Stefan Neufeind [2004-05-28 08:16 UTC] Image_Text already does support rotation - have a look at the option "angle" - or do you mean rotation of single characters (no, do you)?
Could you provide a demo-image (or two) as well?
Is there a real "algorithm" that the creators of CAPTCHA describe, that makes test best readable by humans but not OCR? Or does everybody implement it his way?
Generally I like the idea of having such a package - although lately on another mailinglist a blind person said that having such images is "not funny" ... so it should be used with care (and that could maybe be mentioned in the docs/readme).
Antônio Carlos Venâncio Júnior [2004-05-28 12:11 UTC] Nice proposal and take a look at this:
Breaking a Visual CAPTCHA
http://www.cs.berkeley.edu/~mori/gimpy/
Martin Jansen [2004-06-11 12:33 UTC] A few points:
- You are using var_dump() at some point in the code, which is probably not desired.
- Can you replace NULL with null?
- The comment
/**
* Image_CAPTCHA - see above
*
* see above
*
* @package Image_Text
*/
is misleading, because in the API documentation there may be no text "above", because the blocks are split up into multiple files.
- Inside a for-loop, you do not make use of the 4-spaces indentation.
Apart from that the code seems to be fine.
Tobias Schlitt [2004-06-22 13:07 UTC] I recently saw truing using ASCII art like output. That's also a nice alternative. Maybe one could rework the package structure to implement a driver backend, rename it to Text_Turing (or similar) and provide several backends for the turing?
There's an example for ASCII truing in Wez's blog: http://netevil.org/node.php?nid=57&SC=1#comments
Colin Viebrock has published some experiences on audio turing:
http://viebrock.ca/code/16/turing-with-audio
Would be nice to have those methods in one package. I would be happy to help out with some stuff (ASCII art driver?), if you like.
Daniel Convissor [2004-06-23 15:48 UTC] Please take a look at this posting and the links therein.
http://lists.nyphp.org/pipermail/talk/2004-June/010218.html
They say their system "solves a lot of the issues I dealt with in breaking captchas on various sites to automate singins etc."
While I haven't checked out their code or yours, there's a possibility that their code may prove helpful to this proposal.
Jason Lotito [2004-07-12 16:32 UTC] "I have also experimented with other effects like color gradients."
Look at using Image_Color::getRange() for color gradients, as well as being able to determine which color you should use for text against a certain background color with Image_Color::getTextColor().
I can also look into providing Image_Color with support for color blind protection, so you don't end up mixing colors that would be a problem for color blind people.
Daniel Convissor [2004-07-20 20:38 UTC] It'd be great if this package can get approved soon. php.net just had a spate of spam submitted via the comment form. CAPTCHA's would be helpful in reducing that problem.
Also, minor nit to pick: you use double quotes in several places that don't need to be evaluated, therefore single quotes would be better.
Thanks.
Daniel Convissor [2004-07-20 20:41 UTC] Another tidbit that might be helpful, using audio to transmit the data:
http://www.viebrock.ca/code/16/turing-with-audio
Haven't read it myself.
Justin Patrin [2004-07-21 20:37 UTC] Looks good. Could you give source for the driver as well. :-)
Daniel Convissor [2004-07-22 17:11 UTC] Very important points to keep in mind when designing CAPTCHAs that are hard to reverse-engineer:
http://lists.nyphp.org/pipermail/talk/2004-July/010996.html
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