一百一十四：CMS系统之图形验证码生成

安装Pillow库，用于生成图形验证码：pip install Pillow

字体文件来源

生成一个验证码图片

import random
import string
from PIL import Image, ImageDraw, ImageFont

# Image：一个画布
# ImageDraw：一个画笔
# ImageFont:画笔的字体

class Captcha(object):
    """ 生成图形验证码 """

    number = 4  # 生成几位数的验证码
    size = (100, 30)  # 验证码图片的宽度和高度
    fontsize = 25  # 验证码字体大小
    line_number = 2  # 加入干扰线的条数

    # 构建一个验证码源文本
    SOURCE = list(string.ascii_letters)
    for index in range(0, 10):
        SOURCE.append(str(index))

    # 用来绘制干扰线
    @classmethod
    def __gene_line(cls, draw, width, height):
        begin = (random.randint(0, width), random.randint(0, height))
        end = (random.randint(0, width), random.randint(0, height))
        draw.line([begin, end], fill=cls.__gene_random_color(), width=2)

    # 用来绘制干扰点
    @classmethod
    def __gene_points(cls, draw, point_chance, width, height):
        chance = min(100, max(0, int(point_chance)))  # 大小限制在[0, 100]
        for w in range(width):
            for h in range(height):
                tmp = random.randint(0, 100)
                if tmp > 100 - chance:
                    draw.point((w, h), fill=cls.__gene_random_color())

    # 生成随机的颜色
    @classmethod
    def __gene_random_color(cls, start=0, end=255):
        random.seed()
        return (random.randint(start, end), random.randint(start, end), random.randint(start, end))

    # 随机选择一个字体
    @classmethod
    def __gene_random_font(cls):
        fonts = [
            'Courgette-Regular.ttf',
            'LHANDW.TTF',
            'Lobster-Regular.ttf',
            'verdana.ttf'
        ]
        font = random.choice(fonts)
        return 'utils/captcha/' + font  # 返回字体路径

    # 用来随机生成一个字符串(包括英文和数字)
    @classmethod
    def gene_text(cls, number):  # number是生成验证码的位数
        return ''.join(random.sample(cls.SOURCE, number))

    # 生成验证码
    @classmethod
    def gene_graph_captcha(cls):
        width, height = cls.size  # 验证码图片的宽和高
        # 创建图片
        # R：Red（红色）0-255
        # G：G（绿色）0-255
        # B：B（蓝色）0-255
        # A：Alpha（透明度）
        image = Image.new('RGBA', (width, height), cls.__gene_random_color(0, 100))
        font = ImageFont.truetype(cls.__gene_random_font(), cls.fontsize)  # 验证码的字体
        draw = ImageDraw.Draw(image)  # 创建画笔
        text = cls.gene_text(cls.number)  # 生成字符串
        font_width, font_height = font.getsize(text)  # 获取字体的尺寸
        # 填充字符串
        draw.text(((width - font_width) / 2, (height - font_height) / 2), text, font=font,
                  fill=cls.__gene_random_color(150, 255))
        # 绘制干扰线
        for x in range(0, cls.line_number):
            cls.__gene_line(draw, width, height)
        cls.__gene_points(draw, 10, width, height)  # 绘制噪点
        # 保存到本地
        with open('captcha.png', 'wb') as fp:
            image.save(fp)
        return (text, image)

if __name__ == '__main__':
    Captcha.gene_graph_captcha()

写一个获取验证码的视图给前端调用

from io import BytesIO
from flask import Blueprint, views, render_template, make_response

from utils.captcha import Captcha

bp = Blueprint("front", __name__)

@bp.route('/captcha/')
def graph_captcha():
    """ 获取验证码 """
    text, image = Captcha.gene_graph_captcha()
    out = BytesIO()  # 二进制流
    image.save(out, 'png')
    out.seek(0)
    resp = make_response(out.read())  # 二进制流读取出来放到响应对象中
    resp.content_type = 'image/png'
    return resp