Returns true if the specified image has transparent pixels. - Java 2D Graphics

Java examples for 2D Graphics:BufferedImage Pixel

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Description

Returns true if the specified image has transparent pixels.

Demo Code

/*/*ww w .j  av a  2 s. c  o m*/
 * Image conversion utilities.
 * 
 * Copyright (c) 2006 Jean-Sebastien Senecal (js@drone.ws)
 * 
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 2 of the License, or (at your option) any later
 * version.
 * 
 * This program 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 General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 675 Mass
 * Ave, Cambridge, MA 02139, USA.
 */
//package com.java2s;

import java.awt.Image;

import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;

import java.awt.image.PixelGrabber;

public class Main {
    /**
     * Returns true if the specified image has transparent pixels.
     * 
     * @param image the image to test
     * @return true if the specified image has transparent pixels
     */
    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();
    }
}

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