""" ChapterOO/Balloon.py 
"""
from graphics import *
winW, winH = 400, 400    # window size
class Balloon:
    def __init__(self, c, r ):    # constructor: c= center point, radius
        self.bCircle = Circle( c, r )
        self.line = Line(Point(c.getX(), c.getY()+r), Point(c.getX(), c.getY()+3*r ))
     
    def setFill( self, colorb ):
        self.bCircle.setFill( colorb )
                
    def ddraw( self, win ):
         self.bCircle.draw( win )
         self.line.draw( win )

    def mmove(self, dx, dy ):
        self.bCircle.move( dx, dy )
        self.line.move( dx, dy )

    def getCenter( self ):
        return self.bCircle.getCenter()

    def getRadius( self ):
        return self.bCircle.getRadius()

def main():
    win = GraphWin( "Demo: Wheels moving", winW, winH  )
    b1 = Balloon( Point( 250, 230 ), 20 )  
    b1.setFill( "blue")
    b1.ddraw( win )
    while True:
        b1.mmove( 0, -0.01 )
        if b1.getCenter().getY() < b1.getRadius():
            b1.setFill("red")
            break 

main()