Paperclip processor to save dimensions of an image

thubmnail_with_dimensions.rb

# Filename: RAILS_ROOT/lib/paperclip_processors/thumbnail_with_dimensions.rb
# Required Configuration in the model
#   has_attached_file :image,
#    :styles => {
#      :thumbnail => {
#        :geometry => "100x100>",
#        :format => :png,
#        :processors => [:thumbnail_with_dimensions],
#        :mystyle => :thumbnail
#      },
#      :some_other_style => {
#        :geometry => "640x480>",
#        :processors => [:thumbnail_with_dimensions],
#        :mystyle => :some_other_style
#      }
#    }
#
# NOTE: Since the name of the style isn't available in the processor we need to pass it in using a configuration variable.
# I've called it :mystyle just to make sure I don't step on anything in the core.
#
# To get a dimension in a view just do:
# <%= @object.image.width(:thumbnail) %> # Gives the width of the thumbnail
# <%= @object.image.height(:thumbnail) %> # Gives the height of the thumbnail
# <%= @object.image.width %> # Gives the width of the original
# <%= @object.image.dimensions %> Will return the dimensions hash


 module Paperclip
  class Attachment

    def width style = :original
      @dimensions = dimensions unless @dimensions
      begin
        Integer(@dimensions[style.to_s]['width'])
      rescue
        # Integer() throws an exception if it can't do it,
        # we'll eat the exception incase any of our items don't have dimensions saved
        return nil
      end
    end

    def height style = :original
      @dimensions = dimensions unless @dimensions
      begin
        Integer(@dimensions[style.to_s]['height'])
      rescue
        # Integer() throws an exception if it can't do it,
        # we'll eat the exception incase any of our items don't have dimensions saved
        return nil
      end
    end

    def dimensions
      unless @dimensions
        dim = instance_read(:dimensions)
        @dimensions = JSON.parse(dim) unless dim.nil?
      end
      @dimensions
    end
  end
end

module Paperclip
  class ThumbnailWithDimensions < Thumbnail

    def initialize file, options = {}, attachment = nil
      super
      @myinstance = attachment
      @mystyle = options[:mystyle]
      @dimensions = attachment.dimensions
    end

    def make
      dst = super
      @dimensions ||= {} # make sure he have a hash
      @dimensions[@mystyle] = Geometry.from_file dst

      # make sure the original dimensions are saved since we don't actually process the original
      @dimensions[:original] ||= @current_geometry

      @myinstance.instance_write(:dimensions, @dimensions.to_json)
      return dst
    end

  end
end

Thanks! Your explanation allowed me to get it working.

…

On 05/28/2011 07:45 AM, r3ap3r2004 wrote: I assume that Paperclip is seeing the :processors entry for your attachment and since it is named :thumbnail_with_dimensions it is trying to load Paperclip::ThumbnailWithDimensions and just can't find it. This would tell me that you probably haven't put this code in the proper location in the filesystem for Paperclip to find it. The code needs to go in RAILS_ROOT/lib/paperclip_processors/thumbnail_with_dimensions.rb If that isn't the problem then I'm not sure what to tell you without more information. If you want to see if Paperclip/Rails is even finding the file then put something at the top of the file that will cause the Ruby parser to choke when it hits it (ie. asjfpoauhsodf, or any other random string that won't possibly evaluate to a real method). If you don't get an error related to that line of code then you know it isn't even reading the file. Alternatively you could do something like. raise "I read in the file" Which should throw an exception when it is hit. If you don't get the exception then you know the file wasn't read. If you have the file in the right location, but it still isn't being read then you may need to ask the paperclip guys what they changed. http://groups.google.com/group/paperclip-plugin

Just added the processor to my app. Everything work fine if i manually call save on my model after a file is uploaded. Trying to reprocess all my attachements calling rake paperclip:refresh CLASS=MyModel I see that that processor is executed but results are not persisted to the database. Please advice what's wrong.