203 lines
7.4 KiB
Java
203 lines
7.4 KiB
Java
/*
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* Copyright 1997-2003 Sun Microsystems, Inc. All Rights Reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Sun designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Sun in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*/
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package javax.swing;
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import java.awt.LayoutManager;
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import java.awt.Component;
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import java.awt.Container;
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import java.awt.Rectangle;
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import java.awt.Point;
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import java.awt.Dimension;
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import java.awt.Insets;
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import java.io.Serializable;
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/**
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* The default layout manager for <code>JViewport</code>.
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* <code>ViewportLayout</code> defines
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* a policy for layout that should be useful for most applications.
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* The viewport makes its view the same size as the viewport,
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* however it will not make the view smaller than its minimum size.
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* As the viewport grows the view is kept bottom justified until
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* the entire view is visible, subsequently the view is kept top
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* justified.
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* <p>
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* <strong>Warning:</strong>
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* Serialized objects of this class will not be compatible with
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* future Swing releases. The current serialization support is
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* appropriate for short term storage or RMI between applications running
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* the same version of Swing. As of 1.4, support for long term storage
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* of all JavaBeans<sup><font size="-2">TM</font></sup>
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* has been added to the <code>java.beans</code> package.
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* Please see {@link java.beans.XMLEncoder}.
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*
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* @author Hans Muller
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*/
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public class ViewportLayout implements LayoutManager, Serializable
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{
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// Single instance used by JViewport.
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static ViewportLayout SHARED_INSTANCE = new ViewportLayout();
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/**
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* Adds the specified component to the layout. Not used by this class.
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* @param name the name of the component
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* @param c the the component to be added
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*/
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public void addLayoutComponent(String name, Component c) { }
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/**
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* Removes the specified component from the layout. Not used by
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* this class.
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* @param c the component to remove
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*/
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public void removeLayoutComponent(Component c) { }
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/**
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* Returns the preferred dimensions for this layout given the components
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* in the specified target container.
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* @param parent the component which needs to be laid out
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* @return a <code>Dimension</code> object containing the
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* preferred dimensions
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* @see #minimumLayoutSize
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*/
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public Dimension preferredLayoutSize(Container parent) {
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Component view = ((JViewport)parent).getView();
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if (view == null) {
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return new Dimension(0, 0);
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}
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else if (view instanceof Scrollable) {
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return ((Scrollable)view).getPreferredScrollableViewportSize();
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}
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else {
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return view.getPreferredSize();
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}
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}
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/**
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* Returns the minimum dimensions needed to layout the components
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* contained in the specified target container.
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*
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* @param parent the component which needs to be laid out
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* @return a <code>Dimension</code> object containing the minimum
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* dimensions
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* @see #preferredLayoutSize
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*/
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public Dimension minimumLayoutSize(Container parent) {
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return new Dimension(4, 4);
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}
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/**
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* Called by the AWT when the specified container needs to be laid out.
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*
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* @param parent the container to lay out
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*
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* @exception AWTError if the target isn't the container specified to the
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* <code>BoxLayout</code> constructor
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*/
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public void layoutContainer(Container parent)
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{
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JViewport vp = (JViewport)parent;
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Component view = vp.getView();
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Scrollable scrollableView = null;
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if (view == null) {
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return;
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}
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else if (view instanceof Scrollable) {
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scrollableView = (Scrollable) view;
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}
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/* All of the dimensions below are in view coordinates, except
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* vpSize which we're converting.
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*/
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Insets insets = vp.getInsets();
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Dimension viewPrefSize = view.getPreferredSize();
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Dimension vpSize = vp.getSize();
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Dimension extentSize = vp.toViewCoordinates(vpSize);
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Dimension viewSize = new Dimension(viewPrefSize);
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if (scrollableView != null) {
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if (scrollableView.getScrollableTracksViewportWidth()) {
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viewSize.width = vpSize.width;
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}
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if (scrollableView.getScrollableTracksViewportHeight()) {
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viewSize.height = vpSize.height;
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}
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}
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Point viewPosition = vp.getViewPosition();
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/* If the new viewport size would leave empty space to the
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* right of the view, right justify the view or left justify
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* the view when the width of the view is smaller than the
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* container.
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*/
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if (scrollableView == null ||
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vp.getParent() == null ||
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vp.getParent().getComponentOrientation().isLeftToRight()) {
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if ((viewPosition.x + extentSize.width) > viewSize.width) {
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viewPosition.x = Math.max(0, viewSize.width - extentSize.width);
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}
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} else {
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if (extentSize.width > viewSize.width) {
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viewPosition.x = viewSize.width - extentSize.width;
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} else {
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viewPosition.x = Math.max(0, Math.min(viewSize.width - extentSize.width, viewPosition.x));
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}
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}
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/* If the new viewport size would leave empty space below the
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* view, bottom justify the view or top justify the view when
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* the height of the view is smaller than the container.
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*/
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if ((viewPosition.y + extentSize.height) > viewSize.height) {
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viewPosition.y = Math.max(0, viewSize.height - extentSize.height);
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}
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/* If we haven't been advised about how the viewports size
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* should change wrt to the viewport, i.e. if the view isn't
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* an instance of Scrollable, then adjust the views size as follows.
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*
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* If the origin of the view is showing and the viewport is
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* bigger than the views preferred size, then make the view
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* the same size as the viewport.
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*/
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if (scrollableView == null) {
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if ((viewPosition.x == 0) && (vpSize.width > viewPrefSize.width)) {
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viewSize.width = vpSize.width;
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}
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if ((viewPosition.y == 0) && (vpSize.height > viewPrefSize.height)) {
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viewSize.height = vpSize.height;
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}
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}
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vp.setViewPosition(viewPosition);
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vp.setViewSize(viewSize);
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}
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}
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