Saving signatures has never been easier!
Add this line to your application's Gemfile:
gem 'john_hancock'
And then execute:
$ bundle
Or install it yourself as:
$ gem install john_hancock
With the gem installed, simply include it in the relevant JS manifest
//= require john_hancock
Then you are free to use it in the view
<%= form_for @user do |f| %>
<%= f.signature_field :signature %>
<%= f.submit %>
<% end %>
Once this is saved, you can output the string as an image.
<%= image_tag @user.signature %>
The signature_field method generates a canvas as well as a hidden field. If you would like more flexibility in the placement of these elements you can use them separately.
<%= form_for @user do |f| %>
<%= f.signature_canvas %>
<p>some text about the form</p>
<%= f.hidden_signature_field :signature %>
<%= f.submit %>
<% end %>
This gem is maintained by Brandon Lawrence and Ben Miller.
The underlying JS library, Signature Pad, is written by Thomas J Bradley.
Bug reports and pull requests are welcome on GitHub at https://github.com/Brantron/john_hancock.
The gem is available as open source under the terms of the MIT License.