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 }