IJ/macros/Filter_Plugin.src

import ij.*;
import ij.process.*;
import ij.gui.*;
import java.awt.*;
import ij.plugin.filter.*;

public class Filter_Plugin implements PlugInFilter {
	ImagePlus imp;

	public int setup(String arg, ImagePlus imp) {
		this.imp = imp;
		return DOES_ALL;
	}

	public void run(ImageProcessor ip) {
		ip.invert();
	}

}