function _setBounds(width, height) {
			// adjust the viewport bounds if level is smaller
			game.viewport.setBounds(
				0,
				0,
				Math.max(levelBounds.width, width),
				Math.max(levelBounds.height, height),
			);
			// center the map if smaller than the current viewport
			container.pos.set(
				Math.max(0, ~~((width - levelBounds.width) / 2)),
				Math.max(0, ~~((height - levelBounds.height) / 2)),
				// don't change the container z position if defined
				container.pos.z,
			);
		}
callback funtion for the viewport resize event
@ignore