467 lines
12 KiB
Java
467 lines
12 KiB
Java
/* ScrollPane.java -- Scrolling window
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Copyright (C) 1999 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.awt;
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import java.awt.peer.ScrollPanePeer;
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import java.awt.peer.ContainerPeer;
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import java.awt.peer.ComponentPeer;
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/**
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* This widget provides a scrollable region that allows a single
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* subcomponent to be viewed through a smaller window.
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*
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* @author Aaron M. Renn (arenn@urbanophile.com)
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*/
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public class ScrollPane extends Container implements java.io.Serializable
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{
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/*
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* Static Variables
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*/
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/**
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* Constant indicating that scrollbars are created as needed in this
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* windows.
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*/
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public static final int SCROLLBARS_AS_NEEDED = 0;
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/**
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* Constant indicating that scrollbars are always displayed in this
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* window.
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*/
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public static final int SCROLLBARS_ALWAYS = 1;
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/**
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* Constant indicating that scrollbars are never displayed in this window.
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*/
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public static final int SCROLLBARS_NEVER = 2;
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// Serialization constant
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private static final long serialVersionUID = 7956609840827222915L;
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/*************************************************************************/
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/*
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* Instance Variables
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*/
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/**
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* @serial The horizontal scrollbar for this window. The methods
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* <code>setMinimum()</code>, <code>setMaximum</code>, and
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* <code>setVisibleAmount</code> must not be called on this scrollbar.
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*/
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private ScrollPaneAdjustable hAdjustable;
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/**
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* @serial The vertical scrollbar for this window. The methods
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* <code>setMinimum()</code>, <code>setMaximum</code>, and
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* <code>setVisibleAmount</code> must not be called on this scrollbar.
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*/
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private ScrollPaneAdjustable vAdjustable;
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/**
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* @serial Indicates when scrollbars are displayed in this window, will
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* be one of the constants from this class.
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*/
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private int scrollbarDisplayPolicy;
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// Current scroll position
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private Point scrollPosition = new Point(0, 0);
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/*************************************************************************/
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/*
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* Constructors
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*/
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/**
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* Initializes a new instance of <code>ScrollPane</code> with a default
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* scrollbar policy of <code>SCROLLBARS_AS_NEEDED</code>.
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*/
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public
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ScrollPane()
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{
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this(SCROLLBARS_AS_NEEDED);
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}
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/*************************************************************************/
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/**
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* Initializes a new instance of <code>ScrollPane</code> with the
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* specified scrollbar policy.
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*
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* @param scrollbarDisplayPolicy When to display scrollbars, which must
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* be one of the constants defined in this class.
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*/
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public
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ScrollPane(int scrollbarDisplayPolicy)
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{
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this.scrollbarDisplayPolicy = scrollbarDisplayPolicy;
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if ((scrollbarDisplayPolicy != SCROLLBARS_ALWAYS) ||
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(scrollbarDisplayPolicy != SCROLLBARS_AS_NEEDED) ||
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(scrollbarDisplayPolicy != SCROLLBARS_NEVER))
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throw new IllegalArgumentException("Bad scrollbarDisplayPolicy: " +
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scrollbarDisplayPolicy);
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if (scrollbarDisplayPolicy != SCROLLBARS_NEVER)
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{
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hAdjustable = new ScrollPaneAdjustable(Scrollbar.HORIZONTAL);
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vAdjustable = new ScrollPaneAdjustable(Scrollbar.VERTICAL);
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}
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}
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/*************************************************************************/
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/*
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* Instance Variables
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*/
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/**
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* Returns the current scrollbar display policy.
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*
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* @return The current scrollbar display policy.
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*/
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public int
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getScrollbarDisplayPolicy()
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{
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return(scrollbarDisplayPolicy);
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}
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/*************************************************************************/
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/**
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* Returns the horizontal scrollbar for this object. If the scrollbar
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* display policy is set to <code>SCROLLBARS_NEVER</code> then this
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* will be <code>null</code>.
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*
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* @return The horizontal scrollbar for this window.
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*/
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public Adjustable
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getHAdjustable()
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{
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return(hAdjustable);
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}
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/*************************************************************************/
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/**
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* Returns the vertical scrollbar for this object. If the scrollbar
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* display policy is set to <code>SCROLLBARS_NEVER</code> then this
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* will be <code>null</code>.
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*
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* @return The horizontal scrollbar for this window.
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*/
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public Adjustable
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getVAdjustable()
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{
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return(vAdjustable);
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}
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/*************************************************************************/
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/**
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* Returns the current viewport size. The viewport is the region of
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* this object's window where the child is actually displayed.
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*
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* @return The viewport size.
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*/
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public Dimension
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getViewportSize()
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{
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Dimension viewsize = getSize();
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Insets insets = getInsets();
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viewsize.width = viewsize.width - (insets.left + insets.right);
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viewsize.height = viewsize.height - (insets.top + insets.bottom);
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ScrollPaneAdjustable v = (ScrollPaneAdjustable)getVAdjustable();
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ScrollPaneAdjustable h = (ScrollPaneAdjustable)getHAdjustable();
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if ((v != null) && v.isVisible())
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viewsize.width = viewsize.width - v.getSize().width;
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if ((h != null) && h.isVisible())
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viewsize.height = viewsize.height - v.getSize().height;
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return(viewsize);
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}
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/*************************************************************************/
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/**
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* Returns the height of a horizontal scrollbar.
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*
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* @return The height of a horizontal scrollbar.
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*/
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public int
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getHScrollbarHeight()
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{
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ScrollPanePeer spp = (ScrollPanePeer)getPeer();
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if (spp != null)
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return(spp.getHScrollbarHeight());
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else
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return(0); // FIXME: What to do here?
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}
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/*************************************************************************/
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/**
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* Returns the width of a vertical scrollbar.
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*
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* @return The width of a vertical scrollbar.
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*/
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public int
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getVScrollbarWidth()
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{
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ScrollPanePeer spp = (ScrollPanePeer)getPeer();
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if (spp != null)
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return(spp.getVScrollbarWidth());
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else
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return(0); // FIXME: What to do here?
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}
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/*************************************************************************/
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/**
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* Returns the current scroll position of the viewport.
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*
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* @return The current scroll position of the viewport.
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*/
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public Point
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getScrollPosition()
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{
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int x = 0;
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int y = 0;
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Adjustable v = getVAdjustable();
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Adjustable h = getHAdjustable();
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if (v != null)
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y = v.getValue();
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if (h != null)
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x = h.getValue();
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return(new Point(x, y));
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}
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/*************************************************************************/
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/**
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* Sets the scroll position to the specified value.
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*
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* @param scrollPosition The new scrollPosition.
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*
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* @exception IllegalArgumentException If the specified value is outside
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* the legal scrolling range.
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*/
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public void
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setScrollPosition(Point scrollPosition) throws IllegalArgumentException
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{
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setScrollPosition(scrollPosition.x, scrollPosition.y);
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}
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/*************************************************************************/
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/**
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* Sets the scroll position to the specified value.
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*
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* @param x The new X coordinate of the scroll position.
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* @param y The new Y coordinate of the scroll position.
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*
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* @exception IllegalArgumentException If the specified value is outside
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* the legal scrolling range.
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*/
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public void
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setScrollPosition(int x, int y)
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{
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Adjustable h = getHAdjustable();
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Adjustable v = getVAdjustable();
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if (h != null)
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h.setValue(x);
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if (v != null)
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v.setValue(y);
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ScrollPanePeer spp = (ScrollPanePeer)getPeer();
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if (spp != null)
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spp.setScrollPosition(x, y);
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}
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/*************************************************************************/
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/**
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* Notifies this object that it should create its native peer.
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*/
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public void
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addNotify()
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{
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if (getPeer() == null)
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return;
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setPeer((ComponentPeer)getToolkit().createScrollPane(this));
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if (hAdjustable != null)
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hAdjustable.addNotify();
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if (vAdjustable != null)
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vAdjustable.removeNotify();
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}
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/*************************************************************************/
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/**
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* Notifies this object that it should destroy its native peers.
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*/
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public void
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removeNotify()
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{
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if (hAdjustable != null)
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hAdjustable.removeNotify();
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if (vAdjustable != null)
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vAdjustable.removeNotify();
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super.removeNotify();
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}
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/*************************************************************************/
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/**
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* Adds the specified child component to this container. A
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* <code>ScrollPane</code> can have at most one child, so if a second
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* one is added, then first one is removed.
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*
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* @param component The component to add to this container.
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* @param constraints A list of layout constraints for this object.
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* @param index The index at which to add the child, which is ignored
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* in this implementation.
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*/
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public final void
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addImpl(Component component, Object constraints, int index)
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{
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Component[] list = getComponents();
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if ((list != null) && (list.length > 0))
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remove(list[0]);
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super.addImpl(component, constraints, -1);
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doLayout();
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}
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/*************************************************************************/
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/**
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* Lays out this component. This consists of resizing the sole child
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* component to its perferred size.
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*/
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public void
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doLayout()
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{
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Component[] list = getComponents();
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if ((list != null) && (list.length > 0))
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{
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Dimension dim = list[0].getPreferredSize();
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list[0].resize(dim);
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Point p = getScrollPosition();
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if (p.x > dim.width)
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p.x = dim.width;
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if (p.y > dim.height)
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p.y = dim.height;
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setScrollPosition(p);
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}
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}
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/*************************************************************************/
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/**
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* Lays out this component. This consists of resizing the sole child
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* component to its perferred size.
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*
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* @deprecated This method is deprecated in favor of
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* <code>doLayout()</code>.
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*/
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public void
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layout()
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{
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doLayout();
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}
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/*************************************************************************/
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/**
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* This method overrides its superclass method to ensure no layout
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* manager is set for this container. <code>ScrollPane</code>'s do
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* not have layout managers.
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*
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* @param layoutManager Ignored
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*/
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public final void
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setLayout(LayoutManager layoutManager)
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{
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return;
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}
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/*************************************************************************/
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/**
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* Prints all of the components in this container.
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*
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* @param graphics The desired graphics context for printing.
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*/
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public void
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printComponents(Graphics graphics)
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{
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super.printComponents(graphics);
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}
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/*************************************************************************/
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/**
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* Returns a debug string for this object.
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*
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* @return A debug string for this object.
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*/
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public String
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paramString()
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{
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return(getClass().getName());
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}
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} // class ScrollPane
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