framedball.java

书籍"Java_面向事件编程"的附带光盘代码

import objectdraw.*;
import java.awt.Color;

// A simple, round oval will a black border and a filled interior.
public class FramedBall {

        // the interior of the ball
        private FilledOval body;
        
        // the black frame around the ball
        private FramedOval border;

        // Create the Framed and Filled ovals to make a ball with a border
        public FramedBall(      double left, double top, double size, 
                                    DrawingCanvas aCanvas) {

                body = new FilledOval(left, top, size, size, aCanvas);
                border = new FramedOval(left, top, size, size, aCanvas);
        }

        // move the ball by specified offsets
        public void move(double dx, double dy) {

                body.move(dx, dy);
                border.move(dx, dy);
        }

        // set the color of the interior of the ball
        public void setColor(Color hue) {
                body.setColor(hue);
        }

        
        // get the x coordinate of the corner of the ball
        public double getX() {
                return body.getX();
        }

        // get the y coordinate of the corner of the ball
        public double getY() {
                return body.getY();
        }

        // check to see if the ball contains a specified location
        public boolean contains(Location point) {
                return body.contains(point);
        }

        // move the ball to a specified position
        public void moveTo(double x, double y) {
                // move the ball by offsets needed to reach desired location
                this.move(x - body.getX(), y - body.getY());
        }

        // move the ball to a specified position
        public void moveTo(Location point) {
                this.moveTo(point.getX(), point.getY());
        }

}