Getting width and height of image in model in the Ruby Paperclip GEM

问题

Trying to get the width and height of the uploaded image while still in the model on the initial save.

Any way to do this?

Here's the snippet of code I've been testing with from my model. Of course it fails on "instance.photo_width".

has_attached_file :photo,
                      :styles => {
                      :original  => "634x471>",
                      :thumb => Proc.new { |instance|                       
                                  ratio = instance.photo_width/instance.photo_height
                                  min_width   = 142
                                  min_height  = 119
                                  if ratio > 1
                                    final_height  = min_height
                                    final_width   = final_height * ratio
                                  else
                                    final_width   = min_width
                                    final_height  = final_width * ratio
                                  end
                                  "#{final_width}x#{final_height}" 
                                }
                    }, 
                    :storage => :s3,
                    :s3_credentials => "#{RAILS_ROOT}/config/s3.yml",
                    :path => ":attachment/:id/:style.:extension",
                    :bucket => 'foo_bucket'

So I'm basically trying to do this to get a custom thumbnail width and height based on the initial image dimensions.

Any ideas?

回答1:

Ahh, figured it out. I just needed to make a proc.

Here's the code from my model:

class Submission < ActiveRecord::Base

  #### Start Paperclip ####

  has_attached_file :photo, 
                    :styles => {
                      :original  => "634x471>",
                      :thumb => Proc.new { |instance| instance.resize }
                    }, 
                    :storage => :s3,
                    :s3_credentials => "#{RAILS_ROOT}/config/s3.yml",
                    :path => ":attachment/:id/:style.:extension",
                    :bucket => 'foo_bucket' 

  #### End Paperclip ####

  def resize     
     geo = Paperclip::Geometry.from_file(photo.to_file(:original))

     ratio = geo.width/geo.height  

     min_width  = 142
     min_height = 119

     if ratio > 1
       # Horizontal Image
       final_height = min_height
       final_width  = final_height * ratio
       "#{final_width.round}x#{final_height.round}!"
     else
       # Vertical Image
       final_width  = min_width
       final_height = final_width * ratio
       "#{final_height.round}x#{final_width.round}!"
     end
  end  
end

回答2:

class Asset

include Mongoid::Paperclip
before_save :extract_dimensions

field :width, type: Integer
field :height, type: Integer

has_mongoid_attached_file :data

  def extract_dimensions
    return unless is_image?

    tempfile = data.queued_for_write[:original]
    unless tempfile.nil?
      geometry = Paperclip::Geometry.from_file(tempfile)
      self.width = geometry.width.to_i
      self.height = geometry.height.to_i
    end

    true # wont save if false 
  end

  def is_image?
    data_content_type =~ %r{^(image|(x-)?application)/(bmp|gif|jpeg|jpg|pjpeg|png|x-png)$}
  end

end

来源：https://stackoverflow.com/questions/2768527/getting-width-and-height-of-image-in-model-in-the-ruby-paperclip-gem

标签

ruby-on-rails

paperclip