Java code to drwa shortest path tree

[laian.alsabbagh]

Hello, I have this java code which draws to me 100 nodes(with the sink node)(like the figure) that are connected by links, at the end I will get a tree , now I need to redraw the tree in(shortest path tree using prim algorithm )I have the nods in ( x,y) coordinate, and the number of hops from any node to the sink node and the parent for each node(these result I got them from my c++ prim algorithm code )
I’m really confused and I don’t know how to improve the code to redraw the shortest path tree
Any suggestions or comments will be appreciated

package heuristic;
import javax.swing.*;
import java.awt.Color;
import java.io.*;
import java.util.*;
import java.awt.Graphics;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;


public class multitreeplot extends JFrame {
    public void paint(Graphics paint){
        super.paint(paint);
        int[][] data;
        int NMax = 500; // number of nodes in the topology
        int dx = 100, dy = 100 , rectSize = 500;
        data = new int[NMax][2];
        int Ovalsize = 6;
        int Plus = 1;
        double radiorange =50;
     try{
//nodes

    FileReader fG = new FileReader("OriginalTopoPos.txt");
        BufferedReader bufReadG = new BufferedReader(fG);
//sink
        FileReader fSinks = new FileReader("SinksFile.txt");
        BufferedReader bufReadSinks = new BufferedReader(fSinks);

             setTitle("MultiTree Drawer");


            // The whole background
            paint.setColor (Color.white);
            paint.fillRect (0,0,700,700);

             // Determine the size of the area.
             paint.setColor (Color.black);
             paint.drawRect (dx-1,dy-1,rectSize+1,rectSize+1);
             paint.drawRect (dx-2,dy-2,rectSize+1,rectSize+1);
             paint.setColor (Color.white);
             paint.fillRect (dx+1,dy+1,rectSize-2,rectSize-2);

             //Plot the original topology.
            NMax = 0;
            String lineG =new String( bufReadG.readLine());
            while (lineG != null){
                int index= lineG.indexOf("-");
                double x= (new Double(lineG.substring(0, index))).doubleValue();
                double y= (new Double(lineG.substring(index+1, lineG.length()))).doubleValue();

                // ** Reflect the image
                      // Aseel, in your experiment do not divide y, x by 10///
                y=rectSize-y/10;                                                    
                x = (int)(x/10.0) + 100;
                y = (int)(y) + 100;                 
                data[NMax][0] = (int)(x);
                data[NMax][1] = (int)(y);

                System.out.println((int)x+","+(int)y);

                String s = String.valueOf(NMax);
                paint.setColor (Color.gray);
                paint.drawString(s, (int)x+4,(int)y-1);

                paint.setColor (Color.blue);
                paint.drawOval((int)x-4,(int)y-4, Ovalsize+Plus, Ovalsize+Plus);

                paint.setColor (Color.blue);
                paint.fillOval((int)x-3,(int)y-3, Ovalsize, Ovalsize);
                lineG = bufReadG.readLine();
                NMax++;
            }



            //Plot the links in original Topology.
            // *********************************
        //  
             for (int i =0 ; i < NMax; i++)
                for (int j =i ; j < NMax; j++){
                    double distance = Math.pow(data[i][0]-data[j][0],2)+ Math.pow(data[i][1]-data[j][1],2);
                    distance = Math.sqrt(distance);
                    paint.setColor (Color.gray);
                    if (distance <= radiorange)
                        {
                            //gradient
                            //pink
                            //magenta
                            //cyan
            paint.setColor (Color.magenta);
                        paint.drawLine( data[i][0], data[i][1], data[j][0],data[j][1] );
                        }


                }
    //    */


            //Plot Sink Nodes.
            int Sinks = 0;
            String lineSinks =new String( bufReadSinks.readLine());
            while(lineSinks != null){
                int index= lineSinks.indexOf("-");
                double x= (new Double(lineSinks.substring(0, index))).doubleValue();
                double y= (new Double(lineSinks.substring(index+1, lineSinks.length()))).doubleValue();

                //Reflect the image
                y=rectSize-y/10;                                                    
                x = (int)(x/10.0) + 100;
                y = (int)(y) + 100;   

                paint.setColor (Color.blue);
                paint.drawRect((int)x-5,(int)y-4, Ovalsize+Plus, Ovalsize+Plus);

                paint.setColor (Color.green);
                paint.fillRect((int)x-4,(int)y-3, Ovalsize, Ovalsize);  

                //String s = String.valueOf(NMax);
                String s = "Sink";
                paint.setColor (Color.gray);
                paint.setColor (Color.black);
                paint.drawString(s, (int)x+12,(int)y-5);        

                lineSinks = bufReadSinks.readLine();
                Sinks++;
            }
            //System.out.println(Sinks);


     }catch(Exception e){
        System.out.println(e);
        System.exit(-1);
     }

   }

    public multitreeplot(){
        super("");
        int WSize = 700;
        setSize(WSize,WSize);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        }
public static void main(String [] args) throws Exception{
    JFrame win= new JFrame();
    multitreeplot drawing= new multitreeplot();
    drawing.setVisible(true);
}
}
//System.out.println((int)x+","+(int)y);

[Taywin]

Do you want each path from each node to the sink node to be different color? If so, you will need to reconstruct the path to get back to the sink node. If not, you imply ignore the hop value and draw only the line from itself to its parent node. That way, it will display all paths of the shortest spanning tree.

[laian.alsabbagh]

So you mean that the hops are not important to use,???

[Taywin]

To draw a spanning tree, you don't need to know the path from each node to the sink node because those paths away from each node (the one which is the 2nd, 3rd, etc hop) are already covered (the same) by itself to its parent node.

/*
i.e.

  2---------1------------Sink node
            |
            3
           / \
          /   \
         4     5

So your result would be...
Node  Parent  Hop#
  1      S     1
  2      1     2
  3      1     2
  4      3     3
  5      3     3

That's why the hop number doesn't mean anything. The path from node 2 to 1 is enough for the drawing because the path from node 1 to the sink node is a part of it.
*/

[laian.alsabbagh]

ahha , okk i will try it :)