private static double distance( double x1, double y1, double x2, double y2 ) {
		double dx = x2 - x1;
		double dy = y2 - y1;
		return Math.sqrt( (dx * dx) + (dy * dy) );
	}
Calculates the distance between two points.
flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatUIUtils.java