Java Image Gray Scale isGrayscale(ImageIcon icon)

Description

Determine whether the given image icon is grayscale

License

Open Source License

Parameter

Parameter	Description
icon	the image icon

Return

true if the image is grayscale

Declaration

public static boolean isGrayscale(ImageIcon icon) 

Method Source Code

//package com.java2s;
//       Distributed under the GNU Lesser General Public License

import java.awt.image.*;

import javax.swing.*;

public class Main {
    /**/*  w w  w  . j  av a 2s  .co  m*/
     * 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;
    }
}

Related

1. createGrayedImage(Image i, final boolean b, final int p)
2. grayScaleImage(Image img, int percent)
3. makeGrayImage(Image in)