Python编写生成验证码的脚本的教程

#!/usr/bin/env python#coding=utf-8import randomimport Image, ImageDraw, ImageFont, ImageFilter _letter_cases = "abcdefghjkmnpqrstuvwxy" # 小写字母，去除可能干扰的i，l，o，z_upper_cases = _letter_cases.upper() # 大写字母_numbers = ''.join(map(str, range(3, 10))) # 数字init_chars = ''.join((_letter_cases, _upper_cases, _numbers))fontType="/usr/share/fonts/truetype/freefont/FreeSans.ttf" def create_validate_code(size=(120, 30),               chars=init_chars,               img_type="GIF",               mode="RGB",               bg_color=(255, 255, 255),               fg_color=(0, 0, 255),               font_size=18,               font_type=fontType,               length=4,               draw_lines=True,               n_line=(1, 2),               draw_points=True,               point_chance = 2): ''' @todo: 生成验证码图片 @param size: 图片的大小，格式（宽，高），默认为(120, 30) @param chars: 允许的字符集合，格式字符串 @param img_type: 图片保存的格式，默认为GIF，可选的为GIF，JPEG，TIFF，PNG @param mode: 图片模式，默认为RGB @param bg_color: 背景颜色，默认为白色 @param fg_color: 前景色，验证码字符颜色，默认为蓝色#0000FF @param font_size: 验证码字体大小 @param font_type: 验证码字体，默认为 ae_AlArabiya.ttf @param length: 验证码字符个数 @param draw_lines: 是否划干扰线 @param n_lines: 干扰线的条数范围，格式元组，默认为(1, 2)，只有draw_lines为True时有效 @param draw_points: 是否画干扰点 @param point_chance: 干扰点出现的概率，大小范围[0, 100] @return: [0]: PIL Image实例 @return: [1]: 验证码图片中的字符串 '''  width, height = size # 宽， 高 img = Image.new(mode, size, bg_color) # 创建图形 draw = ImageDraw.Draw(img) # 创建画笔 if draw_lines:  create_lines(draw,n_line,width,height) if draw_points:  create_points(draw,point_chance,width,height) strs = create_strs(draw,chars,length,font_type, font_size,width,height,fg_color)  # 图形扭曲参数 params = [1 - float(random.randint(1, 2)) / 100,      0,      0,      0,      1 - float(random.randint(1, 10)) / 100,      float(random.randint(1, 2)) / 500,      0.001,      float(random.randint(1, 2)) / 500      ] img = img.transform(size, Image.PERSPECTIVE, params) # 创建扭曲  img = img.filter(ImageFilter.EDGE_ENHANCE_MORE) # 滤镜，边界加强（阈值更大）  return img, strs  def create_lines(draw,n_line,width,height): '''绘制干扰线''' line_num = random.randint(n_line[0],n_line[1]) # 干扰线条数 for i in range(line_num):  # 起始点  begin = (random.randint(0, width), random.randint(0, height))  #结束点  end = (random.randint(0, width), random.randint(0, height))  draw.line([begin, end], fill=(0, 0, 0)) def create_points(draw,point_chance,width,height): '''绘制干扰点''' chance = min(100, max(0, int(point_chance))) # 大小限制在[0, 100]   for w in xrange(width):  for h in xrange(height):   tmp = random.randint(0, 100)   if tmp > 100 - chance:    draw.point((w, h), fill=(0, 0, 0)) def create_strs(draw,chars,length,font_type, font_size,width,height,fg_color): '''绘制验证码字符''' '''生成给定长度的字符串，返回列表格式''' c_chars = random.sample(chars, length) strs = ' %s ' % ' '.join(c_chars) # 每个字符前后以空格隔开   font = ImageFont.truetype(font_type, font_size) font_width, font_height = font.getsize(strs)  draw.text(((width - font_width) / 3, (height - font_height) / 3),strs, font=font, fill=fg_color)   return ''.join(c_chars)  if __name__ == "__main__":  code_img = create_validate_code()  code_img[0].save("validate.gif", "GIF")  print code_img[1]