Python3使用Pillow模块生成简单验证码的实现方法

# -*- coding: utf-8 -*-
# __author__: Pad0y

from PIL import Image, ImageDraw, ImageFont
from random import choice, randint, randrange
import string

# 候选字符集,大小写字母+数字
chrs = string.ascii_letters + string.digits


def selected_chrs(length):
  """
  返回length个随机字符串
  :param length:
  :return:
  """
  result = ''.join(choice(chrs) for _ in range(length))
  return result


def get_color():
  """
  设置随机颜色
  :return:
  """
  r = randint(0, 255)
  g = randint(0, 255)
  b = randint(0, 255)
  return (r, g, b)


def main(size=(200, 100), chrNumber=6, bgcolor=(255, 255, 255)):
  """
  定义图片大小，验证码长度，背景颜色
  :param size:
  :param chrNumber:
  :param bgcolor:
  :return:
  """
  # 创建空白图像和绘图对象
  image_tmp = Image.new('RGB', size, bgcolor)
  draw = ImageDraw.Draw(image_tmp)

  # 生成并计算随机字符的宽度和高度
  text = selected_chrs(chrNumber)
  font = ImageFont.truetype('c:\\windows\\fonts\\Roboto-Regular.ttf', 48) # 选定一款系统字体
  width, height = draw.textsize(text, font)
  if width + 2*chrNumber > size[0] or height > size[1]:
    print('Size Error!')
    return

  # 绘制字符串
  startX = 0
  width_eachchr = width // chrNumber # 计算每个字符宽度
  for i in range(chrNumber):
    startX += width_eachchr + 1
    position = (startX, (size[1]-height)//2+randint(-10, 10)) # 字符坐标, Y坐标上下浮动
    draw.text(xy=position, text=text[i], font=font, fill=get_color()) # 绘制函数

  # 对像素位置进行微调，实现验证码扭曲效果
  img_final = Image.new('RGB', size, bgcolor)
  pixels_final = img_final.load()
  pixels_tmp = image_tmp.load()
  for y in range(size[1]):
    offset = randint(-1, 0) # randint()相当于闭区间[x,y]
    for x in range(size[0]):
      newx = x + offset # 像素微调
      if newx >= size[0]:
        newx = size[0] - 1
      elif newx < 0:
        newx = 0
      pixels_final[newx, y] = pixels_tmp[x, y]

  # 绘制随机颜色随机位置的干扰像素
  draw = ImageDraw.Draw(img_final)
  for i in range(int(size[0]*size[1]*0.07)): # 7%密度的干扰像素
    draw.point((randrange(size[0]), randrange(size[1])), fill=get_color()) # randrange取值范围是左开右闭

  # 绘制随机干扰线，这里设置为8条
  for i in range(8):
    start = (0, randrange(size[1]))
    end = (size[0], randrange(size[1]))
    draw.line([start, end], fill=get_color(), width=1)

  # 绘制随机弧线
  for i in range(8):
    start = (-50, -50) # 起始位置在外边看起来才会像弧线
    end = (size[0]+10, randint(0, size[1]+10))
    draw.arc(start+end, 0, 360, fill=get_color())

  # 保存图片
  img_final.save('Veri_code.jpg')
  img_final.show()


if __name__ == '__main__':
  main((200, 100), 6, (255, 255, 255))