In this tutorial we are going to show you how to draw on an Image. This is quite useful when you want to further customize the graphics of your application, if you are not pleased with the original Image.
In short in order to Draw on a Buffered Image one should take the following steps:
- Load an image from a source using
Toolkit.getDefaultToolkit().getImagemethod - Use an
ImageObserverto monitor the loading of the image. When the image is fully load the user will be notified - Create class that extends
Componentand overrite thepaintmethod - Use
graphics.setColor(Color.red)andgraphics.fill(new Ellipse2D.Float(0, 0, 100, 50))to draw a simple shape in the Image - Use G
raphics2D.drawImageto draw the image
Let’s take a look at 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.Image;
import java.awt.Toolkit;
public class DrawImage {
static Image image;
public static void main(String[] args) {
// The image URL - change to where your image file is located!
String imageURL = "image.png";
// This call returns immediately and pixels are loaded in the background
image = Toolkit.getDefaultToolkit().getImage(imageURL);
// 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 Image object
* 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.
*/
int x = 0;
int y = 0;
g2d.drawImage(image, x, y, this);
}
}
}
This was an example on drawing an image.
