Module: CombinePDF

Defined in:
lib/combine_pdf.rb,
lib/combine_pdf/api.rb,
lib/combine_pdf/fonts.rb,
lib/combine_pdf/fonts.rb,
lib/combine_pdf/filter.rb,
lib/combine_pdf/parser.rb,
lib/combine_pdf/decrypt.rb,
lib/combine_pdf/version.rb,
lib/combine_pdf/renderer.rb,
lib/combine_pdf/operations.rb,
lib/combine_pdf/pdf_public.rb,
lib/combine_pdf/basic_writer.rb,
lib/combine_pdf/page_methods.rb,
lib/combine_pdf/pdf_protected.rb

Overview

This is a pure ruby library to combine/merge, stmap/overlay and number PDF files - as well as to create tables (ment for indexing combined files).

You can also use this library for writing basic text content into new or existing PDF files (For authoring new PDF files look at the Prawn ruby library).

here is the most basic application for the library, a one-liner that combines the PDF files and saves them:

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

Loading PDF data

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

Load data from a file:

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

parse PDF files from memory:

pdf = CombinePDF.parse(pdf_data)

Combine/Merge PDF files or Pages

To combine PDF files (or data):

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

It is possible to add only specific pages. in this example, only even pages will be added:

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 the whole file is faster then adding each page seperately.

Add content to existing pages (Stamp / Watermark)

It is possible “stamp” one PDF page using another PDF page. In this example, a company logo will be stamped over each page:

 = CombinePDF.load("company_logo.pdf").pages[0]
pdf = CombinePDF.load "content_file.pdf"
pdf.pages.each {|page| page << }
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.

Page Numbering

It is possible to number the pages. in this example we will add very simple numbering:

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, different locations on each page and even with opacity values.

Writing Content

page numbering actually adds content using the PDFWriter object (a very basic writer).

in this example, all the PDF pages will be stamped, along the top, with a red box, with blue text, stating “Draft, page #”. here is the easy way (we can even use “number_pages” without page numbers, if we wish):

pdf = CombinePDF.load "file_to_stamp.pdf"
pdf.number_pages number_format: " - Draft, page %d - ", number_location: [:top], font_color: [0,0,1], box_color: [0.4,0,0], opacity: 0.75, font_size:16
pdf.save "draft.pdf"

in this example we will add a first page with the word “Draft”, in red over a colored background:

pdf = CombinePDF.load "file.pdf"
pdf_first_page = pdf.pages[0]
mediabox = page[:CropBox] || page[:MediaBox] #copy page size
title_page = CombinePDF.create_page mediabox #make title page same size as first page
title_page.textbox "DRAFT", font_color: [0.8,0,0], font_size: :fit_text, box_color: [1,0.8,0.8], opacity: 1
pdf >> title_page # the >> operator adds pages at the begining
pdf.save "draft.pdf"

font support for the writer is still in the works and is limited to extracting know fonts by location of the 14 standard fonts.

Resizing pages

Using the PDF standards for page sizes, it is now possible to resize existing PDF pages, as well as stretch and shrink their content to the new size.

pdf = CombinePDF.load "file.pdf"
a4_size = [0, 0, 595, 842]
# keep aspect ratio intact
pdf.pages.each {|p| p.resize a4_size}
pdf.save "a4.pdf"

pdf = CombinePDF.load "file.pdf"
a4_squared = [0, 0, 595, 595]
# stretch or shrink content to fit new size
pdf.pages.each {|p| p.resize a4_squared, false}
pdf.save "square.pdf"

Decryption & Filters

Some PDF files are encrypted and some are compressed (the use of filters)… not all files can be opened, merged, stamped or used and stamps.

Comments and file structure

If you want to help with the code, please be aware:

The code itself should be very straight forward, but feel free to ask whatever you want.

Credit

Caige Nichols wrote an amazing RC4 gem which I reference in my code. Credit to his wonderful is given here. Please respect his license and copyright… and mine.

License

MIT

Defined Under Namespace

Modules: Fonts, PDFFilter, PDFOperations, Page_Methods, Renderer Classes: PDF, PDFDecrypt, PDFParser, PDFWriter

Constant Summary collapse

VERSION = 
"0.2.5"
CONTENT_CONTAINER_START =

holds a simple content stream that starts a PDF graphic state container - used for wrapping malformed PDF content streams.

{ is_reference_only: true , referenced_object: {indirect_reference_id: 0, raw_stream_content: 'q'} }
CONTENT_CONTAINER_MIDDLE =

holds a simple content stream that ends a PDF graphic state container - used for wrapping malformed PDF content streams.

{ is_reference_only: true , referenced_object: {indirect_reference_id: 0, raw_stream_content: "Q\nq"} }
CONTENT_CONTAINER_END =

holds a simple content stream that ends a PDF graphic state container - used for wrapping malformed PDF content streams.

{ is_reference_only: true , referenced_object: {indirect_reference_id: 0, raw_stream_content: 'Q'} }

Class Method Summary collapse

Class Method Details

.calc_ctm(parameters) ⇒ Object

calculate a CTM value for a specific transformation.

this could be used to apply transformation in #textbox and to convert visual rotation values into actual rotation transformation.

this method accepts a Hash containing any of the following parameters:

deg

the clockwise rotation to be applied, in degrees

tx

the x translation to be applied.

ty

the y translation to be applied.

sx

the x scaling to be applied.

sy

the y scaling to be applied.

  • scaling will be applied after the transformation is applied.



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# File 'lib/combine_pdf/api.rb', line 118

def calc_ctm parameters
	p = {deg: 0, tx: 0, ty: 0, sx: 1, sy: 1}.merge parameters
	r = p[:deg] * Math::PI / 180
	s = Math.sin(r)
	c = Math.cos(r)
	# start with tranlation matrix
	m = Matrix[ [1,0,0], [0,1,0], [ p[:tx], p[:ty], 1] ]
	# then rotate
	m = m * Matrix[ [c, s, 0], [-s, c, 0], [0, 0, 1]] if parameters[:deg]
	# then scale
	m = m * Matrix[ [p[:sx], 0, 0], [0, p[:sy], 0], [0,0,1] ] if parameters[:sx] || parameters[:sy]
	# flaten array and round to 6 digits
	m.to_a.flatten.values_at(0,1,3,4,6,7).map! {|f| f.round 6}
end

.create_page(mediabox = [0, 0, 612.0, 792.0]) ⇒ Object

makes a PDFWriter object

PDFWriter objects reresent an empty page and have the method “textbox” that adds content to that page.

PDFWriter objects are used internally for numbering pages (by creating a PDF page with the page number and “stamping” it over the existing page).

::mediabox an Array representing the size of the PDF document. defaults to: [0.0, 0.0, 612.0, 792.0] (US Letter)

if the page is PDFWriter object as a stamp, the final size will be that of the original page.



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# File 'lib/combine_pdf/api.rb', line 53

def create_page(mediabox = [0, 0, 612.0, 792.0])
	PDFWriter.new mediabox
end

.create_table(options = {}) ⇒ Object

makes a PDF object containing a table

all the pages in this PDF object are PDFWriter objects and are writable using the texbox function (should you wish to add a title, or more info)

the main intended use of this method is to create indexes (a table of contents) for merged data.

example:

pdf = CombinePDF.create_table headers: ["header 1", "another header"], table_data: [ ["this is one row", "with two columns"] , ["this is another row", "also two columns", "the third will be ignored"] ]
pdf.save "table_file.pdf"

accepts a Hash with any of the following keys as well as any of the Page_Methods#textbox options:

headers

an Array of strings with the headers (will be repeated every page).

table_data

as Array of Arrays, each containing a string for each column. the first row sets the number of columns. extra columns will be ignored.

font

a registered or standard font name (see Page_Methods). defaults to nil (:Helvetica).

header_font

a registered or standard font name for the headers (see Page_Methods). defaults to nil (the font for all the table rows).

max_font_size

the maximum font size. if the string doesn’t fit, it will be resized. defaults to 14.

column_widths

an array of relative column widths ([1,2] will display only the first two columns, the second twice as big as the first). defaults to nil (even widths).

header_color

the header color. defaults to [0.8, 0.8, 0.8] (light gray).

main_color

main row color. defaults to nil (transparent / white).

alternate_color

alternate row color. defaults to [0.95, 0.95, 0.95] (very light gray).

font_color

font color. defaults to [0,0,0] (black).

border_color

border color. defaults to [0,0,0] (black).

border_width

border width in PDF units. defaults to 1.

header_align

the header text alignment within each column (:right, :left, :center). defaults to :center.

row_align

the row text alignment within each column. defaults to :left (:right for RTL table).

direction

the table’s writing direction (:ltr or :rtl). this reffers to the direction of the columns and doesn’t effect text (rtl text is automatically recognized). defaults to :ltr.

max_rows

the number of rows per page, INCLUDING the header row. deafults to 25.

page_size

the size of the page in PDF points. defaults to [0, 0, 595.3, 841.9] (A4).



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# File 'lib/combine_pdf/api.rb', line 86

def create_table(options = {})
	options[:max_rows] = options[:rows_per_page] if options[:rows_per_page]

	page_size = options[:page_size] || [0, 0, 595.3, 841.9]
	table = PDF.new()
	page = nil
	until options[:table_data].empty?
		page = create_page page_size
		page.write_table options
		table << page
	end
	table
end

.load(file_name = "") ⇒ Object

Create an empty PDF object or create a PDF object from a file (parsing the file).

file_name

is the name of a file to be parsed.

Raises:

  • (TypeError) 


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# File 'lib/combine_pdf/api.rb', line 12

def load(file_name = "")
	raise TypeError, "couldn't parse data, expecting type String" unless file_name.is_a?(String) || file_name.is_a?(Pathname)
	return PDF.new() if file_name == ''
	PDF.new( PDFParser.new(  IO.read(file_name, mode: 'rb').force_encoding(Encoding::ASCII_8BIT) ) )
end

.new(string = false) ⇒ Object

creats a new PDF object.

Combine PDF will check to see if ‘string` is a filename. If it’s a file name, it will attempt to load the PDF file using ‘CombinePDF.load`. Otherwise it will attempt parsing `string` using `CombinePDF.parse`.

If the string is empty it will return a new PDF object (the same as parse).

For both performance and code readability reasons, ‘CombinePDF.load` and `CombinePDF.parse` should be preffered unless creating a new PDF object.

Raises:

  • (TypeError) 


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# File 'lib/combine_pdf/api.rb', line 25

def new(string = false)
	return PDF.new unless string
	raise TypeError, "couldn't create PDF object, expecting type String" unless string.is_a?(String) || string.is_a?(Pathname)
	begin
		(File.file? string rescue false) ? load(string) : parse(string)
	rescue => e
		raise 'General PDF error - Use CombinePDF.load or CombinePDF.parse for a non-general error message (the requested file was not found OR the string received is not a valid PDF stream OR the file was found but not valid).'
	end
	
end

.new_table(options = {}) ⇒ Object 



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# File 'lib/combine_pdf/api.rb', line 99

def new_table(options = {})
	create_table options
end

.parse(data) ⇒ Object

Create a PDF object from a raw PDF data (parsing the data).

data

is a string that represents the content of a PDF file.

Raises:

  • (TypeError) 


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# File 'lib/combine_pdf/api.rb', line 38

def parse(data)
	raise TypeError, "couldn't parse and data, expecting type String" unless data.is_a? String
	PDF.new( PDFParser.new(data) )
end

.register_existing_font(font_name, font_object) ⇒ Object

adds an existing font (from any PDF Object) to the font library.

returns the font on success or false on failure.

example:

fonts = CombinePDF.new("japanese_fonts.pdf").fonts(true)
CombinePDF.register_font_from_pdf_object :david, fonts[0]

VERY LIMITTED SUPPORT:

  • at the moment it only imports Type0 fonts.

  • also, to extract the Hash of the actual font object you were looking for, is not a trivial matter. I do it on the console.

font_name

a Symbol with the name of the font registry. if the fonts exists in the library, it will be overwritten!

font_object

a Hash in the internal format recognized by CombinePDF, that represents the font object.



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# File 'lib/combine_pdf/api.rb', line 161

def register_existing_font font_name, font_object
	Fonts.register_font_from_pdf_object font_name, font_object
end

.register_font(font_name, font_metrics, font_pdf_object, font_cmap = nil) ⇒ Object

adds a correctly formatted font object to the font library.

registered fonts will remain in the library and will only be embeded in PDF objects when they are used by PDFWriter objects (for example, for numbering pages).

this function enables plug-ins to expend the font functionality of CombinePDF.

font_name

a Symbol with the name of the font. if the fonts exists in the library, it will be overwritten!

font_metrics

a Hash of font metrics, of the format char => char_width, boundingbox: [left_x, buttom_y, right_x, top_y] where char == character itself (i.e. “ ” for space). The Hash should contain a special value :missing for the metrics of missing characters. an optional :wy might be supported in the future, for up to down fonts.

font_pdf_object

a Hash in the internal format recognized by CombinePDF, that represents the font object.

font_cmap

a CMap dictionary Hash) which maps unicode characters to the hex CID for the font (i.e. {“a” => “61”, “z” => “7a” }).



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# File 'lib/combine_pdf/api.rb', line 144

def register_font(font_name, font_metrics, font_pdf_object, font_cmap = nil)
	Fonts.register_font font_name, font_metrics, font_pdf_object, font_cmap
end

.register_font_from_pdf_object(font_name, font_object) ⇒ Object 



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# File 'lib/combine_pdf/api.rb', line 164

def register_font_from_pdf_object font_name, font_object
	register_existing_font font_name, font_object
end