With this tutorial we shall show you how to swap RGB values in an Image. This is very useful when you are trying to create some effects to your Application.
Basically all you have to do in order to swapp RGD values of an Image is:
- Load an image using
ImageIconandgetImagemethod - Create a class that extends
RGBImageFilterand override the filterRGB method which is executed for every pixel in the image. Inside this method you can do all the RGB transformations you need - Create a filtered source image using
FilteredImageSourceand provide theRGBImageFilterclass you created in the previous step as an argument - And simply paint the buffered image in a new
Frame
Let’s see how the code looks like:
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;
import java.awt.image.FilteredImageSource;
import java.awt.image.RGBImageFilter;
import javax.swing.ImageIcon;
public class RGBSwapping {
static Image image;
public static void main(String[] args) {
// Get image - change to where your image file is located!
image = new ImageIcon("image.png").getImage();
// Create the filtered source image
FilteredImageSource filteredImageSource = new FilteredImageSource(image.getSource(), new RedBlueSwapFilter());
// Create the filtered image
image = Toolkit.getDefaultToolkit().createImage(filteredImageSource);
// Create frame with specific title
Frame frame = new Frame("Example 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 filter swaps the red and blue values in an image
static class RedBlueSwapFilter extends RGBImageFilter {
public RedBlueSwapFilter() {
// The filter's operation does not depend on the
// pixel's location, so IndexColorModels can be
// filtered directly.
canFilterIndexColorModel = true;
}
// This method is called for every pixel in the image
public int filterRGB(int x, int y, int rgb) {
return ((rgb & 0xff00ff00)
| ((rgb & 0xff0000) >> 16)
| ((rgb & 0xff) << 16));
}
}
}
This was an example on how to Swap the RGB values of an Image .
