public function fit(Size $size, $position = 'center')
    {
        // create size with auto height
        $auto_height = clone $size;

        $auto_height->resize($this->width, null, function ($constraint) {
            $constraint->aspectRatio();
        });

        // decide which version to use
        if ($auto_height->fitsInto($this)) {

            $size = $auto_height;

        } else {

            // create size with auto width
            $auto_width = clone $size;

            $auto_width->resize(null, $this->height, function ($constraint) {
                $constraint->aspectRatio();
            });

            $size = $auto_width;
        }

        $this->align($position);
        $size->align($position);
        $size->setPivot($this->relativePosition($size));

        return $size;
    }