javaswinggridgraphics2dpath-finding
How to obtain the state of grid cells based on a specific location on a 2D array
Consider a 2D grid with n rows and n columns (here 75x75). The symbols (tokens) are drawn in each cell on mouse click. The code below is used to draw grid lines and symbols within cells:
class DrawCanvas extends JPanel{
@Override
public void paintComponent(Graphics g){
super.paintComponent(g);
setBackground(Color.WHITE);
//Lines
g.setColor(Color.BLACK);
for(int ligne = 1; ligne < ROWS; ++ligne){
g.fillRoundRect(0, cellSize * ligne - halfGridWidth, canvasWidth - 1,
gridWidth, gridWidth, gridWidth);
}
for(int colonne = 1; colonne < COLS; ++colonne){
g.fillRoundRect(cellSize * colonne - halfGridWidth, 0
, gridWidth, canvasHeight - 1,
gridWidth, gridWidth);
}
//Symbols
Graphics2D g2d = (Graphics2D)g;
g2d.setStroke(new BasicStroke(symbolStrokeWidth,
BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
for(int ligne = 0; ligne < ROWS; ++ligne){
for(int colonne = 0; colonne < COLS; ++colonne){
int x1 = colonne * cellSize + cellPadding;
int y1 = ligne * cellSize + cellPadding;
if(board[ligne][colonne] == Token.CERCLE_ROUGE){
g2d.setColor(Color.RED);
g2d.drawOval(x1, y1, symbolSize, symbolSize);
g2d.fillOval(x1, y1, symbolSize, symbolSize);
} else
if(board[ligne][colonne] == Token.CERCLE_BLEU){
int x2 = colonne * cellSize + cellPadding;
g2d.setColor(Color.BLUE);
g2d.drawOval(x1, y1, symbolSize, symbolSize);
g2d.fillOval(x2, y1, symbolSize, symbolSize);
}
}
}
With the code below, I can find all neighbors of a given cell:
private void neighbours(int col, int row) {
//find all serouding cell by adding +/- 1 to col and row
for (int colNum = col - 1 ; colNum <= (col + 1) ; colNum +=1 ) {
for (int rowNum = row - 1 ; rowNum <= (row + 1) ; rowNum +=1 ) {
//if not the center cell
if(! ((colNum == col) && (rowNum == row))) {
//make sure it is within grid
if(withinGrid (colNum, rowNum)) {
System.out.println("Neighbor of "+ col+ " "+ row + " - " + colNum +" " + rowNum );
}
}
}
}
}
//define if cell represented by colNum, rowNum is inside grid
private boolean withinGrid(int colNum, int rowNum) {
if((colNum < 0) || (rowNum <0) ) {
return false; //false if row or col are negative
}
if((colNum >= COLS) || (rowNum >= ROWS)) {
return false; //false if row or col are > 75
}
return true;
}
Consider cells contents:
public enum Token{
VIDE, CERCLE_BLEU, CERCLE_ROUGE
}
Now I want to know if there is a way to determinate what a cell contains: is it empty: Token.VIDE, has Token.CERCLE_BLEU or has Token.CERCLE_ROUGE. And how I can achieve that.
UPDATE: Below is my code:
import javax.swing.JFrame;
import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.*;
public final class Pha extends JFrame {
public static int ROWS = 75;
public static int COLS = 75;
public static int cellSize = 15;
public static int canvasWidth = cellSize * COLS + (ROWS *4) ;
public static int canvasHeight = cellSize * ROWS ;
public static int gridWidth = 1;
public static int halfGridWidth = gridWidth / 2;
public static int cellPadding = cellSize / 5;
public static int symbolSize = cellSize - cellPadding * 2;
public static int symbolStrokeWidth = 3;
public enum GameState{
JOUE, NUL, CERCLE_ROUGE_GAGNE, CERCLE_BLEU_GAGNE
}
private GameState actualState;
public enum Token{
VIDE, CERCLE_ROUGE, CERCLE_BLEU
}
private Token actualPlayer;
private Token[][] board;
private final DrawCanvas canvas;
private JLabel statusBar;
public Pha(){
canvas = new DrawCanvas();
canvas.setPreferredSize(new Dimension(canvasWidth, canvasHeight));
canvas.addMouseListener(new MouseAdapter() {
@Override
public void mouseClicked(MouseEvent e) {
int x = e.getX();
int y = e.getY();
int selectedRow = y / cellSize;
int selectedCol;
selectedCol = x / cellSize;
if(actualState == GameState.JOUE){
if(selectedRow >= 0 && selectedRow < ROWS && selectedCol >= 0
&& selectedCol < COLS &&
board[selectedRow][selectedCol] == Token.VIDE){
board[selectedRow][selectedCol] = actualPlayer;
updateGame(actualPlayer, selectedRow, selectedCol);
actualPlayer = (actualPlayer == Token.CERCLE_BLEU)? Token.CERCLE_ROUGE : Token.CERCLE_BLEU;
neighbours(selectedRow, selectedCol);
}
} else {
initGame();
}
repaint();
}
});
statusBar = new JLabel(" ");
statusBar.setFont(new Font(Font.DIALOG_INPUT, Font.ITALIC, 15));
statusBar.setBorder(BorderFactory.createEmptyBorder(2, 5, 4, 5));
Container cp = getContentPane();
cp.setLayout(new BorderLayout());
cp.add(canvas, BorderLayout.EAST);
cp.add(statusBar, BorderLayout.NORTH);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
setTitle("Pha par esQmo");
setVisible(true);
board = new Token[ROWS][COLS];
initGame();
}
public void initGame(){
for(int ligne = 0; ligne < ROWS; ++ligne){
for(int colonne = 0; colonne < COLS; ++colonne){
board[ligne][colonne] = Token.VIDE;
}
}
actualState = GameState.JOUE;
actualPlayer = Token.CERCLE_ROUGE;
}
public void updateGame(Token theSeed, int ligneSelectionnee, int colonneSelectionnee) {
if (aGagne(theSeed, ligneSelectionnee, colonneSelectionnee)) {
actualState= (theSeed == Token.CERCLE_ROUGE) ? GameState.CERCLE_ROUGE_GAGNE : GameState.CERCLE_BLEU_GAGNE;
} else if (estNul()) {
actualState = GameState.CERCLE_BLEU_GAGNE;
}
}
public boolean estNul() {
/*for (int row = 0; row < ROWS; ++row) {
for (int col = 0; col < COLS; ++col) {
if (board[row][col] == Token.VIDE) {
return false;
}
}
}*/
return false;
}
public boolean aGagne(Token token, int ligneSelectionnee, int colonneSelectionnee) {
return false;
}
public void neighbours(int row, int col) {
for (int colNum = col - 1 ; colNum <= (col + 1) ; colNum +=1 ) {
for (int rowNum = row - 1 ; rowNum <= (row + 1) ; rowNum +=1 ) {
if(!((colNum == col) && (rowNum == row))) {
if(withinGrid (rowNum, colNum )) {
System.out.println("Neighbor of "+ row + " " + col + " is " + rowNum +" " + colNum );
}
}
}
}
}
private boolean withinGrid(int colNum, int rowNum) {
if((colNum < 0) || (rowNum <0) ) {
return false;
}
if((colNum >= COLS) || (rowNum >= ROWS)) {
return false;
}
return true;
}
class DrawCanvas extends JPanel{
@Override
public void paintComponent(Graphics g){ //Invoqué via repaint()
super.paintComponent(g); //Pour remplir l'arriere plan
setBackground(Color.WHITE); //Defini la couleur de l'arriere plan
g.setColor(Color.BLACK);
for(int ligne = 1; ligne < ROWS; ++ligne){
g.fillRoundRect(0, cellSize * ligne - halfGridWidth, canvasWidth - 1,
gridWidth, gridWidth, gridWidth);
}
for(int colonne = 1; colonne < COLS; ++colonne){
g.fillRoundRect(cellSize * colonne - halfGridWidth, 0
, gridWidth, canvasHeight - 1,
gridWidth, gridWidth);
}
Graphics2D g2d = (Graphics2D)g;
g2d.setStroke(new BasicStroke(symbolStrokeWidth,
BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
for(int ligne = 0; ligne < ROWS; ++ligne){
for(int colonne = 0; colonne < COLS; ++colonne){
int x1 = colonne * cellSize + cellPadding;
int y1 = ligne * cellSize + cellPadding;
if(board[ligne][colonne] == Token.CERCLE_ROUGE){
g2d.setColor(Color.RED);
g2d.drawOval(x1, y1, symbolSize, symbolSize);
g2d.fillOval(x1, y1, symbolSize, symbolSize);
} else
if(board[ligne][colonne] == Token.CERCLE_BLEU){
int x2 = colonne * cellSize + cellPadding;
g2d.setColor(Color.BLUE);
g2d.drawOval(x1, y1, symbolSize, symbolSize);
g2d.fillOval(x2, y1, symbolSize, symbolSize);
}
}
}
if(actualState == GameState.JOUE){
if(actualPlayer == Token.CERCLE_ROUGE){
statusBar.setText("ROUGE, c'est votre tour");
statusBar.setForeground(Color.RED);
} else {
statusBar.setText("BLEU, c'est votre tour");
statusBar.setForeground(Color.BLUE);
statusBar.addMouseMotionListener(null);
}
} else
if(actualState == GameState.NUL){
statusBar.setForeground(Color.yellow);
statusBar.setText("Match nul! Cliquez pour rejouer");
} else
if(actualState == GameState.CERCLE_ROUGE_GAGNE){
statusBar.setText("Le jouer X a remporté la partie, cliquez pour rejouer");
statusBar.setForeground(Color.RED);
} else
if(actualState == GameState.CERCLE_BLEU_GAGNE){
statusBar.setForeground(Color.BLUE);
statusBar.setText("Le joueur O a remporté la partie, cliquez pour rejouer");
}
}
}
public static void main(String[] args){
SwingUtilities.invokeLater(() -> {
Pha pha = new Pha();
});
}
}
Solution
In board array you store the Token for each cell.
To retrieve this information you could change
System.out.println("Neighbor of "+ row + " " + col + " is " + rowNum +" " + colNum );
In neighbors() to:
System.out.println("Neighbor of "+ row + " " + col + " is " + rowNum +" " + colNum +
" Contains "+ board[rowNum][colNum]);
Clicking the middle cell (17,19):
Prints out:
Neighbor of 17 19 is 16 18 Contains CERCLE_ROUGE
Neighbor of 17 19 is 17 18 Contains CERCLE_BLEU
Neighbor of 17 19 is 18 18 Contains CERCLE_ROUGE
Neighbor of 17 19 is 16 19 Contains CERCLE_BLEU
Neighbor of 17 19 is 18 19 Contains CERCLE_BLEU
Neighbor of 17 19 is 16 20 Contains CERCLE_ROUGE
Neighbor of 17 19 is 17 20 Contains CERCLE_BLEU
Neighbor of 17 19 is 18 20 Contains CERCLE_ROUGE
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