In this example we shall show you how to set a clipping area from a component, in this case an image. This is a very basic operations that you will need when you are working in Java desktop applications that have rich graphcis.
Basically all you have to do in order to set a clipping aread from a shape is:
- Use
Toolkit.getDefaultToolkit().getImage(String imageURL)to load an image. Or you can just use the built int functions to create simple shape. - Create a class that extends component
- Use
java.awt.geom.Ellipse2D.Floatto set up a simple ellipse shape. - Use
Graphics2D.setClipto set the above ellipse as the clipping area.
Let’s see the code:
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.Shape;
import java.awt.Toolkit;
public class ShapeClipping {
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;
// Create an oval shape that's as large as the component
int x = 0;
int y = 0;
int width = getSize().width - 1;
int height = getSize().height - 1;
Shape shape = new java.awt.geom.Ellipse2D.Float(x, y, width, height);
// Set the clipping area
g2d.setClip(shape);
// Draw an image
g2d.drawImage(image, x, y, this);
}
}
}
This was an example on how to set a clipping area from a Shape.
