This method returns true if the specified image has transparent pixels. - Java 2D Graphics

Java examples for 2D Graphics:BufferedImage Pixel

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Description

This method returns true if the specified image has transparent pixels.

Demo Code

/*// w w w . j ava2s  . c  o m
 * VectorGraphics2D: Vector export for Java(R) Graphics2D
 *
 * (C) Copyright 2010-2012 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.Image;

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

public class Main {
    /**
     * This method returns {@code true} if the specified image
     * has transparent pixels.
     * Taken from http://www.exampledepot.com/egs/java.awt.image/HasAlpha.html
     * @param image
     * @return {@code true} if the specified image has transparent pixels,
     *         {@code false} otherwise
     */
    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) {
            return false;
        }
        // Get the image's color model
        ColorModel cm = pg.getColorModel();
        return cm.hasAlpha();
    }
}

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