Source for javax.swing.Scrollable

   1: /* Scrollable.java -- 
   2:    Copyright (C) 2002, 2004 Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: package javax.swing;
  39: 
  40: import java.awt.Dimension;
  41: import java.awt.Rectangle;
  42: 
  43: /**
  44:  * Defines the method that a component should implement to behave nicely
  45:  * in {@link JScrollPane}s. Note that this is not required for a component
  46:  * to be used in a <code>JScrollPane</code>, but can highly improve the
  47:  * user experience when scrolling the component.
  48:  */
  49: public interface Scrollable
  50: {
  51:   Dimension getPreferredScrollableViewportSize();
  52: 
  53:   /**
  54:    * Return the preferred scrolling amount (in pixels) for the given
  55:    * scrolling direction and orientation when scrolling in small amounts
  56:    * like table lines.
  57:    * 
  58:    * @param visibleRect the currently visible part of the component. 
  59:    * @param orientation the scrolling orientation
  60:    * @param direction the scrolling direction (negative - up, positive -down).
  61:    * The values greater than one means that more mouse wheel or similar 
  62:    * events were generated, and hence it is better to scroll the longer
  63:    * distance.
  64:    * 
  65:    * @return the preferred scrolling distance, negative if up or left.
  66:    */
  67:   int getScrollableUnitIncrement(Rectangle visibleRect, int orientation,
  68:                                  int direction);
  69: 
  70:   /**
  71:    * Return the preferred scrolling amount (in pixels) for the given
  72:    * scrolling direction and orientation when scrolling in large amounts
  73:    * (pages).
  74:    * 
  75:    * @param visibleRect the currently visible part of the component. 
  76:    * @param orientation the scrolling orientation
  77:    * @param direction the scrolling direction (negative - up, positive -down).
  78:    * The values greater than one means that more mouse wheel or similar 
  79:    * events were generated, and hence it is better to scroll the longer
  80:    * distance.
  81:    * 
  82:    * @return the preferred scrolling distance, negative if up or left. 
  83:    */
  84:   int getScrollableBlockIncrement(Rectangle visibleRect, int orientation,
  85:                                   int direction);
  86: 
  87:   /**
  88:    * Return true if the width of the scrollable is always equal to the
  89:    * view, where it is displayed, width (for instance, the text area with
  90:    * the word wrap). In such case, the horizontal scrolling should not be
  91:    * performed.
  92:    * 
  93:    * @return true is no horizontal scrolling is assumed, faster otherwise.
  94:    */
  95:   boolean getScrollableTracksViewportWidth();
  96: 
  97:   /**
  98:    * Return true if the height of the scrollable is always equal to the view,
  99:    * 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: }