Carrierwave getting image width and height and storing it in an hstore field

问题

My FileHandler model can allows all types of files

class FileHandler < ActiveRecord::Base
   serialize :properties, ActiveRecord::Coders::Hstore
   mount_uploader :file_path, FileUploader

  //I'm already setting some of the file attributes here
  def update_file_attributes
    if file_path.present? && file_path_changed?
      self.file_name = file_path.file.filename
      self.file_type = file_path.file.content_type
      self.file_size = file_path.file.size
    end
  end
  //I want to get height and width here
  #Hstore
  %w[ImageHeight ImageWidth].each do |key|
    attr_accessible key

    define_method(key) do
      properties && properties[key]
    end

    define_method("#{key}=") do |value|
      self.properties = (properties || {}).merge(key => value)
    end
  end

And my fileUploader class

class FileUploader < CarrierWave::Uploader::Base

  # Include RMagick or MiniMagick support:
  include CarrierWave::RMagick

   version :big, :if => :image? do
    process :resize_to_limit => [760, nil]
   end

   version :thumb_big, :if => :image? do
    process :resize_to_limit => [200, 200]
   end

   version :thumb, :if => :image? do
    process :resize_to_limit => [160, 160]
   end

   version :tiny, :if => :image? do
    process :resize_to_limit => [40, 40]
   end

   protected
     def image?(new_file)
      new_file.content_type.include? 'image'
     end
end

My question is, how do i get the height and width property of the original image and store it in the hstore field? Any help would be greatly appreciated.

回答1:

Try this

class FileUploader < CarrierWave::Uploader::Base

  # Include RMagick or MiniMagick support:
  include CarrierWave::RMagick
  process :store_geometry, :if => :image?

  #......
  #......
  #......

  def store_geometry
    if image?(@file)
      img = ::Magick::Image::read(@file.file).first
      if model
        model.ImageWidth = img.columns
        model.ImageHeight = img.rows
      end
    end
  end
end

#Hstore

  %w[ImageHeight ImageWidth].each do |key|
    attr_accessible key

    define_method(key) do
      properties && properties[key]
    end

    define_method("#{key}=") do |value|
      self.properties = (properties || {}).merge(key => value)
    end
  end

Assumptions
I'm assuming there's a reason you have the image method that checks if the file is an image, that must mean you're uploading other file formats as well. Well, i've put it to good use here, it calls process_geometry method only if the file is an image. Hope it helps.

回答2:

Well you can get the dimension of Image by using Rmagick as far as I know

All I remember is that you can do is this

  img = Magick::Image::read("image_file").first

  img.columns  => width of image
  img.rows   => height of image

Perhaps then you can set them in HSTORE

Hope this help

Thanks

回答3:

As an addition to Tommy's comment. This is what I did to save size of every particular image version not just a size of original image. You have to add "geometry" field to your model so you'll have something like: "phone=146x220&tablet=292x440"

    class ImageUploader < CarrierWave::Uploader::Base
        include CarrierWave::RMagick

        storage :file

        version :thumb do
            process :resize_to_fill => [80, 80]
        end

        version :phone do
            process :resize_to_limit => [290, 220]
            process :store_geometry => :phone
            process :quality => 75
        end

        version :tablet do
            process :resize_to_limit => [580, 440]
            process :store_geometry => :tablet
            process :quality => 35
        end

        process 

        def extension_white_list
            %w(jpg jpeg gif png)
        end

        def store_geometry(version)
            manipulate! do |img|
                model.geometry ||= ""
                model.geometry << "&" unless model.geometry.empty?
                model.geometry << "#{version}=#{img.columns}x#{img.rows}"
                img
            end
        end

    end

来源：https://stackoverflow.com/questions/17413730/carrierwave-getting-image-width-and-height-and-storing-it-in-an-hstore-field