ImageUtils.java Source code

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Here is the source code for ImageUtils.java

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/**
 * Balloontip - Balloon tips for Java Swing applications
 * Copyright 2007, 2008 Bernhard Pauler, Tim Molderez
 * 
 * This file is part of Balloontip.
 * 
 * Balloontip is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Balloontip is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with Balloontip.  If not, see <http://www.gnu.org/licenses/>.
 */

import java.awt.Graphics;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.HeadlessException;
import java.awt.Image;
import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.PixelGrabber;

import javax.swing.ImageIcon;

/**
 * Some methods for use with an Image
 * @author Tim Molderez
 */
public class ImageUtils {

    /*
     * Disallow instantiating this class
     */
    private ImageUtils() {
    };

    /**
     * This method returns true if the specified image has transparent pixels
     * This snippet was taken from: http://www.exampledepot.com/egs/java.awt.image/HasAlpha.html
     * @param image
     * @return True if the image has any transparency
     */
    public static boolean hasAlpha(Image image) {
        // If buffered image, the color model is readily available
        if (image instanceof BufferedImage) {
            BufferedImage bimage = (BufferedImage) image;
            return bimage.getColorModel().hasAlpha();
        }

        // Use a pixel grabber to retrieve the image's color model;
        // grabbing a single pixel is usually sufficient
        PixelGrabber pg = new PixelGrabber(image, 0, 0, 1, 1, false);
        try {
            pg.grabPixels();
        } catch (InterruptedException e) {
        }

        // Get the image's color model
        ColorModel cm = pg.getColorModel();
        return cm.hasAlpha();
    }

    /**
     * This method returns a buffered image with the contents of an image
     * This snippet was taken from: http://www.exampledepot.com/egs/java.awt.image/Image2Buf.html
     * @param image
     * @return The buffered image
     */
    public static BufferedImage toBufferedImage(Image image) {
        if (image instanceof BufferedImage) {
            return (BufferedImage) image;
        }

        // This code ensures that all the pixels in the image are loaded
        image = new ImageIcon(image).getImage();

        // Determine if the image has transparent pixels; for this method's
        // implementation, see e661 Determining If an Image Has Transparent Pixels
        boolean hasAlpha = hasAlpha(image);

        // Create a buffered image with a format that's compatible with the screen
        BufferedImage bimage = null;
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        try {
            // Determine the type of transparency of the new buffered image
            int transparency = Transparency.OPAQUE;
            if (hasAlpha) {
                transparency = Transparency.BITMASK;
            }

            // Create the buffered image
            GraphicsDevice gs = ge.getDefaultScreenDevice();
            GraphicsConfiguration gc = gs.getDefaultConfiguration();
            bimage = gc.createCompatibleImage(image.getWidth(null), image.getHeight(null), transparency);
        } catch (HeadlessException e) {
            // The system does not have a screen
        }

        if (bimage == null) {
            // Create a buffered image using the default color model
            int type = BufferedImage.TYPE_INT_RGB;
            if (hasAlpha) {
                type = BufferedImage.TYPE_INT_ARGB;
            }
            bimage = new BufferedImage(image.getWidth(null), image.getHeight(null), type);
        }

        // Copy image to buffered image
        Graphics g = bimage.createGraphics();

        // Paint the image onto the buffered image
        g.drawImage(image, 0, 0, null);
        g.dispose();

        return bimage;
    }
}