tray/src/messenger/webim/libs/captcha.php
2013-03-06 22:22:53 +01:00

71 lines
2.0 KiB
PHP

<?php
/*
* Copyright 2005-2013 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
function can_show_captcha()
{
return extension_loaded("gd");
}
function gen_captcha()
{
$md5_hash = md5(rand(0, 9999));
return substr($md5_hash, 15, 5);
}
function draw_captcha($security_code)
{
//Set the image width and height
$width = 100;
$height = 25;
//Create the image resource
$image = ImageCreate($width, $height);
if (function_exists('imageantialias')) {
imageantialias($image, true);
}
//We are making three colors, white, black and gray
$white = ImageColorAllocate($image, 255, 255, 255);
$black = ImageColorAllocate($image, 15, 50, 15);
$grey = ImageColorAllocate($image, 204, 204, 204);
$ellipsec = ImageColorAllocate($image, 0, 100, 60);
//Make the background black
ImageFill($image, 0, 0, $black);
imagefilledellipse($image, 56, 15, 30, 17, $ellipsec);
//Add randomly generated string in white to the image
ImageString($image, 5, 30, 4, $security_code, $white);
//Throw in some lines to make it a little bit harder for any bots to break
ImageRectangle($image, 0, 0, $width - 1, $height - 1, $grey);
imageline($image, 0, $height / 2 + 3, $width, $height / 2 + 5, $grey);
imageline($image, $width / 2 - 14, 0, $width / 2 + 7, $height, $grey);
//Tell the browser what kind of file is come in
header("Content-Type: image/jpeg");
//Output the newly created image in jpeg format
ImageJpeg($image);
//Free up resources
ImageDestroy($image);
}
?>