Pacman open/close mouth animation

Solution 1:

Something like this might work for PacMan images. It uses a Java 2D based Shape instance to represent the form, and an AffineTransform to produce the different orientations.

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
import javax.swing.*;

import java.io.*;
import javax.imageio.ImageIO;

class PacManShape {

    private double size;
    private double rotation;
    final int maxSize = 4;
    static File home = new File(System.getProperty("user.home"));
    static File images = new File(home, "images");

    PacManShape(int size, double rotation) {
        this.size = size;
        this.rotation = rotation;
    }

    public Area getPacManShape(double jaws) {
        Area area = new Area(new Ellipse2D.Double(0d, 0d, size, size));

        double x1 = size / 2 + (2d * size * Math.cos(jaws / 2d));
        double y1 = size / 2 + (2d * size * Math.sin(jaws / 2d));
        double x2 = x1;
        double y2 = size / 2 - (2d * size * Math.sin(jaws / 2d));

        Polygon mouth = new Polygon();
        mouth.addPoint((int) (size / 2), (int) (size / 2));
        mouth.addPoint((int) x1, (int) y1);
        mouth.addPoint((int) x2, (int) y2);
        mouth.addPoint((int) (size / 2), (int) (size / 2));

        area.subtract(new Area(mouth));

        return area;
    }

    public BufferedImage getPacManImage(double angle, Color color) {
        BufferedImage bi = new BufferedImage(
                (int) size, (int) size, BufferedImage.TYPE_INT_ARGB);

        Graphics2D g2 = bi.createGraphics();

        g2.setColor(color);
        g2.fillRect(0, 0, (int) size, (int) size);

        AffineTransform rotate = AffineTransform.getRotateInstance(
                rotation, size / 2, size / 2);
        g2.setTransform(rotate);

        Area pacMan = getPacManShape(angle);
        g2.setRenderingHint(
                RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON);
        g2.setColor(Color.YELLOW);
        float[] dist = {.15f, .9f};
        Color[] colors = {Color.YELLOW, Color.ORANGE};
        Point2D center = new Point2D.Double(size / 2, size / 2);
        RadialGradientPaint radial = new RadialGradientPaint(
                center, (float) ((size / 2) - 2f), dist, colors);
        g2.setPaint(radial);
        g2.fill(pacMan);
        GradientPaint gradient = new GradientPaint(
                0, 0, new Color(255, 255, 225, 220),
                (int) (size / 3), 0, new Color(255, 255, 255, 0));
        g2.setPaint(gradient);
        g2.fill(pacMan);

        g2.dispose();

        return bi;
    }

    public void savePacManImage(int q, int num) throws IOException {
        double angle = Math.PI*2 / 3d * ((double) num / (double) maxSize);
        BufferedImage bi = getPacManImage(angle, Color.WHITE);

        images.mkdirs();
        File img = new File(images, "PacMan-" + q + "x" + num + ".gif");
        ImageIO.write(bi, "gif", img);
    }

    public static void main(String[] args) {

        try {
            for (int ii = 0; ii < 4; ii++) {
                PacManShape pms = new PacManShape(100, (double) ii * Math.PI / 2d);
                for (int jj = 0; jj <= pms.maxSize; jj++) {
                    pms.savePacManImage(ii, jj);
                }
            }
            Desktop.getDesktop().open(images);
        } catch (IOException ex) {
            ex.printStackTrace();
        }

        Runnable r = new Runnable() {

            @Override
            public void run() {
                JPanel gui = new JPanel(new BorderLayout());

                gui.add(new PacManComponent());

                JOptionPane.showMessageDialog(null, gui);
            }
        };
        // Swing GUIs should be created and updated on the EDT
        // http://docs.oracle.com/javase/tutorial/uiswing/concurrency/initial.html
        SwingUtilities.invokeLater(r);
    }
}

class PacManComponent extends JPanel {

    double angle = 0d;
    int preferredSize = 100;
    double diff = Math.PI / 8;
    boolean chomp = true;
    Timer timer;

    PacManComponent() {
        ActionListener listener = new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                repaint();
            }
        };
        timer = new Timer(180, listener);
        timer.start();
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(preferredSize, preferredSize);
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g.create();
        //double size = (getWidth() < getHeight() ? getWidth() : getHeight());
        if (angle > 2 * Math.PI / 3) {
            chomp = true;
        } else if (angle < 0.01) {
            chomp = false;
        }
        if (chomp) {
            angle -= diff;
        } else {
            angle += diff;
        }
        PacManShape pms = new PacManShape(100, 0d);

        Image image = pms.getPacManImage(angle, new Color(0, 0, 0, 0));
        g2.drawImage(image, 0, 0, this);

        g2.dispose();
    }
}

If you wanted to transform & render images at run-time, try starting with this series of PNG format images that uses partial transparency to soften the edges.

Solution 2:

For the animation, you could use a Swing Timer to move the Pacman graphic as well as adjusting the angle by which the "mouth" opens, by varying the parameters used by fillArc.

Interaction with KeyEvents for movement control can be acheived using Key Bindings.

Also, I would move the paint functionality to a paintComponent method in a sub-classed JComponent for better paint performance.

Related: Painting with Swing

Edit:

As youre starting Java there are a number of tasks to get working first

1. Create the JComponent based class with a static Pacman graphic. Move your painting logic to paintComponent
2. Get the Swing Timer functionality working. Follow the Oracle guide for Timers.
3. Implement the Key Bindings
4. Other functionality such as score keeping, etc.

Solution 3:

2d animation: http://en.wikipedia.org/wiki/File:The_Horse_in_Motion.jpg

Pseudocode:

while programActive:
    deltatime = get_time_since_last_call()
    update_animation_frame(deltatime)
    image = get_animation_frame()
    draw_background()
    draw(image)
    enforce_framerate(24)

To learn and do this sort of thing in Pygame would be easy compared to Java, but unsuitable for larger projects