Example

function roundCorners($image_path)
{
    $imagick = new \Imagick(realpath($image_path));
    $imagick->setBackgroundColor('red');

    $imagick->setbackgroundcolor('pink');

    $x_rounding = 40;
    $y_rounding = 40;
    $stroke_width = 5;
    $displace = 0;
    $size_correction = 0;

    $imagick->roundCornersImage(
        $x_rounding,
        $y_rounding,
        $stroke_width,
        $displace,
        $size_correction
    );

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