Effect.java 文件源码

/**
 * This method returns true if the specified image has transparent pixels
 *
 * @param  image an image.
 *
 * @return {@code true} if the image has transparent pixels, {@code false}
 *         otherwise.
 */
private 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();
}