php多张图片合并方法分享

$dst = imagecreatefromstring(file_get_contents($dst_path));
$src = imagecreatefromstring(file_get_contents($src_path));
imagecopy($dst, $src, 100, 100, 0, 0, 100, 100);//完成合并

  function imagecopymerge_alpha($dst_im, $src_im, $dst_x, $dst_y, $src_x, $src_y, $src_w, $src_h, $pct){
        $opacity=$pct;
        // getting the watermark width
        $w = imagesx($src_im);
        // getting the watermark height
        $h = imagesy($src_im);
        
        // creating a cut resource
        $cut = imagecreatetruecolor($src_w, $src_h);
        // copying that section of the background to the cut
        imagecopy($cut, $dst_im, 0, 0, $dst_x, $dst_y, $src_w, $src_h);
        // inverting the opacity
        $opacity = 100 - $opacity;
        
        // placing the watermark now
        imagecopy($cut, $src_im, 0, 0, $src_x, $src_y, $src_w, $src_h);
        imagecopymerge($dst_im, $cut, $dst_x, $dst_y, $src_x, $src_y, $src_w, $src_h, $opacity);
    }