Add bin and edit workflow

bin/gems/pdf-reader-2.14.1/lib/pdf/reader/form_xobject.rb

@@ -0,0 +1,121 @@
+# coding: utf-8
+# typed: true
+# frozen_string_literal: true
+
+require 'digest/md5'
+
+module PDF
+  class Reader
+
+    # High level representation of a single PDF form xobject. Form xobjects
+    # are contained pieces of content that can be inserted onto multiple
+    # pages. They're generally used as a space efficient way to store
+    # repetative content (like logos, header, footers, etc).
+    #
+    # This behaves and looks much like a limited PDF::Reader::Page class.
+    #
+    class FormXObject
+      extend Forwardable
+
+      attr_reader :xobject
+
+      def_delegators :resources, :color_spaces
+      def_delegators :resources, :fonts
+      def_delegators :resources, :graphic_states
+      def_delegators :resources, :patterns
+      def_delegators :resources, :procedure_sets
+      def_delegators :resources, :properties
+      def_delegators :resources, :shadings
+      def_delegators :resources, :xobjects
+
+      def initialize(page, xobject, options = {})
+        @page    = page
+        @objects = page.objects
+        @cache   = options[:cache] || {}
+        @xobject = @objects.deref_stream(xobject)
+      end
+
+      # return a hash of fonts used on this form.
+      #
+      # The keys are the font labels used within the form content stream.
+      #
+      # The values are a PDF::Reader::Font instances that provide access
+      # to most available metrics for each font.
+      #
+      def font_objects
+        raw_fonts = @objects.deref_hash(fonts)
+        ::Hash[raw_fonts.map { |label, font|
+          [label, PDF::Reader::Font.new(@objects, @objects.deref_hash(font) || {})]
+        }]
+      end
+
+      # processes the raw content stream for this form in sequential order and
+      # passes callbacks to the receiver objects.
+      #
+      # See the comments on PDF::Reader::Page#walk for more detail.
+      #
+      def walk(*receivers)
+        receivers = receivers.map { |receiver|
+          ValidatingReceiver.new(receiver)
+        }
+        content_stream(receivers, raw_content)
+      end
+
+      # returns the raw content stream for this page. This is plumbing, nothing to
+      # see here unless you're a PDF nerd like me.
+      #
+      def raw_content
+        @xobject.unfiltered_data
+      end
+
+      private
+
+      # Returns the resources that accompany this form.
+      #
+      def resources
+        @resources ||= Resources.new(@objects, @objects.deref_hash(@xobject.hash[:Resources]) || {})
+      end
+
+      def callback(receivers, name, params=[])
+        receivers.each do |receiver|
+          receiver.send(name, *params) if receiver.respond_to?(name)
+        end
+      end
+
+      def content_stream_md5
+        @content_stream_md5 ||= Digest::MD5.hexdigest(raw_content)
+      end
+
+      def cached_tokens_key
+        @cached_tokens_key ||= "tokens-#{content_stream_md5}"
+      end
+
+      def tokens
+        @cache[cached_tokens_key] ||= begin
+                      buffer = Buffer.new(StringIO.new(raw_content), :content_stream => true)
+                      parser = Parser.new(buffer, @objects)
+                      result = []
+                      while (token = parser.parse_token(PagesStrategy::OPERATORS))
+                        result << token
+                      end
+                      result
+                    end
+      end
+
+      def content_stream(receivers, instructions)
+        params       = []
+
+        tokens.each do |token|
+          if token.kind_of?(Token) and PagesStrategy::OPERATORS.has_key?(token)
+            callback(receivers, PagesStrategy::OPERATORS[token], params)
+            params.clear
+          else
+            params << token
+          end
+        end
+      rescue EOFError
+        raise MalformedPDFError, "End Of File while processing a content stream"
+      end
+    end
+  end
+end