php制作验证码

2/10/2017来源:ASP.NET技巧人气:1272

//通过GD库做验证码
function verifyImage($type = 1,$length = 4,$pixel = 25, $line = 0,$sess_name = "verify"){
    // 创建画布
    $width = 80;
    $height = 28;
    $image = imagecreatetruecolor($width, $height);
    $white = imagecolorallocate($image, 255, 255, 255);
    $black = imagecolorallocate($image, 0, 0, 0);
    // 用填充矩形填充画布
    imagefilledrectangle($image, 1, 1, $width - 2, $height - 2, $white);
    $chars = buildRandomString($type, $length);//生成随机字符串
    $_session[$sess_name] = $chars;
    
    for ($i = 0; $i < $length; $i ++) {
        $size = mt_rand(14, 18);
        $angle = mt_rand(- 15, 15);
        $x = 5 + $i * $size;
        $y = mt_rand(20, 26);
        $color = imagecolorallocate($image, mt_rand(50, 90), mt_rand(80, 200), mt_rand(90, 180));
        $fontfile = "../fonts/SIMYOU.TTF";
        $text = substr($chars, $i, 1);
       // echo $text;
        imagettftext($image, $size, $angle, $x, $y, $color, $fontfile, $text);
    }
    
    // 加上干扰元素---点
    if ($pixel) {
        for ($i = 0; $i < $pixel; $i ++) {
            imagesetpixel($image, mt_rand(0, $width - 1), mt_rand(0, $height - 1), $black);
        }
    }
    
    // 加上干扰元素--线
    if ($line) {
        for ($i = 0; $i < $line; $i ++) {
            
            imageline($image, mt_rand(0, $width - 1), mt_rand(0, $height - 1), mt_rand(0, $width - 1), mt_rand(0, $height - 1), $black);
        }
    }
    ob_clean();
    // 显示之前要告诉浏览器
    header("content-type:image/gif");
    // 显示画布
    imagegif($image);
    // 销毁资源
    imagedestroy($image);
}