/**
* 生成验证码字符串，写入SESSION，将字符串图片返回给浏览器
*
* @param $len
* @param int $width
* @param int $height
* @param int $font_size
*/
public static function generate($len, $width = 110, $height = 30, $font_size = 18)
{
$sizes = array('18' => array('width' => 25, 'height' => 25));
$words = self::words($len);
$session_key = 'captcha';
//$_SESSION[$session_key] = strtolower($words);
Tools_help::setSession($session_key, strtolower($words));
$image = Files_ImageManager::createWhiteImage($width, $height);
$font_config = array('spacing' => -17, 'font' => '5.ttf');
$font_path = dirname(__FILE__) . '/' . $font_config['font'];
$color = imagecolorallocate($image, mt_rand(0, 100), mt_rand(20, 120), mt_rand(50, 150));
$rand = 0;
$w = $sizes[$font_size]['width'] * $len;
$h = $sizes[$font_size]['height'];
$x = round(($width - $w) / 2);
$y = round(($height + $h) / 2) - 6;
$coors = imagettftext($image, $font_size, $rand, $x, $y, $color, $font_path, $words);
if ($coors) {
header("Cache-Control: no-cache, must-revalidate");
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Pragma: no-cache");
header("Cache-control: private");
header('Content-Type: image/png');
imagepng($image);
imagedestroy($image);
}
exit;
}
/**
* 验证上传文件的类型是否为图片及大小是否越界
* @param $file
* @param int $max_file_size
* @return bool|string
*/
public static function validateUpload($file, $max_file_size = 0)
{
if ((int) $max_file_size > 0 && $file['size'] > (int) $max_file_size) {
return sprintf(Tools_help::displayError('Image is too large (%1$d kB). Maximum allowed: %2$d kB'), $file['size'] / 1024, $max_file_size / 1024);
}
if (!Files_ImageManager::isRealImage($file['tmp_name'], $file['type']) || !Files_ImageManager::isCorrectImageFileExt($file['name'])) {
return 'Image format not recognized, allowed formats are: .gif, .jpg, .png';
}
if ($file['error']) {
return sprintf(Tools_help::displayError('Error while uploading image; please change your server\'s settings. (Error code: %s)'), $file['error']);
}
return true;
}