Dragonfly is a Rack framework for on-the-fly processing and encoding. It includes an extension for Ruby on Rails to enable easy image handling.
To use simply for image thumbnails etc. in Rails...
environment.rb (Rails 2.3 only):
config.gem 'rmagick', :lib => 'RMagick'
config.gem 'rack-cache', :lib => 'rack/cache'
config.gem 'dragonfly'
Gemfile (Rails 3 only):
gem 'rmagick', :require => 'RMagick'
gem 'rack-cache', :require => 'rack/cache'
gem 'dragonfly'
The above assumes that you have http://gemcutter.org as one of your gem sources.
If not you should add it, e.g. gem source --add http://gemcutter.org from the command line,
or add source http://gemcutter.org to your Gemfile.
Initializer (e.g. config/initializers/dragonfly.rb):
require 'dragonfly/rails/images'
Migration:
add_column :albums, :cover_image_uid, :string
Model:
class Album < ActiveRecord::Base
image_accessor :cover_image # Defines reader/writer for cover_image
# ...
end
View (for uploading via a file field):
<% form_for @album, :html => {:multipart => true} do |f| %>
...
<%= f.file_field :cover_image %>
...
<% end %>
View (to display):
<%= image_tag @album.cover_image.url(:gif) %>
<%= image_tag @album.cover_image.url('400x200') %>
<%= image_tag @album.cover_image.url('100x100!', :png) %>
<%= image_tag @album.cover_image.url('100x100#') %>
<%= image_tag @album.cover_image.url('50x50+30+30sw', :tiff) %>
<%= image_tag @album.cover_image.url(:rotate, 15) %>
...etc.
Dragonfly is primarily a Rack app, the Rails part of it being nothing more than a separate layer on top of the main code, which means you can use it as a standalone app, or with Sinatra, Merb, etc.
It is intended to be highly customizable, and is not limited to images, but any data type that could suit on-the-fly processing/encoding.
For more info, consult the DOCUMENTATION
Please use the github issue tracker if you have any issues.
- Mark Evans (author)
Copyright (c) 2009-2010 Mark Evans. See LICENSE for details.