Class: CombinePDF::PDF

Inherits:
Object
  • Object
show all
Defined in:
lib/combine_pdf/combine_pdf_pdf.rb,
lib/combine_pdf/combine_pdf_pdf.rb

Overview

PDF class is the PDF object that can save itself to a file and that can be used as a container for a full PDF file data, including version, information etc’.

PDF objects can be used to combine or to inject data.

Combine/Merge PDF files or Pages

To combine PDF files (or data):

pdf = CombinePDF.new
pdf << CombinePDF.new("file1.pdf") # one way to combine, very fast.
pdf << CombinePDF.new("file2.pdf")
pdf.save "combined.pdf"

or even a one liner:

(CombinePDF.new("file1.pdf") << CombinePDF.new("file2.pdf") << CombinePDF.new("file3.pdf")).save("combined.pdf")

you can also add just odd or even pages:

pdf = CombinePDF.new
i = 0
CombinePDF.new("file.pdf").pages.each do |page|
  i += 1
  pdf << page if i.even?
end
pdf.save "even_pages.pdf"

notice that adding all the pages one by one is slower then adding the whole file.

Add content to existing pages (Stamp / Watermark)

To add content to existing PDF pages, first import the new content from an existing PDF file. after that, add the content to each of the pages in your existing PDF.

in this example, we will add a company logo to each page:

 = CombinePDF.new("company_logo.pdf").pages[0]
pdf = CombinePDF.new "content_file.pdf"
pdf.pages.each {|page| page << } # notice the << operator is on a page and not a PDF object.
pdf.save "content_with_logo.pdf"

Notice the << operator is on a page and not a PDF object. The << operator acts differently on PDF objects and on Pages.

The << operator defaults to secure injection by renaming references to avoid conflics. For overlaying pages using compressed data that might not be editable (due to limited filter support), you can use:

pdf.pages(nil, false).each {|page| page << stamp_page}

Page Numbering

adding page numbers to a PDF object or file is as simple as can be:

pdf = CombinePDF.new "file_to_number.pdf"
pdf.number_pages
pdf.save "file_with_numbering.pdf"

numbering can be done with many different options, with different formating, with or without a box object, and even with opacity values.

Loading PDF data

Loading PDF data can be done from file system or directly from the memory.

Loading data from a file is easy:

pdf = CombinePDF.new("file.pdf")

you can also parse PDF files from memory:

pdf_data = IO.read 'file.pdf' # for this demo, load a file to memory
pdf = CombinePDF.parse(pdf_data)

Loading from the memory is especially effective for importing PDF data recieved through the internet or from a different authoring library such as Prawn.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*args) ⇒ PDF

Returns a new instance of PDF.



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 83

def initialize (*args)
  # default before setting
  @objects = []
  @version = 0 
  @info = {}
  if args[0].is_a? PDFParser
    @objects = args[0].parse
    @version = args[0].version if args[0].version.is_a? Float
    @info = args[0].info_object || {}
  elsif args[0].is_a? Array
    # object initialization
    @objects = args[0]
    @version = args[1] if args[1].is_a? Float
  elsif args[0].is_a? Hash
    @objects = args
  end
  # connecting references with original objects
  serialize_objects_and_references
  # general globals
  @string_output = :literal
  @need_to_rebuild_resources = false
  @set_start_id = 1
  @info[:Producer] = "Ruby CombinePDF Library by Boaz Segev"
  @info.delete :CreationDate
  @info.delete :ModDate
  warn "finished to initialize PDF object."
end

Instance Attribute Details

#info ⇒ Object (readonly)

the info attribute is a Hash that sets the Info data for the PDF. use, for example:

pdf.info[:Title] = "title"



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 74

def info
  @info
end

#objects ⇒ Object (readonly)

the objects attribute is an Array containing all the PDF sub-objects for te class.



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 70

def objects
  @objects
end

#string_output ⇒ Object

gets/sets the string output format (PDF files store strings in to type of formats).

Accepts:

  • :literal

  • :hex



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 80

def string_output
  @string_output
end

#version ⇒ Object

set/get the PDF version of the file (1.1-1.7) - shuold be type Float.



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 82

def version
  @version
end

Instance Method Details

#<<(obj) ⇒ Object

this function adds pages or CombinePDF objects at the end of the file (merge) for example:

pdf = CombinePDF.new "first_file.pdf"

pdf << CombinePDF.new "second_file.pdf"

pdf.save "both_files_merged.pdf"



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 247

def << (obj)
  #########
  ## how should we add data to PDF?
  ## and how to handles imported pages?
  case
  when (obj.is_a?(PDF))
    @version = [@version, obj.version].max

    obj.renumber_object_ids @set_start_id + @objects.length

    @objects.push(*obj.objects)
    # rebuild_catalog
    @need_to_rebuild_resources = true
  when (obj.is_a?(Hash) && obj[:Type] == :Page), (obj.is_a?(Array) && (obj.reject {|i| i.is_a?(Hash) && i[:Type] == :Page}).empty?)
     # set obj paramater to array if it's only one page
     obj = [obj] if obj.is_a?(Hash)
    # add page(s) to objects
    @objects.push(*obj)
    # add page dependencies to objects
    add_referenced(obj)
    # add page(s) to Catalog(s)
    rebuild_catalog obj
    @need_to_rebuild_resources = true
  when (obj.is_a?(Hash) && obj[:indirect_reference_id] && obj[:referenced_object].nil?)
    #only let top level indirect objects into the PDF tree.
    @objects << obj
    @need_to_rebuild_resources = true
  else
    warn "Shouldn't add objects to the file if they are not top-level indirect PDF objects."
    retrun false # return false, which will also stop any chaining.
  end
  return self #return self object for injection chaining (pdf << page << page << page)
end

#add_referenced(object) ⇒ Object

Some PDF objects contain references to other PDF objects.

this function adds the references contained in “object”, but DOESN’T add the object itself.

this is used for internal operations, such as injectng data using the << operator.



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 397

def add_referenced(object)
  # add references but not root
  case 
  when object.is_a?(Array)
    object.each {|it| add_referenced(it)}
  when object.is_a?(Hash)
    if object[:is_reference_only] && object[:referenced_object]
      found_at = @objects.find_index object[:referenced_object]
      if found_at
        #if the objects are equal, they might still be different objects!
        # so, we need to make sure they are the same object for the pointers to effect id numbering
        # and formatting operations.
        object[:referenced_object] = @objects[found_at]
      else @objects.include? object[:referenced_object]
        #the object wasn't found - add it to the @objects array
        @objects << object[:referenced_object]
        object[:referenced_object].each do |k, v|
          add_referenced(v) unless k == :Parent
        end           
      end

    else
      object.each do |k, v|
        add_referenced(v) unless k == :Parent 
      end
    end
  end
end

#author ⇒ Object

get the author value for the pdf. The author is stored in the information dictionary and isn’t required



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 375

def author
  return @info[:Author]
end

#author=(new_author = nil) ⇒ Object

set the author value for the pdf. The author is stored in the information dictionary and isn’t required

new_title

a string that is the new author value.



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 382

def author=(new_author = nil)
  @info[:Author] = new_author
end

#each_object(&block) ⇒ Object

run block of code on evey PDF object (PDF objects are class Hash)



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 427

def each_object(&block)
  PDFOperations._each_object(@objects, &block)
end

#number_pages(options = {}) ⇒ Object

add page numbers to the PDF

For unicode text, a unicode font(s) must first be registered. the registered font(s) must supply the subset of characters used in the text. UNICODE IS AN ISSUE WITH THE PDF FORMAT - USE CAUSION.

options

a Hash of options setting the behavior and format of the page numbers:

  • :number_format a string representing the format for page number. defaults to ‘ - %s - ’ (allows for letter numbering as well, such as “a”, “b”…).

  • :number_location an Array containing the location for the page numbers, can be :top, :buttom, :top_left, :top_right, :bottom_left, :bottom_right. defaults to [:top, :buttom].

  • :start_at a Fixnum that sets the number for first page number. also accepts a letter (“a”) for letter numbering. defaults to 1.

  • :margin_from_height a number (PDF points) for the top and buttom margins. defaults to 45.

  • :margin_from_side a number (PDF points) for the left and right margins. defaults to 15.

the options Hash can also take all the options for PDFWriter.textbox. defaults to font: :Helvetica, font_size: 12 and no box (:border_width => 0, :box_color => nil).



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 294

def number_pages(options = {})
  opt = {
    number_format: ' - %s - ',
    number_location: [:top, :bottom],
    start_at: 1,
    font_size: 12,
    font: :Helvetica,
    margin_from_height: 45,
    margin_from_side: 15
  }
  opt.update options
  page_number = opt[:start_at]
  pages.each do |page|
    # create a "stamp" PDF page with the same size as the target page
    mediabox = page[:MediaBox]
    stamp = PDFWriter.new mediabox
    # set the visible dimensions to the CropBox, if it exists.
    cropbox = page[:CropBox]
    mediabox = cropbox if cropbox
    # set stamp text
    text = opt[:number_format] % page_number
    # compute locations for text boxes
    text_dimantions = stamp.dimensions_of( text, opt[:font], opt[:font_size] )
    box_width = text_dimantions[0] * 1.2
    box_height = text_dimantions[1] * 2
    opt[:width] = box_width
    opt[:height] = box_height
    from_height = 45
    from_side = 15
    page_width = mediabox[2]
    page_height = mediabox[3]
    center_position = (page_width - box_width)/2
    left_position = from_side
    right_position = page_width - from_side - box_width
    top_position = page_height - from_height
    buttom_position = from_height + box_height
    x = center_position
    y = top_position
    if opt[:number_location].include? :top
       stamp.textbox text, {x: x, y: y }.merge(opt)
    end
    y = buttom_position #bottom position
    if opt[:number_location].include? :bottom
       stamp.textbox text, {x: x, y: y }.merge(opt)
    end
    y = top_position #top position
    x = left_position # left posotion
    if opt[:number_location].include? :top_left
       stamp.textbox text, {x: x, y: y }.merge(opt)
    end
    y = buttom_position #bottom position
    if opt[:number_location].include? :bottom_left
       stamp.textbox text, {x: x, y: y }.merge(opt)
    end
    x = right_position # right posotion
    y = top_position #top position
    if opt[:number_location].include? :top_right
       stamp.textbox text, {x: x, y: y }.merge(opt)
    end
    y = buttom_position #bottom position
    if opt[:number_location].include? :bottom_right
       stamp.textbox text, {x: x, y: y }.merge(opt)
    end
    page << stamp
    page_number = page_number.succ
  end
end

#pages(catalogs = nil, secure_injection = true) ⇒ Object

this method returns all the pages cataloged in the catalog.

if no catalog is passed, it seeks the existing catalog(s) and searches for any registered Page objects.

This method also adds the << operator to each page instance, so that content can be injected to the pages, as described above.

if the secure_injection is false, then the << operator will not alter the any of the information added to the page. this might cause conflicts in the added content, but is available for situations in which the content added is compressed using unsupported filters or options.

the default is for the << operator to attempt a secure copy, by attempting to rename the content references and avoiding conflicts. because not all PDF files are created equal (some might have formating errors or variations), it is imposiible to learn if the attempt was successful.

(page objects are Hash class objects. the << operator is added to the specific instances without changing the class)

catalogs

a catalog, or an Array of catalog objects. defaults to the existing catalog.

secure_injection

a boolean (true / false) controling the behavior of the << operator.



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 191

def pages(catalogs = nil, secure_injection = true)
  page_list = []
  if catalogs == nil
    catalogs = @objects.select {|obj| obj.is_a?(Hash) && obj[:Type] == :Catalog}
    catalogs ||= []
  end
  case 
  when catalogs.is_a?(Array)
    catalogs.each {|c| page_list.push *(pages(c)) unless c.nil?}
  when catalogs.is_a?(Hash)
    if catalogs[:is_reference_only]
      catalogs[:referenced_object] = pages(PDFOperations.get_refernced_object @objects, catalogs) unless catalogs[:referenced_object]
      if catalogs[:referenced_object]
        page_list.push *( pages(catalogs[:referenced_object]) )
      else
        warn "couldn't follow reference!!! #{catalogs} not found!"
      end
    else
      case catalogs[:Type]
      when :Page
        holder = self
        if secure_injection
          catalogs.define_singleton_method("<<".to_sym) do |obj|
            obj = PDFOperations.copy_and_secure_for_injection obj
            PDFOperations.inject_to_page self, obj
            holder.add_referenced self # add new referenced objects
            self
          end
        else
          catalogs.define_singleton_method("<<".to_sym) do |obj|
            obj = PDFOperations.create_deep_copy obj
            PDFOperations.inject_to_page self, obj
            holder.add_referenced self # add new referenced objects
            self
          end
        end
        page_list << catalogs
      when :Pages
        page_list.push *(pages(catalogs[:Kids])) unless catalogs[:Kids].nil?
      when :Catalog
        page_list.push *(pages(catalogs[:Pages])) unless catalogs[:Pages].nil?
      end
    end
  end
  page_list
end

#save(file_name) ⇒ Object

Save the PDF to file.

file_name

is a string or path object for the output.

Notice! if the file exists, it WILL be overwritten.



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 168

def save(file_name)
  IO.binwrite file_name, to_pdf
end

#title ⇒ Object

get the title for the pdf The title is stored in the information dictionary and isn’t required



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 364

def title
  return @info[:Title]
end

#title=(new_title = nil) ⇒ Object

set the title for the pdf The title is stored in the information dictionary and isn’t required

new_title

a string that is the new author value.



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 370

def title=(new_title = nil)
  @info[:Title] = new_title
end

#to_pdf ⇒ Object

Formats the data to PDF formats and returns a binary string that represents the PDF file content.

This method is used by the save(file_name) method to save the content to a file.

use this to export the PDF file without saving to disk (such as sending through HTTP ect’).



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 116

def to_pdf
  #reset version if not specified
  @version = 1.5 if @version.to_f == 0.0
  #set creation date for merged file
  @info[:CreationDate] = Time.now.strftime "D:%Y%m%d%H%M%S%:::z'00"
  #rebuild resources if needed
  if @need_to_rebuild_resources
    rebuild_resources
  end
  catalog = rebuild_catalog_and_objects #rebuild_catalog

  warn "Formatting PDF output"

  out = []
  xref = []
  indirect_object_count = 1 #the first object is the null object
  #write head (version and binanry-code)
  out << "%PDF-#{@version.to_s}\n%\x00\x00\x00\x00".force_encoding(Encoding::ASCII_8BIT)

  #collect objects and set xref table locations
  loc = 0
  out.each {|line| loc += line.bytes.length + 1}
  @objects.each do |o|
    indirect_object_count += 1
    xref << loc
    out << PDFOperations._object_to_pdf(o)
    loc += out.last.length + 1
  end
  warn "Building XREF"
  xref_location = 0
  out.each { |line| xref_location += line.bytes.length + 1}
  out << "xref\n\r0 #{(indirect_object_count).to_s}\n\r0000000000 65535 f \n\r"
  xref.each {|offset| out << ( out.pop + ("%010d 00000 n \n\r" % offset) ) }
  out << out.pop + "trailer"
  out << "<<\n/Root #{false || "#{catalog[:indirect_reference_id]} #{catalog[:indirect_generation_number]} R"}"
  out << "/Size #{indirect_object_count.to_s}"
  if @info.is_a?(Hash)
    PRIVATE_HASH_KEYS.each {|key| @info.delete key} # make sure the dictionary is rendered inline, without stream
    out << "/Info #{PDFOperations._object_to_pdf @info}"
  end
  out << ">>\nstartxref\n#{xref_location.to_s}\n%%EOF"
  # when finished, remove the numbering system and keep only pointers
  PDFOperations.remove_old_ids @objects
  # output the pdf stream
  out.join("\n").force_encoding(Encoding::ASCII_8BIT)
end