Softens the edges of the image in vignette style. This method is available if Imagick has been compiled against ImageMagick version 6.2.9 or newer.
function vignetteImage($image_path, $blackPoint, $whitePoint, $x, $y)
{
    $imagick = new \Imagick(realpath($image_path));
    $imagick->vignetteImage($blackPoint, $whitePoint, $x, $y);
    header("Content-Type: image/jpeg");
    echo $imagick->getImageBlob();
}