Cutting image background is black (PHP,PNG)

Cutting image background is black.

My code :

$filename = "../upload/".$name;
    $new_filename = "../upload/".$name;
    list($current_width, $current_height) = getimagesize($filename);
    $x1    = clear($_POST["x1"]);
    $y1    = clear($_POST["y1"]);
    $x2    = clear($_POST["x2"]);
    $y2    = clear($_POST["y2"]);
    $w    = clear($_POST["width"]);
    $h    = clear($_POST["height"]);
    $crop_width = clear($_POST["width"]);
    $crop_height = clear($_POST["height"]);
    $new = imagecreatetruecolor($crop_width, $crop_height);
    $current_image = imagecreatefrompng($filename);

    $red = imagecolorallocate($current_image, 255, 0, 0);
    $black = imagecolorallocate($current_image, 0, 0, 0);

    imagecopyresampled($new, $current_image, 0, 0, $x1, $y1, $crop_width, $crop_height, $w, $h);
    header('Content-Type: image/png');
    imagepng($new, $new_filename);    
    imagedestroy($current_image);