#!/usr/bin/env python
#coding=utf-8
import random
from PIL import Image, ImageDraw, ImageFont, ImageFilter
_letter_cases = "abcdefghjkmnpqrstuvwxy" # 小寫字母，去除可能干擾的i，l，o，z
_upper_cases = _letter_cases.upper() # 大寫字母
_numbers = ''.join(map(str, range(3, 10))) # 數(shù)字
init_chars = ''.join((_letter_cases, _upper_cases, _numbers))
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="ae_AlArabiya.ttf",
             length=4,
             draw_lines=True,
             n_line=(1, 2),
             draw_points=True,
             point_chance = 2):
  '''
  @todo: 生成驗證碼圖片
  @param size: 圖片的大小，格式（寬，高），默認(rèn)為(120, 30)
  @param chars: 允許的字符集合，格式字符串
  @param img_type: 圖片保存的格式，默認(rèn)為GIF，可選的為GIF，JPEG，TIFF，PNG
  @param mode: 圖片模式，默認(rèn)為RGB
  @param bg_color: 背景顏色，默認(rèn)為白色
  @param fg_color: 前景色，驗證碼字符顏色，默認(rèn)為藍色#0000FF
  @param font_size: 驗證碼字體大小
  @param font_type: 驗證碼字體，默認(rèn)為 ae_AlArabiya.ttf
  @param length: 驗證碼字符個數(shù)
  @param draw_lines: 是否劃干擾線
  @param n_lines: 干擾線的條數(shù)范圍，格式元組，默認(rèn)為(1, 2)，只有draw_lines為True時有效
  @param draw_points: 是否畫干擾點
  @param point_chance: 干擾點出現(xiàn)的概率，大小范圍[0, 100]
  @return: [0]: PIL Image實例
  @return: [1]: 驗證碼圖片中的字符串
  '''
  width, height = size # 寬， 高
  img = Image.new(mode, size, bg_color) # 創(chuàng)建圖形
  draw = ImageDraw.Draw(img) # 創(chuàng)建畫筆
  def get_chars():
    '''生成給定長度的字符串，返回列表格式'''
    return random.sample(chars, length)
  def create_lines():
    '''繪制干擾線'''
    line_num = random.randint(*n_line) # 干擾線條數(shù)
    for i in range(line_num):
      # 起始點
      begin = (random.randint(0, size[0]), random.randint(0, size[1]))
      #結(jié)束點
      end = (random.randint(0, size[0]), random.randint(0, size[1]))
      draw.line([begin, end], fill=(0, 0, 0))
  def create_points():
    '''繪制干擾點'''
    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():
    '''繪制驗證碼字符'''
    c_chars = get_chars()
    strs = ' %s ' % ' '.join(c_chars) # 每個字符前后以空格隔開
    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 draw_lines:
    create_lines()
  if draw_points:
    create_points()
  strs = create_strs()
  # 圖形扭曲參數(shù)
  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) # 創(chuàng)建扭曲
  img = img.filter(ImageFilter.EDGE_ENHANCE_MORE) # 濾鏡，邊界加強（閾值更大）
  return img, strs
if __name__ == "__main__":
  code_img = create_validate_code()
  code_img.save("validate.gif", "GIF")

try:
  import cStringIO as StringIO
except ImportError:
  import StringIO
mstream = StringIO.StringIO()
img = create_validate_code()[0]
img.save(mstream, "GIF") 

from django.conf.urls.defaults import *
urlpatterns = patterns('example.views',
  url(r'^validate/$', 'validate', name='validate'),
)

from django.shortcuts import HttpResponse
from validate import create_validate_code
def validate(request):
  mstream = StringIO.StringIO()
  validate_code = create_validate_code()
  img = validate_code[0]
  img.save(mstream, "GIF")
  request.session['validate'] = validate_code[1]
  return HttpResponse(mstream.getvalue(), "image/gif")