Filter.java

package org.openstreetmap.josm.plugins.rasterfilters.filters;

import java.awt.image.BufferedImage;
import java.rmi.server.UID;

import javax.json.JsonObject;

/**
 * The Filter interface is inherited by all filters which are implemented.
 * <p>
 * This interface has four methods that should be overrided in
 * <p>
 * implementation.
 *
 * @author Nipel-Crumple
 */
public interface Filter {

    /**
     * This method should take external fields values of filter's parameters
     * which should be described in the meta-information. In other words, if you have 3
     * controls of type 'linear_slider' and if state at least one of these
     * controls has changed, you will get new filter state in the form of
     * json object 'filterState', then parse it and
     * store given parameters' values in class.
     *
     * @param filterState json that has information about current filter state
     * @return json object 'filterState'
     */
    JsonObject changeFilterState(JsonObject filterState);

    /**
     * This method processes given image and returns
     * updated version of the image. Algorithm and implementation of
     * this method depends on your needs and wishes.
     *
     * @param img image to process
     * @return processed image
     */
    BufferedImage applyFilter(BufferedImage img);

    /**
     * Every filter must have his own unique ID number.
     * In case of rasterfilters plugin it ID is the type of UID.
     *
     * @param id sets value of ID field
     */
    void setId(UID id);

    /**
     * Getter for filter's ID field.
     *
     * @return id of filter
     */
    UID getId();
}