package examples;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/*
 * @author Kenneth J. Goldman, Washington University, kjg@wustl.edu
 * Created: Feb 3, 2005
 * Modified: March 30, 2006
 * 
 */
public class PanelWithOverlay extends JLayeredPane {
	private static final long serialVersionUID = 1L;
	JComponent content;
	
	/**
	 * Creates an PanelWithOverlay with the given content.
	 * The content is resized whenever the PanelWithOverlay is resized.
	 * @param content the component to be displayed in the default layer
	 */
	public PanelWithOverlay(final JComponent content) {
		this.content = content;
		content.setSize(content.getPreferredSize());
		add(content);
		addComponentListener(new ComponentAdapter() {
			public void componentResized(ComponentEvent arg0) {
				content.setSize(getSize());
				content.revalidate();
			}
		});
	}
	
	/**
	 * Raises the given component to the drag layer.
	 * MODIFIES: x, x.parent(), this
	 * EFFECTS: If x is not already a child of this JLayeredPane, x is added to
	 * the drag layer.  The component's position is converted to the coordinate system of
	 * the layered panel, so that it is appears to stay in the same place.
	 * @param x the Component to be moved to the overlay plane 
	 */
	void raiseToOverlay(Component x) {
		x.setLocation(SwingUtilities.convertPoint(x.getParent(), x.getLocation(), this));
		add(x,JLayeredPane.DRAG_LAYER);
	}

	/**
	 * Drops the given component from the drag layer into the content component, placing it in
	 * the content's container that is at the given point.
	 * MODIFIES: x, this, and the container beneath the cursor in the content panel
	 * EFFECTS: If the given cursor position is above a JComponent in the content panel, then
	 * x is added to that container 
	 * @param x
	 * @param cursor the position of the drop
	 * @return true if the cursor was above a container, and x was therefore dropped in
	 */
	boolean dropToContainerBeneath(Component x, Point cursor) {
		//Get the top level component under the cursor:
		Component beneath = content.getComponentAt(cursor);
		//Alternatively, allow component to be placed inside of the deepest component:
		//Component beneath = SwingUtilities.getDeepestComponentAt(content,cursor.x,cursor.y);
		if (beneath instanceof JComponent) {
			JComponent destination = (JComponent) beneath; 
			destination.add(x);
			destination.revalidate();  // force the layout manager to run
			repaint();
			return true;
		}
		return false;
	}
	
	/**
	 * Drops the given component (from the drag layer) into the content component, placing it in
	 * the content's container that is at the upper-left corner of the given component.
	 * MODIFIES: x, this, and the container beneath component in the content panel
	 * EFFECTS: If the given component is above a JComponent in the content panel, then
	 * x is added to that container .
	 * @param x
	 * @return true if the component was was above a JComponent in the content panel
	 */
	boolean dropToContainerBeneath(Component x) {
		return dropToContainerBeneath(x, x.getLocation());
	}
	
	public Dimension getPreferredSize() {
		return content.getPreferredSize();
	}
}