1. /*

  2.  * @(#)Autoscroll.java	1.10 00/02/02

  3.  *

  4.  * Copyright 1998-2000 Sun Microsystems, Inc. All Rights Reserved.

  5.  * 

  6.  * This software is the proprietary information of Sun Microsystems, Inc.  

  7.  * Use is subject to license terms.

  8.  * 

  9.  */

  10. 

  11. package java.awt.dnd;

  12. 

  13. import java.awt.Insets;

  14. import java.awt.Point;

  15. 

  16. /**

  17.  * During DnD operations it is possible that a user may wish to drop the 

  18.  * subject of the operation on a region of a scrollable GUI control that is

  19.  * not currently visible to the user.

  20.  * <p>

  21.  * In such situations it is desirable that the GUI control detect this

  22.  * and institute a scroll operation in order to make obscured region(s)

  23.  * visible to the user. This feature is known as autoscrolling.

  24.  * <p>

  25.  * If a GUI control is both an active <code>DropTarget</code>

  26.  * and is also scrollable, it

  27.  * can receive notifications of autoscrolling gestures by the user from

  28.  * the DnD system by implementing this interface.

  29.  * <p>

  30.  * An autoscrolling gesture is initiated by the user by keeping the drag

  31.  * cursor motionless with a border region of the <code>Component</code>, 

  32.  * referred to as

  33.  * the "autoscrolling region", for a predefined period of time, this will

  34.  * result in repeated scroll requests to the <code>Component</code> 

  35.  * until the drag <code>Cursor</code> resumes its motion.

  36.  *

  37.  * @version 	1.10, 02/02/00

  38.  * @since 1.2

  39.  */

  40. 

  41. public interface Autoscroll {

  42. 

  43.     /**

  44.      * This method returns the <code>Insets</code> describing 

  45.      * the autoscrolling region or border relative

  46.      * to the geometry of the implementing Component.

  47.      * <P>

  48.      * This value is read once by the <code>DropTarget</code> 

  49.      * upon entry of the drag <code>Cursor</code>

  50.      * into the associated <code>Component</code>.

  51.      * <P>

  52.      * @return the Insets

  53.      */

  54. 

  55.     public Insets getAutoscrollInsets();

  56. 

  57.     /**

  58.      * notify the <code>Component</code> to autoscroll

  59.      * <P>

  60.      * @param cursorLocn A <code>Point</code> indicating the 

  61.      * location of the cursor that triggered this operation.

  62.      */

  63. 

  64.     public void autoscroll(Point cursorLocn);

  65. 

  66. }