mycanvas.java

Dijkstra algorithm in Java.

/*
 * MyCanvas.java
 *
 * Created on June 2, 2007, 10:20 AM
 *
 * To change this template, choose Tools | Template Manager
 * and open the template in the editor.
 */

package termproject_dijkstra;

/**
 *
 * @author Peto
 */
import java.awt.*;
import java.awt.event.*;


public class MyCanvas extends Canvas{
    
    int[]  m_iFrameSize = {0,0};
    
    public Dijkstra m_graph;
    public boolean m_bDrawOnlyPaths;    // Drawing only paths to the start node
    
/***********************************************************
/  Source code PARTIALLY from : http://www.codeproject.com/java/javadoublebuffer.asp
 ***********************************************************/
    
    
 //    class variables
    private int bufferWidth;
    private int bufferHeight;
    private Image bufferImage;
    private Graphics bufferGraphics;

   public void paint(Graphics g)
   {
           resetBuffer();

        if(bufferGraphics!=null){
            //this clears the offscreen image, not the onscreen one
            bufferGraphics.clearRect(0,0,bufferWidth,bufferHeight);

            //calls the paintbuffer method with 
            //the offscreen graphics as a param
            paintBuffer(bufferGraphics);

            //we finaly paint the offscreen image onto the onscreen image
            g.drawImage(bufferImage,0,0,this);
        }
    }
   
   MyCanvas()
   {
      bufferWidth = 0;
      bufferHeight = 0;
      
      m_graph = new Dijkstra();
    }

    private void resetBuffer()
    {
        // always keep track of the image size
        int newBufferWidth = getSize().width;
        int newBufferHeight = getSize().height;
        
       
        //    clean up the previous image
        if(newBufferWidth != bufferWidth || newBufferHeight != bufferHeight)
        {
            if (bufferGraphics!=null)
                bufferGraphics.dispose();
            if (bufferImage!=null)
                bufferImage.flush();
    
            bufferWidth = newBufferWidth;
            bufferHeight = newBufferHeight;
            bufferImage=createImage(bufferWidth,bufferHeight);
            bufferGraphics=bufferImage.getGraphics();
          
        }

        
        
    }      
 /***********************************************************
/  END Source code from : http://www.codeproject.com/java/javadoublebuffer.asp
 ***********************************************************/   
    
    public void paintBuffer(Graphics g)
    {
        float fxInc = (float)getWidth()/(float)m_iFrameSize[0];
        float fyInc = (float)getHeight()/(float)m_iFrameSize[1];
        
        g.setColor(new Color(255,255,255));
        g.fillRect(0,0,getWidth(),getHeight());
        
        if (GlobalVars.bConstCanvasSize)    
            m_graph.Draw(g,1.0f,1.0f);
        else
            m_graph.Draw(g,fxInc,fyInc);


    }
    
    public void update()
    {
         paint(getGraphics());
    }
    
    /** Creates a new instance of MyCanvas */
    public MyCanvas(int[] iFrameSize) 
    {
        m_iFrameSize[0] = iFrameSize[0];
        m_iFrameSize[1] = iFrameSize[1];
        
        m_graph = new Dijkstra();
        

    }
    

    
}