Module: Prawn::Graphics::Dash

Included in:
Prawn::Graphics
Defined in:
lib/prawn/graphics/dash.rb

Stable API collapse

Instance Method Details

#dash(length = nil, options = {}) ⇒ Object Also known as: dash=

Sets the dash pattern for stroked lines and curves or return the current dash pattern setting if length is nil.

There are two ways to set the dash pattern:

  • If the parameter length is an Integer/Float, it specifies the length of the dash and of the gap. The length of the gap can be customized by setting the :space option.

    Examples:

    length = 3
  3 on, 3 off, 3 on, 3 off, ...
length = 3, :space =2
  3 on, 2 off, 3 on, 2 off, ...

  • If the parameter length is an array, it specifies the lengths of alternating dashes and gaps. The numbers must be non-negative and not all zero. The :space option is ignored in this case.

    Examples:

    length = [2, 1]
  2 on, 1 off, 2 on, 1 off, ...
length = [3, 1, 2, 3]
  3 on, 1 off, 2 on, 3 off, 3 on, 1 off, ...
length = [3, 0, 1]
  3 on, 0 off, 1 on, 3 off, 0 on, 1 off, ...

Options may contain the keys :space and :phase

:space

The space between the dashes (only used when length is not an array)

:phase

The distance into the dash pattern at which to start the dash. For example, a phase of 0 starts at the beginning of the dash; whereas, if the phase is equal to the length of the dash, then stroking will begin at the beginning of the space. Default is 0.

Integers or Floats may be used for length and the option values. Dash units are in PDF points (1/72 inch).



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# File 'lib/prawn/graphics/dash.rb', line 58

def dash(length = nil, options = {})
  return current_dash_state if length.nil?

  length = Array(length)

  if length.all?(&:zero?)
    raise ArgumentError,
      'Zero length dashes are invalid. Call #undash to disable dashes.'
  elsif length.any?(&:negative?)
    raise ArgumentError,
      'Negative numbers are not allowed for dash lengths.'
  end

  length = length.first if length.length == 1

  self.current_dash_state = {
    dash: length,
    space: length.is_a?(Array) ? nil : options[:space] || length,
    phase: options[:phase] || 0
  }

  write_stroke_dash
end

#dashed? ⇒ Boolean

Returns when stroke is dashed, false otherwise

Returns:

  • (Boolean) 


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# File 'lib/prawn/graphics/dash.rb', line 93

def dashed?
  current_dash_state != undashed_setting
end

#undash ⇒ Object

Stops dashing, restoring solid stroked lines and curves



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# File 'lib/prawn/graphics/dash.rb', line 86

def undash
  self.current_dash_state = undashed_setting
  write_stroke_dash
end