Class: HexaPDF::Extras::GraphicObject::Zint

Inherits:
Object
  • Object
show all
Defined in:
lib/hexapdf/extras/graphic_object/zint.rb

Overview

Generates a barcode using the ruby-zint library that uses the libzint barcode generation library.

It implements the HexaPDF graphic object interface and can therefore easily be used via the :barcode name:

canvas.draw(:barcode, width: 50, at: [10, 40], value: 'Hello!', symbology: :code128)

Except for a few keyword arguments all are passed through to ruby-zint, so everything that is supported by Zint::Barcode can be used. To make specifying symbologies easier, it is possible to use symbolic names instead of the constants, see #configure.

Examples

  • Linear barcode

    #>pdf-canvas100
canvas.draw(:barcode, width: 60, at: [20, 45], value: '1123456', symbology: :upce)
canvas.draw(:barcode, width: 60, at: [20, 5], value: 'Hello!', symbology: :code128)

  • Stacked barcode

    #>pdf-canvas100
canvas.draw(:barcode, width: 80, at: [10, 40], symbology: :codablockf,
            value: 'Hello HexaPDF!', option_1: 3)

  • Composite barcode

    #>pdf-canvas100
canvas.draw(:barcode, width: 80, at: [10, 20], symbology: :gs1_128_cc,
            value: '[99]1234-abcd', primary: "[01]03312345678903", option_1: 3)

  • 2D barcode

    #>pdf-canvas100
canvas.draw(:barcode, width: 80, at: [10, 10], symbology: :datamatrix,
            value: 'Hello HexaPDF!', option_3: 100, output_options: 0x0100)

Constant Summary collapse

COLOR_CODES =

Maps the Zint color codes to HexaPDF color names.

{
  1 => "cyan",
  2 => "blue",
  3 => "magenta",
  4 => "red",
  5 => "yellow",
  6 => "green",
  7 => "black",
  8 => "white",
}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Zint

Creates a Zint graphic object.



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# File 'lib/hexapdf/extras/graphic_object/zint.rb', line 124

def initialize
  @at = [0, 0]
  @width = nil
  @height = nil
  @font = 'Helvetica'
  @zint_kws = {}
end

Instance Attribute Details

#at ⇒ Object

The position of the bottom-left corner of the barcode.

Default: [0, 0].

Examples:

#>pdf-canvas100
canvas.draw(:barcode, height: 50, value: 'test', symbology: :code128)
canvas.draw(:barcode, height: 50, value: 'test', symbology: :code128, at: [20, 50])



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# File 'lib/hexapdf/extras/graphic_object/zint.rb', line 65

def at
  @at
end

#font ⇒ Object

The font used when outputting strings.

Any font that is supported by the HexaPDF::Document::Layout module is supported.

Default: ‘Helvetica’.

Examples:

#>pdf-canvas100
canvas.draw(:barcode, height: 50, font: 'Courier', value: 'test', symbology: :code128)



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# File 'lib/hexapdf/extras/graphic_object/zint.rb', line 116

def font
  @font
end

#height ⇒ Object

The height of the barcode.

For details and examples see #width.

Default: nil.



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# File 'lib/hexapdf/extras/graphic_object/zint.rb', line 104

def height
  @height
end

#width ⇒ Object

The width of resulting barcode.

The resulting size of the barcode depends on whether width and #height are set:

  • If neither width nor height are set, the barcode uses the size returned by ruby-zint.

  • If both are set, the barcode is fit exactly into the given rectangle.

  • If either width or height is set, the other dimension is based on the set dimension so that the original aspect ratio is maintained.

Default: nil.

Examples:

  • No dimension set

    #>pdf-canvas100
canvas.draw(:barcode, value: 'test', symbology: :code128)

  • One dimension set

    #>pdf-canvas100
canvas.draw(:barcode, width: 60, value: 'test', symbology: :code128)
canvas.draw(:barcode, height: 50, value: 'test', symbology: :code128, at: [0, 50])

  • Both dimensions set

    #>pdf-canvas100
canvas.draw(:barcode, width: 60, height: 60, value: 'test', symbology: :code128)



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# File 'lib/hexapdf/extras/graphic_object/zint.rb', line 97

def width
  @width
end

#zint_kws ⇒ Object

The keyword arguments that are passed on to Zint::Barcode.new.

Default: {}.



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# File 'lib/hexapdf/extras/graphic_object/zint.rb', line 121

def zint_kws
  @zint_kws
end

Class Method Details

.configure(**kwargs) ⇒ Object

Creates and configures a new Zint drawing support object.

See #configure for the allowed keyword arguments.



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# File 'lib/hexapdf/extras/graphic_object/zint.rb', line 52

def self.configure(**kwargs)
  new.configure(**kwargs)
end

Instance Method Details

#configure(at: nil, width: nil, height: nil, font: nil, symbology: nil, **zint_kws) ⇒ Object

Configures the Zint graphic object and returns self.

The following arguments are allowed:

:at

The position of the bottom-left corner (see #at).

:width

The width of the barcode (see #width).

:height

The height of the barcode (see #height).

:font

The font to use when outputting strings (see #font).

:symbology

The type of barcode. Supports using symbols instead of constants, e.g. :code128 instead of Zint::BARCODE_CODE128.

:zint_kws

Keyword arguments that are passed on to ruby-zint.

Any arguments not specified are not modified and retain their old value, see the attribute methods for the inital default values.



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# File 'lib/hexapdf/extras/graphic_object/zint.rb', line 157

def configure(at: nil, width: nil, height: nil, font: nil, symbology: nil, **zint_kws)
  @at = at if at
  @width = width if width
  @height = height if height
  @font = font if font
  @zint_kws = zint_kws unless zint_kws.empty?
  @zint_kws[:symbology] = if symbology && symbology.kind_of?(Symbol)
                            ::Zint.const_get("BARCODE_#{symbology.upcase}")
                          elsif symbology
                            symbology
                          end
  self
end

#draw(canvas) ⇒ Object

Draws the Zint::Barcode object onto the given canvas, with the bottom-left corner at the position specified by #at and the size specified by #width and #height.



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# File 'lib/hexapdf/extras/graphic_object/zint.rb', line 185

def draw(canvas)
  form = form_xobject(canvas.context.document)
  canvas.xobject(form, at: @at, width: @width, height: @height)
end

#form_xobject(document) ⇒ Object

Creates a Form XObject for the given HexaPDF::Document that contains the visual representation of the barcode.



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# File 'lib/hexapdf/extras/graphic_object/zint.rb', line 192

def form_xobject(document)
  barcode = ::Zint::Barcode.new(**@zint_kws)
  vector = barcode.to_vector

  height = vector.height
  form = document.add({Type: :XObject, Subtype: :Form, BBox: [0, 0, vector.width, height]})
  canvas = form.canvas

  canvas.fill_color(barcode.bgcolour).rectangle(0, 0, vector.width, height).fill
  vector.each_rectangle.group_by {|rect| rect.colour }.each do |color, rects|
    canvas.fill_color(COLOR_CODES.fetch(color, barcode.fgcolour))
    rects.each {|rect| canvas.rectangle(rect.x, height - rect.y, rect.width, -rect.height) }
    canvas.fill
  end
  vector.each_circle.group_by {|circle| circle.colour }.each do |color, circles|
    canvas.fill_color(COLOR_CODES.fetch(color, barcode.fgcolour))
    circles.each {|circle| canvas.circle(circle.x, height - circle.y, circle.diameter / 2.0) }
    canvas.fill
  end
  layout = canvas.context.document.layout
  vector.each_string do |string|
    fragment = layout.text_fragments(string.text, font: @font, font_size: string.fsize)[0]
    x = string.x + case string.halign
                   when 0 then -fragment.width / 2.0
                   when 1 then 0
                   when 2 then -fragment.width
                   end
    fragment.draw(canvas, x, height - string.y)
  end

  form
end