Java The Complete Reference, Seventh Edition

778 Part II: The Java Library

The two concrete subclasses, shown in the next section, simply implement theconvolve( )

method, usingimgpixelsfor source data andnewimgpixelsto storethe result.

import java.applet.*;

import java.awt.*;

import java.awt.image.*;

abstract class Convolver implements ImageConsumer, PlugInFilter {

int width, height;

int imgpixels[], newimgpixels[];

boolean imageReady = false;

abstract void convolve(); // filter goes here...

public Image filter(Applet a, Image in) {

in.getSource().startProduction(this);

imageReady = false;

waitForImage();

newimgpixels = new int[width*height];

try {

convolve();

} catch (Exception e) {

System.out.println("Convolver failed: " + e);

e.printStackTrace();

}

FIGURE 25-9

Using theContrast

filter with

ImageFilterDemo