Draw a circle by getting center X/Y from a rectangle in Java

Description

The following code shows how to draw a circle by getting center X/Y from a rectangle.

Example


//from w w w.  ja  v  a2s  .c  o m
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Rectangle2D;

import javax.swing.JComponent;
import javax.swing.JFrame;

class MyCanvas extends JComponent {
  public void paint(Graphics g) {
    Graphics2D g2 = (Graphics2D) g;

    double leftX = 100;
    double topY = 100;
    double width = 200;
    double height = 150;

    Rectangle2D rect = new Rectangle2D.Double(leftX, topY, width, height);
    g2.draw(rect);
    
    double centerX = rect.getCenterX();
    double centerY = rect.getCenterY();
    double radius = 150;

    Ellipse2D circle = new Ellipse2D.Double();
    circle.setFrameFromCenter(centerX, centerY, centerX + radius, centerY + radius);
    g2.draw(circle);

  }
}

public class Main {
  public static void main(String[] a) {
    JFrame window = new JFrame();
    window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    window.setBounds(30, 30, 450, 450);
    window.getContentPane().add(new MyCanvas());
    window.setVisible(true);
  }
}

The code above generates the following result.

Draw a circle by getting center X/Y from a rectangle in Java




















Home »
  Java Tutorial »
    Graphics »




Animation
BufferedImage
Color
Font
Gradient
Graphics Settings
Image
Mouse Draw
Print
Shape
Text
Transform