/* |
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* Copyright (c) 1997, 2013, Oracle and/or its affiliates. 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. Oracle designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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*/ |
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package javax.swing; |
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import java.awt.AWTError; |
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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™ |
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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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* @throws 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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} |