crop_image in gd equivalent to cropImage in imagick

gd.cropimage.php

<?php

function cropImage ($image, $width, $height, $x, $y) {

    list($w, $h) = getimagesize($image);

    $nw = (($width + $x) >= $w) ? $w - $x : $width;
    $nh = (($height + $y) >= $h) ? $h - $y : $height;
    // var_dump($nw);
    // var_dump($nh);
    if ($nw == 0 || $nh == 0) {
        throw new Exception ('cannot crop image, dst image\'s width or height is 0!');
    }

    $src = imagecreatefromjpeg($image);
    $dst = imagecreatetruecolor($nw, $nh);

    imagecopyresampled($dst, $src, 0, 0, $x, $y, $nw, $nh, $nw, $nh);

    return $dst;

}

$gd = cropImage('saya.jpg', 1600, 1200, 1200, 900);

imagejpeg($gd);