php图片添加水印的例子

<?php
    /**
     * 图片添加水印
     * $target 源文件路径
     * $wtrmrk_file 水印图片路径
     * $newcopy 添加水印后的图片路径
     * 
     */
    public function watermark_image($target, $wtrmrk_file, $newcopy) {
        $watermark = imagecreatefrompng($wtrmrk_file);
        imagealphablending($watermark, false);
        imagesavealpha($watermark, true);
        $img = imagecreatefromjpeg($target);
        $img_w = imagesx($img);
        $img_h = imagesy($img);
        $wtrmrk_w = imagesx($watermark);
        $wtrmrk_h = imagesy($watermark);
        $dst_x = ($img_w ) – ($wtrmrk_w); // For centering the watermark on any image
        $dst_y = ($img_h) – ($wtrmrk_h ); // For centering the watermark on any image
        imagecopy($img, $watermark, $dst_x, $dst_y, 0, 0, $wtrmrk_w, $wtrmrk_h);
       
        imagejpeg($img, $newcopy, 100);
        imagedestroy($img);
        imagedestroy($watermark);
        //return $img;
    }
?>