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| 1 | /* | ||
| 2 | * Copyright (c) 1998, 1999, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package java.awt.dnd; | ||
| 27 | |||
| 28 | import java.awt.Insets; | ||
| 29 | import java.awt.Point; | ||
| 30 | |||
| 31 | /** | ||
| 32 | * During DnD operations it is possible that a user may wish to drop the | ||
| 33 | * subject of the operation on a region of a scrollable GUI control that is | ||
| 34 | * not currently visible to the user. | ||
| 35 | * <p> | ||
| 36 | * In such situations it is desirable that the GUI control detect this | ||
| 37 | * and institute a scroll operation in order to make obscured region(s) | ||
| 38 | * visible to the user. This feature is known as autoscrolling. | ||
| 39 | * <p> | ||
| 40 | * If a GUI control is both an active <code>DropTarget</code> | ||
| 41 | * and is also scrollable, it | ||
| 42 | * can receive notifications of autoscrolling gestures by the user from | ||
| 43 | * the DnD system by implementing this interface. | ||
| 44 | * <p> | ||
| 45 | * An autoscrolling gesture is initiated by the user by keeping the drag | ||
| 46 | * cursor motionless with a border region of the <code>Component</code>, | ||
| 47 | * referred to as | ||
| 48 | * the "autoscrolling region", for a predefined period of time, this will | ||
| 49 | * result in repeated scroll requests to the <code>Component</code> | ||
| 50 | * until the drag <code>Cursor</code> resumes its motion. | ||
| 51 | * | ||
| 52 | * @since 1.2 | ||
| 53 | */ | ||
| 54 | |||
| 55 | public interface Autoscroll { | ||
| 56 | |||
| 57 | /** | ||
| 58 | * This method returns the <code>Insets</code> describing | ||
| 59 | * the autoscrolling region or border relative | ||
| 60 | * to the geometry of the implementing Component. | ||
| 61 | * <P> | ||
| 62 | * This value is read once by the <code>DropTarget</code> | ||
| 63 | * upon entry of the drag <code>Cursor</code> | ||
| 64 | * into the associated <code>Component</code>. | ||
| 65 | * <P> | ||
| 66 | * @return the Insets | ||
| 67 | */ | ||
| 68 | |||
| 69 | public Insets getAutoscrollInsets(); | ||
| 70 | |||
| 71 | /** | ||
| 72 | * notify the <code>Component</code> to autoscroll | ||
| 73 | * <P> | ||
| 74 | * @param cursorLocn A <code>Point</code> indicating the | ||
| 75 | * location of the cursor that triggered this operation. | ||
| 76 | */ | ||
| 77 | |||
| 78 | public void autoscroll(Point cursorLocn); | ||
| 79 | |||
| 80 | } | ||