Messages posted by: anotsu

i don't know what is wrong with my applet but it seems that it is not working

can you help me fix the problem please?

i didnt implement the applet into a html file yet

the applet is a ball that is bouncing and we can choose if we want to see it with its trails or with fading trail

thank you very much

import java.awt.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
import javax.swing.JApplet;

public class AnimeBall extends JApplet {
    Motivator fullMover;
    Motivator fadeMover;

public void init() {
        getContentPane().add(getContent());
    }

public void start() {
        fullMover.start();
        fadeMover.start();
    }

public void stop() {
        fullMover.stop();
        fadeMover.stop();
    }

private JTabbedPane getContent() {
        FullTrail fullTrail = new FullTrail();
        fullMover = new Motivator(fullTrail);
        FadingTrail fader = new FadingTrail();
        fadeMover = new Motivator(fader);
        JTabbedPane tabbedPane = new JTabbedPane();
        tabbedPane.addTab("full trail", fullTrail);
        tabbedPane.addTab("fading trail", fader);
        return tabbedPane;
    }
}

public class AnimeBall {
    Motivator fullMover;
    Motivator fadeMover;
 
    private void start() {
        fullMover.start();
        fadeMover.start();
    }
 
    private JTabbedPane getContent() {
        FullTrail fullTrail = new FullTrail();
        fullMover = new Motivator(fullTrail);
        FadingTrail fader = new FadingTrail();
        fadeMover = new Motivator(fader);
        JTabbedPane tabbedPane = new JTabbedPane();
        tabbedPane.addTab("full trail", fullTrail);
        tabbedPane.addTab("fading trail", fader);
        return tabbedPane;
    }
 
    public static void main(String[] args) {
        AnimeBall trails = new AnimeBall();
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(trails.getContent());
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
        trails.start();
    }
}
class FullTrail extends JPanel implements Movable {
    BufferedImage offscreen;
    Point loc;
    int dx = 3;
    int dy = 2;
    final int D = 30;
 
    protected void paintComponent(Graphics g) {
        if(offscreen == null) {
            initOffscreen();
        }
        g.drawImage(offscreen, 0, 0, this);
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        g2.setPaint(Color.red);
        g2.fillOval(loc.x-D/2, loc.y-D/2, D, D);
    }
 
    public void moveBall() {
        updateOffscreen();
        checkBoundries();
        loc.x += dx;
        loc.y += dy;
        repaint();
    }
 
    private void checkBoundries() {
        if(loc.x - D/2 + dx < 0 || loc.x + D/2 + dx > getWidth())
            dx *= -1;
        if(loc.y - D/2 + dy < 0 || loc.y + D/2 + dy > getHeight())
            dy *= -1;
    }
 
    private void initOffscreen() {
        int w = getWidth();
        int h = getHeight();
        loc = new Point(w/2, h/2);
        offscreen = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = offscreen.createGraphics();
        g2.setColor(UIManager.getColor("Panel.background"));
        g2.fillRect(0,0,w,h);
        g2.dispose();
    }
 
    private void updateOffscreen() {
        Graphics g = offscreen.getGraphics();
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        g2.setPaint(new Color(240,200,240));
        g2.fillOval(loc.x-2, loc.y-2, 4, 4);
        g2.dispose();
    }
}
 
class FadingTrail extends JPanel implements Movable {
    Point[] trail;
    Point loc;
    int dx = 2;
    int dy = 3;
    final int D = 30;
 
    public FadingTrail() {
        int trailLength = 20;
        trail = new Point[trailLength];
        for(int j = 0; j < trail.length; j++) {
            trail[j] = new Point();
        }
        loc = new Point(200,100);
    }
 
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        Graphics2D copy = (Graphics2D)g.create();
        copy.setPaint(new Color(240,200,240));
        float alpha = 1f;
        float alphaInc = 1f/20.5f;
        AlphaComposite ac = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, alpha);
        for(int j = 0; j < trail.length; j++) {
            copy.setComposite(ac);
            copy.fillOval(trail[j].x-2, trail[j].y-2, 4, 4);
            alpha -= alphaInc;
            ac = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, alpha);
        }
        copy.dispose();
        g2.setPaint(Color.red);
        g2.fillOval(loc.x-D/2, loc.y-D/2, D, D);
    }
 
    public void moveBall() {
        updateTrail();
        checkBoundries();
        loc.x += dx;
        loc.y += dy;
        repaint();
    }
 
    private void checkBoundries() {
        if(loc.x - D/2 + dx < 0 || loc.x + D/2 + dx > getWidth())
            dx *= -1;
        if(loc.y - D/2 + dy < 0 || loc.y + D/2 + dy > getHeight())
            dy *= -1;
    }
 
    private void updateTrail() {
        for(int j = trail.length-1; j > 0; j--) {
            trail[j].setLocation(trail[j-1].getLocation());
        }
        double theta = Math.atan2(dy,dx) + Math.PI;
        int x = loc.x + (int)((D/2)*Math.cos(theta));
        int y = loc.y + (int)((D/2)*Math.sin(theta));
        trail[0].setLocation(x, y);
    }
}
 
interface Movable {
    public void moveBall();
}
 
class Motivator implements Runnable {
    Movable movable;
    Thread thread;
    boolean keepMoving;
 
    public Motivator(Movable m) {
        movable = m;
    }
 
    public void run() {
        while(keepMoving) {
            try {
                Thread.sleep(50);
            } catch(InterruptedException e) {
                keepMoving = false;
            }
            movable.moveBall();
        }
    }
 
    public void start() {
        if(!keepMoving) {
            keepMoving = true;
            thread = new Thread(this);
            thread.setPriority(Thread.NORM_PRIORITY);
            thread.start();
        }
    }
 
    public void stop() {
        keepMoving = false;
        thread.interrupt();
        thread = null;
    }
}

I would like to change this screensaver that draw multiple lines in different and color in different positions, to a screensaver that put a picture (let's call it pict01) in the screensaver and change its position.
but i am new in java, can somebody help me

file number 1----->saver1.java

import javax.swing.JFrame;

public class Saver1
{
public static void main( String args[] )
{
// create frame for Saver1JPanel
JFrame frame = new JFrame( "Saver1" );
frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );

Saver1JPanel saver1JPanel = new Saver1JPanel();
frame.add( saver1JPanel ); // add saver1JPanel to frame
frame.setSize( 300, 300 ); // set frame size
frame.setVisible( true ); // display frame
} // end main
}

file number 2-------->Saver1JPanel

import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JPanel;

public class Saver1JPanel extends JPanel
{
private final int DELAY = 9999999;

// draw lines
public void paintComponent( Graphics g )
{
super.paintComponent( g ); // call superclass's paintComponent

int x, y, x1, y1;

// draw 100 random lines
for ( int i = 0; i < 100; i++ )
{
x = ( int ) ( Math.random() * 300 );
y = ( int ) ( Math.random() * 300 );
x1 = ( int ) ( Math.random() * 300 );
y1 = ( int ) ( Math.random() * 300 );

g.setColor( new Color( ( float ) Math.random(),
( float ) Math.random(), ( float ) Math.random() ) );
g.drawLine( x, y, x1, y1 );

// slow the drawing down. the body of the for loop is empty
for ( int q = 1; q < DELAY; q++ ) ;
} // end outer for

repaint(); // repaint component
} // end method paintComponent
}

thank you