EasyCaptcha is lightweight gem providing possibility to generate captcha image to your website. If you can't use imagemagick or use external services like recaptcha see this gem.
Just add dependency to your gemfile:
gem 'easy_captcha', :git => "[email protected]:dfens/easy_captcha.git"
In your view just use easy_captcha method:
<%= easy_captcha("ASDF") %>
There are also additional options: distortion and snow.
See this example:
<%= easy_captcha("ASDF") %>
<br/>
<%= easy_captcha("JTGIAEJOFA", {:snow => true}) %>
<br/>
<%= easy_captcha("ASFAIEJRFO", {:distortion => true}) %>
<br/>
<%= easy_captcha("JGII", {:distortion => true, :snow => true}) %>
Result:
[
Currently you can't change fonts and add another effects. Also this is just logic-less gem. To verify captcha you should implement your own logic.
This project rocks and uses MIT-LICENSE.