Scrollable.java

/* Scrollable.java --
   Copyright (C) 2002, 2004 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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General Public License for more details.

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02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
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package javax.swing;

import java.awt.Dimension;
import java.awt.Rectangle;

/**
 * Defines the method that a component should implement to behave nicely
 * in {@link JScrollPane}s. Note that this is not required for a component
 * to be used in a <code>JScrollPane</code>, but can highly improve the
 * user experience when scrolling the component.
 */
public interface Scrollable
{
  Dimension getPreferredScrollableViewportSize();

  /**
   * Return the preferred scrolling amount (in pixels) for the given
   * scrolling direction and orientation when scrolling in small amounts
   * like table lines.
   *
   * @param visibleRect the currently visible part of the component.
   * @param orientation the scrolling orientation
   * @param direction the scrolling direction (negative - up, positive -down).
   * The values greater than one means that more mouse wheel or similar
   * events were generated, and hence it is better to scroll the longer
   * distance.
   *
   * @return the preferred scrolling distance, negative if up or left.
   */
  int getScrollableUnitIncrement(Rectangle visibleRect, int orientation,
                                 int direction);

  /**
   * Return the preferred scrolling amount (in pixels) for the given
   * scrolling direction and orientation when scrolling in large amounts
   * (pages).
   *
   * @param visibleRect the currently visible part of the component.
   * @param orientation the scrolling orientation
   * @param direction the scrolling direction (negative - up, positive -down).
   * The values greater than one means that more mouse wheel or similar
   * events were generated, and hence it is better to scroll the longer
   * distance.
   *
   * @return the preferred scrolling distance, negative if up or left.
   */
  int getScrollableBlockIncrement(Rectangle visibleRect, int orientation,
                                  int direction);

  /**
   * Return true if the width of the scrollable is always equal to the
   * view, where it is displayed, width (for instance, the text area with
   * the word wrap). In such case, the horizontal scrolling should not be
   * performed.
   *
   * @return true is no horizontal scrolling is assumed, faster otherwise.
   */
  boolean getScrollableTracksViewportWidth();

  /**
   * Return true if the height of the scrollable is always equal to the view,
   * where it is displayed, height.In such case, the vertical scrolling should
   * not be performed.
   *
   * @return true is no horizontal scrolling is assumed, faster otherwise.
   */
  boolean getScrollableTracksViewportHeight();

}