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From Pier Fumagalli <>
Subject Re: Warped Text...
Date Mon, 05 Sep 2005 00:33:15 GMT
On 3 Sep 2005, at 15:22, Tony Collen wrote:
> Pier Fumagalli wrote:
>> On 2 Sep 2005, at 16:23, Gianugo Rabellino wrote:
>>> On 9/2/05, Pier Fumagalli <> wrote:
>>>> Guys,
>>>>      for one of our registration projects, we needed to verify  
>>>> that a
>>>> user is really in front of the browser (no automatons allowed). I
>>>> wrote, then, a little "text-warper" that randomly stretches text  
>>>> for
>>>> a user to see (and re-type) and writes out JPEG files.
>>>> In addition to that I wrote a little random-text generator and
>>>> encryptor (so that you can be sure the text displayed is nowhere in
>>>> your HTML). An example of a generated image is attached here.
>>> Did you look at what Ugo did with captchas?
>>> Ciao,
>> Yep, but SVG IMVHO is quite overkill to generate a simple  
>> image...  Plus I suspect that the blurring algorithm is quite easy  
>> to recognize  (in terms of running a simple image analysis package  
>> over the  generated output).
>> I kinda like more random things! :-P :-P
>>     Pier
> Ugo's work built on some stuff I did a long time ago.  I did a  
> gaussian blur on the text just as a proof of concept.  Of course,  
> the SVG filters have displacement maps, so ideally you'd add one in  
> addition to the stuff that's already there.

As Sylvain said, this can replace the default "gaussian blur" for the  

I've now committed it as its own block in the 2.1.x branch, so feel  
free to test it out, and if someone is into CFORMs (ping Ross, where  
are you - my minions are nowhere to be found on a Sunday night! :- 
D ), we can try to replace the SVG->Blur->IMAGE with this little Reader.

Anyhow, samples are in there, both for a simple CAPTCHA flow and for  
a more generic showcase of what the CaptchaReader is capable of (not  
much, but it's all there). As for the "validation" block, the  
documentation is in Daisy (one gotta love that little piece of junk,  
makes documenting so easy): 

Have fun...


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