Converts an arbitrary image to a BufferedImage .

Description

Demo Code

/*/*from   ww  w  . j a v  a2s. c  o  m*/
 * VectorGraphics2D: Vector export for Java(R) Graphics2D
 *
 * (C) Copyright 2010-2015 Erich Seifert <dev[at]erichseifert.de>
 *
 * This file is part of VectorGraphics2D.
 *
 * VectorGraphics2D 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.
 *
 * VectorGraphics2D 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 VectorGraphics2D.  If not, see <http://www.gnu.org/licenses/>.
 */
//package com.java2s;

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 java.awt.image.RenderedImage;
import java.awt.image.WritableRaster;

import java.util.Hashtable;

import javax.swing.ImageIcon;

public class Main {
    /**
     * Converts an arbitrary image to a {@code BufferedImage}.
     * @param image Image that should be converted.
     * @return a buffered image containing the image pixels, or the original
     *         instance if the image already was of type {@code BufferedImage}.
     */
    public static BufferedImage toBufferedImage(RenderedImage image) {
        if (image instanceof BufferedImage) {
            return (BufferedImage) image;
        }

        ColorModel cm = image.getColorModel();
        WritableRaster raster = cm.createCompatibleWritableRaster(
                image.getWidth(), image.getHeight());
        boolean isRasterPremultiplied = cm.isAlphaPremultiplied();
        Hashtable<String, Object> properties = null;
        if (image.getPropertyNames() != null) {
            properties = new Hashtable<String, Object>();
            for (String key : image.getPropertyNames()) {
                properties.put(key, image.getProperty(key));
            }
        }

        BufferedImage bimage = new BufferedImage(cm, raster,
                isRasterPremultiplied, properties);
        image.copyData(raster);
        return bimage;
    }

    /**
     * This method returns a buffered image with the contents of an image.
     * Taken from http://www.exampledepot.com/egs/java.awt.image/Image2Buf.html
     * @param image Image to be converted
     * @return a buffered image with the contents of the specified 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
        boolean hasAlpha = hasAlpha(image);

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

    /**
     * This method returns {@code true} if the specified image has the
     * possibility to store transparent pixels.
     * Inspired by http://www.exampledepot.com/egs/java.awt.image/HasAlpha.html
     * @param image Image that should be checked for alpha channel.
     * @return {@code true} if the specified image can have transparent pixels,
     *         {@code false} otherwise
     */
    public static boolean hasAlpha(Image image) {
        ColorModel cm;
        // If buffered image, the color model is readily available
        if (image instanceof BufferedImage) {
            BufferedImage bimage = (BufferedImage) image;
            cm = bimage.getColorModel();
        } else {
            // 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) {
                return false;
            }
            // Get the image's color model
            cm = pg.getColorModel();
        }
        return cm.hasAlpha();
    }
}
Converts an arbitrary image to a BufferedImage . - Java 2D Graphics

Description

Demo Code

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