Home » Desktop Java » awt » Draw shapes example

About Ilias Tsagklis

Ilias Tsagklis
Ilias is a software developer turned online entrepreneur. He is co-founder and Executive Editor at Java Code Geeks.

Draw shapes example

With this tutorial we shall show you how to draw simple shapes in a Java Desktop Application. This is a very important step when designing your own graphics for your App.

Basically, all you have to do in order to draw shapes in a Java application is:

  • Create a new Frame.
  • Create a class that extends the Component class and override the paint method.
  • Use Graphics2D.drawLine to draw a simple line.
  • Use Graphics2D.drawOval to draw an oval shape in the screen.
  • Use Graphics2D.drawRect to draw a rectangle on the screen.
  • Use Graphics2D.drawArc to draw an arch.
  • Create a new Polygon to add a polygon to your drawing, and use addPoint to add more points to the polygon.

Let’s see the code snippet that follows:

package com.javacodegeeks.snippets.desktop;

import java.awt.Component;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Polygon;

public class DrawShapesExample {

  public static void main(String[] args) {

// Create a frame

Frame frame = new Frame();

// Add a component with a custom paint method

frame.add(new CustomPaintComponent());

// Display the frame

int frameWidth = 300;

int frameHeight = 300;

frame.setSize(frameWidth, frameHeight);

frame.setVisible(true);

  }

 /**
  * To draw on the screen, it is first necessary to subclass a Component 
  * and override its paint() method. The paint() method is automatically called 
  * by the windowing system whenever component's area needs to be repainted.
  */
  static class CustomPaintComponent extends Component {

public void paint(Graphics g) {

  // Retrieve the graphics context; this object is used to paint shapes

  Graphics2D g2d = (Graphics2D)g;

  // Draw an oval that fills the window

  int x = 0;

  int y = 0;

  int w = getSize().width-1;

  int h = getSize().height-1;

  /**
    * The coordinate system of a graphics context is such that the origin is at the 
    * northwest corner and x-axis increases toward the right while the y-axis increases 
    * toward the bottom.
    */

  g2d.drawLine(x, y, w, h);

  // to draw a filled oval use : g2d.fillOval(x, y, w, h) instead

  g2d.drawOval(x, y, w, h);

  // to draw a filled rectangle use : g2d.fillRect(x, y, w, h) instead

  g2d.drawRect(x, y, w, h);

  // A start angle of 0 represents a 3 o'clock position, 90 represents a 12 o'clock position,

  // and -90 (or 270) represents a 6 o'clock position

  int startAngle = 45;

  int arcAngle = -60;

  // to draw a filled arc use : g2d.fillArc(x, y, w, h, startAngle, arcAngle) instead

  g2d.drawArc(x, y, w/2, h/2, startAngle, arcAngle);

  // to draw a filled round rectangle use : g2d.fillRoundRect(x, y, w, h, arcWidth, arcHeight) instead

  g2d.drawRoundRect(x, y, w, h, w/2, h/2);

  Polygon polygon = new Polygon();

  polygon.addPoint(w/4, h/2);

  polygon.addPoint(0, h/2);

  polygon.addPoint(w/4, 3*h/4);

  polygon.addPoint(w/2, 3*h/4);

  // Add more points...

  // to draw a filled round rectangle use : g2d.fillPolygon(polygon) instead

  g2d.drawPolygon(polygon);

}

  }

}

This was an example on how to draw shapes in a Java Desktop Application.

(No Ratings Yet)
Start the discussion Views Tweet it!

Do you want to know how to develop your skillset to become a Java Rockstar?

Subscribe to our newsletter to start Rocking right now!

To get you started we give you our best selling eBooks for FREE!

 

1. JPA Mini Book

2. JVM Troubleshooting Guide

3. JUnit Tutorial for Unit Testing

4. Java Annotations Tutorial

5. Java Interview Questions

6. Spring Interview Questions

7. Android UI Design

 

and many more ....

 

Receive Java & Developer job alerts in your Area

 

Leave a Reply

avatar
  Subscribe  
Notify of