python生成圆形图片

# -*- 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()