Making Circles smaller via a loop

[Bob BigMac]

I am trying to write a program so when it runs, it makes one circle of say 50 radius, then the next one would be 45 and so on going down by 5 each time.

What I am unsure of is how can I do this with a loop or is it impossible. I look forwards to any help that I can get.

[bvdet]

Are you planning to use Tkinter or some other GUI interface? Your radiuses can be defined in a list comprehension.

>>> [rad for rad in range(50, 0, -5)]
[50, 45, 40, 35, 30, 25, 20, 15, 10, 5]
>>>

Using Tkinter, you can create a canvas and place circles on the canvas. Here's an example:

from Tkinter import *

class Point(object):
    def __init__(self, x=0.0, y=0.0):
        self.x = float(x)
        self.y = float(y)
    def __add__(self, other):
        return Point(self.x+other.x, self.y+other.y)

def drawCircles(columns, rows, radius=100, space=0):
    root = Tk()
    canvas_width = columns*(radius*2+space)
    canvas_height = rows*(radius*2+space)
    
    w = Canvas(root, width=canvas_width, height=canvas_height)
    # create a black background
    w.create_rectangle(0,0,canvas_width,canvas_height,fill="black")
    # calculate UL and LR coordinates in column 1, row 1
    pt1 = Point(space/2.0, space/2.0)
    pt2 = pt1+Point(radius*2, radius*2)
    for i in range(0, columns):
        for j in range(0, rows):
            # xy = UL.x, UL.y, LR.x, LR.y
            xy = pt1.x+i*(radius*2+space), \
                 pt1.y+j*(radius*2+space), \
                 pt2.x+i*(radius*2+space), \
                 pt2.y+j*(radius*2+space)
            # create a circle with red fill
            w.create_oval(xy, fill='red')
            
    w.pack()
    root.mainloop()

if __name__ == '__main__':
    drawCircles(4, 3, 125)
    drawCircles(4, 2, 75, 20)
    drawCircles(4, 2, 75, 100)
    drawCircles(24, 16, 12, 6)