ruby script/plugin install svn://rubyforge.org/var/svn/expressica/plugins/simple_captcha/

Pre-requisites
==============
1.) RMagick
RMagick is the image handling library in ruby and is required to implement the SimpleCaptcha.
RMagick is available on RubyForge http://rubyforge.org


===Controller Based
In the view file within the form tags write this code

<%= show_simple_captcha %>

and in the controller' action authenticate it as

if simple_captcha_valid?
 do this
else
 do that
end

===Model Based
In the view file within the form tags write this code

<%= show_simple_captcha(:object=>"user") %>

and in the model class add this code

class User < ActiveRecord::Basse
  apply_simple_captcha
end

We may need to save the instance where captcha is not at all needed, actually captcha is usually needed on some particular screen only eg. signing up of a new user. So, here is the detail of explicit methods to authenticate and validate the instance with captcha.

===for validating

use @user.valid_with_captcha? when captcha authentication is required and use @user.valid? when captcha authentication is not required.

=== for saving

use @user.save_with_captcha when captcha authentication is required and use @user.save when captcha authentication is not required.

===Options for View Helper method show_simple_captcha

1.) :label
provide the custom text b/w the image and the text field, the default is "type the text from the image"

2.) :image_style
we can provide the specific image style out of the eight styles available,

"simply_blue"
"simply_red"
"simply_green"
"distorted_black"
"all_black"
"embosed_silver"
"charcoal_grey"
"almost_invisible"

the default is "simply_blue".

3.) :object
the name of the object of the model class, to implement the model based captcha.

4.) :distortion
there are three level of distortion, which measures the complexity of the text of the image as
"low"
"medium"
"high"
the default is "medium"

example

<%= show_simple_captcha(:object => "user", :image_style => "embosed_silver", :label => "human authentication", :distortion => "low") %>

===Options for Model method apply_simple_captcha

1.) :message
we can provide the custom message on failure of captcha authentication the default is "image did not match with text"

example --

apply_simple_captcha :message => " image and text were different"

There is currently no advanced documentation for this plugin.