captcha

[force123]

hi .

does AOA registeration captcha image use php ?

if so , can you tell me :
1.how to rotate EACH letter or number ?
2. how to set background image ? (all i use is solid colors)
3.how to set color for EACH letter or number?

can anyone show some example codes ?

thanks in advance

(if not uses php , just some tip on how to do it will be so helpful)

[Aedan]

It does indeed use PHP, together with GD to do graphical manipulation.

There are a number of example scripts already on the 'net - Google php captcha to find some of them. I can't provide details for AOA, as the code itself is under license. If you wish to write your own captcha code, then it might be worth looking at pages like Breaking a Visual CAPTCHA to get an idea of what's breakable.

[force123]

thanks for the links.
i can write mu own captcha.

i don't want the code under licence.
in the second link you posted, the are examples , almost all of them use an image for their background. i don't know how can i set an image for my captcha background . or rotate just one letter or digit or change each color ...
i'll keep searching , most i found on the net was each making captchas.

[force123]

i just download a captcha image zip file, and looked into his code :


ImageCreateFromJPG("image.jpg");

now must search for letter rotating and color .

[force123]

find it AALLL !!!!

thanks aedan!

BTW , that breaking link of captcha is using a dictionary to match similar words . all of their exampls are words NOT CODES .

[Aedan]

It might be possible to render a letter to an image, distort that image and then overlay the distorted image on top of the background. That'd get you one letter. Rinse and repeat for other letters.

If you're using GD:
imagecopymerge allows you to overlay one image onto another existing image, and to specify where the copy should sit - it also honours alpha channel.)

imagerotate allows you to rotate the image through 360 degrees (in 2D space, not 3D)

imageconvolution allows you to do matrix transforms on an image.

imageresize can be used to distort the dimensions of an image.

[Gizmo]

Actually, we use ImageMagick, not GD.

[Aedan]

Which is even better...