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/* * @(#)Scrollable.java 1.13 05/11/17 * * Copyright 2006 Sun Microsystems, Inc. All rights reserved. * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. */ package javax.swing; import java.awt.Dimension; import java.awt.Rectangle; /** * An interface that provides information to a scrolling container * like JScrollPane. A complex component that's likely to be used * as a viewing a JScrollPane viewport (or other scrolling container) * should implement this interface. * * @see JViewport * @see JScrollPane * @see JScrollBar * @version 1.13 11/17/05 * @author Hans Muller */ public interface Scrollable { /** * Returns the preferred size of the viewport for a view component. * For example, the preferred size of a <code>JList</code> component * is the size required to accommodate all of the cells in its list. * However, the value of <code>preferredScrollableViewportSize</code> * is the size required for <code>JList.getVisibleRowCount</code> rows. * A component without any properties that would affect the viewport * size should just return <code>getPreferredSize</code> here. * * @return the preferredSize of a <code>JViewport</code> whose view * is this <code>Scrollable</code> * @see JViewport#getPreferredSize */ Dimension getPreferredScrollableViewportSize(); /** * Components that display logical rows or columns should compute * the scroll increment that will completely expose one new row * or column, depending on the value of orientation. Ideally, * components should handle a partially exposed row or column by * returning the distance required to completely expose the item. * <p> * Scrolling containers, like JScrollPane, will use this method * each time the user requests a unit scroll. * * @param visibleRect The view area visible within the viewport * @param orientation Either SwingConstants.VERTICAL or SwingConstants.HORIZONTAL. * @param direction Less than zero to scroll up/left, greater than zero for down/right. * @return The "unit" increment for scrolling in the specified direction. * This value should always be positive. * @see JScrollBar#setUnitIncrement */ int getScrollableUnitIncrement(Rectangle visibleRect, int orientation, int direction); /** * Components that display logical rows or columns should compute * the scroll increment that will completely expose one block * of rows or columns, depending on the value of orientation. * <p> * Scrolling containers, like JScrollPane, will use this method * each time the user requests a block scroll. * * @param visibleRect The view area visible within the viewport * @param orientation Either SwingConstants.VERTICAL or SwingConstants.HORIZONTAL. * @param direction Less than zero to scroll up/left, greater than zero for down/right. * @return The "block" increment for scrolling in the specified direction. * This value should always be positive. * @see JScrollBar#setBlockIncrement */ int getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction); /** * Return true if a viewport should always force the width of this * <code>Scrollable</code> to match the width of the viewport. * For example a normal * text view that supported line wrapping would return true here, since it * would be undesirable for wrapped lines to disappear beyond the right * edge of the viewport. Note that returning true for a Scrollable * whose ancestor is a JScrollPane effectively disables horizontal * scrolling. * <p> * Scrolling containers, like JViewport, will use this method each * time they are validated. * * @return True if a viewport should force the Scrollables width to match its own. */ boolean getScrollableTracksViewportWidth(); /** * Return true if a viewport should always force the height of this * Scrollable to match the height of the viewport. For example a * columnar text view that flowed text in left to right columns * could effectively disable vertical scrolling by returning * true here. * <p> * Scrolling containers, like JViewport, will use this method each * time they are validated. * * @return True if a viewport should force the Scrollables height to match its own. */ boolean getScrollableTracksViewportHeight(); }