Image handling and processing - JavaTech: An Introduction to Scientific and Technical Computing with Java - page 387

public final BufferedImage filter (BufferedImage source - img,
BufferedImage dest - img) {

// If no destination image provided, make one of same
// form as source
if (dest - img == null)
dest - img = createCompatibleDestImage
(source - img, null);

int width = source - img.getWidth ();
int height = source - img.getHeight ();

for (int y = 0; y < height; y++) {
for (int x = 0; x < width; x++) {
int pixel = source - img.getRGB (x,y);

// Get the component colors
int red = (pixel >> 16) & 0xff;
int green = (pixel >> 8) & 0xff;
int blue = pixel & 0xff;

// Rotate the values
int tmp = blue;
blue = green;
green = red;
red = tmp;

// Put new value into corresponding pixel of
// destination image;
pixel = (255 << 24) | (red << 16) | (green << 8) |
blue;
dest - img.setRGB (x,y,pixel);

}

}
return dest - img;
} // filter

/**
*Create a destination image if needed. Must be same
*width as source and will by default use the same
*color model. Otherwise, it will use the one passed
*toit.
*/
public BufferedImage createCompatibleDestImage (
BufferedImage source - img,
ColorModel dest - color - model

) {