public static double getLineAngle(Line2D line) { double angle; // Calculate the length of the line double rise = line.getY2() - line.getY1(); double run = line.getX2() - line.getX1(); if(run != 0.0d) { angle = java.lang.Math.atan(rise/run); } else { // must be either 90 or 270 degrees. if(rise > 0.00) { angle = java.lang.Math.toRadians(90); } else { angle = java.lang.Math.toRadians(270); } } // Convert the angle to the correct quadrant if(line.getX2() < line.getX1()) { // Point B is in the 3rd or 4th quadrant angle += java.lang.Math.toRadians(180); } System.out.println("--------angle: " + angle); return angle; }