点击展开源码：
# coding: utf-8
"""
captcha.image
~~~~~~~~~~~~~
Generate Image CAPTCHAs, just the normal image CAPTCHAs you are using.
"""
import os
import random
from PIL import Image
from PIL import ImageFilter
from PIL.ImageDraw import Draw
from PIL.ImageFont import truetype
try:
from cStringIO import StringIO as BytesIO
except ImportError:
from io import BytesIO
try:
from wheezy.captcha import image as wheezy_captcha
except ImportError:
wheezy_captcha = None
DATA_DIR = os.path.join(os.path.abspath(os.path.dirname(__file__)), 'data')
DEFAULT_FONTS = [os.path.join(DATA_DIR, 'DroidSansMono.ttf')]
if wheezy_captcha:
__all__ = ['ImageCaptcha', 'WheezyCaptcha']
else:
__all__ = ['ImageCaptcha']
table = []
for i in range( 256 ):
table.append( i * 1.97 )
class _Captcha(object):
def generate(self, chars, format='png'):
"""Generate an Image Captcha of the given characters.
:param chars: text to be generated.
:param format: image file format
"""
im = self.generate_image(chars)
out = BytesIO()
im.save(out, format=format)
out.seek(0)
return out
def write(self, chars, output, format='png'):
"""Generate and write an image CAPTCHA data to the output.
:param chars: text to be generated.
:param output: output destination.
:param format: image file format
"""
im = self.generate_image(chars)
return im.save(output, format=format)
class WheezyCaptcha(_Captcha):
"""Create an image CAPTCHA with wheezy.captcha."""
def __init__(self, width=200, height=75, fonts=None):
self._width = width
self._height = height
self._fonts = fonts or DEFAULT_FONTS
def generate_image(self, chars):
text_drawings = [
wheezy_captcha.warp(),
wheezy_captcha.rotate(),
wheezy_captcha.offset(),
]
fn = wheezy_captcha.captcha(
drawings=[
wheezy_captcha.background(),
wheezy_captcha.text(fonts=self._fonts, drawings=text_drawings),
wheezy_captcha.curve(),
wheezy_captcha.noise(),
wheezy_captcha.smooth(),
],
width=self._width,
height=self._height,
)
return fn(chars)
class ImageCaptcha(_Captcha):
"""Create an image CAPTCHA.
Many of the codes are borrowed from wheezy.captcha, with a modification
for memory and developer friendly.
ImageCaptcha has one built-in font, DroidSansMono, which is licensed under
Apache License 2. You should always use your own fonts::
captcha = ImageCaptcha(fonts=['/path/to/A.ttf', '/path/to/B.ttf'])
You can put as many fonts as you like. But be aware of your memory, all of
the fonts are loaded into your memory, so keep them a lot, but not too
many.
:param width: The width of the CAPTCHA image.
:param height: The height of the CAPTCHA image.
:param fonts: Fonts to be used to generate CAPTCHA images.
:param font_sizes: Random choose a font size from this parameters.
"""
def __init__(self, width=160, height=60, fonts=None, font_sizes=None):
self._width = width
self._height = height
self._fonts = fonts or DEFAULT_FONTS
self._font_sizes = font_sizes or (42, 50, 56)
self._truefonts = []
@property
def truefonts(self):
if self._truefonts:
return self._truefonts
self._truefonts = tuple([
truetype(n, s)
for n in self._fonts
for s in self._font_sizes
])
return self._truefonts
@staticmethod
def create_noise_curve(image, color):
w, h = image.size
x1 = random.randint(0, int(w / 5))
x2 = random.randint(w - int(w / 5), w)
y1 = random.randint(int(h / 5), h - int(h / 5))
y2 = random.randint(y1, h - int(h / 5))
points = [x1, y1, x2, y2]
end = random.randint(160, 200)
start = random.randint(0, 20)
Draw(image).arc(points, start, end, fill=color)
return image
@staticmethod
def create_noise_dots(image, color, width=3, number=30):
draw = Draw(image)
w, h = image.size
while number:
x1 = random.randint(0, w)
y1 = random.randint(0, h)
draw.line(((x1, y1), (x1 - 1, y1 - 1)), fill=color, width=width)
number -= 1
return image
def create_captcha_image(self, chars, color, background):
"""Create the CAPTCHA image itself.
:param chars: text to be generated.
:param color: color of the text.
:param background: color of the background.
The color should be a tuple of 3 numbers, such as (0, 255, 255).
"""
image = Image.new('RGB', (self._width, self._height), background)
draw = Draw(image)
def _draw_character(c):
font = random.choice(self.truefonts)
w, h = draw.textsize(c, font=font)
dx = random.randint(0, 4)
dy = random.randint(0, 6)
im = Image.new('RGBA', (w + dx, h + dy))
Draw(im).text((dx, dy), c, font=font, fill=color)
# rotate
im = im.crop(im.getbbox())
im = im.rotate(random.uniform(-30, 30), Image.BILINEAR, expand=1)
# warp
dx = w * random.uniform(0.1, 0.3)
dy = h * random.uniform(0.2, 0.3)
x1 = int(random.uniform(-dx, dx))
y1 = int(random.uniform(-dy, dy))
x2 = int(random.uniform(-dx, dx))
y2 = int(random.uniform(-dy, dy))
w2 = w + abs(x1) + abs(x2)
h2 = h + abs(y1) + abs(y2)
data = (
x1, y1,
-x1, h2 - y2,
w2 + x2, h2 + y2,
w2 - x2, -y1,
)
im = im.resize((w2, h2))
im = im.transform((w, h), Image.QUAD, data)
return im
images = []
for c in chars:
if random.random() > 0.5:
images.append(_draw_character(" "))
images.append(_draw_character(c))
text_width = sum([im.size[0] for im in images])
width = max(text_width, self._width)
image = image.resize((width, self._height))
average = int(text_width / len(chars))
rand = int(0.25 * average)
offset = int(average * 0.1)
for im in images:
w, h = im.size
mask = im.convert('L').point(table)
image.paste(im, (offset, int((self._height - h) / 2)), mask)
offset = offset + w + random.randint(-rand, 0)
if width > self._width:
image = image.resize((self._width, self._height))
return image
def generate_image(self, chars):
"""Generate the image of the given characters.
:param chars: text to be generated.
"""
background = random_color(238, 255)
color = random_color(10, 200, random.randint(220, 255))
im = self.create_captcha_image(chars, color, background)
self.create_noise_dots(im, color)
self.create_noise_curve(im, color)
im = im.filter(ImageFilter.SMOOTH)
return im
def random_color(start, end, opacity=None):
red = random.randint(start, end)
green = random.randint(start, end)
blue = random.randint(start, end)
if opacity is None:
return (red, green, blue)
return (red, green, blue, opacity)