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""" Captcha.Visual.BAse
Base classes for visual CAPTCHAs. We use the Python Imaging Library
to manipulate these images.
"""
#
# PyCAPTCHA Package
# Copyright (C) 2004 Micah Dowty <micah@navi.cx>
#
import Captcha
import Image
__all__ = ['ImageCaptcha', 'Layer']
class ImageCaptcha(Captcha.BaseCaptcha):
"""Base class for image-based CAPTCHA tests.
The render() function generates the CAPTCHA image at the given size by
combining Layer instances from self.layers, which should be created by
the subclass-defined getLayers().
"""
defaultSize = (256,96)
def __init__(self, *args, **kwargs):
Captcha.BaseCaptcha.__init__(self)
self._layers = self.getLayers(*args, **kwargs)
def getImage(self):
"""Get a PIL image representing this CAPTCHA test, creating it if necessary"""
if not self._image:
self._image = self.render()
return self._image
def getLayers(self):
"""Subclasses must override this to return a list of Layer instances to render.
Lists within the list of layers are recursively rendered.
"""
return []
def render(self, size=None):
"""Render this CAPTCHA, returning a PIL image"""
if size is None:
size = self.defaultSize
img = Image.new("RGB", size)
return self._renderList(self._layers, Image.new("RGB", size))
def _renderList(self, l, img):
for i in l:
if type(i) == tuple or type(i) == list:
img = self._renderList(i, img)
else:
img = i.render(img) or img
return img
class Layer(object):
"""A renderable object representing part of a CAPTCHA.
The render() function should return approximately the same result, regardless
of the image size. This means any randomization must occur in the constructor.
If the render() function returns something non-None, it is taken as an image to
replace the current image with. This can be used to implement transformations
that result in a separate image without having to copy the results back to the first.
"""
def render(self, img):
pass
### The End ###
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