Difference between revisions of "Captcha"
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img_ext = 'png' # image extension. Supported formats: eps, jpeg, jpg, pdf, pgf, png, ps, raw, rgba, svg, svgz, tif, tiff. | img_ext = 'png' # image extension. Supported formats: eps, jpeg, jpg, pdf, pgf, png, ps, raw, rgba, svg, svgz, tif, tiff. | ||
def makeImage(text, width=400, height=200, angle=None, ext='png'): | def makeImage(text, width=400, height=200, angle=None, ext='png', rgbcolor=(1,0,1)): | ||
'''Generate a 3d CAPTCHA image. | '''Generate a 3d CAPTCHA image. | ||
Args: | Args: | ||
text: Text in the image. | text: Text in the image. | ||
width: Image width in pixel. | width: Image width in pixel. | ||
height: Image height in pixel. | height: Image height in pixel. | ||
angle: The angle between text and X axis. | angle: The angle between text and X axis. | ||
Returns: | Returns: | ||
Binary data of CAPTCHA image in PNG format. | Binary data of CAPTCHA image in PNG format. | ||
''' | ''' | ||
angle = angle if angle != None else uniform(-20, 20) | angle = angle if angle != None else uniform(-20, 20) | ||
try: | try: | ||
font = ImageFont.truetype(fontPath, 24) | font = ImageFont.truetype(fontPath, 24) | ||
except IOError: | except IOError: | ||
raise IOError( | raise IOError( | ||
'Font file doesn\'t exist. Please set `fontPath` correctly.') | 'Font file doesn\'t exist. Please set `fontPath` correctly.') | ||
txtW, txtH = font.getsize(text) | txtW, txtH = font.getsize(text) | ||
img = Image.new('L', (txtW * 3, txtH * 3), 255) | img = Image.new('L', (txtW * 3, txtH * 3), color=255) | ||
drw = ImageDraw.Draw(img) | drw = ImageDraw.Draw(img) | ||
drw.text((txtW, txtH), text, font=font) | drw.text((txtW, txtH), text, font=font) | ||
fig = pylab.figure(figsize=(width/100.0, height/100.0)) | fig = pylab.figure(figsize=(width/100.0, height/100.0)) | ||
ax = Axes3D(fig) | ax = Axes3D(fig) | ||
X, Y = numpy.meshgrid(range(img.size[0]), range(img.size[1])) | X, Y = numpy.meshgrid(range(img.size[0]), range(img.size[1])) | ||
Z = 1 - numpy.asarray(img) / 255 | Z = 1 - numpy.asarray(img) / 255 | ||
ax.plot_wireframe(X, -Y, Z, rstride=1, cstride=1) | ax.plot_wireframe(X, -Y, Z, rstride=1, cstride=1, color=( rgbcolor ) ) # "plot_wireframe" can be replace by "plot_surface" to produce a surface | ||
ax.set_zlim((-3, 3)) | ax.set_zlim((-3, 3)) | ||
ax.set_xlim((txtW * 1.1, txtW * 1.9)) | ax.set_xlim((txtW * 1.1, txtW * 1.9)) | ||
ax.set_ylim((-txtH * 1.9, -txtH * 1.1)) | ax.set_ylim((-txtH * 1.9, -txtH * 1.1)) | ||
ax.set_axis_off() | ax.set_axis_off() | ||
ax.view_init(elev=60, azim=-90 + angle) | ax.view_init(elev=60, azim=-90 + angle) | ||
fim = StringIO() | fim = StringIO() | ||
fig.savefig(fim, format=ext) | fig.savefig(fim, format=ext) | ||
| Line 90: | Line 89: | ||
Example output: | Example output: | ||
[[File:human_010.svg]] | [[File:human_010.svg]] | ||
[[Category:cookbook]] | [[Category:cookbook]] | ||
Revision as of 15:37, 10 June 2015
How to generate captchas
The easies way for generating captchas is through libraries in different programming languages (Python, Javascript, PHP, etc) dedicated to this task
Bellow is a list of different libraries used to produce different kind of captchas, dependencies, instructions of how to use them.
Python
3D Captcha
https://github.com/013231/3D-CAPTCHA
Run in the terminal:
python captcha.py
possible changes to script
captcha.py allows different parameters to be changed, namely
- font-face: fontPath = '/Library/Fonts/Arial.ttf'
- text used in captch
- image dimension and format
- image color
- image 3D position
Here is a modified, simplified, and commented version of the captcha.py script:
#!/usr/bin/env python
# encoding=utf-8
from random import uniform, shuffle
from cStringIO import StringIO
from PIL import ImageFont, Image, ImageDraw
import numpy, pylab
from mpl_toolkits.mplot3d import Axes3D
fontPath = '/Library/Fonts/Arial.ttf' # path to font used
img_ext = 'png' # image extension. Supported formats: eps, jpeg, jpg, pdf, pgf, png, ps, raw, rgba, svg, svgz, tif, tiff.
def makeImage(text, width=400, height=200, angle=None, ext='png', rgbcolor=(1,0,1)):
'''Generate a 3d CAPTCHA image.
Args:
text: Text in the image.
width: Image width in pixel.
height: Image height in pixel.
angle: The angle between text and X axis.
Returns:
Binary data of CAPTCHA image in PNG format.
'''
angle = angle if angle != None else uniform(-20, 20)
try:
font = ImageFont.truetype(fontPath, 24)
except IOError:
raise IOError(
'Font file doesn\'t exist. Please set `fontPath` correctly.')
txtW, txtH = font.getsize(text)
img = Image.new('L', (txtW * 3, txtH * 3), color=255)
drw = ImageDraw.Draw(img)
drw.text((txtW, txtH), text, font=font)
fig = pylab.figure(figsize=(width/100.0, height/100.0))
ax = Axes3D(fig)
X, Y = numpy.meshgrid(range(img.size[0]), range(img.size[1]))
Z = 1 - numpy.asarray(img) / 255
ax.plot_wireframe(X, -Y, Z, rstride=1, cstride=1, color=( rgbcolor ) ) # "plot_wireframe" can be replace by "plot_surface" to produce a surface
ax.set_zlim((-3, 3))
ax.set_xlim((txtW * 1.1, txtW * 1.9))
ax.set_ylim((-txtH * 1.9, -txtH * 1.1))
ax.set_axis_off()
ax.view_init(elev=60, azim=-90 + angle)
fim = StringIO()
fig.savefig(fim, format=ext)
binData = fim.getvalue()
fim.close()
return binData
if __name__ == '__main__':
degrees = [i*10 for i in range(0,36)] # list different degrees
for n in degrees: # for loop will produce 35 different images, each in a different angle
img = makeImage(text='Are you human?', width=600, height=300, angle=n, ext=img_ext ) # Essential command: text, width, height, angle
n = str(n).rjust(3, '0')
filename = 'human_{}.{}'.format(n, img_ext)
print filename
with open(filename, 'wb') as f:
f.write(img)
Example output:
