回形针自定义处理器不更改图像类型 [英] Paperclip custom processor not changing image type

问题描述

我在使用回形针自定义处理器时遇到了一些问题。

I'm having a few problems with a paperclip custom processor.

在命令行这一行：

$ convert cats.jpg -thumbnail 300x400  -bordercolor white -background black  +polaroid  cats.png

成功转换此信息：

https://dl.dropboxusercontent.com/u/4233433/cats.jpg

进入：

https://dl.dropboxusercontent.com /u/4233433/cats.png

即JPEG转换为具有透明背景的PNG。这正是我想要实现的目标。

i.e a JPEG converted into a PNG with a transparent background. Which is exactly what I am trying to achieve.

然而，当我尝试使用Paperclip在Rails（4.0.1）中执行此操作时，我最终得到：

However when I attempt to do this within Rails (4.0.1) using Paperclip I end up with :

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它被重命名为PNG，但实际上是JPEG。

It's renamed as a PNG but is actually a JPEG.

我的模特：

class Submission < ActiveRecord::Base
    has_attached_file :photo,
              processors: [:polarize],
              styles: {
                polarized: {
                  format: 'png',
                  is_polarized: true
                }
              } 

    belongs_to :user
end

和我的处理器：

module Paperclip
  class Polarize < Processor
    def initialize file, options = {}, attachment = nil
      super
      @file           = file
      @attachment     = attachment
      @is_polarized   = options[:is_polarized]
      @current_format = File.extname(@file.path) 
      @format         = options[:format]
      @basename       = File.basename(@file.path, @current_format)
    end

    def make
      temp_file = Tempfile.new([@basename, @format].compact.join("."))
      temp_file.binmode

      if @is_polarized
        run_string =  "convert #{fromfile} -thumbnail 300x400  -bordercolor white -background white  +polaroid  #{tofile(temp_file)}"    
        Paperclip.run(run_string)
      end

      temp_file
    end

    def fromfile
      File.expand_path(@file.path)
    end

    def tofile(destination)
      File.expand_path(destination.path)
    end
   end
 end

在我的数据库中 photo_content_type 是 image / jpeg 和 photo_file_name 是 cats.jpg 当我预料到的时候分别为 image / png 和 cats.png 。有什么想法？

In my Database photo_content_type is image/jpeg and photo_file_name is cats.jpg when I would have expected image/png and cats.png respectively. Any ideas?

更新

错误在这一行

temp_file = Tempfile.new([@basename, @format].compact.join("."))

将其更改为

temp_file = Tempfile.new([@basename, @format])

修复问题。感谢shaun-frost-duke-jackson

fixes things. Credit to shaun-frost-duke-jackson

推荐答案

看看网站上的文档，但很确定它应该像下面：

Have a look at the documentation on the website but pretty sure it should be like below:

has_attached_file :avatar, :styles => { :thumb => ["32x32#", :png] }

https://github.com/thoughtbot/paperclip

在后期处理中

猜猜你的问题在这里：

@format         = options[:format]
@basename       = File.basename(@file.path, @current_format)
temp_file = Tempfile.new([@basename, @format].compact.join("."))

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