Class: Prawn::QRCode::Renderer

Inherits:
Object
  • Object
show all
Defined in:
lib/prawn/qrcode.rb

Overview

Renderer is responsible for actually rendering a QR code to pdf

Since:

  • 0.5.0

Constant Summary collapse

RENDER_OPTS =

Since:

  • 0.5.0

%I[dot pos stroke foreground_color background_color stroke_color margin align debug extent].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(qr_code, **options) ⇒ Renderer

creates a new renderer for the given QR code

Options :dot and :extent are mutually exclusive.

Parameters:

  • qr_code (RQRCode::QRCode) —

    QR code to render

  • options (Hash) —

    additional options

Options Hash (**options):

  • :dot (Float) —

    size of a dot in pt (1/72 in)

  • :pos (Array) —

    Two-element array containing the position at which the QR-Code should be rendered. Defaults to [0,cursor]

  • :stroke (bool) —

    whether to draw bounds around the QR Code. Defaults to true.

  • :foreground_color (string) —

    6-digit hex string specifying foreground color; default: ‘000000’

  • :background_color (string) —

    6-digit hex string specifying background color; default: ‘FFFFFF’

  • :stroke_color (string) —

    6-digit hex string specifying stroke color; default: ‘000000’

  • :margin (integer) —

    number of modules as margin around QRcode (default: 4)

  • :extent (float) —

    overall width/height of QR code in pt (1/72 in)

  • :debug (bool) —

    render a coordinate grid around the QRCode if true (uses Prawn#stroke_axis)

  • :align (symbol) —

    alignment within the current bounding box. Valid values are :left, :right, and :center. If set this option overrides the horizontal positioning specified in :pos. Defaults to nil.

Raises:

  • (QRCodeError) —

    if both extent and dot are specified.

Since:

  • 0.5.0



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# File 'lib/prawn/qrcode.rb', line 124

def initialize(qr_code, **options)
  raise QRCodeError, 'Specify either :dot or :extent, not both' if options.key?(:dot) && options.key?(:extent)

  @stroke = true
  @qr_code = qr_code
  options.select { |k, _v| RENDER_OPTS.include?(k) }.each { |k, v| send("#{k}=", v) }
end

Instance Attribute Details

#qr_code ⇒ Object

Since:

  • 0.5.0



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# File 'lib/prawn/qrcode.rb', line 100

def qr_code
  @qr_code
end

#stroke ⇒ Object (readonly)

Since:

  • 0.5.0



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# File 'lib/prawn/qrcode.rb', line 138

def stroke
  @stroke
end

Instance Method Details

#align(bounding_box) ⇒ Object

Since:

  • 0.5.0



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# File 'lib/prawn/qrcode.rb', line 165

def align(bounding_box)
  rlim = bounding_box.right
  case @align
  when :center
    @pos[0] = (rlim / 2) - (extent / 2)
  when :right
    @pos[0] = rlim - extent
  when :left
    @pos[0] = 0
  end
end

#background_color ⇒ Object

Since:

  • 0.5.0



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# File 'lib/prawn/qrcode.rb', line 144

def background_color
  @background_color ||= 'FFFFFF'
end

#dot ⇒ Object

Since:

  • 0.5.0



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# File 'lib/prawn/qrcode.rb', line 132

def dot
  @dot ||= Prawn::QRCode.dotsize(qr_code, @extent, margin) if defined?(@extent)
  @dot ||= DEFAULT_DOTSIZE unless defined?(@extent)
  @dot
end

#extent ⇒ Object

Since:

  • 0.5.0



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# File 'lib/prawn/qrcode.rb', line 156

def extent
  @extent ||= (2 * margin + qr_code.modules.length) * dot
  @extent
end

#foreground_color ⇒ Object

Since:

  • 0.5.0



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# File 'lib/prawn/qrcode.rb', line 140

def foreground_color
  @foreground_color ||= '000000'
end

#margin ⇒ Object

Since:

  • 0.5.0



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# File 'lib/prawn/qrcode.rb', line 152

def margin
  @margin ||= 4
end

#margin_size ⇒ Object

Since:

  • 0.5.0



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# File 'lib/prawn/qrcode.rb', line 161

def margin_size
  margin * dot
end

#render(pdf) ⇒ Object

rubocop:disable Metrics/AbcSize

Since:

  • 0.5.0



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# File 'lib/prawn/qrcode.rb', line 178

def render(pdf)
  pdf.fill_color background_color

  pos(pdf) # make sure the @pos attribute is set before calling align
  align(pdf.bounds)
  
  pdf.bounding_box(pos(pdf), width: extent, height: extent) do |_box|
    pdf.fill_color foreground_color
    margin_dist = margin * dot

    m = qr_code.modules

    pos_y = margin_dist + m.length * dot

    m.each_with_index do |row, index|
      pos_x = margin_dist
      dark_col = 0

      row.each_index do |col|
        pdf.move_to [pos_x, pos_y]
        if qr_code.qrcode.checked?(index, col)
          dark_col += 1
        else
          if dark_col > 0
            dark_col_extent = dark_col * dot
            pdf.fill { pdf.rectangle([pos_x - dark_col_extent, pos_y], dark_col_extent, dot) }
            dark_col = 0
          end
        end
        pos_x += dot
      end

      pdf.fill { pdf.rectangle([pos_x - dark_col * dot, pos_y], dot * dark_col, dot) } if dark_col > 0

      pos_y -= dot
    end

    if stroke
      pdf.fill_color stroke_color
      pdf.stroke_bounds
    end
    pdf.stroke_axis(at: [-1, -1], negative_axes_length: 0, color: '0C0C0C', step_length: 50) if debug
  end
end

#stroke_color ⇒ Object

Since:

  • 0.5.0



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# File 'lib/prawn/qrcode.rb', line 148

def stroke_color
  @stroke_color ||= '000000'
end