How to create an RMagick image from a Paperclip attachment?

Question

Suppose I've got an image stored as a paperclip attachment. I want to use this image in RMagick to compose other images. But when I ask paperclip about it, I'm handed a URL which hands back the image data; and I guess I could read this into a file, and then read the file back into RMagick -- and in fact, that's what I'm planning on doing for now -- but it seems like there very well ought to be a more direct way.

In other words, my question is the inverse of this one: how to create a Paperclip attachment from an RMagick image? I want to know the most direct means of creating an RMagick image from a Paperclip-attached picture.

UPDATE: Just in case it wasn't clear -- the basic problem is that ImageList.new() won't accept the path because paperclip hands back a URL and RMagick is apparently expecting a local filesystem path. Perhaps I'm missing something here, though. Thanks!

Answer 1

You're using Ruby. Monkey-patch Paperclip::Attachment!

# lib/paperclip_magick.rb
require 'RMagick'

module PaperclipMagick
  def to_rmagick(style_name = default_style)
     @image_list ||= ImageList.new(self.path(style_name))
  end
end

Paperclip::Attachment.send(:include, Magick)
Paperclip::Attachment.send(:include, PaperclipMagick)

Or something along those lines.