists('imageantialias')) {
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imageantialias($image, true);
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}
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//We are making three colors, white, black and gray
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$white = ImageColorAllocate($image, 255, 255, 255);
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$black = ImageColorAllocate($image, 15, 50, 15);
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$grey = ImageColorAllocate($image, 204, 204, 204);
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$ellipsec = ImageColorAllocate($image, 0, 100, 60);
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//Make the background black
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ImageFill($image, 0, 0, $black);
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imagefilledellipse($image, 56, 15, 30, 17, $ellipsec);
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//Add randomly generated string in white to the image
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ImageString($image, 5, 30, 4, $security_code, $white);
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//Throw in some lines to make it a little bit harder for any bots to break
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ImageRectangle($image, 0, 0, $width - 1, $height - 1, $grey);
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imageline($image, 0, $height / 2 + 3, $width, $height / 2 + 5, $grey);
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imageline($image, $width / 2 - 14, 0, $width / 2 + 7, $height, $grey);
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//Tell the browser what kind of file is come in
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header("Content-Type: image/jpeg");
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//Output the newly created image in jpeg format
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ImageJpeg($image);
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//Free up resources
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ImageDestroy($image);
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}
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?>
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