/* class JViewport
*
* Copyright (C) 2001-2003 R M Pitman
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package charvax.swing;
import charva.awt.Component;
import charva.awt.Container;
import charva.awt.Dimension;
import charva.awt.Point;
import charva.awt.Rectangle;
import charva.awt.Scrollable;
import charva.awt.Toolkit;
import charvax.swing.table.TableHeader;
/**
* The JViewport class provides a scrollable window onto an underlying
* component, whose size can be greater than the size of the JViewport.
* The underlying component must implement the Scrollable interface.
*/
public class JViewport
extends Container
{
/** Construct a JViewport.
*/
public JViewport () {
}
/** Set the JViewport's one child.
*/
public void setView(Component child_) {
if ((child_ instanceof Scrollable) == false &&
(child_ instanceof TableHeader) == false) {
throw new IllegalArgumentException(
"JViewport's view must be a Scrollable or a TableHeader");
}
if (_child != null)
super.remove(_child); // only allow one child.
super.add(child_);
_child = child_;
}
/** Returns the JViewport's one child.
*/
public Component getView() {
return _child;
}
public void draw(Toolkit toolkit) {
/* Get the absolute origin of this Viewport
*/
Point origin = getLocationOnScreen();
toolkit.setClipRect(new Rectangle(origin, getExtentSize()));
_child.draw(toolkit);
toolkit.resetClipRect();
}
/** Gets the coordinates of the origin of the view, relative to
* the origin of the viewport.
*/
public Point getViewPosition() { return _child.getLocation(); }
/** Sets the coordinates of the origin of the view, relative to
* the origin of the viewport.
*/
public void setViewPosition(Point origin_) {
_child.setLocation(origin_);
}
/** Returns the child component's size.
*/
public Dimension getViewSize() {
return _child.getSize();
}
public Rectangle getBounds() {
return new Rectangle(getLocation(), getExtentSize());
}
/** This package-private method is called by JScrollPane to
* determine the size of the visible viewport (when the
* component being displayed does not implement the Scrollable
* interface - for example, a TableHeader).
*/
void setExtentSize(int width, int height) {
_extent = new Dimension(width, height);
}
/** Returns the size of the visible part of the view.
*/
public Dimension getExtentSize() {
return new Dimension(_extent);
}
public void debug(int level_) {
for (int i=0; i<level_; i++)
System.err.print(" ");
System.err.println("Viewport origin=" + _origin +
" size=" + getSize() );
super.debug(level_ + 1);
}
//====================================================================
// INSTANCE VARIABLES
private Component _child;
private Dimension _extent;
}