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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