source: products/qPloneCaptchas/branches/plone-3.1/utils.py @ 2284

import os
from string import atoi
import md5
from random import randint
from Products.qPloneCaptchas.data import basic_english
from Products.qPloneCaptchas.config import *
from DateTime import DateTime
import re
import math
try:
    import Crypto.Cipher.DES as Crypto
except:
    import Crypto

def encrypt1(s):
    return md5.new(s).hexdigest().upper()

def getTransform(x, y, a, p, o):
    return (math.sin( (y+o[0])*p )*a + x, math.sin( (x+o[1])*p )*a + y)

def gen_captcha(**kwargs):
    """Generate a captcha image"""
    import ImageFile
    import Image
    import ImageFont
    import ImageDraw
    import ImageFilter
    import random
    from PIL import ImageFile as pyImageFile
    import sys
    sys.modules['ImageFile'] = pyImageFile
    from cStringIO import StringIO

    text = kwargs.get('text', None)
    fnt_sz = kwargs.get('size', DEFAULT_IMAGE_SIZE)
    bkground = kwargs.get('bkground', DEFAULT_BG)
    font_color = kwargs.get('font_color', DEFAULT_FONT_COLOR)
    distortion = kwargs.get('distortion', DEFAULT_DISTORTION)

    period = distortion[0]
    amplitude = distortion[1]
    offset = distortion[2]

    outFile = StringIO()

    DATA_PATH = os.path.abspath(os.path.dirname(__file__)) + '/data'
    FONT_PATH = DATA_PATH + '/fonts'

    #select font for captcha text
    ALL_FONTS=('Bd', 'It', 'MoBI', 'Mono', 'Se', 'BI', 'MoBd', 'MoIt', 'SeBd', '')
    rand_font = random.choice(ALL_FONTS)
    font = ImageFont.truetype(FONT_PATH+'/vera/Vera%s.ttf'%rand_font, fnt_sz)
    textSize = font.getsize(text)

#------------------------------render   background1 -----------------------
    image = Image.new('RGB', (textSize[0]+7,textSize[1]+7), bkground)
    image.paste(bkground)
#------------------------------render       Text2 ------------------------
    draw = ImageDraw.Draw(image)
    alignment = (random.uniform(0,1), random.uniform(0,1))
    x = int((image.size[0] - textSize[0]) * alignment[0] + 0.5)
    y = int((image.size[1] - textSize[1]) * alignment[1] + 0.5)

    draw.text((x,y), text, font=font, fill=font_color)

#------------------------------render       Distortion -----------------------
    r = 1
    xPoints = image.size[0] / r + 2
    yPoints = image.size[1] / r + 2

    # Create a list of arrays with transformed points
    xRows = []
    yRows = []
    for j in xrange(yPoints):
        xRow = []
        yRow = []
        for i in xrange(xPoints):
            x, y = getTransform(i*r, j*r, amplitude, period, offset)

            # Clamp the edges so we don't get black undefined areas
            x = max(0, min(image.size[0]-1, x))
            y = max(0, min(image.size[1]-1, y))

            xRow.append(x)
            yRow.append(y)
        xRows.append(xRow)
        yRows.append(yRow)

    # Create the mesh list, with a transformation for
    # each square between points on the grid
    mesh = []
    for j in xrange(yPoints-1):
        for i in xrange(xPoints-1):
            mesh.append((
                # Destination rectangle
                (i*r, j*r,
                 (i+1)*r, (j+1)*r),
                # Source quadrilateral
                (xRows[j  ][i  ], yRows[j  ][i  ],
                 xRows[j+1][i  ], yRows[j+1][i  ],
                 xRows[j+1][i+1], yRows[j+1][i+1],
                 xRows[j  ][i+1], yRows[j  ][i+1]),
                ))

    img = image.transform(image.size, Image.MESH, mesh, Image.BILINEAR)

    # save the image to a file
    img.save(outFile, format='jpeg')
    outFile.seek(0)
    src = outFile.read()
    size = len(src)
    sys.modules['ImageFile'] = ImageFile
    return {'src':src, 'size':size}


def getWord(index):
    words = basic_english.words.split()
    return words[index]

def getIndex(word):
    words = basic_english.words.split()
    try:
        res = words.index(word)
    except ValueError:
        res = getLen()+1
    return res

def getCaptchasCount(havePIL):
    def getLen():
        return len(basic_english.words.split())
    return havePIL and getLen() or CAPTCHAS_COUNT

def formKey(num):
    def normalize(s):
        return (not len(s)%8 and s) or normalize(s+str(randint(0, 9)))

    return normalize('%s_%i_'%(str(DateTime().timeTime()), num))

def encrypt(key, s):
    return toHex(Crypto.new(key).encrypt(s))

def decrypt(key, s):
    return Crypto.new(key).decrypt(toStr(s))

def parseKey(s):
    ps = re.match('^(.+?)_(.+?)_', s)
    if ps is None:
        return {'date': '', 'key': ''}
    return {'date': ps.group(1), 'key':ps.group(2)}

def toHex(s):
    lst = []
    for ch in s:
        hv = hex(ord(ch)).replace('0x', '')
        if len(hv) == 1:
            hv = '0'+hv
        lst.append(hv)

    return reduce(lambda x,y:x+y, lst)

def toStr(s):
    return s and chr(atoi(s[:2], base=16)) + toStr(s[2:]) or ''