001 /* Scrollable.java --
002 Copyright (C) 2002, 2004 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038 package javax.swing;
039
040 import java.awt.Dimension;
041 import java.awt.Rectangle;
042
043 /**
044 * Defines the method that a component should implement to behave nicely
045 * in {@link JScrollPane}s. Note that this is not required for a component
046 * to be used in a <code>JScrollPane</code>, but can highly improve the
047 * user experience when scrolling the component.
048 */
049 public interface Scrollable
050 {
051 Dimension getPreferredScrollableViewportSize();
052
053 /**
054 * Return the preferred scrolling amount (in pixels) for the given
055 * scrolling direction and orientation when scrolling in small amounts
056 * like table lines.
057 *
058 * @param visibleRect the currently visible part of the component.
059 * @param orientation the scrolling orientation
060 * @param direction the scrolling direction (negative - up, positive -down).
061 * The values greater than one means that more mouse wheel or similar
062 * events were generated, and hence it is better to scroll the longer
063 * distance.
064 *
065 * @return the preferred scrolling distance, negative if up or left.
066 */
067 int getScrollableUnitIncrement(Rectangle visibleRect, int orientation,
068 int direction);
069
070 /**
071 * Return the preferred scrolling amount (in pixels) for the given
072 * scrolling direction and orientation when scrolling in large amounts
073 * (pages).
074 *
075 * @param visibleRect the currently visible part of the component.
076 * @param orientation the scrolling orientation
077 * @param direction the scrolling direction (negative - up, positive -down).
078 * The values greater than one means that more mouse wheel or similar
079 * events were generated, and hence it is better to scroll the longer
080 * distance.
081 *
082 * @return the preferred scrolling distance, negative if up or left.
083 */
084 int getScrollableBlockIncrement(Rectangle visibleRect, int orientation,
085 int direction);
086
087 /**
088 * Return true if the width of the scrollable is always equal to the
089 * view, where it is displayed, width (for instance, the text area with
090 * the word wrap). In such case, the horizontal scrolling should not be
091 * performed.
092 *
093 * @return true is no horizontal scrolling is assumed, faster otherwise.
094 */
095 boolean getScrollableTracksViewportWidth();
096
097 /**
098 * Return true if the height of the scrollable is always equal to the view,
099 * where it is displayed, height.In such case, the vertical scrolling should
100 * not be performed.
101 *
102 * @return true is no horizontal scrolling is assumed, faster otherwise.
103 */
104 boolean getScrollableTracksViewportHeight();
105
106 }