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About Byron Kiourtzoglou

Byron Kiourtzoglou
Byron is a master software engineer working in the IT and Telecom domains. He is an applications developer in a wide variety of applications/services. He is currently acting as the team leader and technical architect for a proprietary service creation and integration platform for both the IT and Telecom industries in addition to a in-house big data real-time analytics solution. He is always fascinated by SOA, middleware services and mobile development. Byron is co-founder and Executive Editor at Java Code Geeks.

Flipping a Buffered Image

With this example we are going to show you how to perform one of the most basic graphics transformations. When you perform flipping of an image you simply rotate the image.

In short in order to flip an image one should take the following steps:

  • Load an image from a source using Toolkit.getDefaultToolkit().getImage method
  • Use an ImageObserver to monitor the loading of the image. When the image is fully load the user will be notified
  • Create a buffed image from the source image with a format more close to the custom display environment using GraphicsEnvironmentGraphicsDevice and GraphicsConfiguration to perform several image configurations
  • Use AffineTransform class and its method translate to flip the image horizontally or vertically or both.
  • And simply paint the buffered image in a new Frame
as you can see in the following code snippet:
package com.javacodegeeks.snippets.desktop;

import java.awt.Component;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.Transparency;
import java.awt.geom.AffineTransform;
import java.awt.image.AffineTransformOp;
import java.awt.image.BufferedImage;
import java.awt.image.ImageObserver;

public class BufferedImageFlipps {

    static BufferedImage image;
    static boolean imageLoaded = false;

    public static void main(String[] args) {

  // The ImageObserver implementation to observe loading of the image

  ImageObserver myImageObserver = new ImageObserver() {

    public boolean imageUpdate(Image image, int flags, int x, int y, int width, int height) {

if ((flags & ALLBITS) != 0) {

  imageLoaded = true;

  System.out.println("Image loading finished!");

  return false;

}

return true;

    }

  };

  // 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

   * We use an ImageObserver to be notified when the loading of the image

   * is complete

   */

  Image sourceImage = Toolkit.getDefaultToolkit().getImage(imageURL);

  sourceImage.getWidth(myImageObserver);

  // We wait until the image is fully loaded

  while (!imageLoaded) {

try {

    Thread.sleep(100);

} catch (InterruptedException e) {

}

  }

  // Create a buffered image from the source image with a format that's compatible with the screen

  GraphicsEnvironment graphicsEnvironment = GraphicsEnvironment.getLocalGraphicsEnvironment();

  GraphicsDevice graphicsDevice = graphicsEnvironment.getDefaultScreenDevice();

  GraphicsConfiguration graphicsConfiguration = graphicsDevice.getDefaultConfiguration();

  // If the source image has no alpha info use Transparency.OPAQUE instead

  image = graphicsConfiguration.createCompatibleImage(sourceImage.getWidth(null), sourceImage.getHeight(null), Transparency.BITMASK);

  // Copy image to buffered image

  Graphics graphics = image.createGraphics();

  // Paint the image onto the buffered image

  graphics.drawImage(sourceImage, 0, 0, null);

  graphics.dispose();

  // Flip the image vertically

  AffineTransform tx = AffineTransform.getScaleInstance(1, -1);

  tx.translate(0, -image.getHeight(null));

  AffineTransformOp op = new AffineTransformOp(tx, AffineTransformOp.TYPE_NEAREST_NEIGHBOR);

  image = op.filter(image, null);

  // Flip the image horizontally

  tx = AffineTransform.getScaleInstance(-1, 1);

  tx.translate(-image.getWidth(null), 0);

  op = new AffineTransformOp(tx, AffineTransformOp.TYPE_NEAREST_NEIGHBOR);

  image = op.filter(image, null);

  // Flip the image vertically and horizontally; equivalent to rotating the image 180 degrees

  tx = AffineTransform.getScaleInstance(-1, -1);

  tx.translate(-image.getWidth(null), -image.getHeight(null));

  op = new AffineTransformOp(tx, AffineTransformOp.TYPE_NEAREST_NEIGHBOR);

  image = op.filter(image, null);

  // 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 was an example on how to Flip a Buffered Image in Java.

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