#----------------------------------------------------------------------
# Introduction to JES Graphics
#
# Copyright (C) September 27-29, 2017 -- Dr. William T. Verts
#----------------------------------------------------------------------

import time

#----------------------------------------------------------------------
# Graphics helper functions to translate what we really want into the
# appropriate calls to JES graphics routines.
#
# Box and Block use corner coordinates of the rectangles, instead of
# upper-left location, width, and height as required by JES functions
# addRect and addRectFilled.
#
# addCircle and addCircle filled use center coordinate and radius,
# instead of upper-left location, width, and height as required by JES
# functions addOval and addOvalFilled.
#----------------------------------------------------------------------

def addBox (Canvas,X1,Y1,X2,Y2,NewColor):                               # Want: <X1,Y1> to <X2,Y2>
    addRect(Canvas,X1,Y1,X2-X1,Y2-Y1,NewColor)                          # Need: X,Y,Width,Height
    return

def addBlock(Canvas,X1,Y1,X2,Y2,NewColor):                              # Want: <X1,Y1> to <X2,Y2>
    addRectFilled(Canvas,X1,Y1,X2-X1,Y2-Y1,NewColor)                    # Need: X,Y,Width,Height
    return
    
def addCircle(Canvas,X,Y,Radius,NewColor):                              # Want: <X,Y>, Radius
    addOval(Canvas,X-Radius,Y-Radius,2*Radius,2*Radius,NewColor)        # Need: X,Y,Width,Height
    return
    
def addCircleFilled(Canvas,X,Y,Radius,NewColor):                        # Want: <X,Y>, Radius
    addOvalFilled(Canvas,X-Radius,Y-Radius,2*Radius,2*Radius,NewColor)  # Need: X,Y,Width,Height
    return

#----------------------------------------------------------------------
# Bounce a ball around screen
#----------------------------------------------------------------------
    
def Main():
    Canvas = makeEmptyPicture(600,400,red)
    show(Canvas)
    
    # Initialize position and direction variables
    X = 300        # X location of center
    Y = 200        # Y location of center
    ChangeX = 1    # Direction of motion in X
    ChangeY = 1    # Direction of motion in Y
    Radius = 40    # Size of Ball
    
    while (True):
        # Fill the screen with the background color
        #addRectFilled(Canvas,0,0,getWidth(Canvas),getHeight(Canvas),red)
        setAllPixelsToAColor(Canvas,red)
        
        # Paint the new geometry on screen
        addCircleFilled(Canvas, X, Y, Radius, green)
        
        # Make the updated screen visible
        repaint(Canvas)
        
        # Wait to eliminate flicker
        time.sleep(0.01)
        
        # Update position and direction variables
        # Bounce ball off of its edge instead of its center.
        X = X + ChangeX
        Y = Y + ChangeY
        
        if X > getWidth(Canvas) - Radius:    # Hit right wall
            ChangeX = -1
        if X < Radius:                       # Hit left wall
            ChangeX = 1
        if Y > getHeight(Canvas) - Radius:   # Hit bottom wall
            ChangeY = -1
        if Y < Radius:                       # Hit top wall
            ChangeY = 1

    return