canvas.java

Java based Snakes and Ladders game.

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
//----------------------
import java.util.List;
import java.util.*;

public class Canvas
{
    private static final String VERSION = "Version 1.0";
    
    private static Canvas canvasStart;
    private GameEngine gameengine;

    // Start canvas with the setup below.
    public static Canvas getCanvas()
    {
        if(canvasStart == null) {
            canvasStart = new Canvas("Snakes & Ladders - By Reece Warrender", 450, 373, 
                                         Color.white);
        }
        canvasStart.setVisible(true);
        return canvasStart;
    }
  
    //  ----- instance part -----
    private JFrame frame;
    private CanvasPane canvas;
    private Graphics2D graphic;
    private Color backgroundColour;
    private Image canvasImage;
    private List objects;
    private HashMap shapes;
    
    // Create a Canvas.
    private Canvas(String title, int width, int height, Color bgColour)
    {
        frame = new JFrame();
        canvas = new CanvasPane();
        frame.setContentPane(canvas);
        frame.setTitle(title);
        canvas.setPreferredSize(new Dimension(width, height));
        backgroundColour = bgColour;
        frame.pack();
        objects = new ArrayList();
        shapes = new HashMap();
        makeMenuBar(frame);
        gameengine = new GameEngine();
    }

    // Set the canvas visible (to the front).
    public void setVisible(boolean visible)
    {
        if(graphic == null) {
            // first time: instantiate the offscreen image and fill it with
            // the background colour
            Dimension size = canvas.getSize();
            canvasImage = canvas.createImage(size.width, size.height);
            graphic = (Graphics2D)canvasImage.getGraphics();
            graphic.setColor(backgroundColour);
            graphic.fillRect(0, 0, size.width, size.height);
            graphic.setColor(Color.black);
        }
        frame.setVisible(visible);
    }

    // Drawing the objects
    public void draw(Object referenceObject, String color, Shape shape)
    {
        objects.remove(referenceObject);   // just in case it was already there
        objects.add(referenceObject);      // add at the end
        shapes.put(referenceObject, new ShapeDescription(shape, color));
        redraw();
    }
 
    // Erasing objects from the screen.
    public void erase(Object referenceObject)
    {
        objects.remove(referenceObject);   // just in case it was already there
        shapes.remove(referenceObject);
        redraw();
    }

    // Sets the colour - Default value is colour BLACK.
    public void setForegroundColor(String colorString)
    {
        if(colorString.equals("red"))
            graphic.setColor(Color.red);
        else if(colorString.equals("black"))
            graphic.setColor(Color.black);
        else if(colorString.equals("green"))
            graphic.setColor(Color.green);
        else if(colorString.equals("gray"))
            graphic.setColor(Color.lightGray);
        else if(colorString.equals("white"))
            graphic.setColor(Color.white);
        else
            graphic.setColor(Color.black);
    }

    // May be used for animation.
    /**public void wait(int milliseconds)
    {
        try
        {
            Thread.sleep(milliseconds);
        } 
        catch (Exception e)
        {
            // ignoring exception at the moment
        }
    }*/

    // Redraw all the shapes on the canvas.
    private void redraw()
    {
        erase();
        for(Iterator i=objects.iterator(); i.hasNext(); ) {
            ((ShapeDescription)shapes.get(i.next())).draw(graphic);
        }
        canvas.repaint();
    }
       
    // Erase all the canvas
    private void erase()
    {
        Color original = graphic.getColor();
        graphic.setColor(backgroundColour);
        Dimension size = canvas.getSize();
        graphic.fill(new Rectangle(0, 0, size.width, size.height));
        graphic.setColor(original);
    }

    // The actual canvas, tis is essentually a JPanel with added refresh ability.
    private class CanvasPane extends JPanel
    {
        public void paint(Graphics g)
        {
            g.drawImage(canvasImage, 0, 0, null);
        }
    }
    
    // The actual canvas, tis is essentually a JPanel with added refresh ability.
    private class ShapeDescription
    {
        private Shape shape;
        private String colorString;

        public ShapeDescription(Shape shape, String color)
        {
            this.shape = shape;
            colorString = color;
        }

        public void draw(Graphics2D graphic)
        {
            setForegroundColor(colorString);
            graphic.fill(shape);
        }
    }
    
    // Create a menu bar at the top of the page
    public void makeMenuBar(JFrame frame){

        JMenuBar menubar = new JMenuBar();
        frame.setJMenuBar(menubar);
        
        // create the File menu
        JMenu fileMenu = new JMenu("Game");
        menubar.add(fileMenu);
        
        //JMenuItem newgameItem = new JMenuItem("New Game");
        //    newgameItem.addActionListener(new ActionListener() {
        //        public void actionPerformed(ActionEvent e) { newgame(); }
        //    });
        //fileMenu.add(newgameItem);
        
        JMenuItem rollItem = new JMenuItem("Roll");
            rollItem.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) { roll(); }
            });
        fileMenu.add(rollItem);

        JMenuItem quitItem = new JMenuItem("Quit");
            quitItem.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) { quit(); }
            });
        fileMenu.add(quitItem);
        
        // Place the newxt menu choice to the Right.
        menubar.add(Box.createHorizontalGlue());

        // create the Help menu
        JMenu helpMenu = new JMenu("Help");
        menubar.add(helpMenu);
        
        //item = new JMenuItem("About Snakes & Ladders");
        JMenuItem helpItem = new JMenuItem("About Snakes & Ladders");
            helpItem.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) { showAbout(); }
            });
        helpMenu.add(helpItem);

    }
           
    //Function New Game - In the Menu Bar
    //private void newgame()
    //{
    //   gameengine.NewGame();
    //}
    
    //Function Roll - In the Menu Bar
    private void roll()
    {
        gameengine.RunGame();
    }
    
    // Function Quit - In the Menu Bar
    private void quit()
    {
        System.exit(0);
    }

    // Function About - In the Menu Bar (To the right)
    private void showAbout()
    {
        JOptionPane.showMessageDialog(frame, 
                    "Snakes and Ladders\nBy Reece Warrender\n" + VERSION,
                    "About Snakes and Ladders", 
                    JOptionPane.INFORMATION_MESSAGE);
    }
    
}