// This example is from the book _Java AWT Reference_ by John Zukowski.
// Written by John Zukowski. Copyright (c) 1997 O'Reilly & Associates.
// You may study, use, modify, and distribute this example for any purpose.
// This example is provided WITHOUT WARRANTY either expressed or
import java.awt.image.*;
class TransparentImageFilter extends RGBImageFilter {
float alphaPercent;
public TransparentImageFilter () {
this (0.75f);
}
public TransparentImageFilter (float aPercent)
throws IllegalArgumentException {
if ((aPercent < 0.0) || (aPercent > 1.0))
throw new IllegalArgumentException();
alphaPercent = aPercent;
canFilterIndexColorModel = true;
}
public int filterRGB (int x, int y, int rgb) {
int a = (rgb >> 24) & 0xff;
a *= alphaPercent;
return ((rgb & 0x00ffffff) | (a << 24));
}
}