home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Visual Cafe 3
/
Visual Cafe 3.ISO
/
Vcafe
/
JFC.bin
/
ViewportLayout.java
< prev
next >
Wrap
Text File
|
1998-06-30
|
6KB
|
179 lines
/*
* @(#)ViewportLayout.java 1.16 98/03/16
*
* Copyright (c) 1997 Sun Microsystems, Inc. All Rights Reserved.
*
* This software is the confidential and proprietary information of Sun
* Microsystems, Inc. ("Confidential Information"). You shall not
* disclose such Confidential Information and shall use it only in
* accordance with the terms of the license agreement you entered into
* with Sun.
*
* SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF THE
* SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
* IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
* PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR ANY DAMAGES
* SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING
* THIS SOFTWARE OR ITS DERIVATIVES.
*
*/
package com.sun.java.swing;
import java.awt.LayoutManager;
import java.awt.Component;
import java.awt.Container;
import java.awt.Rectangle;
import java.awt.Point;
import java.awt.Dimension;
import java.awt.Insets;
import java.io.Serializable;
/**
* The default layout manager for JViewport. JViewportLayout defines
* a policy for layout that should be useful for most applications.
* The viewport makes its view the same size as the viewport,
* however it will not make the view smaller than its minimum size.
* As the viewport grows the view is kept bottom justified until
* the entire view is visible, subsequently the view is kept top
* justified.
* <p>
* Warning: serialized objects of this class will not be compatible with
* future swing releases. The current serialization support is appropriate
* for short term storage or RMI between Swing1.0 applications. It will
* not be possible to load serialized Swing1.0 objects with future releases
* of Swing. The JDK1.2 release of Swing will be the compatibility
* baseline for the serialized form of Swing objects.
*
* @version 1.16 03/16/98
* @author unknown
*/
public class ViewportLayout implements LayoutManager, Serializable
{
/**
* Adds the specified component to the layout. Not used by this class.
* @param name the name of the component
* @param comp the the component to be added
*/
public void addLayoutComponent(String name, Component c) { }
/**
* Removes the specified component from the layout. Not used by
* this class.
* @param comp the component to remove
*/
public void removeLayoutComponent(Component c) { }
/**
* Returns the preferred dimensions for this layout given the components
* in the specified target container.
* @param target the component which needs to be laid out
* @return a Dimension object containing the preferred dimensions
* @see target the Container to be laid out
* @see #minimumLayoutSize
*/
public Dimension preferredLayoutSize(Container parent) {
Component view = ((JViewport)parent).getView();
if (view == null) {
return new Dimension(0, 0);
}
else if (view instanceof Scrollable) {
return ((Scrollable)view).getPreferredScrollableViewportSize();
}
else {
return view.getPreferredSize();
}
}
/**
* Returns the minimum dimensions needed to layout the components
* contained in the specified target container.
*
* @param target the component which needs to be laid out
* @return a Dimension object containing the minimum dimensions
* @see #preferredLayoutSize
*/
public Dimension minimumLayoutSize(Container parent) {
return new Dimension(4, 4);
}
/**
* Called by the AWT when the specified container needs to be laid out.
*
* @param parent the container to lay out
*
* @exception AWTError if the target isn't the container specified to the
* BoxLayout constructor
*/
public void layoutContainer(Container parent)
{
JViewport vp = (JViewport)parent;
Component view = vp.getView();
Scrollable scrollableView = null;
if (view == null) {
return;
}
else if (view instanceof Scrollable) {
scrollableView = (Scrollable) view;
}
/* All of the dimensions below are in view coordinates, except
* vpSize which we're converting.
*/
Insets insets = vp.getInsets();
Dimension viewPrefSize = view.getPreferredSize();
Dimension vpSize = vp.getSize();
Dimension extentSize = vp.toViewCoordinates(vpSize);
Dimension viewSize = viewPrefSize;
if (scrollableView != null) {
if (scrollableView.getScrollableTracksViewportWidth()) {
viewSize.width = vpSize.width;
}
if (scrollableView.getScrollableTracksViewportHeight()) {
viewSize.height = vpSize.height;
}
}
Point viewPosition = vp.getViewPosition();
/* If the new viewport size would leave empty space below the
* view, top justify the view.
*/
if ((viewPosition.y + extentSize.height) > viewSize.height) {
viewPosition.y = 0;
}
/* If the new viewport size would leave empty space to the
* right of the view, left justify the view.
*/
if ((viewPosition.x + extentSize.width) > viewSize.width) {
viewPosition.x = 0;
}
/* If the orgin of the view is showing and the viewport is
* bigger than the views preferred size, then make the view
* the same size as the viewport.
*/
if ((viewPosition.y == 0) && (vpSize.height > viewPrefSize.height)) {
viewPrefSize.height = vpSize.height;
}
if ((viewPosition.x == 0) && (vpSize.width > viewPrefSize.width)) {
viewPrefSize.width = vpSize.width;
}
vp.setViewPosition(viewPosition);
vp.setViewSize(viewPrefSize);
}
}