Finding closed boundaries

ClosedSurfaceFinder.java

/*Java source to find closed boundaries an array of binary pixels.

Author: Prithvijit Chakrabarty (prithvichakra@gmail.com)
*/
package projectjava;

import java.awt.Color;

public class ClosedSurfaceFinder {

    static int[][] pixels=new int[][]{{0,0,0,0,0,0,0,0,0,0},
                                      {0,0,0,0,0,0,0,0,0,0},
                                      {0,0,0,0,0,0,0,0,0,0},
                                      {0,0,0,0,0,0,0,0,0,0},
                                      {0,0,0,0,0,0,0,0,0,0},
                                      {0,0,0,0,0,0,0,0,0,0},
                                      {0,0,0,0,0,0,0,0,0,0},
                                      {0,0,0,0,0,0,0,0,0,0},
                                      {0,0,0,0,0,0,0,0,0,0},
                                      {0,0,0,0,0,0,0,0,0,0}};
    
    static ClosedSurfaceSelector c;
    
    public static void findSurfaces(){
        for(int i=0;i<pixels.length;i++)
            for(int j=0;j<pixels[0].length;j++)
                if(pixels[i][j]==1)
                    if(numberOfLinks(i,j)<2)
                        pixels[i][j]=0;
        
        for(int i=pixels.length-1;i>=0;i--)
            for(int j=pixels[0].length-1;j>=0;j--)
                if(pixels[i][j]==1)
                    if(numberOfLinks(i,j)<2)
                        pixels[i][j]=0;
    }
                    
    public static int numberOfLinks(int i,int j){
        int linkCount=0;
        int limI=pixels.length-1;
        int limJ=pixels[0].length-1;
        
        if(i!=0){
            if(pixels[i-1][j]==1)
                linkCount++;
        }
        
        if(i!=limI){
            if(pixels[i+1][j]==1)
                linkCount++;
        }
           
        if(j!=limJ&&pixels[i][j+1]==1)
            linkCount++;
        if(j!=0&&pixels[i][j-1]==1)
            linkCount++;
        
        return linkCount;
    }

    public static void main(String args[]){
        findSurfaces();
        for(int i=0;i<pixels.length;i++){
            for(int j=0;j<pixels[0].length;j++)
                System.out.print(pixels[i][j]+" ");
            System.out.println();
        }
    }
    
    public static void showSurfaces(){
        for(int i=0;i<pixels.length;i++)
            for(int j=0;j<pixels[0].length;j++)
                if(pixels[i][j]==1)
                    c.pixels[i][j].setBackground(Color.ORANGE);
    }
    
    public static void reload(){
        for(int i=0;i<pixels.length;i++)
            for(int j=0;j<pixels[0].length;j++){
                pixels[i][j]=0;
                c.pixels[i][j].setBackground(null);
            }
    }
}

ClosedSurfaceSelector.java

/*GUI frontend for closed boundary selection.
Detects closed boundaries clicked out by the user (doesn't consider diagonal elements to be adjacent).
User must click Reload before selecting a new boundary.

Author: Prithvijit Chakrabarty (prithvichakra@gmail.com)
*/
package projectjava;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class ClosedSurfaceSelector extends JPanel{
    
    JButton[][] pixels;
    
    public ClosedSurfaceSelector() {
        super();
        pixels=new JButton[10][10];
        JPanel panel=new JPanel();
        ClosedSurfaceFinder.c=this;
        panel.setLayout(new GridLayout(pixels.length,pixels[0].length));
        for(int i=0;i<pixels.length;i++)
            for(int j=0;j<pixels[0].length;j++){
                pixels[i][j]=new JButton();
                pixels[i][j].addActionListener(new ClosedPixelAction(pixels[i][j],i,j));
                panel.add(pixels[i][j]);
            }
        setLayout(new GridLayout(2,1));
        add(panel);
        JPanel lower=new JPanel();
        JButton find=new JButton("Find Closed Surfaces");
        find.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                ClosedSurfaceFinder.findSurfaces();
                ClosedSurfaceFinder.findSurfaces();
                ClosedSurfaceFinder.showSurfaces();
            }
        });
        JButton reload=new JButton("Reload");
        reload.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                ClosedSurfaceFinder.reload();
            }
        });
        
        lower.add(find);
        lower.add(reload);
        add(lower);
    }
    
    public static void main(String[] args){
        JFrame frame=new JFrame("Closed Surface Finder");
        frame.add(new ClosedSurfaceSelector());
        frame.setSize(700,700);
        frame.setVisible(true);
    }
}