Class: CombinePDF::PDF

Inherits:
Object
  • Object
show all
Includes:
Renderer
Defined in:
lib/combine_pdf/pdf_public.rb,
lib/combine_pdf/pdf_protected.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.load("file1.pdf") # one way to combine, very fast.
pdf << CombinePDF.load("file2.pdf")
pdf.save "combined.pdf"

or even a one liner:

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

you can also add just odd or even pages:

pdf = CombinePDF.new
i = 0
CombinePDF.load("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.load("company_logo.pdf").pages[0]
pdf = CombinePDF.load "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.load "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.load("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.

Constant Summary collapse

PRIVATE_HASH_KEYS =

lists the Hash keys used for PDF objects

the CombinePDF library doesn’t use special classes for its objects (PDFPage class, PDFStream class or anything like that).

there is only one PDF class which represents the whole of the PDF file.

this Hash lists the private Hash keys that the CombinePDF library uses to differentiate between complex PDF objects.

[:indirect_reference_id, :indirect_generation_number, :raw_stream_content, :is_reference_only, :referenced_object, :indirect_without_dictionary]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(parser = nil) ⇒ PDF

Returns a new instance of PDF.

Raises:

  • (TypeError) 


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# File 'lib/combine_pdf/pdf_public.rb', line 93

def initialize (parser = nil)
	# default before setting
	@objects = []
	@version = 0
	@viewer_preferences, @info  = {}, {}
	parser ||= PDFParser.new("")
	raise TypeError, "initialization error, expecting CombinePDF::PDFParser or nil, but got #{parser.class.name}" unless parser.is_a? PDFParser
	@objects = parser.parse
	# remove any existing id's
	remove_old_ids
	# set data from parser
	@version = parser.version if parser.version.is_a? Float
	@info = parser.info_object || {}

	# general globals
	@set_start_id = 1
	@info[:Producer] = "Ruby CombinePDF #{CombinePDF::VERSION} Library by B. Segev"
	@info.delete :CreationDate
	@info.delete :ModDate
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/pdf_public.rb', line 85

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/pdf_public.rb', line 81

def objects
  @objects
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/pdf_public.rb', line 87

def version
  @version
end

#viewer_preferences ⇒ Object (readonly)

the viewer_preferences attribute is a Hash that sets the ViewerPreferences data for the PDF. use, for example:

pdf.viewer_preferences[:HideMenubar] = true



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# File 'lib/combine_pdf/pdf_public.rb', line 91

def viewer_preferences
  @viewer_preferences
end

Instance Method Details

#<<(data) ⇒ Object

add the pages (or file) to the PDF (combine/merge) and RETURNS SELF, for nesting. 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/pdf_public.rb', line 267

def << (data)
	insert -1, data
end

#>>(data) ⇒ Object

add the pages (or file) to the BEGINNING of the PDF (combine/merge) and RETURNS SELF for nesting operators. 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/pdf_public.rb', line 280

def >> (data)
	insert 0, data
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/pdf_public.rb', line 136

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/pdf_public.rb', line 143

def author=(new_author = nil)
	@info[:Author] = new_author
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/pdf_public.rb', line 245

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! (unlike ‘#<<`, doesn’t return self!)

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/pdf_public.rb', line 290

def insert(location, data)
	pages_to_add = nil
	if data.is_a? PDF
 		@version = [@version, data.version].max
		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)."
		return 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.flatten!
	self
end

#new_page(mediabox = [0, 0, 595.3, 841.9], location = -1)) ⇒ Object

adds a new page to the end of the PDF object.

returns the new page object.



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# File 'lib/combine_pdf/pdf_public.rb', line 117

def new_page(mediabox = [0, 0, 595.3, 841.9], location = -1)
	p = PDFWriter.new(mediabox)
	insert(-1, p )
	p
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/pdf_public.rb', line 345

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|
		# Get page dimensions
		mediabox = page[:CropBox] || page[:MediaBox] || [0, 0, 595.3, 841.9]
		# set stamp text
		text = opt[:number_format] % page_number
		# compute locations for text boxes
		text_dimantions = page.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 = opt[:margin_from_height]
		from_side = opt[:margin_from_side]
		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
		bottom_position = from_height + box_height
		if opt[:number_location].include? :top
			 page.textbox text, {x: center_position, y: top_position }.merge(opt)
		end
		if opt[:number_location].include? :bottom
			 page.textbox text, {x: center_position, y: bottom_position }.merge(opt)
		end
		if opt[:number_location].include? :top_left
			 page.textbox text, {x: left_position, y: top_position }.merge(opt)
		end
		if opt[:number_location].include? :bottom_left
			 page.textbox text, {x: left_position, y: bottom_position }.merge(opt)
		end
		if opt[:number_location].include? :top_right
			 page.textbox text, {x: right_position, y: top_position }.merge(opt)
		end
		if opt[:number_location].include? :bottom_right
			 page.textbox text, {x: right_position, y: bottom_position }.merge(opt)
		end
		page_number = page_number.succ
	end
end

#pages(catalogs = nil) ⇒ 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.

Page objects are Hash class objects. the page methods are added using a mixin or inheritance.

catalogs

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



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# File 'lib/combine_pdf/pdf_public.rb', line 213

def pages(catalogs = nil)
	page_list = []
	catalogs ||= get_existing_catalogs

	if catalogs.is_a?(Array)
		catalogs.each {|c| page_list.push *( pages(c) ) unless c.nil?}
	elsif catalogs.is_a?(Hash)
		if catalogs[:is_reference_only]
			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
				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

#remove(page_index) ⇒ Object

removes a PDF page from the file and the catalog

returns the removed page.

returns nil if failed or if out of bounds.

page_index

the page’s index in the zero (0) based page array. negative numbers represent a count backwards (-1 being the end of the page array and 0 being the begining).



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# File 'lib/combine_pdf/pdf_public.rb', line 323

def remove(page_index)
	catalog = rebuild_catalog
	pages_array = catalog[:Pages][:referenced_object][:Kids]
	removed_page = pages_array.delete_at page_index
	catalog[:Pages][:referenced_object][:Count] = pages_array.length
	removed_page
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/pdf_public.rb', line 152

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/pdf_public.rb', line 125

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/pdf_public.rb', line 131

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/pdf_public.rb', line 161

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_catalog
	catalog = rebuild_catalog_and_objects
	# add ID and generation numbers to objects
	renumber_object_ids

	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%\xFF\xFF\xFF\xFF\xFF\x00\x00\x00\x00".force_encoding(Encoding::ASCII_8BIT)

	#collect objects and set xref table locations
	loc = 0
	out.each {|line| loc += line.bytesize + 1}
	@objects.each do |o|
		indirect_object_count += 1
		xref << loc
		out << object_to_pdf(o)
		loc += out.last.bytesize + 1
	end
	xref_location = loc
	# xref_location = 0
	# out.each { |line| xref_location += line.bytesize + 1}
	out << "xref\n0 #{(indirect_object_count).to_s}\n0000000000 65535 f \n"
	xref.each {|offset| out << ( out.pop + ("%010d 00000 n \n" % 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 #{object_to_pdf @info}"
	end
	out << ">>\nstartxref\n#{xref_location.to_s}\n%%EOF"
	# when finished, remove the numbering system and keep only pointers
	remove_old_ids
	# output the pdf stream
	out.join("\n").force_encoding(Encoding::ASCII_8BIT)
end