python生成圆形图片的方法

# -*- coding: utf-8 -*- 
""" 
__author__= 'Du' 
__creation_time__= '2018/1/5 9:08' 
""" 
 
import os, math 
from PIL import Image 
 
 
def circle(): 
 ima = Image.open("ball1.jpg").convert("RGBA") 
 # ima = ima.resize((600, 600), Image.ANTIALIAS) 
 size = ima.size 
 print(size) 
 
 # 因为是要圆形，所以需要正方形的图片 
 r2 = min(size[0], size[1]) 
 if size[0] != size[1]: 
 ima = ima.resize((r2, r2), Image.ANTIALIAS) 
 
 # 最后生成圆的半径 
 r3 = 60 
 imb = Image.new('RGBA', (r3*2, r3*2),(255,255,255,0)) 
 pima = ima.load() # 像素的访问对象 
 pimb = imb.load() 
 r = float(r2/2) #圆心横坐标 
 
 for i in range(r2): 
 for j in range(r2): 
 lx = abs(i-r) #到圆心距离的横坐标 
 ly = abs(j-r)#到圆心距离的纵坐标 
 l = (pow(lx,2) + pow(ly,2))** 0.5 # 三角函数 半径 
 
 if l < r3: 
 pimb[i-(r-r3),j-(r-r3)] = pima[i,j] 
 imb.save("test_circle.png") 
 
circle()