/*
 * Copyright (c) 2005, the JUNG Project and the Regents of the University 
 * of California
 * All rights reserved.
 *
 * This software is open-source under the BSD license; see either
 * "license.txt" or
 * http://jung.sourceforge.net/license.txt for a description.
 * Created on Mar 8, 2005
 *
 */
package edu.uci.ics.jung.visualization.control;

import java.awt.Cursor;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.geom.Point2D;

import edu.uci.ics.jung.visualization.Layer;
import edu.uci.ics.jung.visualization.VisualizationViewer;
import edu.uci.ics.jung.visualization.transform.MutableTransformer;

/** 
 * TranslatingGraphMousePlugin uses a MouseButtonOne press and
 * drag gesture to translate the graph display in the x and y
 * direction. The default MouseButtonOne modifier can be overridden
 * to cause a different mouse gesture to translate the display.
 * 
 * 
 * @author Tom Nelson
 */
public class TranslatingGraphMousePlugin extends AbstractGraphMousePlugin
    implements MouseListener, MouseMotionListener {

	/**
	 */
	public TranslatingGraphMousePlugin() {
	    this(MouseEvent.BUTTON1_MASK);
	}

	/**
	 * create an instance with passed modifer value
	 * @param modifiers the mouse event modifier to activate this function
	 */
	public TranslatingGraphMousePlugin(int modifiers) {
	    super(modifiers);
        this.cursor = Cursor.getPredefinedCursor(Cursor.MOVE_CURSOR);
	}

	/**
     * Check the event modifiers. Set the 'down' point for later
     * use. If this event satisfies the modifiers, change the cursor
     * to the system 'move cursor'
	 * @param e the event
	 */
	public void mousePressed(MouseEvent e) {
	    VisualizationViewer vv = (VisualizationViewer)e.getSource();
	    boolean accepted = checkModifiers(e);
	    down = e.getPoint();
	    if(accepted) {
	        vv.setCursor(cursor);
	    }
	}
    
	/**
	 * unset the 'down' point and change the cursoe back to the system
     * default cursor
	 */
    public void mouseReleased(MouseEvent e) {
        VisualizationViewer vv = (VisualizationViewer)e.getSource();
        down = null;
        vv.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
    }
    
    /**
     * chack the modifiers. If accepted, translate the graph according
     * to the dragging of the mouse pointer
     * @param e the event
	 */
    public void mouseDragged(MouseEvent e) {
        VisualizationViewer vv = (VisualizationViewer)e.getSource();
        boolean accepted = checkModifiers(e);
        if(accepted) {
            MutableTransformer modelTransformer = vv.getRenderContext().getMultiLayerTransformer().getTransformer(Layer.LAYOUT);
            vv.setCursor(cursor);
            try {
                Point2D q = vv.getRenderContext().getMultiLayerTransformer().inverseTransform(down);
                Point2D p = vv.getRenderContext().getMultiLayerTransformer().inverseTransform(e.getPoint());
                float dx = (float) (p.getX()-q.getX());
                float dy = (float) (p.getY()-q.getY());
                
                modelTransformer.translate(dx, dy);
                down.x = e.getX();
                down.y = e.getY();
            } catch(RuntimeException ex) {
                System.err.println("down = "+down+", e = "+e);
                throw ex;
            }
        
            e.consume();
            vv.repaint();
        }
    }

    public void mouseClicked(MouseEvent e) {
        // TODO Auto-generated method stub
        
    }

    public void mouseEntered(MouseEvent e) {
        // TODO Auto-generated method stub
        
    }

    public void mouseExited(MouseEvent e) {
        // TODO Auto-generated method stub
        
    }

    public void mouseMoved(MouseEvent e) {
        // TODO Auto-generated method stub
        
    }
}