[java] How to draw a circle with given X and Y coordinates as the middle spot of the circle?

I have developed a telecommunication application for locating signal strengths from the towers. I have used java swing and I'm having a problem when drawing the circle around the given point of the mobile signal transmitter tower location. I have already calculated the X, Y coordinates and also the radius value.

Please find the below code which I've used to draw the circle and it is having issues.

JPanel panelBgImg = new JPanel() {
    public void paintComponent(Graphics g) {
        g.drawOval(X, Y, r, r);
    }
}

The issue is, it creates the circle but it didn't take the X and Y coordinates as the center point. It took the X and Y coordinates as the top left point of the circle.

Could anyone please help me to draw the circle by having the given X and Y coordinates as the center point of the circle.

This question is related to java swing jpanel java-2d paintcomponent

The answer is


JPanel pnlCircle = new JPanel() {
        public void paintComponent(Graphics g) {
            int X=100;
            int Y=100;
            int d=200;
            g.drawOval(X, Y, d, d);
        }
};

you can change X,Y coordinates and radius what you want.


So we are all doing the same home work?

Strange how the most up-voted answer is wrong. Remember, draw/fillOval take height and width as parameters, not the radius. So to correctly draw and center a circle with user-provided x, y, and radius values you would do something like this:

public static void drawCircle(Graphics g, int x, int y, int radius) {

  int diameter = radius * 2;

  //shift x and y by the radius of the circle in order to correctly center it
  g.fillOval(x - radius, y - radius, diameter, diameter); 

}

both answers are is incorrect. it should read:

x-=r;
y-=r;


drawOval(x,y,r*2,r*2);

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Graphics;
import javax.swing.JFrame;

public class Graphiic
{   
    public Graphics GClass;
    public Graphics2D G2D;
    public  void Draw_Circle(JFrame jf,int radius , int  xLocation, int yLocation)
    {
        GClass = jf.getGraphics();
        GClass.setPaintMode();
        GClass.setColor(Color.MAGENTA);
        GClass.fillArc(xLocation, yLocation, radius, radius, 0, 360);
        GClass.drawLine(100, 100, 200, 200);    
    }

}

This draws an arc with the center in the specified rectangle. You can draw, half-circles, quarter-circles, etc.

g.drawArc(x - r, y - r, r * 2, r * 2, 0, 360)

drawCircle(int X, int Y, int Radius, ColorFill, Graphics gObj) 

Replace your draw line with

g.drawOval(X - r, Y - r, r, r)

This should make the top-left of your circle the right place to make the center be (X,Y), at least as long as the point (X - r,Y - r) has both components in range.


The only thing that worked for me:

g.drawOval((getWidth()-200)/2,(getHeight()-200)/2, 200, 200);    

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