canvasstate.java

GEo 地理操作源代码

/**************************************************************************************************
 **
 ** $Id: CanvasState.java,v 1.3 2004/05/12 19:11:56 crossley Exp $
 **
 ** $Source: /cvsroot/geoapi/src/org/opengis/go/display/canvas/CanvasState.java,v $
 **
 ** Copyright (C) 2003 Open GIS Consortium, Inc. All Rights Reserved. http://www.opengis.org/Legal/
 **
 *************************************************************************************************/
package org.opengis.go.display.canvas;

import org.opengis.spatialschema.geometry.DirectPosition;

/**
 * Instances of this interface (and its sub-interfaces) describe the current
 * state of a <code>Canvas</code>.  The information contained by instances
 * of this interface should only describe the viewing area or volume of the
 * Canvas and should not contain any state information regarding the data 
 * contained within it.
 * <p>
 * When an instance of this class is returned from <code>Canvas</code>
 * methods, a "snapshot" of the current state of the Canvas is taken
 * and the values will never change (even if the Canvas changes state).
 *
 * @author Open GIS Consortium, Inc.
 * @version $Revision: 1.3 $, $Date: 2004/05/12 19:11:56 $
 */
public interface CanvasState {

    /**
     * Returns the title of the <code>Canvas</code>.
     */
    public String getTitle();

    /**
     * Returns the position of the center pixel of this Canvas.
     */
    public DirectPosition getCenter();

    /**
     * Returns a copy of this state object. The implementation should also clone
     * the object returned by <code>getCanvasParameterAccessor()</code>.
     */
    public Object clone() throws CloneNotSupportedException;

    /**
     * Determines if the given object is the same type of Canvas state object
     * and has values equal to this one. As part of the test, the implementation 
     * should also test equivalency of the object returned by 
     * <code>getCanvasParameterAccessor()</code>.
     */
    public boolean equals(Object object);

    

}