ruby-on-rails - Rails 回形针从其他样式生成缩略图

Question

我正在关注 jcrop rails 教程，但遇到了障碍。归根结底是回形针从原始文件生成缩略图，但我需要从另一种样式生成缩略图。原始文件在产品照片和文档边缘之间没有任何空间。因此我无法进一步裁剪。为了解决这个问题，我制作了另一种具有白色像素填充的样式。这就是我想从中生成缩略图的内容。

# croppable is the one with the padding...it's what shows up in the crop view.
# I want :thumb to be generated from THAT style, not :original.
# When generating from :original, the crop offset/size is screwed because the dimensions of :original don't match :cropped
# and I can't crop beyond the pixel dimensions of :original.
has_attached_file :photo, :styles => {
                    :thumb => { :geometry => "300x300#", :format => :jpg, :processors => [:cropper] },
                    :general => ["150x375", :jpg],
                    :show => ["x425", :jpg],
                    :croppable => ["1200x1200>", :jpg]
        },
        :url  => "/assets/wines/:style/:wine_name",
        :path => ":rails_root/public:url",
        :default_url => ":wine_default",
        :default_path => ":rails_root/public:wine_default",
        :default_style => :show,
        :convert_options => {
            :thumb => '-gravity center -rotate -30',
            :croppable => '-gravity center -extent 1200x1200',
            :general => '-gravity center -extent 150x375 -quality 95',
            :all => '-quality 100 -antialias -flatten -background white -unsharp 0.3x0.3+5+0'
        },
        :processors => [:thumbnail, :compression]

Answer 1

我遇到了一个其他人在网上制作并自己使用的处理器。详情请见 http://pjkh.com/articles/speeding-up-thumbnail-generation-with-paperclip/获取高级使用信息。

recursive_thumbnail.rb (包括在 lib/paperclip_processors 中)

module Paperclip
    class RecursiveThumbnail < Thumbnail
      def initialize file, options = {}, attachment = nil
        super Paperclip.io_adapters.for(attachment.styles[options[:thumbnail] || :original]), options, attachment
      end
    end
end

对于您的模型:

:styles => {
    :croppable => ["1200x1200>", :jpg],
    :show => ["x425", :jpg],
    :general => ["150x375", :jpg],
    :thumb => {
        :geometry => "150x150^",
        :format => :jpg,
        :processors => [:recursive_thumbnail] },
        :thumbnail => :croppable
    }