如何在PHP ImageMagick中画一条虚线？

$image = new Imagick();
$image->newImage(500, 500, new ImagickPixel('white'));

$draw = new ImagickDraw();
$draw->setStrokeColor('black');
$draw->setStrokeWidth(2);
$draw->setStrokeDashArray([2, 2]); // 设置虚线的线型

$startX = 50;
$startY = 250;
$endX = 450;
$endY = 250;

$draw->line($startX, $startY, $endX, $endY);

$image->drawImage($draw);
$image->setImageFormat('png');
header('Content-Type: image/png');
echo $image;