# Circles on Circles
# adapted from Pascal Program by Bernie Gunn
# by Kirby Urner
# Version 1.0: Sept 19, 2004

# Requires PIL (Python Imaging Library)

from math import sin, cos, radians
import Image, ImageDraw, ImageFont # PIL must be installed

def setup(rot, width, height, bg = 'White', txtcolor = "Blue"):
    """
    Initialize/return canvas, draw objects, draw text
    """
    canvas = Image.new('RGB',(width, height), bg)
    draw   = ImageDraw.Draw(canvas)

    # add title and caption to canvas
    font1   = ImageFont.truetype('verdana.ttf', 32)  # requires latest PIL, ttfs
    font2   = ImageFont.truetype('verdana.ttf', 16)  

    title  = "Circles on Circles"
    wtitle, htitle = font1.getsize(title) # used to place text

    caption = "Rotation Factor = %s" % rot
    wcaption = font2.getsize(caption)[0]
    
    draw.text((width/2  - wtitle/2, 20),  title,   font = font1, fill = txtcolor)
    draw.text((height/2 - wcaption/2, 40 + htitle), caption, font = font2, fill = txtcolor)

    return (canvas, draw)  # objects required in other modules, avoiding any global variables
    
def mainloop(rot, width, height, draw, color = 'Black'):
    """
    Compute the points, draw lines connecting them
    """
    
    R1 = 140
    R2 = 140    
    j  = 0

    xcenter = width/2
    ycenter = height/2
    
    while j <= 360:

        k = j * rot
        
        y1 = round(sin(radians(j)) * R1)
        x1 = round(cos(radians(j)) * R2)

        y2 = round(sin(radians(k)) * R1)
        x2 = round(cos(radians(k)) * R2)
        
        point    = (x1 + x2 + xcenter, y1 + y2 + ycenter)
                
        if j > 0:
             draw.line([oldpoint, point], color)

        oldpoint = point
        j += 0.25  # quarter-degree increments (smoother curves)
        
def finish(canvas):
    """
    Display the canvas in a default viewer, then save it to file
    """
    canvas.show()  # in Windows, uses default bmp viewer
    canvas.save("./Lib/site-packages/mycircles.png","PNG") # presuming this path exists
    print "Image saved."

def main(width=800, height=800):
    rot = int(raw_input("Rotate Outer circle by what factor of inner?: "))    
    canvas, draw = setup(rot, width, height, bg='Black', txtcolor='Yellow')  # bg, txtcolor optional
    mainloop(rot, width, height, draw, color='Orange')        # draw color optional  
    finish(canvas)

# added so this may run as a script, vs imported as a module
if __name__ == "__main__":
    main()