Determine whether the given image is grayscale - Java 2D Graphics

Java examples for 2D Graphics:BufferedImage Scale

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Description

Determine whether the given image is grayscale

Demo Code

/*/*from w  w w.  ja  v  a  2 s.c o  m*/
 * A Collection of Miscellaneous Utilities
 *
 * Copyright 2010
 *      The President and Fellows of Harvard College.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
//package com.java2s;

import java.awt.image.*;

import javax.swing.*;

public class Main {
    /**
     * Determine whether the given image is grayscale
     *
     * @param rgb the RGB data
     * @return true if the image is grayscale
     */
    public static boolean isGrayscale(int[] rgb) {

        for (int i = 0; i < rgb.length; i++) {
            int pixel = rgb[i];
            int red = (pixel >> 16) & 0xff;
            int green = (pixel >> 8) & 0xff;
            int blue = (pixel) & 0xff;
            if ((red != blue) || (red != green) || (blue != green))
                return false;
        }

        return true;
    }

    /**
     * Determine whether the given image icon is grayscale
     *
     * @param icon the image icon
     * @return true if the image is grayscale
     */
    public static boolean isGrayscale(ImageIcon icon) {
        return isGrayscale(grabRGB(icon));
    }

    /**
     * Grabs a RGB values of the given image icon
     *
     * @param icon the image icon
     * @return an array of RGB values
     */
    public static int[] grabRGB(ImageIcon icon) {

        int width = icon.getIconWidth();
        int height = icon.getIconHeight();

        int[] rgb = new int[width * height];
        PixelGrabber pg = new PixelGrabber(icon.getImage(), 0, 0, width,
                height, rgb, 0, width);

        try {
            pg.grabPixels();
        } catch (InterruptedException e) {
            throw new RuntimeException("Interrupted waiting for pixels!");
        }

        if ((pg.getStatus() & ImageObserver.ABORT) != 0) {
            throw new RuntimeException("Image fetch aborted or errored");
        }

        for (int i = 0; i < rgb.length; i++)
            rgb[i] &= 0xffffff;

        return rgb;
    }
}

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