Paperclip obtain real image size - ruby-on-rails

Question

My problem is the next:
I am trying resize a image size depending a proportial size. Example If i have a image whose size is 1440*1000 its new size will be 648*440 (I use a proportion depending a max_size)
NOTE: Then i post my code so you will understand the size relations.
Ok. so I am reading this stackoverflow post:
Getting width and height of image in model in the Ruby Paperclip GEM
Now i post my code and then i will describe my problem.
class ProductImage < ActiveRecord::Base
belongs_to :product, :dependent => :destroy
MAXIMUM_SIZE = 650
has_attached_file :photo, :url => "/:attachment/:class/:id/:style_:basename.:extension", :styles => {:real_size => Proc.new { |instance| instance.real_size }, :original => "400x400>", :medium => "300x300>", :principal => "240x240>", :thumb => "100x100>", :small => "80x50>"}
def real_size
#image = Paperclip::Geometry.from_file(photo.to_file(:maximum_size))
#OBTAIN REAL IMAGE SIZE, NOT ATTACHMENT SIZES
if image_less_than_maximum_size?
return "#{image.width}x#{image.height}"
else
return adjust_image_size(self.width, self.height)
end
end
def adjust_image_size(image_width, image_height)
ratio = (image_width/image_height).to_f
difference_between_size = (image_width - image_height).abs
percentage_difference = ratio > 1 ? difference_between_size * 100.0 / image_width : difference_between_size * 100.0 / image_height
difference_respect_maximum_size = ratio > 1 ? MAXIMUM_SIZE * 100.0 / image_width : MAXIMUM_SIZE * 100.0 / image_height
width = height = 0.0
if ratio > 1
#USE 101.0 FOR INCREMENT OR DECREMENT THE VALUE A LITTLE BIT
width = image_width * difference_respect_maximum_size / 101.0
height = width - (percentage_difference * width / 101.0)
else
heigth = image_height * difference_respect_maximum_size / 101.0
width = height - (percentage_difference * height / 101.0)
end
return "#{width}x#{height}"
end
def image_less_than_maximum_size?
if self.width > self.height
return self.width < MAXIMUM_SIZE
else
return self.height < MAXIMUM_SIZE
end
end
end
My problem is how could i obtain the "real_size"?.
i.e, if image size is "1440*1000" to obtain this size (no attachment size)
UPDATE:
I am thinking a solution. So i think in declare two temp variable to ProductImage model and during initialize method use a before_post_process paperclip callback.
class ProductImage < ActiveRecord::Base
belongs_to :product, :dependent => :destroy
attr_accessor :height, :width
MAXIMUM_SIZE = 650
has_attached_file :photo, :url => "/:attachment/:class/:id/:style_:basename.:extension", :styles => {:real_size => Proc.new { |instance| instance.real_size }, :original => "400x400>", :medium => "300x300>", :principal => "240x240>", :thumb => "100x100>", :small => "80x50>"}
before_post_process :image?
before_post_process :assign_size
...
def assign_size
#width = Paperclip::Geometry.from_file(remote_original_photo_path).width
#height = Paperclip::Geometry.from_file(remote_original_photo_path).height
end
end
Then i could use this size in the other method.
My new problem is how could I determine the remote_original_photo_path in model?
in controller i use the params[:product][:product_images_attributes][index][:photo].
I could save the temp path in model. However because my real_size method during initilize i don´t know how to pass the params info.
Thanks in advance again

Answer 1

With using a gem like image_size ?
[EDIT]
To determine the original upload path may be you can use :
remote_original_photo_path = File.basename(upload['datafile'].original_path)