attachment_fu, deferred thumbnail li

rubyonrails-talk
1

Hi,

I'm using attachment_fu with great success, but have run into a requirement that I'd like to solve elegantly -- but I've outstripped my ruby skills. I have a class that returns a hash of thumbnail definitions, like so:     class Thumb        def self.get_thumbs(style)           return { :small => "100x50", :large => "200x100" } if style == 'landscape'           return { :small => "50x100", :large => "100x200" } if style == 'portrait'        end     end

My attachment model is defined like this:

    class Photo < ActiveRecord::Base          has_attachment :content_type => :image,              :thumbnails => Thumb.get_thumbs(???)        [...more stuff ...]     end

My photos controller has the following line:

     @photo = Photo.new(params[:photo])

My question:

I'd like dynamically determine what value to set to Thumbnail.get_thumbs based on values set in the Photo.new constructor. Is this possible? I've fooled around with attr_accessors, lambdas, etc, but, I can't seem to do what I want. Is it possible to make such a run-time decision as I'm trying to make?

Which is to say, if params[:photo][:style] = 'portrait', i'd like to cut the thumbnails accordingly?

Does anyone have an elegant solution for this?

2

Elliott Blatt wrote:

Hi,

I'm using attachment_fu with great success, but have run into a requirement that I'd like to solve elegantly -- but I've outstripped my ruby skills. I have a class that returns a hash of thumbnail definitions, like so:     class Thumb        def self.get_thumbs(style)           return { :small => "100x50", :large => "200x100" } if style == 'landscape'           return { :small => "50x100", :large => "100x200" } if style == 'portrait'        end     end

My attachment model is defined like this:

    class Photo < ActiveRecord::Base          has_attachment :content_type => :image,              :thumbnails => Thumb.get_thumbs(???)        [...more stuff ...]     end

My photos controller has the following line:

     @photo = Photo.new(params[:photo])

My question:

I'd like dynamically determine what value to set to Thumbnail.get_thumbs based on values set in the Photo.new constructor. Is this possible? I've fooled around with attr_accessors, lambdas, etc, but, I can't seem to do what I want. Is it possible to make such a run-time decision as I'm trying to make?

Which is to say, if params[:photo][:style] = 'portrait', i'd like to cut the thumbnails accordingly?

Does anyone have an elegant solution for this?

A non-thread-safe solution may be:

after_save 'attachment_options[:thumbnails] = Thumb.get_thumbs(style)' has_attachment :content_type => :image,                 :thumbnails => Thumb.get_thumbs('landscape')

but a better solution may be to add PortraitPhoto and LandscapePhoto sub-classes.