/*
    * Copyright (c) 2005, The JUNG Authors 
    *
    * All rights reserved.
    *
    * This software is open-source under the BSD license; see either
    * "license.txt" or
    * https://github.com/jrtom/jung/blob/master/LICENSE 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;
  
  /** 
   * ViewTranslatingGraphMousePlugin uses a MouseButtonOne press and
   * drag gesture to translate the graph display in the x and y
   * direction by changing the AffineTransform applied to the Graphics2D.
   * The default MouseButtonOne modifier can be overridden
   * to cause a different mouse gesture to translate the display.
   * 
   * 
   * @author Tom Nelson
   */
  public class ViewTranslatingGraphMousePlugin extends AbstractGraphMousePlugin
      implements MouseListener, MouseMotionListener {
  
  	/**
  	 */
  	public ViewTranslatingGraphMousePlugin() {
  	    this(MouseEvent.BUTTON1_MASK);
  	}
  
  	/**
  	 * create an instance with passed modifer value
  	 * @param modifiers the mouse event modifier to activate this function
  	 */
  	public ViewTranslatingGraphMousePlugin(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 viewTransformer = vv.getRenderContext().getMultiLayerTransformer().getTransformer(Layer.VIEW);
              vv.setCursor(cursor);
              try {
                  Point2D q = viewTransformer.inverseTransform(down);
                  Point2D p = viewTransformer.inverseTransform(e.getPoint());
                  float dx = (float) (p.getX()-q.getX());
                  float dy = (float) (p.getY()-q.getY());
                  
                  viewTransformer.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();
         }
     }
 
     public void mouseClicked(MouseEvent e) {
     }
 
     public void mouseEntered(MouseEvent e) {
     }
 
     public void mouseExited(MouseEvent e) {
     }
 
     public void mouseMoved(MouseEvent e) {
     }
 }