在 Ruby Paperclip GEM 中获取模型中图像的宽度和高度 [英] Getting width and height of image in model in the Ruby Paperclip GEM

问题描述

尝试在初始保存时仍在模型中时获取上传图像的宽度和高度.

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

有没有办法做到这一点?

Any way to do this?

这是我一直在用我的模型测试的代码片段.当然，它在instance.photo_width"上失败了.

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' 

所以我基本上是在尝试这样做，以根据初始图像尺寸获得自定义缩略图宽度和高度.

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

有什么想法吗?

推荐答案

啊，想通了.我只需要制作一个过程.

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

这是我的模型中的代码:

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

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