ImageProcessing.java 文件源码

/**
 * All pixels that have the specified color are rendered transparent.
 *
 * @param img
 *          the img
 * @param color
 *          the color
 * @return the image
 */
public static Image applyAlphaChannel(final Image img, final Color color) {
  if (color == null || img == null) {
    return img;
  }

  final ImageFilter filter = new RGBImageFilter() {

    // the color we are looking for... Alpha bits are set to opaque
    public final int markerRGB = color.getRGB() | 0xFF000000;

    @Override
    public final int filterRGB(final int x, final int y, final int rgb) {
      if ((rgb | 0xFF000000) == this.markerRGB) {
        // Mark the alpha bits as zero - transparent
        return 0x00FFFFFF & rgb;
      } else {
        // nothing to do
        return rgb;
      }
    }
  };

  final ImageProducer ip = new FilteredImageSource(img.getSource(), filter);
  return Toolkit.getDefaultToolkit().createImage(ip);
}