J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1997-2003 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package javax.swing; |
| 27 | |
| 28 | import java.awt.Dimension; |
| 29 | import java.awt.Rectangle; |
| 30 | |
| 31 | |
| 32 | /** |
| 33 | * An interface that provides information to a scrolling container |
| 34 | * like JScrollPane. A complex component that's likely to be used |
| 35 | * as a viewing a JScrollPane viewport (or other scrolling container) |
| 36 | * should implement this interface. |
| 37 | * |
| 38 | * @see JViewport |
| 39 | * @see JScrollPane |
| 40 | * @see JScrollBar |
| 41 | * @author Hans Muller |
| 42 | */ |
| 43 | public interface Scrollable |
| 44 | { |
| 45 | /** |
| 46 | * Returns the preferred size of the viewport for a view component. |
| 47 | * For example, the preferred size of a <code>JList</code> component |
| 48 | * is the size required to accommodate all of the cells in its list. |
| 49 | * However, the value of <code>preferredScrollableViewportSize</code> |
| 50 | * is the size required for <code>JList.getVisibleRowCount</code> rows. |
| 51 | * A component without any properties that would affect the viewport |
| 52 | * size should just return <code>getPreferredSize</code> here. |
| 53 | * |
| 54 | * @return the preferredSize of a <code>JViewport</code> whose view |
| 55 | * is this <code>Scrollable</code> |
| 56 | * @see JViewport#getPreferredSize |
| 57 | */ |
| 58 | Dimension getPreferredScrollableViewportSize(); |
| 59 | |
| 60 | |
| 61 | /** |
| 62 | * Components that display logical rows or columns should compute |
| 63 | * the scroll increment that will completely expose one new row |
| 64 | * or column, depending on the value of orientation. Ideally, |
| 65 | * components should handle a partially exposed row or column by |
| 66 | * returning the distance required to completely expose the item. |
| 67 | * <p> |
| 68 | * Scrolling containers, like JScrollPane, will use this method |
| 69 | * each time the user requests a unit scroll. |
| 70 | * |
| 71 | * @param visibleRect The view area visible within the viewport |
| 72 | * @param orientation Either SwingConstants.VERTICAL or SwingConstants.HORIZONTAL. |
| 73 | * @param direction Less than zero to scroll up/left, greater than zero for down/right. |
| 74 | * @return The "unit" increment for scrolling in the specified direction. |
| 75 | * This value should always be positive. |
| 76 | * @see JScrollBar#setUnitIncrement |
| 77 | */ |
| 78 | int getScrollableUnitIncrement(Rectangle visibleRect, int orientation, int direction); |
| 79 | |
| 80 | |
| 81 | /** |
| 82 | * Components that display logical rows or columns should compute |
| 83 | * the scroll increment that will completely expose one block |
| 84 | * of rows or columns, depending on the value of orientation. |
| 85 | * <p> |
| 86 | * Scrolling containers, like JScrollPane, will use this method |
| 87 | * each time the user requests a block scroll. |
| 88 | * |
| 89 | * @param visibleRect The view area visible within the viewport |
| 90 | * @param orientation Either SwingConstants.VERTICAL or SwingConstants.HORIZONTAL. |
| 91 | * @param direction Less than zero to scroll up/left, greater than zero for down/right. |
| 92 | * @return The "block" increment for scrolling in the specified direction. |
| 93 | * This value should always be positive. |
| 94 | * @see JScrollBar#setBlockIncrement |
| 95 | */ |
| 96 | int getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction); |
| 97 | |
| 98 | |
| 99 | /** |
| 100 | * Return true if a viewport should always force the width of this |
| 101 | * <code>Scrollable</code> to match the width of the viewport. |
| 102 | * For example a normal |
| 103 | * text view that supported line wrapping would return true here, since it |
| 104 | * would be undesirable for wrapped lines to disappear beyond the right |
| 105 | * edge of the viewport. Note that returning true for a Scrollable |
| 106 | * whose ancestor is a JScrollPane effectively disables horizontal |
| 107 | * scrolling. |
| 108 | * <p> |
| 109 | * Scrolling containers, like JViewport, will use this method each |
| 110 | * time they are validated. |
| 111 | * |
| 112 | * @return True if a viewport should force the Scrollables width to match its own. |
| 113 | */ |
| 114 | boolean getScrollableTracksViewportWidth(); |
| 115 | |
| 116 | /** |
| 117 | * Return true if a viewport should always force the height of this |
| 118 | * Scrollable to match the height of the viewport. For example a |
| 119 | * columnar text view that flowed text in left to right columns |
| 120 | * could effectively disable vertical scrolling by returning |
| 121 | * true here. |
| 122 | * <p> |
| 123 | * Scrolling containers, like JViewport, will use this method each |
| 124 | * time they are validated. |
| 125 | * |
| 126 | * @return True if a viewport should force the Scrollables height to match its own. |
| 127 | */ |
| 128 | boolean getScrollableTracksViewportHeight(); |
| 129 | } |