# ChapterOO/Balloon2.py 
from graphics import *
winW, winH = 400, 400    # window geometry
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, 330 ), 20 ) # make n balloons
    b2 = Balloon( Point( 150, 230 ), 25 )
    b3 = Balloon( Point(  50, 240 ), 20 )
    b4 = Balloon( Point( 100, 350 ), 10 )
    blist = [b1,b2,b3,b4]
    for b in blist:
        b.setFill( "blue")
        b.ddraw( win )
    
    while (len(blist) > 0 ):
        for b in blist:
            b.mmove( 0, -0.1 )
            if b.getCenter().getY() < b.getRadius():
                b.setFill("red")
                blist.remove(b)
      

main()