在Ruby Paperclip GEM中获取模型中图像的宽度和高度

尝试在初始保存时仍然在模型中获取上载图像的宽度和高度。

有什么办法吗？

这是我从我的模型中测试过的代码片段。 当然它在“instance.photo_width”上失败了。

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' 

因此，我基本上尝试这样做，以根据初始图像尺寸获得自定义缩略图的宽度和高度。

有任何想法吗？

Answer 1

啊，想通了。 我只需要做一个过程。

这是我的模型中的代码：

 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 

Answer 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