Image handling and processing - JavaTech: An Introduction to Scientific and Technical Computing with Java - page 377

else
green = 255 — (255 * (x — half - width))/half - width;
// Blue starts from center and peaks at right side.
int blue = 0;
if (x > half - width)
blue = (255 * (x — half - width))/half - width;
int alpha = 255; // non — transparent
fPixels[i++] = (alpha << 24) | (red << 16)
| (green << 8) | blue;
}
}
// Now create the image from the pixel array.
fImage = createImage (
new MemoryImageSource (fWidth, fHeight, fPixels,
0, fWidth));
} // init
/** Paint the image on the panel. **/
public void paintComponent (Graphics g) {
super.paintComponent (g);
g.drawImage (fImage, 0, 0, this);
}
} // class ImagePanel
The MemoryImageSource can be set so that if the pixel array is modified the
image changes as well. This involves a subtle aspect of the way the Image class
works. The MemoryImageSource implements the ImageProducer interface.
The Image class obtains its pixel data from an ImageProducer rather than
simply reading an array.
To animate the display, use setAnimate() as follows:
source = new MemoryImageSource (width, height, pixels, 0,
width);
source.setAnimate (true);
image = createImage (source);
To create frames for the animation, we could use a loop in a run() method of a
threaded class as in the following code:
... in the run() method ...
while (true) {
// Invoke a method in the class that
// modifies the pixels in some way
modifyPixels ();