Ruby on rails 回形针图像Magick转换为灰度并裁剪以适合144x144#

客户端.rb

  has_attached_file :avatar,
  :path => ":rails_root/public/system/:attachment/:id/:style/:filename",
  :url => "/system/:attachment/:id/:style/:filename",
  :styles => {:thumb => "144x144#", :grayscale => { :processors => [:grayscale] }}

module Paperclip
  # Handles grayscale conversion of images that are uploaded.
  class Grayscale < Processor

    def initialize file, options = {}, attachment = nil
      super
      @format = File.extname(@file.path)
      @basename = File.basename(@file.path, @format)
    end

     def make
       src = @file
       dst = Tempfile.new([@basename, @format])
       dst.binmode

       begin
         parameters = []
         parameters << ":source"
         parameters << "-colorspace Gray"
         parameters << ":dest"

         parameters = parameters.flatten.compact.join(" ").strip.squeeze(" ")

         success = Paperclip.run("convert", parameters, :source => "#{File.expand_path(src.path)}[0]", :dest => File.expand_path(dst.path))
       rescue PaperclipCommandLineError => e
         raise PaperclipError, "There was an error during the grayscale conversion for #{@basename}" if @whiny
       end

       dst
     end
  end
end

  has_attached_file :avatar,
  :path => ":rails_root/public/system/:attachment/:id/:style/:filename",
  :url => "/system/:attachment/:id/:style/:filename",
  :styles => {:thumb => "144x144#", :grayscale => "144x144#"}

  after_save :convert_grayscale

  def convert_grayscale
    system "convert public/system/avatars/#{self.id}/thumb/#{self.avatar.original_filename} -fx '(r+g+b)/3' public/system/avatars/#{self.id}/grayscale/#{self.avatar.original_filename}"
  end

thumb版本工作得很好，图像被裁剪到所需大小，灰度仅将该图像转换为灰度，但图像未被裁剪，以下是我在StackOverflow上找到的灰度生成器：

lib/grayscale.rb

  has_attached_file :avatar,
  :path => ":rails_root/public/system/:attachment/:id/:style/:filename",
  :url => "/system/:attachment/:id/:style/:filename",
  :styles => {:thumb => "144x144#", :grayscale => { :processors => [:grayscale] }}

module Paperclip
  # Handles grayscale conversion of images that are uploaded.
  class Grayscale < Processor

    def initialize file, options = {}, attachment = nil
      super
      @format = File.extname(@file.path)
      @basename = File.basename(@file.path, @format)
    end

     def make
       src = @file
       dst = Tempfile.new([@basename, @format])
       dst.binmode

       begin
         parameters = []
         parameters << ":source"
         parameters << "-colorspace Gray"
         parameters << ":dest"

         parameters = parameters.flatten.compact.join(" ").strip.squeeze(" ")

         success = Paperclip.run("convert", parameters, :source => "#{File.expand_path(src.path)}[0]", :dest => File.expand_path(dst.path))
       rescue PaperclipCommandLineError => e
         raise PaperclipError, "There was an error during the grayscale conversion for #{@basename}" if @whiny
       end

       dst
     end
  end
end

  has_attached_file :avatar,
  :path => ":rails_root/public/system/:attachment/:id/:style/:filename",
  :url => "/system/:attachment/:id/:style/:filename",
  :styles => {:thumb => "144x144#", :grayscale => "144x144#"}

  after_save :convert_grayscale

  def convert_grayscale
    system "convert public/system/avatars/#{self.id}/thumb/#{self.avatar.original_filename} -fx '(r+g+b)/3' public/system/avatars/#{self.id}/grayscale/#{self.avatar.original_filename}"
  end

如果我使用了之前上传的同一张图片，看起来效果不错，如果我上传了另一张图片，那么图片的裁剪就完全错误了。因此，我得出结论，回形针生成的参数：

-crop'144x144+30+0'

用于特定的图像大小，而对于另一个具有不同大小的图像，通常会发送不同的参数以适合144px

---

如何在生成器中裁剪图像，使其与回形针中的

144x144 

等效，或者需要向imagemagick发送哪些参数才能实现此目的。谢谢。

我决定换一种方式，所以我将使用具有所需大小的裁剪文件，并使用imagemagick将其转换为灰度，并在保存模型后将其保存到正确的文件夹中。当我使用系统命令处理imagemagick时，可以删除灰度处理器

p、 这个答案可能有一些缺点，但目前我找不到

客户端.rb

  has_attached_file :avatar,
  :path => ":rails_root/public/system/:attachment/:id/:style/:filename",
  :url => "/system/:attachment/:id/:style/:filename",
  :styles => {:thumb => "144x144#", :grayscale => { :processors => [:grayscale] }}

module Paperclip
  # Handles grayscale conversion of images that are uploaded.
  class Grayscale < Processor

    def initialize file, options = {}, attachment = nil
      super
      @format = File.extname(@file.path)
      @basename = File.basename(@file.path, @format)
    end

     def make
       src = @file
       dst = Tempfile.new([@basename, @format])
       dst.binmode

       begin
         parameters = []
         parameters << ":source"
         parameters << "-colorspace Gray"
         parameters << ":dest"

         parameters = parameters.flatten.compact.join(" ").strip.squeeze(" ")

         success = Paperclip.run("convert", parameters, :source => "#{File.expand_path(src.path)}[0]", :dest => File.expand_path(dst.path))
       rescue PaperclipCommandLineError => e
         raise PaperclipError, "There was an error during the grayscale conversion for #{@basename}" if @whiny
       end

       dst
     end
  end
end

  has_attached_file :avatar,
  :path => ":rails_root/public/system/:attachment/:id/:style/:filename",
  :url => "/system/:attachment/:id/:style/:filename",
  :styles => {:thumb => "144x144#", :grayscale => "144x144#"}

  after_save :convert_grayscale

  def convert_grayscale
    system "convert public/system/avatars/#{self.id}/thumb/#{self.avatar.original_filename} -fx '(r+g+b)/3' public/system/avatars/#{self.id}/grayscale/#{self.avatar.original_filename}"
  end

---

结果

---

我决定换一种方式，因此我将使用具有所需大小的裁剪文件，并使用imagemagick将其转换为灰度，并在保存模型后将其保存到正确的文件夹中。当我使用系统命令处理imagemagick时，可以删除灰度处理器

p、 这个答案可能有一些缺点，但目前我找不到

客户端.rb

  has_attached_file :avatar,
  :path => ":rails_root/public/system/:attachment/:id/:style/:filename",
  :url => "/system/:attachment/:id/:style/:filename",
  :styles => {:thumb => "144x144#", :grayscale => { :processors => [:grayscale] }}

module Paperclip
  # Handles grayscale conversion of images that are uploaded.
  class Grayscale < Processor

    def initialize file, options = {}, attachment = nil
      super
      @format = File.extname(@file.path)
      @basename = File.basename(@file.path, @format)
    end

     def make
       src = @file
       dst = Tempfile.new([@basename, @format])
       dst.binmode

       begin
         parameters = []
         parameters << ":source"
         parameters << "-colorspace Gray"
         parameters << ":dest"

         parameters = parameters.flatten.compact.join(" ").strip.squeeze(" ")

         success = Paperclip.run("convert", parameters, :source => "#{File.expand_path(src.path)}[0]", :dest => File.expand_path(dst.path))
       rescue PaperclipCommandLineError => e
         raise PaperclipError, "There was an error during the grayscale conversion for #{@basename}" if @whiny
       end

       dst
     end
  end
end

  has_attached_file :avatar,
  :path => ":rails_root/public/system/:attachment/:id/:style/:filename",
  :url => "/system/:attachment/:id/:style/:filename",
  :styles => {:thumb => "144x144#", :grayscale => "144x144#"}

  after_save :convert_grayscale

  def convert_grayscale
    system "convert public/system/avatars/#{self.id}/thumb/#{self.avatar.original_filename} -fx '(r+g+b)/3' public/system/avatars/#{self.id}/grayscale/#{self.avatar.original_filename}"
  end

---

结果

---

通过反复试验，我找到了一种更简单的方法。使用找到的灰度处理器代码，将其放入lib/paperclip/grayscale.rb中

然后，按如下方式设置样式：

:styles => {
  :thumb => "144x144#",
  :grayscale => { :geometry => "144x144#", :processors => [:grayscale, :thumbnail] }
}

---

这样，灰度样式将由灰度处理器和缩略图处理器使用提供的“几何体”进行处理。作为奖励，您将能够使用曲别针内置的rake任务重新处理现有附件。

通过反复试验，我找到了一种更简单的方法。使用找到的灰度处理器代码，将其放入lib/paperclip/grayscale.rb中

然后，按如下方式设置样式：

:styles => {
  :thumb => "144x144#",
  :grayscale => { :geometry => "144x144#", :processors => [:grayscale, :thumbnail] }
}

---

这样，灰度样式将由灰度处理器和缩略图处理器使用提供的“几何体”进行处理。作为奖励，您将能够使用曲别针内置的rake任务重新处理现有附件。

为了简化操作，您可以使用，

convert\u选项直接附加到
convert

e、 g

变成：

  has_attached_file :file, styles: {
    ir: {geometry: '640x640>', convert_options: '-colorspace Gray'}, 
    thumb: '150x150>'
  }

为了简化操作，您可以使用，
convert\u选项：

e、 g

变成：

  has_attached_file :file, styles: {
    ir: {geometry: '640x640>', convert_options: '-colorspace Gray'}, 
    thumb: '150x150>'
  }

这是迄今为止最干净的选择。谢谢你，汤姆邓宁！这是迄今为止最干净的选择。谢谢你，汤姆邓宁！