#wpp to control the velocity of ball using arrow keys

import SimpleGUICS2Pygame.simpleguics2pygame as simplegui
width=500
height=500
rod=20
ball_pos=[width/2,height/2]
vel=[0,1]

def draw(canvas):
    ball_pos[0]+=vel[0]
    ball_pos[1]+=vel[1]
    if ball_pos[0]<=rod:
        vel[0]=-vel[0]
    elif ball_pos[0]>=(width-rod):
        vel[0]=-vel[0]
    elif ball_pos[1]<=rod:
        vel[1]=-vel[1]
    elif ball_pos[1]>=(height-rod):
        vel[1]=-vel[1]
    canvas.draw_circle(ball_pos,rod,2,'red','red')
def keydown(key):
    acc=1
    global vel
    if key==simplegui.KEY_MAP['left']:
        vel[0]-=acc
    elif key==simplegui.KEY_MAP['right']:
        vel[0]+=acc
    elif key==simplegui.KEY_MAP['right']:
        vel[0]=-vel[0]
    elif key==simplegui.KEY_MAP['up']:
        vel[1]-=acc
    elif key==simplegui.KEY_MAP['down']:
        vel[1]+=acc
    else:
        vel=[0,0]

frame=simplegui.create_frame('rod',width,height)
frame.set_draw_handler(draw)
frame.set_keydown_handler(keydown)
frame.start()