ruby-on-rails – 使用回形针,导轨4的水印图像

概述我一直在尝试按照 watermark with paperclip中列出的答案为我的图像添加水印： Watermark.rb： module Paperclip class Watermark < Processor # Handles watermarking of images that are uploaded. attr_accessor :current_geomet 我一直在尝试按照 watermark with paperclip中列出的答案为我的图像添加水印：

Watermark.rb：

module Paperclip  class Watermark < Processor    # Handles watermarking of images that are uploaded.    attr_accessor :current_geometry,:target_geometry,:format,:whiny,:convert_options,:watermark_path,:watermark_offset,:overlay,:position    def initialize file,options = {},attachment = nil      super      geometry = options[:geometry]      @file = file      @crop = geometry[-1,1] == '#'      @target_geometry = Geometry.parse geometry      @current_geometry = Geometry.from_file @file      @convert_options = options[:convert_options]      @whiny = options[:whiny].nil? ? true : options[:whiny]      @format = options[:format]      @watermark_path = options[:watermark_path]      @position = options[:position].nil? ? "SouthEast" : options[:position]      @watermark_offset = options[:watermark_offset]      @overlay = options[:overlay].nil? ? true : false      @current_format = file.extname(@file.path)      @basename = file.basename(@file.path,@current_format)    end    # Todo: extend watermark    # Returns true if the +target_geometry+ is meant to crop.    def crop?      @crop    end    # Returns true if the image is meant to make use of additional convert options.    def convert_options?      not @convert_options.blank?    end    # Performs the conversion of the +file+ into a watermark. Returns the Tempfile    # that contains the new image.    def make      dst = Tempfile.new([@basename,@format].compact.join("."))      dst.binmode      if watermark_path        command = "composite"        params = %W[-gravity #{@position}]        params += %W[-geometry '#{@watermark_offset}'] if @watermark_offset        params += %W['#{watermark_path}' '#{fromfile}']        params += transformation_command        params << "'#{tofile(dst)}'"      else        command = "convert"        params = ["'#{fromfile}'"]        params += transformation_command        params << "'#{tofile(dst)}'"      end      begin        Paperclip.run(command,params.join(' '))      rescue ArgumentError,Cocaine::CommandlineError        raise PaperclipError,"There was an error processing the watermark for #{@basename}" if @whiny      end      dst    end    def fromfile      file.expand_path(@file.path)    end    def tofile(destination)      file.expand_path(destination.path)    end    def transformation_command      scale,crop = @current_geometry.transformation_to(@target_geometry,crop?)      trans = %W[-resize '#{scale}']      trans += %W[-crop '#{crop}' +repage] if crop      trans << convert_options if convert_options?      trans    end  endend

和型号代码：

has_attached_file :image,:processors => [:watermark],:styles => {                     :large => "640x480",:thumb => "100x100",:medium => "300x300",:content => {                            :geometry => '150x153',:watermark_path => Rails.root.join('app/assets/images/watermark.jpg'),:position => 'SouthWest'                        },},dependent: :allow_destroy

我试图更新它以使用Rails 4(将attr_accessor移动到模型中的params),但我收到错误：

uninitialized constant Paperclip::Watermark::PaperclipError

有关如何在rails 4 app中实现水印的任何提示？

更新：我能够通过以下更改Graeme的建议来解决未初始化的常量错误：

raise PaperclipError,"There was an error processing the watermark for #{@basename}" if @whiny

至：

raise Paperclip::Error.new("There was an error processing the watermark for #{@basename}") if @whiny

我还必须从模型中删除以下内容才能进行上传处理：

:url => "/images/:style/:ID_:style.:extension",:path => ":rails_root/app/assets/images/:style/:ID_:style.:extension"

我不明白目的是什么：url和：path在这种情况下,当用户上传图片时？

问题是,即使现在上传了图像,也没有显示水印.思考？

更新2：
为了正确显示水印,我不得不将模型更改为：

has_attached_file :image,:url => "/system/:class/:attachment/:ID_partition/:style/:filename",:path => ":rails_root/public/system/:class/:attachment/:ID_partition/:style/:filename",:styles => {     :large => "640x480",:medium => {             :processors => [:watermark],:geometry => '300x300',:watermark_path => Rails.root.join('app/assets/images/icon.gif'),:position => 'SouthWest'        },dependent: :allow_destroy

关键是删除：content => .唯一剩下的问题是水印正在按比例放大以适应图像的整个宽度.有关如何停止水印缩放的任何建议？

解决方法 水印被拉伸的问题是Imagemagick命令,它将两个图像组合在一起,然后调整结果的大小.

有效地运行命令将是(为了清楚起见,我缩写了实际的文件名)：

composite -gravity SouthWest icon.gif uploaded_image.gif -resize 300x300 output_image.gif

如您所见,图像已连接,然后调整大小.

我相信你需要的命令是：

convert uploaded_image.gif -resize 300x300 icon.gif -gravity SouthWest -composite output_image.gif

即调整上传图像的大小,然后添加水印.

我已经使用复合测试了这个并在命令行进行转换,它完成了我认为你正在寻找的东西.

要在代码中实现它,您需要更改make方法中的watermark_path语句：

def make  dst = Tempfile.new([@basename,@format].compact.join("."))  dst.binmode  if watermark_path    # -- original code --    # command = "composite"    # params = %W[-gravity #{@position}]    # params += %W[-geometry '#{@watermark_offset}'] if @watermark_offset    # params += %W['#{watermark_path}' '#{fromfile}']    # params += transformation_command    # params << "'#{tofile(dst)}'"    # -- new code --    command = "convert"    params  = %W['#{fromfile}']    params += transformation_command    params += %W['#{watermark_path}' -gravity #{@position} -composite]    params << "'#{tofile(dst)}'"  else    command = "convert"    params = ["'#{fromfile}'"]    params += transformation_command    params << "'#{tofile(dst)}'"  end  begin    Paperclip.run(command,params.join(' '))  rescue ArgumentError,Cocaine::CommandlineError    raise PaperclipError,"There was an error processing the watermark for #{@basename}" if @whiny  end  dstend

免责声明：我实际上没有对此进行测试,请原谅任何错误.

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