PHP 给图片添加全图水印

<?php
$dst_path = "2.jpg";
$dst = imagecreatefromstring(file_get_contents($dst_path));
$w = imagesx($dst);
$h = imagesy($dst);
$font = 'font/Lato-Black.ttf';
$black = imagecolorallocate($dst, 192, 192, 192);
$hw = 180;
$angle = 45; //倾斜角度
$size = 15;//字体大小

for ($i = 0; $i <= ($w / $hw ); $i++) {
    for ($hs = 1; $hs <= ($h / $hw ); $hs++) {
        imagefttext($dst, $size, $angle , ($i * $hw ) , $hs * $hw , $black, $font, 'looks.wang');
    }
}

list ($dst_w, $dst_h, $dst_type) = getimagesize($dst_path);

switch ($dst_type) {
    case 1: // GIF
        header("content-type:image/gif");
        imagegif($dst);
        break;
    case 2: // JPG
        header("content-type:image/jpeg");
        imagejpeg($dst);
        break;
    case 3: // PNG
        header("content-type:image/png");
        imagepng($dst);
        break;
    default:
        break;
}
// 销毁图片
imagedestroy($dst);