How To Make Wheel Look Like It's Moving?

[kraigballa]

I have a TrainApplet that I have been working on for my first Java Applet. As of right now the train moves across the screen as desired, but how do I get the wheels to look like they are rotating as the train moves? I have tried a couple different things that did not work. Any help would be much appreciated. Also when the Applet is ran the train that is erased is not the same color as the background even though I have it set to the same color...any ideas to why this is?

Here is my current code:

package trainapp;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GraphicsEnvironment;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JApplet;
import javax.swing.Timer;

/**
  @author 
*/

public class TrainApplet extends JApplet {
	
	private final int delay = 50; //milliseconds
	public int TRAIN_x = -50;
	public int TRAIN_y = 170;
	private final int TRAIN_WIDTH = 200;
	private final int TRAIN_HEIGHT = 60;
	private int TRAIN_WHEEL_WIDTH = 40;
	private int TRAIN_WHEEL_HEIGHT = 40;
	private int stepSize = 10;
	
	/** (non-Javadoc)
	  @see java.applet.Applet#init()
	  */
	public void init() 
	{
		setBackground(Color.blue);
		startAnimation();
	}
	
	/** (non-Javadoc)
	  @see java.awt.Container#paint(java.awt.Graphics)
	 */
	public void paint(Graphics page) 
	{	
		// add your code here
		GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
	    ge.getAllFonts();
	    
		int style = Font.BOLD | Font.ITALIC;
		Font font = new Font ("Garamond", style , 50);
		page.setFont(font);
		
		page.drawString("Choo-Choo", 50, 50);
		setSize(1000, 600);
		
    	// Erase new Train
		page.setColor(getBackground());
		page.fillRoundRect(TRAIN_x, height() - TRAIN_y, TRAIN_WIDTH, TRAIN_HEIGHT, 10, 10 ); //2nd Rect
		page.fillRoundRect(TRAIN_x, height() - TRAIN_y - 60, TRAIN_WIDTH - 90, TRAIN_HEIGHT, 10, 10 ); // 3rd Rect
		page.fillRect(TRAIN_x, height() - TRAIN_y - 50, TRAIN_WIDTH - 90, TRAIN_HEIGHT); // cover gap on bottom rounds
		page.fillRect(TRAIN_x, height() - TRAIN_y + 60, TRAIN_WIDTH, TRAIN_HEIGHT); // 1st (bottom) Rect
		page.fillRect(TRAIN_x, height() - TRAIN_y + 50, TRAIN_WIDTH - 150, TRAIN_HEIGHT); // covers middle gap 
		page.fillRect(TRAIN_x + 30, height() - TRAIN_y - 100, TRAIN_WIDTH - 150, TRAIN_HEIGHT); // 4th (top) Rect
		page.fillOval(TRAIN_x + 5, height() - TRAIN_y + 118, TRAIN_WHEEL_WIDTH, TRAIN_WHEEL_HEIGHT); // 1st wheel (back)
		page.fillOval(TRAIN_x + 46, height() - TRAIN_y + 118, TRAIN_WHEEL_WIDTH, TRAIN_WHEEL_HEIGHT); // 2nd Wheel
		page.fillOval(TRAIN_x + 120, height() - TRAIN_y + 118, TRAIN_WHEEL_WIDTH, TRAIN_WHEEL_HEIGHT); //3rd Wheel
		page.fillOval(TRAIN_x + 160, height() - TRAIN_y + 118, TRAIN_WHEEL_WIDTH, TRAIN_WHEEL_HEIGHT); //4th Wheel
		
		page.setColor(getBackground());
		page.fillRect(TRAIN_x+40, height() - TRAIN_y - 40, TRAIN_WIDTH - 150, TRAIN_HEIGHT - 20); // 3rd Rect	
		page.drawLine(TRAIN_x + 10, height() - TRAIN_y + 125,TRAIN_x + 37, height() - TRAIN_y + 155); // Wheel bar

	
		//Move to new position
	    TRAIN_x = (TRAIN_x + stepSize) % width();
    	
	   	// Draw new Train
		page.setColor(Color.gray);
		page.fillRoundRect(TRAIN_x, height() - TRAIN_y, TRAIN_WIDTH, TRAIN_HEIGHT, 10, 10 ); //2nd Rect
		page.fillRoundRect(TRAIN_x, height() - TRAIN_y - 60, TRAIN_WIDTH - 90, TRAIN_HEIGHT, 10, 10 ); // 3rd Rect
		page.fillRect(TRAIN_x, height() - TRAIN_y - 50, TRAIN_WIDTH - 90, TRAIN_HEIGHT); // cover gap on bottom rounds
		page.fillRect(TRAIN_x, height() - TRAIN_y + 60, TRAIN_WIDTH, TRAIN_HEIGHT); // 1st (bottom) Rect
		page.fillRect(TRAIN_x, height() - TRAIN_y + 50, TRAIN_WIDTH - 150, TRAIN_HEIGHT); // covers middle gap 
		page.fillRect(TRAIN_x + 30, height() - TRAIN_y - 100, TRAIN_WIDTH - 150, TRAIN_HEIGHT); // 4th (top) Rect
		page.fillOval(TRAIN_x + 5, height() - TRAIN_y + 118, TRAIN_WHEEL_WIDTH, TRAIN_WHEEL_HEIGHT); // 1st wheel (back)
		page.fillOval(TRAIN_x + 46, height() - TRAIN_y + 118, TRAIN_WHEEL_WIDTH, TRAIN_WHEEL_HEIGHT); // 2nd Wheel
		page.fillOval(TRAIN_x + 120, height() - TRAIN_y + 118, TRAIN_WHEEL_WIDTH, TRAIN_WHEEL_HEIGHT); //3rd Wheel
		page.fillOval(TRAIN_x + 160, height() - TRAIN_y + 118, TRAIN_WHEEL_WIDTH, TRAIN_WHEEL_HEIGHT); //4th Wheel
			
		page.setColor(Color.black);
		page.fillRect(TRAIN_x+40, height() - TRAIN_y - 40, TRAIN_WIDTH - 150, TRAIN_HEIGHT - 20); // 3rd Rect
		page.drawLine(TRAIN_x + 25, height() - TRAIN_y + 120,TRAIN_x + 25, height() - TRAIN_y + 156); // Wheel bar
					
	}


	/**
 		* Create an animation thread that runs periodically
 		**/
    private void startAnimation()
    {
        ActionListener taskPerformer = new ActionListener() {
            public void actionPerformed(ActionEvent evt) {
                repaint();
            }
        };
        new Timer(delay, taskPerformer).start();
    }
    
	public final int width(){
		return getWidth();
	}
	
	public final int height(){
		return getHeight();
	}


}

[kraigballa]

Any ideas? Or if anyone knows how to make a ball spin I'm sure I could figure it from there. Thanks!

[Fubarable]

Suggestions:

• First and foremost, do all of your drawing in the paintComponent method of a JPanel, not the paint method of the JApplet itself. This should allow for smoother graphics since you'll have double buffering to help you.
• The first method in the paintComponent method should be a call to the super's method: super.paintComponent(g). This will do all you need to erase the old train.
• Don't perform program logic inside of paint or paint Component -- that method is only for drawing and nothing else as it needs to be as fast as possible. Also, you do not have complete control over when or even if it will be called. So increment trainX in the Swing Timer ActionListener's actionPerformed method.
• Learn and use Java naming conventions -- use camel case always, capitalize the first letter of classes, capitalize all letters of constants, use lower case first letter for everything else. This will make it easier for others to understand what you're tying to do, be they your instructors, or volunteers in fora trying to help you out.
• I would draw several BufferedImages of your wheel in various states of rotation, put them in an array and swap out the image that you wish to draw in your game loop (your Swing Timer).
• I would probably do the rest of the train images as a BufferedImage and just translate where I draw it.

[Fubarable]

Suggestions:

• First and foremost, do all of your drawing in the paintComponent method of a JPanel, not the paint method of the JApplet itself. This should allow for smoother graphics since you'll have double buffering to help you.
• The first method in the paintComponent method should be a call to the super's method: super.paintComponent(g). This will do all you need to erase the old train.
• Don't perform program logic inside of paint or paint Component -- that method is only for drawing and nothing else as it needs to be as fast as possible. Also, you do not have complete control over when or even if it will be called. So increment trainX in the Swing Timer ActionListener's actionPerformed method.
• Learn and use Java naming conventions -- use camel case always, capitalize the first letter of classes, capitalize all letters of constants, use lower case first letter for everything else. This will make it easier for others to understand what you're tying to do, be they your instructors, or volunteers in fora trying to help you out.
• I would draw several BufferedImages of your wheel in various states of rotation, put them in an array and swap out the image that you wish to draw in your game loop (your Swing Timer).
• I would probably do the rest of the train images as a BufferedImage and just translate where I draw it.

[kraigballa]

I'm not all too familiar with that, but I'll give it a try. Thanks