Class: Paperback::Document

Inherits:
Object
  • Object
show all
Defined in:
lib/paperback/document.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(debug: false) ⇒ Document

Returns a new instance of Document.



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# File 'lib/paperback/document.rb', line 9

def initialize(debug: false)
  log.debug('Document#initialize')
  @debug = debug
  @pdf = Prawn::Document.new
end

Instance Attribute Details

#debug ⇒ Object (readonly)

Returns the value of attribute debug.



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# File 'lib/paperback/document.rb', line 7

def debug
  @debug
end

#pdf ⇒ Object (readonly)

Returns the value of attribute pdf.



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# File 'lib/paperback/document.rb', line 7

def pdf
  @pdf
end

Instance Method Details

#add_newline ⇒ Object

Move cursor down by one line



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# File 'lib/paperback/document.rb', line 92

def add_newline
  pdf.move_down(pdf.font_size)
end

#debug_draw_axes ⇒ Object

If in debug mode, draw axes on the page to assist with layout



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# File 'lib/paperback/document.rb', line 86

def debug_draw_axes
  return unless debug
  pdf.float { pdf.stroke_axis }
end

#draw_base64(b64_content:, b64_bytes:, font_size: nil, is_encrypted: true) ⇒ Object

Parameters:

  • b64_content (String) 


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# File 'lib/paperback/document.rb', line 206

def draw_base64(b64_content:, b64_bytes:, font_size: nil, is_encrypted: true)
  font_size ||= 11

  debug_draw_axes

  if is_encrypted
    header = [
      "This PGP text encodes #{b64_bytes} bytes in #{b64_content.length}",
      " characters. Decode with `gpg -d`."
    ].join
  else
    header = [
      "This base64 text encodes #{b64_bytes} bytes in #{b64_content.length}",
      " characters. Decode with `base64 --decode`."
    ].join
  end

  add_newline
  add_newline
  pdf.text(header)
  add_newline

  pdf.font('Courier') do
    pdf.text(b64_content)
  end

end

#draw_header(labels:, passphrase_sha:, passphrase_len:, repo_url: 'https://github.com/ab/paperback') ⇒ Object 



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# File 'lib/paperback/document.rb', line 96

def draw_header(labels:, passphrase_sha:, passphrase_len:,
                repo_url: 'https://github.com/ab/paperback')

  intro = [
    "This is a paper backup produced by `paperback`. ",
    "<u><link href='#{repo_url}'>#{repo_url}</link></u>",
  ].join
  pdf.text(intro, inline_format: true)
  add_newline

  label_pad = labels.keys.map(&:length).max + 1

  unless passphrase_sha && passphrase_len
    labels['Encrypted'] = 'no'
  end

  pdf.font('Courier') do
    labels.each_pair do |k, v|
      pdf.text("#{(k + ':').ljust(label_pad)} #{v}")
    end

    if passphrase_sha
      pdf.text("SHA256(passphrase)[0...16]: #{passphrase_sha}")
    end
  end

  add_newline

  if passphrase_len
    pdf.font('Helvetica') do
      pdf.font_size(12.8) do
        pdf.text('Passphrase: ' + '_ ' * passphrase_len)
      end
    end

    pdf.move_down(8)
    pdf.indent(72) do
      pdf.text('Be sure to cover the passphrase when scanning the QR code!' +
               ' Decrypt with `gpg -d`.')
    end
  end
end

#draw_paperback(qr_code:, sixword_lines:, sixword_bytes:, labels:, passphrase_sha: nil, passphrase_len: nil, sixword_font_size: nil, base64_content: nil, base64_bytes: nil) ⇒ Object

High level method to draw the paperback content on the pdf document

Parameters:

  • qr_code
  • sixword_lines
  • sixword_bytes
  • labels
  • passphrase_sha (defaults to: nil)
  • passphrase_len (Integer, nil) (defaults to: nil) —

    Length of the passphrase used to encrypt the original content. If this is not provided, then assume the original content was not encrypted and skip adding gpg -d instructions.

  • sixword_font_size (Integer) (defaults to: nil) —

    The font size to use for Sixword text

  • base64_content (String, nil) (defaults to: nil) —

    If provided, then append the original content (possibly encrypted) encoded using Base64.

  • base64_bytes (Integer, nil) (defaults to: nil) —

    The length of the original content before encoding to base64. This is used for the informational header.



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# File 'lib/paperback/document.rb', line 45

def draw_paperback(qr_code:, sixword_lines:, sixword_bytes:, labels:,
                   passphrase_sha: nil, passphrase_len: nil,
                   sixword_font_size: nil, base64_content: nil,
                   base64_bytes: nil)
  unless qr_code.is_a?(RQRCode::QRCode)
    raise ArgumentError.new('qr_code must be RQRCode::QRCode')
  end

  # Header & QR code page
  pdf.font('Times-Roman')

  debug_draw_axes

  draw_header(labels: labels, passphrase_sha: passphrase_sha,
              passphrase_len: passphrase_len)

  add_newline

  draw_qr_code(qr_modules: qr_code.modules)

  pdf.stroke_color '000000'
  pdf.fill_color '000000'

  # Sixword page

  pdf.start_new_page

  draw_sixword(lines: sixword_lines, sixword_bytes: sixword_bytes,
               font_size: sixword_font_size,
               is_encrypted: passphrase_len)

  if base64_content
    draw_base64(b64_content: base64_content, b64_bytes: base64_bytes,
                is_encrypted: passphrase_len)
  end

  pdf.number_pages('<page> of <total>', align: :right,
                   at: [pdf.bounds.right - 100, -2])
end

#draw_qr_code(qr_modules:) ⇒ Object 



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# File 'lib/paperback/document.rb', line 174

def draw_qr_code(qr_modules:)
  qr_height = pdf.cursor # entire rest of page
  qr_width = pdf.bounds.width # entire page width

  # number of modules plus 2 for quiet area
  qr_code_size = qr_modules.length + 2

  pixel_height = qr_height / qr_code_size
  pixel_width = qr_width / qr_code_size

  pdf.bounding_box([0, pdf.cursor], width: qr_width, height: qr_height) do
    if debug
      pdf.stroke_color('888888')
      pdf.stroke_bounds
    end

    qr_modules.each do |row|
      pdf.move_down(pixel_height)

      row.each_with_index do |pixel_val, col_i|
        pdf.stroke do
          pdf.stroke_color(pixel_val ? '000000' : 'ffffff')
          pdf.fill_color(pixel_val ? '000000' : 'ffffff')
          xy = [(col_i + 1) * pixel_width, pdf.cursor]
          pdf.fill_rectangle(xy, pixel_width, pixel_height)
        end
      end
    end
  end
end

#draw_sixword(lines:, sixword_bytes:, columns: 3, hunks_per_row: 1, font_size: nil, is_encrypted: true) ⇒ Object

Parameters:

  • lines (Array<String>) —

    An array of sixword sentences to print

  • columns (Integer) (defaults to: 3) —

    The number of text columns on the page

  • hunks_per_row (Integer) (defaults to: 1) —

    The number of 6-word sentences per line

  • sixword_bytes (Integer) —

    Bytesize of the sixword encoded data



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# File 'lib/paperback/document.rb', line 143

def draw_sixword(lines:, sixword_bytes:, columns: 3, hunks_per_row: 1,
                 font_size: nil, is_encrypted: true)
  font_size ||= 11

  debug_draw_axes

  numbered = lines.each_slice(hunks_per_row).each_with_index.map { |row, i|
    "#{i * hunks_per_row + 1}: #{row.map(&:strip).join('. ')}"
  }

  header = [
    "This sixword text encodes #{sixword_bytes} bytes in #{lines.length}",
    ' six-word sentences.',
    ' Decode with `sixword -d`',
    (is_encrypted ? ', then `gpg -d`.' : '.')
  ].join

  pdf.font('Times-Roman') do
    pdf.text(header)
    add_newline
  end

  pdf.column_box([0, pdf.cursor], columns: columns, width: pdf.bounds.width) do
    pdf.font('Times-Roman') do
      pdf.font_size(font_size) do
        pdf.text(numbered.join("\n"))
      end
    end
  end
end

#log ⇒ Object 



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# File 'lib/paperback/document.rb', line 15

def log
  @log ||= Paperback.class_log(self.class)
end

#render(output_file:, draw_opts:) ⇒ Object 



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# File 'lib/paperback/document.rb', line 19

def render(output_file:, draw_opts:)
  log.info('Rendering PDF')

  # Create all the PDF content
  draw_paperback(**draw_opts)

  # Render to output file
  log.info("Writing PDF to #{output_file.inspect}")
  pdf.render_file(output_file)
end