Signature capture in Web using Ruby on Rails

I need to capture signature from Ruby on Rails application and store it as image. Is there a suitable plugin for this in Ruby on Rails?

Edit

I want something like this in Ruby on Rails(I think this is in dot net):

http://www.realsignature.com/

http://www.re开发者_Python百科alsignature.com/demo/default.aspx

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I've had great success using Thomas Bradley's Signature Pad jQuery plugin.

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To answer your question as asked, no, currently there is no gem nor plugin for this.

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Rails can easily upload images, but capturing an image from a stylus somehow is beyond the scope of web applications.