uni

Circle.java (3915B)

---

 import java.awt.*;
 import java.awt.geom.*;
 
 /**
  * A circle that can be manipulated and that draws itself on a canvas.
  * 
  * @author	Michael Kolling and David J. Barnes
  * @version 1.0  (15 July 2000)
  */
 
 public class Circle
 {
 	private int diameter;
 	private int xPosition;
 	private int yPosition;
 	private String color;
 	private boolean isVisible;
 
 	@Override
 	public String toString(){
 		return "diameter: " + diameter + 
 			", xPosition: " + xPosition + 
 			", yPosition: " + yPosition + 
 			", color: " + color + 
 			", isVisible: " + isVisible;
 	}
 
 	/**
 	 * Create a new circle at default position with default color.
 	 */
 	public Circle()
 	{
 		diameter = 30;
 		xPosition = 0;
 		yPosition = 0;
 		color = "blue";
 		isVisible = false;
 	}
 
 	/**
 	 * Make this circle visible. If it was already visible, do nothing.
 	 */
 	public void makeVisible()
 	{
 		isVisible = true;
 		draw();
 	}
 
 	/**
 	 * Make this circle invisible. If it was already invisible, do nothing.
 	 */
 	public void makeInvisible()
 	{
 		erase();
 		isVisible = false;
 	}
 
 	public void setX(int x) {
 		xPosition = x;	
 	}
 
 	public void setY(int y) {
 		yPosition = y;	
 	}
 
 	/**
 	 * Move the circle a few pixels to the right.
 	 */
 	public void moveRight()
 	{
 		moveHorizontal(20);
 	}
 
 	/**
 	 * Move the circle a few pixels to the left.
 	 */
 	public void moveLeft()
 	{
 		moveHorizontal(-20);
 	}
 
 	/**
 	 * Move the circle a few pixels up.
 	 */
 	public void moveUp()
 	{
 		moveVertical(-20);
 	}
 
 	/**
 	 * Move the circle a few pixels down.
 	 */
 	public void moveDown()
 	{
 		moveVertical(20);
 	}
 
 	/**
 	 * Move the circle horizontally by 'distance' pixels.
 	 */
 	public void moveHorizontal(int distance)
 	{
 		erase();
 		xPosition += distance;
 		draw();
 	}
 
 	/**
 	 * Move the circle vertically by 'distance' pixels.
 	 */
 	public void moveVertical(int distance)
 	{
 		erase();
 		yPosition += distance;
 		draw();
 	}
 
 	/**
 	 * Slowly move the circle horizontally by 'distance' pixels.
 	 */
 	public void slowMoveHorizontal(int distance)
 	{
 		int delta;
 
 		if(distance < 0) 
 		{
 			delta = -1;
 			distance = -distance;
 		}
 		else 
 		{
 			delta = 1;
 		}
 
 		for(int i = 0; i < distance; i++)
 		{
 			xPosition += delta;
 			draw();
 		}
 	}
 
 	/**
 	 * Slowly move the circle vertically by 'distance' pixels.
 	 */
 	public void slowMoveVertical(int distance)
 	{
 		int delta;
 
 		if(distance < 0) 
 		{
 			delta = -1;
 			distance = -distance;
 		}
 		else 
 		{
 			delta = 1;
 		}
 
 		for(int i = 0; i < distance; i++)
 		{
 			yPosition += delta;
 			draw();
 		}
 	}
 
 	/**
 	 * Change the size to the new size (in pixels). Size must be >= 0.
 	 */
 	public void changeSize(int newDiameter)
 	{
 		erase();
 		diameter = newDiameter;
 		draw();
 	}
 
 	/**
 	 * Get the current diameter size
 	 */
 	public int getSize(){
 		return diameter;
 	}
 
 	/**
 	 * Change the color. Valid colors are "red", "yellow", "blue", "green",
 	 * "magenta" and "black".
 	 */
 	public void changeColor(String newColor)
 	{
 		color = newColor;
 		draw();
 	}
 
 	/**
 	 * Get the current color
 	 */
 	public String getColor(){
 		return color.toString();
 	}
 
 	/**
 	 * Get current X coordiate in the canvas
 	 */
 	public int getXCoord(){
 		return xPosition;
 	}
 
 	/**
 	 * Get current Y coordiate in the canvas
 	 */
 	public int getYCoord(){
 		return yPosition;
 	}
 
 	/*
 	 * Draw the circle with current specifications on screen.
 	 */
 	private void draw()
 	{
 		if(isVisible) {
 			Canvas canvas = Canvas.getCanvas();
 			canvas.draw(this, color, new Ellipse2D.Double(xPosition, yPosition, 
 						diameter, diameter));
 			canvas.wait(10);
 		}
 	}
 
 	/*
 	 * Erase the circle on screen.
 	 */
 	private void erase()
 	{
 		if(isVisible) {
 			Canvas canvas = Canvas.getCanvas();
 			canvas.erase(this);
 		}
 	}
 }