"test.zoom.CenteredZoomTest",

        "test.zoom.MouseCenteredZoomTest",

/*

 * The contents of this file are subject to the terms of the Common Development

 * and Distribution License (the License). You may not use this file except in

 * compliance with the License.

 *

 * You can obtain a copy of the License at http://www.netbeans.org/cddl.html

 * or http://www.netbeans.org/cddl.txt.

 *

 * When distributing Covered Code, include this CDDL Header Notice in each file

 * and include the License file at http://www.netbeans.org/cddl.txt.

 * If applicable, add the following below the CDDL Header, with the fields

 * enclosed by brackets [] replaced by your own identifying information:

 * "Portions Copyrighted [year] [name of copyright owner]"

 *

 * The Original Software is NetBeans. The Initial Developer of the Original

 * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun

 * Microsystems, Inc. All Rights Reserved.

 */

package test.zoom;

import test.general.StringGraphScene;

import test.SceneSupport;

import org.netbeans.api.visual.action.ActionFactory;

import org.netbeans.api.visual.widget.Widget;

import java.awt.*;

/**

 * @author David Kaspar

 */

public class MouseCenteredZoomTest {

    public static void main (String[] args) {

        StringGraphScene scene = new StringGraphScene ();

        scene.getActions ().addAction (ActionFactory.createMouseCenteredZoomAction (1.1));

        scene.getActions ().addAction (ActionFactory.createPanAction ());

        for (int a = 0; a < 100; a ++) {

            Widget widget = scene.addNode (Integer.toString (a));

            int y = (int) (Math.random () * 2000);

            int x = (int) (Math.random () * 2000);

            widget.setPreferredLocation (new Point (x, y));

        }

        SceneSupport.show (scene);

    }

}

        <change>

            <api name="general"/>

            <summary>ActionFactory.createMouseCenteredZoomAction method introduced</summary>

            <version major="2" minor="3"/>

            <date day="28" month="5" year="2007"/>

            <author login="dkaspar"/>

            <compatibility addition="yes"/>

            <description>

                ActionFactory.createMouseCenteredZoomAction method introduced.

            </description>

            <class package="org.netbeans.api.visual.action" name="ActionFactory" link="yes"/>

            <issue number="104718"/>

        </change>

    /**

     * Creates a action that controls a zoom factor of a scene where the action is assigned.

     * During zooming the view will be centered to the mouse cursor.

     * @param zoomMultiplier the zoom multiplier

     * @return the zoom action

     * @since 2.3

     */

    public static WidgetAction createMouseCenteredZoomAction (double zoomMultiplier) {

        return new MouseCenteredZoomAction (zoomMultiplier);

    }

/*

 * The contents of this file are subject to the terms of the Common Development

 * and Distribution License (the License). You may not use this file except in

 * compliance with the License.

 *

 * You can obtain a copy of the License at http://www.netbeans.org/cddl.html

 * or http://www.netbeans.org/cddl.txt.

 *

 * When distributing Covered Code, include this CDDL Header Notice in each file

 * and include the License file at http://www.netbeans.org/cddl.txt.

 * If applicable, add the following below the CDDL Header, with the fields

 * enclosed by brackets [] replaced by your own identifying information:

 * "Portions Copyrighted [year] [name of copyright owner]"

 *

 * The Original Software is NetBeans. The Initial Developer of the Original

 * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun

 * Microsystems, Inc. All Rights Reserved.

 */

package org.netbeans.modules.visual.action;

import org.netbeans.api.visual.action.WidgetAction;

import org.netbeans.api.visual.widget.Scene;

import org.netbeans.api.visual.widget.Widget;

import javax.swing.*;

import java.awt.*;

/**

 * @author David Kaspar

 */

public final class MouseCenteredZoomAction extends WidgetAction.Adapter {

    private double zoomMultiplier;

    public MouseCenteredZoomAction (double zoomMultiplier) {

        this.zoomMultiplier = zoomMultiplier;

    }

    public State mouseWheelMoved (Widget widget, WidgetMouseWheelEvent event) {

        Scene scene = widget.getScene ();

        int amount = event.getWheelRotation ();

        double scale = 1.0;

        while (amount > 0) {

            scale /= zoomMultiplier;

            amount --;

        }

        while (amount < 0) {

            scale *= zoomMultiplier;

            amount ++;

        }

        JComponent view = scene.getView ();

        if (view != null) {

            Rectangle viewBounds = view.getVisibleRect ();

            Point center = widget.convertLocalToScene (event.getPoint ());

            Point mouseLocation = scene.convertSceneToView (center);

            scene.setZoomFactor (scale * scene.getZoomFactor ());

            scene.validate (); // HINT - forcing to change preferred size of the JComponent view

            center = scene.convertSceneToView (center);

            view.scrollRectToVisible (new Rectangle (

                    center.x - (mouseLocation.x - viewBounds.x),

                    center.y - (mouseLocation.y - viewBounds.y),

                    viewBounds.width,

                    viewBounds.height

            ));

        } else

            scene.setZoomFactor (scale * scene.getZoomFactor ());

        return State.CONSUMED;

    }

}

<li><strong>test.zoom.MouseCenteredZoomTest</strong> - how to use <code>MouseCenteredZoomAction</code>