// File: ScrollPanel.java
// Classes: ScrollPanel
// Authors: Dave Boatwright and Kevin Carlson
// Date 24 Feb 1997

package uci.graphedit;
import java.awt.*;

public class Scrollpanel extends Panel{
  private Scrollbar hbar, vbar;
  private 
  public Panel panel;  
  private Dimension canvasSize;

  public Scrollpanel(int width, int height){
    super();
    hbar = new Scrollbar( Scrollbar.HORIZONTAL );
    vbar = new Scrollbar( Scrollbar.VERTICAL );
    canvasSize = new Dimension();
 
    hbar.setLineIncrement( 250 );
    vbar.setLineIncrement( 250 );

    panel = new Panel();
    panel.resize( canvasSize.width, canvasSize.height );
    this.setLayout( new BorderLayout(0,0) );
    this.add( "South",  hbar );
    this.add( "East", vbar );
    this.add( "Center", panel );
    
    resizeCanvas( width, height );    
  }

  public Panel getPanel(){
    return panel;
  } 

  public void resizeCanvas(int width, int height){
    canvasSize.width = width;
    canvasSize.height = height;
    this.home();
    this.scrollset();
  }

  public void resizeCanvas(Dimension dim){
    canvasSize = dim;
    this.home();
  }

  public void scrollset(){
    hbar.setPageIncrement( (this.size().width) - 18  );
    vbar.setPageIncrement( (this.size().height) - 18  );
    hbar.setValues(hbar.getValue(),1, 0, canvasSize.width - (this.size().width) - 18 );
    vbar.setValues(vbar.getValue(),1, 0, canvasSize.height - (this.size().height) - 18 );

    panel.resize( canvasSize.width, canvasSize.height );    
    panel.invalidate();
  }

  public void home(){
    hbar.setValue( 0 );
    vbar.setValue( 0 );
    panel.move(0,0);
    this.scrollset();
  }

  public synchronized void reshape( int x, int y, int width, int height ){
   super.reshape( x, y, width, height );
   this.scrollset();
  }

  public boolean handleEvent( Event e ){
   if( (e.target == hbar) || (e.target == vbar) ){
	panel.move( -(hbar.getValue()), -(vbar.getValue()) );
        panel.resize( canvasSize.width ,canvasSize.height);
	panel.invalidate();
        return true;
   }
   else{
        return super.handleEvent( e );
   }	
  }
}