[magick-users] Generate Yahoo's Captcha like graphic?

[Anthony Thyssen]

"howard chen" on  wrote...
| On 1/1/07, Jørn Dahl-Stamnes <im.user at dahl-stamnes.net> wrote:
| > On Monday 01 January 2007 13:09, howard chen wrote:
| > > On 1/1/07, Jørn Dahl-Stamnes <im.user at dahl-stamnes.net> wrote:
| > > > On Monday 01 January 2007 10:05, howard chen wrote:
| > > > > such as the one like this:
| > > > >
| > > > > https://ab.login.yahoo.com/img/ZtfKKOVZFenbN32bIXlEcThdwGPkPbTgTTx.Jemb
| > > > >o0f0 U3oUXhYv800GBqXa5nJpqTwNoaeLlTyorA--.jpg
| > > > >
| > > > > is it possible to generate using IM ?
| > > >
| > > > I'm making something like it by using a script:
| > > >
| > > > #!/bin/sh
| > > >
| > > > convert -size 200x120 xc:lightblue -font Bookman-DemiItalic -pointsize 32
| > > > -fill blue \
| > > > -draw "text 10,20 '$1'" \
| > > > -fill yellow -draw "path 'M 5,5 L 135,5 M 5,10 L 135,10 M 5,15 L 135,15'"
| > > > \ -trim test.gif
| > > > convert -wave 4x70 -swirl 10 test.gif $2
| > >
| > > Hello, what are the test.gif & the 2nd argument to your script?
| >
| > The first argument is the text to generate, the second argument is the final
| > name of the output file, ie:
| >
| > # ./script.sh FQXYR image.jpg
| >
| > You could add a 'rm test.gif' at the end of the script if you want to remove
| > the temporary file test.gif.
| >
| > --
| > Jørn Dahl-Stamnes
| > homepage: http://www.dahl-stamnes.net/dahls/
| >
| 
| Okay, very good work!
| 
Note that as a catchpa it is reasonable. But not good enough.  Your
catcha generator needs to be more sever, and may need to process
individual letters seperatally.  It also needs multiple styles of
catchpa so a 'decoder' has to deal with multiple situations not just
one.

And finally when providing strings, remove letters that could be
difficult for humans to decode, with regards to the font used.

EG: letters like:    Il1!|   O0QD  8B  2Z    etc etc etc

This depends on the font and if the font is serif or san-serif.

Then you have the disabled problem.  Catchpa's do not work for people
with even minor sight problems.  That is they can see but have bad
vision for computer screens.

These are all things that you need to consider, which is why I have not
created a catchpa area in IM examples at this time.


  Anthony Thyssen ( System Programmer )    <A.Thyssen at griffith.edu.au>
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