import java.awt.*; public class Ball { private Color mycolor; private int radius; private int YOFFSET; private double XMIN=-1.0,XMAX=1.0,YMIN=-1.0,YMAX=1.0; private double VX=4.0,VY=4.0; public double x,y,vx,vy; private double xscale,yscale; // Constructor method sets up initial position and velocity and saves // name of applet. Also sets the color and radius of the ball Ball(Color c, int r, int xl, int yl){ mycolor=c; radius=r; x=XMIN+(XMAX-XMIN)*Math.random(); y=YMIN+(YMAX-YMIN)*Math.random(); vx=VX*(Math.random()-0.5); vy=VY*(Math.random()-0.5); xscale=xl/(XMAX-XMIN); yscale=-yl/(YMAX-YMIN); YOFFSET=yl; } // this method draws ball to screen public void draw(Graphics g){ g.setColor(mycolor); g.fillOval((int)((x-XMIN)*xscale)-radius, (int)((y-YMIN)*yscale)-radius+YOFFSET, 2*radius,2*radius); } }