image
Blurring a Buffered Image
In this tutorial we are going to see how can you load an image from a source and blur it. This is one of the most basic graphics effects that you are going to use when you begin with image processing.
In short, to blur a Buffered Image you simply have to take the following steps:
- Load an image from a URL 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
GraphicsEnvironment
,GraphicsDevice
andGraphicsConfiguration
to perform several image configurations - Draw the image into the buffered image
- Use a
BufferedImageOp
andConvolveOp
classes to put a new 3×3Kernel
to the image that blur it - And simply paint the buffered image in a new Frame
as you can see in 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.GraphicsConfiguration; import java.awt.GraphicsDevice; import java.awt.GraphicsEnvironment; import java.awt.Image; import java.awt.Toolkit; import java.awt.Transparency; import java.awt.image.BufferedImage; import java.awt.image.BufferedImageOp; import java.awt.image.ConvolveOp; import java.awt.image.ImageObserver; import java.awt.image.Kernel; public class BufferedImageBlur { 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(); // A 3x3 kernel that blurs an image Kernel kernel = new Kernel(3, 3, new float[] { 1f/9f, 1f/9f, 1f/9f, 1f/9f, 1f/9f, 1f/9f, 1f/9f, 1f/9f, 1f/9f}); BufferedImageOp op = new ConvolveOp(kernel); 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 Blur a Buffered Image in Java.