circular.py

# -*- coding: utf-8 -*-
"""
Created on Sat Aug 08 14:10:15 2015

@author: Django
"""

import math
from PIL import Image

def arrangeImagesInCircle(masterImage, imagesToArrange):
    imgWidth, imgHeight = masterImage.size

    #we want the circle to be as large as possible.
    #but the circle shouldn't extend all the way to the edge of the image.
    #If we do that, then when we paste images onto the circle, those images will partially fall over the edge.
    #so we reduce the diameter of the circle by the width/height of the widest/tallest image.
    diameter = min(
        imgWidth  - max(img.size[0] for img in imagesToArrange),
        imgHeight - max(img.size[1] for img in imagesToArrange)
    )
    radius = diameter / 2

    circleCenterX = imgWidth  / 2
    circleCenterY = imgHeight / 2
    theta = 2*math.pi / len(imagesToArrange)
    for i, curImg in enumerate(imagesToArrange):
        angle = i * theta
        dx = int(radius * math.cos(angle))
        dy = int(radius * math.sin(angle))

        #dx and dy give the coordinates of where the center of our images would go.
        #so we must subtract half the height/width of the image to find where their top-left corners should be.
        pos = (
            circleCenterX + dx - curImg.size[0]/2,
            circleCenterY + dy - curImg.size[1]/2
        )
        masterImage.paste(curImg, pos)

img = Image.new("RGB", (500,500), (255,255,255))

#red.png, blue.png, green.png are simple 50x50 pngs of solid color
imageFilenames = ["label.png", "lena.png", "lena.png"] * 5
images = [Image.open(filename) for filename in imageFilenames]

arrangeImagesInCircle(img, images)

img.save("output.png")