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
		# connecting references with original objects
		serialize_objects_and_references
		# make sure there is only one Catalog (the latest Catalog)
		if args[0].root_object[:Root]
			@objects.delete_if {|obj| obj[:Type] == :Catalog}
			@objects << args[0].root_object[:Root]
		else
			last_calalog = (@objects.select {|obj| obj[:Type] == :Catalog}).last
			unless last_calalog.nil?
			@objects.delete_if {|obj| obj[:Type] == :Catalog}
			@objects << last_calalog
			end
		end
		@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
		# connecting references with original objects
		serialize_objects_and_references
	elsif args[0].is_a? Hash
		@objects = args
		# connecting references with original objects
		serialize_objects_and_references
	end
	# 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

#<<(data) ⇒ Object

add the pages (or file) to the PDF (combine/merge) and return the new pages array. for example:

pdf = CombinePDF.new "first_file.pdf"

pdf << CombinePDF.new "second_file.pdf"

pdf.save "both_files_merged.pdf"
data

is PDF page (Hash), and Array of PDF pages or a parsed PDF object to be added.



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 284

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

		@need_to_rebuild_resources = true

 		@objects.push(*data.objects)
		# rebuild_catalog
		return rebuild_catalog[:Pages][:referenced_object][:Kids]
	end
	insert -1, data
end

#>>(data) ⇒ Object

add the pages (or file) to the BEGINNING of the PDF (combine/merge) and return the new pages array. for example:

pdf = CombinePDF.new "second_file.pdf"

pdf >> CombinePDF.new "first_file.pdf"

pdf.save "both_files_merged.pdf"
data

is PDF page (Hash), and Array of PDF pages or a parsed PDF object to be added.



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 309

def >> (data)
	insert 0, data
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 456

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 434

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 441

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 486

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

#fonts(limit_to_type0 = false) ⇒ Object

returns an array with the different fonts used in the file.

Type0 font objects ( “font == :Type0” ) can be registered with the font library for use in PDFWriter objects (font numbering / table creation etc’).

Parameters:

  • limit_to_type0 (true, false) (defaults to: false) —

    limits the list to type0 fonts.



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 262

def fonts(limit_to_type0 = false)
	fonts_array = []
	pages.each do |p|
		p[:Resources][:Font].values.each do |f|
			f = f[:referenced_object] if f[:referenced_object]
			if (limit_to_type0 || f[:Subtype] = :Type0) && f[:Type] == :Font  && !fonts_array.include?(f)
				fonts_array << f
			end
		end
	end
	fonts_array
end

#insert(location, data) ⇒ Object

add PDF pages (or PDF files) into a specific location.

returns the new pages Array

location

the location for the added page(s). Could be any number. negative numbers represent a count backwards (-1 being the end of the page array and 0 being the begining). if the location is beyond bounds, the pages will be added to the end of the PDF object (or at the begining, if the out of bounds was a negative number).

data

a PDF page, a PDF file (CombinePDF.new “filname.pdf”) or an array of pages (CombinePDF.new(“filname.pdf”).pages).



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# File 'lib/combine_pdf/combine_pdf_pdf.rb', line 319

def insert(location, data)
	pages_to_add = nil
	if data.is_a? PDF
		pages_to_add = data.pages
	elsif data.is_a?(Array) && (data.select {|o| !(o.is_a?(Hash) && o[:Type] == :Page) } ).empty?
		pages_to_add = data
	elsif data.is_a?(Hash) && data[:Type] == :Page
		pages_to_add = [data]
	else
		warn "Shouldn't add objects to the file unless they are PDF objects or PDF pages (an Array or a single PDF page)."
		retrun false # return false, which will also stop any chaining.				
	end
	catalog = rebuild_catalog
	pages_array = catalog[:Pages][:referenced_object][:Kids]
	page_count = pages_array.length
	if location < 0 && (page_count + location < 0 )
		location = 0
	elsif location > 0 && (location > page_count)
		location = page_count
	end
	pages_array.insert location, pages_to_add
	pages_array
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 356

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[:CropBox] || page[:MediaBox] || [0, 0, 595.3, 841.9]
		stamp = PDFWriter.new mediabox
		# 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 206

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
				catalogs[:MediaBox] ||= catalogs[:Parent][:referenced_object][:MediaBox] if catalogs[:Parent].is_a?(Hash) && catalogs[:Parent][:referenced_object].is_a?(Hash) && catalogs[:Parent][:referenced_object][:MediaBox]
				catalogs[:CropBox] ||= catalogs[:Parent][:referenced_object][:CropBox] if catalogs[:CropBox].is_a?(Hash) && catalogs[:CropBox][:referenced_object].is_a?(Hash) && catalogs[:Parent][:referenced_object][:CropBox]
				catalogs[:MediaBox] = catalogs[:MediaBox][:referenced_object][:indirect_without_dictionary] if catalogs[:MediaBox].is_a?(Hash) && catalogs[:MediaBox][:referenced_object].is_a?(Hash) && catalogs[:MediaBox][:referenced_object][:indirect_without_dictionary]
				catalogs[:CropBox] = catalogs[:CropBox][:referenced_object][:indirect_without_dictionary] if catalogs[:CropBox].is_a?(Hash) && catalogs[:CropBox][:referenced_object].is_a?(Hash) && catalogs[:CropBox][:referenced_object][:indirect_without_dictionary]
				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 183

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 423

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 429

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 131

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