Example

function popDefs($strokeColor, $fillColor, $backgroundColor)
{
    $draw = new \ImagickDraw();

    $draw->setStrokeColor($strokeColor);
    $draw->setFillColor($fillColor);
    $draw->setstrokeOpacity(1);
    $draw->setStrokeWidth(2);
    $draw->setFontSize(72);
    $draw->pushDefs();
    $draw->setStrokeColor('white');
    $draw->rectangle(50, 50, 200, 200);
    $draw->popDefs();

    $draw->rectangle(300, 50, 450, 200);

    $imagick = new \Imagick();
    $imagick->newImage(500, 500, $backgroundColor);
    $imagick->setImageFormat("png");

    $imagick->drawImage($draw);

    header("Content-Type: image/png");
    echo $imagick->getImageBlob();
}