Triangle visualization for Java

import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;

import javax.swing.*;
import javax.swing.border.EmptyBorder;
import javax.swing.border.LineBorder;

import java.util.*;

public class GridTest extends JFrame implements ActionListener{

    private static ArrayList<Integer> primes;
    private static int maxPrime = 100;
    private static ArrayList<GridCell> gridCells;
    private static int currentIndex;
    private static JPanel gui;
    private static GridTest cb;
    private int size;
    private JButton[][] unitSquares;
    private JPanel xplusnSquare;
    private JLabel message;
    private static JFrame f = new JFrame("(x+n)(x+n)");;
    private boolean thingsSet = false;
    private JToolBar tools;

    public GridTest(int sizeSend) {
        int size = sizeSend;
        initializeVars(size);
        initializeGui();
    }

    public void initializeVars(int size){
        this.gui = new JPanel(new BorderLayout(0,0));
        this.size = size;
        this.unitSquares = new JButton[size][size];
        this.message = new JLabel(gridCells.get(currentIndex).print());
    }

    public static void initializeCells(){
        currentIndex = 0;
        primes = new ArrayList<Integer>();
        for(int i=3; i<maxPrime; i++){
            if(isPrime(i)){
                primes.add(i);
            }
        }
        gridCells = new ArrayList<GridCell>();
        for(int j=0; j<primes.size(); j++){
            for(int k=0; k<j; k++){
                if(primes.get(k) != primes.get(j)){
                    GridCell testCell = new GridCell(primes.get(k), primes.get(j));
                    if(testCell.oddxplusnsquared()){
                        gridCells.add(testCell);
                    }
                }
            }
        }
    }

    public void setGui(){
        if(thingsSet != true){
            gui.setBorder(new EmptyBorder(5, 5, 5, 5));
            gui.add(tools, BorderLayout.PAGE_START);
        }
        gui.add(xplusnSquare);
    }

    public final void initializeGui() {
        if(tools == null){
            tools = new JToolBar();
            tools.setFloatable(false);
            JButton changeButton = new JButton("Change");
            changeButton.setActionCommand("change");
            changeButton.addActionListener(this);
            tools.add(changeButton);
            tools.addSeparator();
            tools.add(message);
        }

        xplusnSquare = new JPanel(new GridBagLayout());
        xplusnSquare.setBorder(new LineBorder(Color.WHITE));

        Insets buttonMargin = new Insets(0,0,0,0);
        for (int ii = 0; ii < unitSquares.length; ii++) {
            for (int jj = 0; jj < unitSquares[ii].length; jj++) {
                JButton b = new JButton();
                int pixels = 650/size;
                b.setPreferredSize(new Dimension(pixels, pixels));

                ImageIcon icon = new ImageIcon(new BufferedImage(pixels, pixels, BufferedImage.TYPE_INT_ARGB));
                b.setIcon(icon);

                //if you're in the middle, make it black
                if(ii==((size-1)/2) && jj==((size-1)/2)){
                    b.setBorder(BorderFactory.createMatteBorder(1,1,1,1, Color.black)); //diagonal left and down
                    b.setBackground(Color.BLACK);
                } else {
                    b.setBackground(Color.WHITE);
                }
                unitSquares[jj][ii] = b;
                GridBagConstraints c = new GridBagConstraints();
                c.gridx = ii;
                c.gridy = jj;


                /*
                 * This is where I'm drawing the triangles. It's a whole bunch of code so it could probably be moved to
                 * its own method but whatever.
                 */


                if(gridCells.get(currentIndex).xplusn() == 3){
                    //if it's three then the center will be black and the eight remaining squares will be the triangles
                    //these don't need sophisticated border drawing to make triangles out of them
                    b.setBorder(BorderFactory.createMatteBorder(1,1,1,1, Color.black)); //directly left of center
                } else {

                    //drawing the triangles
                    if(jj==((size-1)/2) && ii==(((size-1)/2)-1)){
                        b.setBorder(BorderFactory.createMatteBorder(1,0,1,0, Color.black)); //directly left of center
                    } else if(jj==((size-1)/2) && ii<(((size-1)/2)-1) && ii>0){
                        b.setBorder(BorderFactory.createMatteBorder(1,0,0,0, Color.black)); //left of center to before left edge
                    } else if(((((size-1)/2)-jj)+(((size-1)/2)-ii)==1) && jj>ii && ii>0){
                        b.setBorder(BorderFactory.createMatteBorder(0,0,1,1, Color.black)); //diagonal left and down
                    } else if(ii==(((size-1)/2)-1) && jj>((size-1)/2) && jj<size-1){
                        b.setBorder(BorderFactory.createMatteBorder(0,0,0,1, Color.black)); //downwards directly left of center
                    } else if(ii==0 && jj==((size-1)/2)){
                        b.setBorder(BorderFactory.createMatteBorder(1,1,0,0, Color.black)); //left edge center corner
                    } else if(ii==0 && jj>((size-1)/2) && jj<(size-2)){
                        b.setBorder(BorderFactory.createMatteBorder(0,1,0,0, Color.black)); //left edge downwards from center
                    } else if(ii==0 && jj==(size-2)){
                        b.setBorder(BorderFactory.createMatteBorder(0,1,1,1, Color.black)); //left bottom corner of triangle (2nd last square)
                    } else if(ii==0 && jj==(size-1)){
                        b.setBorder(BorderFactory.createMatteBorder(0,1,1,0, Color.black)); //left bottom corner
                    } else if(ii>0 && ii<(((size-1)/2)-1) && jj==(size-1)){
                        b.setBorder(BorderFactory.createMatteBorder(0,0,1,0, Color.black)); //bottom edge before center
                    } else if(ii==(((size-1)/2)-1) && jj==(size-1)){
                        b.setBorder(BorderFactory.createMatteBorder(0,0,1,1, Color.black)); //bottom left inner corner before center


                    } else if(jj==((size-1)/2) && ii==(((size-1)/2)+1)){
                        b.setBorder(BorderFactory.createMatteBorder(1,0,1,0, Color.black)); //directly right of center
                    } else if(jj==((size-1)/2) && ii>(((size-1)/2)-1) && ii<(size-1)){
                        b.setBorder(BorderFactory.createMatteBorder(0,0,1,0, Color.black)); //right of center to before right edge
                    } else if(((jj-((size-1)/2))+(ii-((size-1)/2))==1) && jj<ii && jj>0){
                        if(ii==(size-1)){
                            b.setBorder(BorderFactory.createMatteBorder(1,1,0,1, Color.black)); //diagonal right and up
                        } else {
                            b.setBorder(BorderFactory.createMatteBorder(1,1,0,0, Color.black)); //diagonal right and up
                        }
                    } else if(ii==(((size-1)/2)+1) && jj<((size-1)/2) && jj>0){
                        b.setBorder(BorderFactory.createMatteBorder(0,1,0,0, Color.black)); //upwards directly right of center
                    } else if(ii==(size-1) && jj==((size-1)/2)){
                        b.setBorder(BorderFactory.createMatteBorder(0,0,1,1, Color.black)); //right edge center corner
                    } else if(ii==(size-1) && jj<0 && jj>(size-2)){
                        b.setBorder(BorderFactory.createMatteBorder(0,1,0,0, Color.black)); //right edge upwards from center
                    } else if(jj==0 && ii>(((size-1)/2)+1) && ii<(size-1)){
                        b.setBorder(BorderFactory.createMatteBorder(1,0,0,0, Color.black)); //top right
                    } else if(ii==(size-1) && jj==0){
                        b.setBorder(BorderFactory.createMatteBorder(1,0,0,1, Color.black)); //diagonal right and up
                    } else if(ii==(((size-1)/2)+1) && jj==0){
                        b.setBorder(BorderFactory.createMatteBorder(1,1,0,0, Color.black)); //diagonal right and up
                    } else if(ii==(size-1) && jj>1 && jj<((size-1)/2)){
                        b.setBorder(BorderFactory.createMatteBorder(0,0,0,1, Color.black)); //diagonal right and up


                    } else if(jj==(((size-1)/2)+1) && ii==((size-1)/2)){
                        b.setBorder(BorderFactory.createMatteBorder(0,0,0,1, Color.black)); //directly below center
                    } else if(jj==(size-1) && ii>=((size-1)/2) && ii<(size-2)){
                        b.setBorder(BorderFactory.createMatteBorder(0,0,1,0, Color.black)); //bottom below center
                    } else if(jj==(size-1) && ii==(size-2)){
                        b.setBorder(BorderFactory.createMatteBorder(1,0,1,1, Color.black)); //directly below center
                    } else if(ii-jj==-1 && ii>((size-1)/2) && jj>((size-1)/2)){
                        b.setBorder(BorderFactory.createMatteBorder(1,0,0,1, Color.black)); //diagonal right and down
                    } else if(jj==(size-1) && ii==(size-1)){
                        b.setBorder(BorderFactory.createMatteBorder(0,0,1,1, Color.black)); //bottom right corner
                    } else if(jj>((size-1)/2) && jj<(size-1) && ii==(size-1)){
                        b.setBorder(BorderFactory.createMatteBorder(0,0,0,1, Color.black)); //right edge downwards


                    } else if(jj==0 && ii==0){
                        b.setBorder(BorderFactory.createMatteBorder(1,1,0,1, Color.black)); //top corner
                    } else if(ii==0 && jj>0 && jj<((size-1)/2)){
                        b.setBorder(BorderFactory.createMatteBorder(0,1,0,0, Color.black)); //left top side edge
                    } else if(jj==0 && ii>0 && ii<(((size-1)/2)+1)){
                        b.setBorder(BorderFactory.createMatteBorder(1,0,0,0, Color.black)); //left top top edge
                    } else if(ii==jj && ii>0 && ii<((size-1)/2) && jj>0 && jj<((size-1)/2)){
                        b.setBorder(BorderFactory.createMatteBorder(1,0,0,1, Color.black)); //directly below center


                    } else {
                        b.setBorder(BorderFactory.createMatteBorder(0,0,0,0, Color.black)); //inner parts blank
                    }

                }

                xplusnSquare.add(unitSquares[jj][ii], c);
            }
        }
        setGui();
    }

    public void actionPerformed(ActionEvent e) {
        if ("change".equals(e.getActionCommand())) {
            initializeVars(13);
            initializeGui();
            startThing();
        }
    }

    public static boolean isPrime(int n){
        if(n==1 || n==2 || n==4){
            return false;
        }
        for(int i=2; i<n; i++){
            if(n%i==0){
                return false;
            }
        }
        return true;
    }

    public JComponent getGui(){
        return gui;
    }

    public static void main(String[] args) {
        Runnable r = new Runnable() {

            @Override
            public void run() {
                startThing();
            }
        };
        SwingUtilities.invokeLater(r);
    }

    public static void startThing(){
            if(cb != null){ //if you're changing the triangles
                currentIndex++;
                if(currentIndex == gridCells.size()){
                    currentIndex = 0;
                }
                cb = new GridTest(gridCells.get(currentIndex).xplusn());
                f.getContentPane().removeAll();
                f.add(cb.getGui());
                f.setMinimumSize(f.getSize());
                f.pack();
                f.setSize(725,725);
            } else { //initial triangles
                initializeCells();
                gui = null;
                cb = new GridTest(gridCells.get(currentIndex).xplusn());
                f.add(cb.getGui());
                f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
                f.setLocationByPlatform(true);
                f.pack();
                f.setSize(725,725);
                f.setMinimumSize(f.getSize());
                f.setVisible(true);
            }
    }
}