预计本章简稿完成日期： 2018-07-18
创建图片
dutchflag.jpg
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Author: xurongzhong#126.com wechat:pythontesting qq:37391319
# 技术支持 钉钉群：21745728(可以加钉钉pythontesting邀请加入)
# qq群：144081101 591302926 567351477
# CreateDate: 2018-6-12
# dutchflag.py
from PIL import Image
def dutchflag(width, height):
"""Return new image of Dutch flag."""
img = Image.new("RGB", (width, height))
for j in range(height):
for i in range(width):
if j < height/3:
img.putpixel((i, j), (255, 0, 0))
elif j < 2*height/3:
img.putpixel((i, j), (0, 255, 0))
else:
img.putpixel((i, j), (0, 0, 255))
return img
def main():
img = dutchflag(600, 400)
img.save("dutchflag.jpg")
main()
创建图片
把下面图片转为灰度图：
lake.jpg
结果：
lake_gray.jpg
代码：
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Author: xurongzhong#126.com wechat:pythontesting qq:37391319
# 技术支持 钉钉群：21745728(可以加钉钉pythontesting邀请加入)
# qq群：144081101 591302926 567351477
# CreateDate: 2018-6-12
# grayscale.py
from PIL import Image
def grayscale(img):
"""Return copy of img in grayscale."""
width, height = img.size
newimg = Image.new("RGB", (width, height))
for j in range(height):
for i in range(width):
r, g, b = img.getpixel((i, j))
avg = (r + g + b) // 3
newimg.putpixel((i, j), (avg, avg, avg))
return newimg
def main():
img = Image.open("lake.jpg")
newimg = grayscale(img)
newimg.save("lake_gray.jpg")
main()
实际应用中，convert方法已经帮我们做好了这些，参见grayscale2.py
代码：
#!/usr/bin/env python3
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Author: xurongzhong#126.com wechat:pythontesting qq:37391319
# 技术支持 钉钉群：21745728(可以加钉钉pythontesting邀请加入)
# qq群：144081101 591302926 567351477
# CreateDate: 2018-6-12
# grayscale2.py
from PIL import Image
Image.open("lake.jpg").convert("L").save("lake_gray.jpg")
