Class: CombinePDF::PDFWriter

Inherits:
Hash
  • Object
show all
Defined in:
lib/combine_pdf/combine_pdf_basic_writer.rb

Overview

not fully tested!

NO UNICODE SUPPORT!

The PDFWriter class is a subclass of Hash and represents a PDF Page object.

Writing on this Page is done using the textbox function.

Setting the page dimensions can be either at the new or using the mediabox method.

the rest of the methods are for internal use.

Once the Page is completed (the last text box was added), we can insert the page to a CombinePDF object.

We can either insert the PDFWriter as a new page:

pdf = CombinePDF.new
new_page = PDFWriter.new
new_page.textbox "some text"
pdf << new_page
pdf.save "file_with_new_page.pdf"

Or we can insert the PDFWriter as an overlay (stamp / watermark) over existing pages:

pdf = CombinePDF.new
new_page = PDFWriter.new "some_file.pdf"
new_page.textbox "some text"
pdf.pages.each {|page| page << new_page }
pdf.save "stamped_file.pdf"

Instance Method Summary collapse

Constructor Details

#initialize(mediabox = [0.0, 0.0, 612.0, 792.0]) ⇒ PDFWriter 



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# File 'lib/combine_pdf/combine_pdf_basic_writer.rb', line 44

def initialize(mediabox = [0.0, 0.0, 612.0, 792.0])
  # indirect_reference_id, :indirect_generation_number
  @contents = ""
  @base_font_name = "Writer" + SecureRandom.urlsafe_base64(7) + "PDF"
  self[:Type] = :Page
  self[:indirect_reference_id] = 0
  self[:Resources] = {}
  self[:Contents] = { is_reference_only: true , referenced_object: {indirect_reference_id: 0, raw_stream_content: @contents} }
  self[:MediaBox] = mediabox
end

Instance Method Details

#dimensions_of(text, fonts, size = 1000) ⇒ Object

gets the dimentions (width and height) of the text, as it will be printed in the PDF.

text

the text to measure

font

a font name or an Array of font names. Font names should be registered fonts. The 14 standard fonts are pre regitered with the font library.

size

the size of the font (defaults to 1000 points).



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# File 'lib/combine_pdf/combine_pdf_basic_writer.rb', line 273

def dimensions_of(text, fonts, size = 1000)
  Fonts.dimensions_of text, fonts, size
end

#fit_text(text, font, length, height = 10000000) ⇒ Object

this method returns the size for which the text fits the requested metrices the size is type Float and is rather exact if the text cannot fit such a small place, returns zero (0). maximum font size possible is set to 100,000 - which should be big enough for anything

text

the text to fit

font

the font name. @see font

length

the length to fit

height

the height to fit (optional - normally length is the issue)



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

def fit_text(text, font, length, height = 10000000)
  size = 100000
  size_array = [size]
  metrics = Fonts.dimensions_of text, font, size
  if metrics[0] > length
    size_array << size * length/metrics[0]
  end
  if metrics[1] > height
    size_array << size * height/metrics[1]
  end
  size_array.min
end

#mediabox ⇒ Object

accessor (getter) for the :MediaBox element of the page



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# File 'lib/combine_pdf/combine_pdf_basic_writer.rb', line 55

def mediabox
  self[:MediaBox]
end

#mediabox=(dimensions = [0.0, 0.0, 612.0, 792.0]) ⇒ Object

accessor (setter) for the :MediaBox element of the page

dimensions

an Array consisting of four numbers (can be floats) setting the size of the media box.



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# File 'lib/combine_pdf/combine_pdf_basic_writer.rb', line 60

def mediabox=(dimensions = [0.0, 0.0, 612.0, 792.0])
  self[:MediaBox] = dimensions
end

#textbox(text, properties = {}) ⇒ Object

This method adds a simple text box to the Page represented by the PDFWriter class. This function takes two values:

text

the text to potin the box.

properties

a Hash of box properties.

the symbols and values in the properties Hash could be any or all of the following:

x

the left position of the box.

y

the BUTTOM position of the box.

width

the width/length of the box. negative values will be computed from edge of page. defaults to 0 (end of page).

height

the height of the box. negative values will be computed from edge of page. defaults to 0 (end of page).

text_align

symbol for horizontal text alignment, can be “:center” (default), “:right”, “:left”

text_valign

symbol for vertical text alignment, can be “:center” (default), “:top”, “:buttom”

font

a registered font name or an Array of names. defaults to “:Helvetica”. The 14 standard fonts names are:

  • :“Times-Roman”

  • :“Times-Bold”

  • :“Times-Italic”

  • :“Times-BoldItalic”

  • :Helvetica

  • :“Helvetica-Bold”

  • :“Helvetica-BoldOblique”

  • :“Helvetica- Oblique”

  • :Courier

  • :“Courier-Bold”

  • :“Courier-Oblique”

  • :“Courier-BoldOblique”

  • :Symbol

  • :ZapfDingbats

font_size

a Fixnum for the font size, or :fit_text to fit the text in the box. defaults to “:fit_text”

max_font_size

if font_size is set to :fit_text, this will be the maximum font size. defaults to nil (no maximum)

font_color

text color in [R, G, B], an array with three floats, each in a value between 0 to 1 (gray will be “[0.5, 0.5, 0.5]”). defaults to black.

stroke_color

text stroke color in [R, G, B], an array with three floats, each in a value between 0 to 1 (gray will be “[0.5, 0.5, 0.5]”). defounlts to nil (no stroke).

stroke_width

text stroke width in PDF units. defaults to 0 (none).

box_color

box fill color in [R, G, B], an array with three floats, each in a value between 0 to 1 (gray will be “[0.5, 0.5, 0.5]”). defaults to nil (none).

border_color

box border color in [R, G, B], an array with three floats, each in a value between 0 to 1 (gray will be “[0.5, 0.5, 0.5]”). defaults to nil (none).

border_width

border width in PDF units. defaults to nil (none).

box_radius

border radius in PDF units. defaults to 0 (no corner rounding).

opacity

textbox opacity, a float between 0 (transparent) and 1 (opaque)



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# File 'lib/combine_pdf/combine_pdf_basic_writer.rb', line 100

def textbox(text, properties = {})
  options = {
    x: 0,
    y: 0,
    width: 0,
    height: -1,
    text_align: :center,
    text_valign: :center,
    font: nil,
    font_size: :fit_text,
    max_font_size: nil,
    font_color: [0,0,0],
    stroke_color: nil,
    stroke_width: 0,
    box_color: nil,
    border_color: nil,
    border_width: 0,
    box_radius: 0,
    opacity: 1
  }
  options.update properties
  # reset the length and height to meaningful values, if negative
  options[:width] = mediabox[2] - options[:x] + options[:width] if options[:width] <= 0
  options[:height] = mediabox[3] - options[:y] + options[:height] if options[:height] <= 0

  # create box stream
  box_stream = ""
  # set graphic state for box
  if options[:box_color] || (options[:border_width].to_i > 0 && options[:border_color])
    # compute x and y position for text
    x = options[:x]
    y = options[:y]

    # set graphic state for the box
    box_stream << "q\nq\nq\n"
    box_graphic_state = { ca: options[:opacity], CA: options[:opacity], LW: options[:border_width], LC: 0, LJ: 0,  LD: 0 }
    if options[:box_radius] != 0 # if the text box has rounded corners
      box_graphic_state[:LC], box_graphic_state[:LJ] =  2, 1
    end
    box_graphic_state = graphic_state box_graphic_state # adds the graphic state to Resources and gets the reference
    box_stream << "#{PDFOperations._object_to_pdf box_graphic_state} gs\n"
    box_stream << "DeviceRGB CS\nDeviceRGB cs\n"
    if options[:box_color]
      box_stream << "#{options[:box_color].join(' ')} rg\n"
    end
    if options[:border_width].to_i > 0 && options[:border_color]
      box_stream << "#{options[:border_color].join(' ')} RG\n"
    end
    # create the path
    radius = options[:box_radius]
    half_radius = (radius.to_f / 2).round 4
    ## set starting point
    box_stream << "#{options[:x] + radius} #{options[:y]} m\n" 
    ## buttom and right corner - first line and first corner
    box_stream << "#{options[:x] + options[:width] - radius} #{options[:y]} l\n" #buttom
    if options[:box_radius] != 0 # make first corner, if not straight.
      box_stream << "#{options[:x] + options[:width] - half_radius} #{options[:y]} "
      box_stream << "#{options[:x] + options[:width]} #{options[:y] + half_radius} "
      box_stream << "#{options[:x] + options[:width]} #{options[:y] + radius} c\n"
    end
    ## right and top-right corner
    box_stream << "#{options[:x] + options[:width]} #{options[:y] + options[:height] - radius} l\n"
    if options[:box_radius] != 0
      box_stream << "#{options[:x] + options[:width]} #{options[:y] + options[:height] - half_radius} "
      box_stream << "#{options[:x] + options[:width] - half_radius} #{options[:y] + options[:height]} "
      box_stream << "#{options[:x] + options[:width] - radius} #{options[:y] + options[:height]} c\n"
    end
    ## top and top-left corner
    box_stream << "#{options[:x] + radius} #{options[:y] + options[:height]} l\n"
    if options[:box_radius] != 0
      box_stream << "#{options[:x] + half_radius} #{options[:y] + options[:height]} "
      box_stream << "#{options[:x]} #{options[:y] + options[:height] - half_radius} "
      box_stream << "#{options[:x]} #{options[:y] + options[:height] - radius} c\n"
    end
    ## left and buttom-left corner
    box_stream << "#{options[:x]} #{options[:y] + radius} l\n"
    if options[:box_radius] != 0
      box_stream << "#{options[:x]} #{options[:y] + half_radius} "
      box_stream << "#{options[:x] + half_radius} #{options[:y]} "
      box_stream << "#{options[:x] + radius} #{options[:y]} c\n"
    end
    # fill / stroke path
    box_stream << "h\n"
    if options[:box_color] && options[:border_width].to_i > 0 && options[:border_color]
      box_stream << "B\n"
    elsif options[:box_color] # fill if fill color is set
      box_stream << "f\n"
    elsif options[:border_width].to_i > 0 && options[:border_color] # stroke if border is set
      box_stream << "S\n"
    end

    # exit graphic state for the box
    box_stream << "Q\nQ\nQ\n"
  end
  contents << box_stream

  # reset x,y by text alignment - x,y are calculated from the buttom left
  # each unit (1) is 1/72 Inch
  # create text stream
  text_stream = ""
  if text.to_s != "" && options[:font_size] != 0 && (options[:font_color] || options[:stroke_color])
    # compute x and y position for text
    x = options[:x]
    y = options[:y]

    # set the fonts (fonts array, with :Helvetica as fallback).
    fonts = [*options[:font], :Helvetica]
    # fit text in box, if requested
    font_size = options[:font_size]
    if options[:font_size] == :fit_text
      font_size = self.fit_text text, fonts, options[:width], options[:height]
      font_size = options[:max_font_size] if options[:max_font_size] && font_size > options[:max_font_size]
    end

    text_size = dimensions_of text, fonts, font_size

    if options[:text_align] == :center
      x = (options[:width] - text_size[0])/2 + x
    elsif options[:text_align] == :right
      x = (options[:width] - text_size[0]) + x
    end
    if options[:text_valign] == :center
      y = (options[:height] - text_size[1])/2 + y
    elsif options[:text_valign] == :top
      y = (options[:height] - text_size[1]) + y
    end

    # set graphic state for text
    text_stream << "q\nq\nq\n"
    text_graphic_state = graphic_state({ca: options[:opacity], CA: options[:opacity], LW: options[:stroke_width].to_f, LC: 2, LJ: 1,  LD: 0})
    text_stream << "#{PDFOperations._object_to_pdf text_graphic_state} gs\n"
    text_stream << "DeviceRGB CS\nDeviceRGB cs\n"
    # set text render mode
    if options[:font_color]
      text_stream << "#{options[:font_color].join(' ')} rg\n"
    end
    if options[:stroke_width].to_i > 0 && options[:stroke_color]
      text_stream << "#{options[:stroke_color].join(' ')} RG\n"
      if options[:font_color]
        text_stream << "2 Tr\n"
      else
        final_stream << "1 Tr\n"
      end
    elsif options[:font_color]
      text_stream << "0 Tr\n"
    else
      text_stream << "3 Tr\n"
    end
    # format text object(s)
      # text_stream << "#{options[:font_color].join(' ')} rg\n" # sets the color state
    encode(text, fonts).each do |encoded|
      text_stream << "BT\n" # the Begine Text marker     
      text_stream << PDFOperations._format_name_to_pdf(set_font encoded[0]) # Set font name
      text_stream << " #{font_size} Tf\n" # set font size and add font operator
      text_stream << "#{x.round 4} #{y.round 4} Td\n" # set location for text object
      text_stream << (  encoded[1] ) # insert the encoded string to the stream
      text_stream << " Tj\n" # the Text object operator and the End Text marker
      text_stream << "ET\n" # the Text object operator and the End Text marker
      x += encoded[2]/1000*font_size #update text starting point
      y -= encoded[3]/1000*font_size #update text starting point
    end
    # exit graphic state for text
    text_stream << "Q\nQ\nQ\n"
  end
  contents << text_stream

  self
end