[SOLVED] Simple Trig Thing

[AndrewM16921]

I'm trying to make a method that finds the angle (in degrees) of the line between two points. It's been a while since I've taken trig, so I looked up some stuff... but honestly, I don't think I got it right. This is what I tried to do, but it isn't working.

		public void mouseReleased(MouseEvent event)
		{
			bullets.add(new Item(X, Y, 5, 5, 50, getAngle(X, Y, event.getX(), event.getY())));
		}

...

	public int getAngle(int x1, int y1, int x2, int y2)
	{
		int a = (int)Math.toDegrees(Math.atan(Math.toRadians((y2-y1)/(x2-x1))));
		
		return a;
	}

[hardwired]

import java.awt.*;
import java.awt.geom.Line2D;
import javax.swing.*;

public class Test extends JPanel {
    Point p1 = new Point(50, 50);
    Point p2 = new Point(250, 175);

    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        ((Graphics2D)g).draw(new Line2D.Double(p1, p2));
    }

    private double getAngle() {
        double dy = p2.y - p1.y;
        double dx = p2.x - p1.x;
        return Math.atan2(dy, dx);
    }

    public static void main(String[] args) {
        Test test = new Test();
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(test);
        f.setSize(300,300);
        f.setLocation(200,200);
        f.setVisible(true);
        double theta = test.getAngle();
        System.out.printf("theta = %.1f%n",
                           Math.toDegrees(theta));
    }
}

[AndrewM16921]

Thanks a ton!

	public int getAngle(int x1, int y1, int x2, int y2)
	{
		int a = (int)Math.toDegrees(Math.atan2((y2-y1), (x2-x1)));
		
		return -a + 90;
	}

The only problem I have is that I have to negate a and add 90 for it to be the right angle, but I don't understand why.

[hardwired]

Java measures angles positive clockwise from 3 o'clock.
The order of p1/p2 is important.

[AndrewM16921]

Ok, thanks