class HexaPDF::Content::LineDashPattern

The line dash pattern defines how a line should be dashed. For use with Content::GraphicsState#line_dash_pattern.

A dash pattern consists of two parts: the dash array and the dash phase. The dash array defines the length of alternating dashes and gaps (important: starting with dashes). And the dash phase defines the distance into the dash array at which to start.

It is easier to show. Following are dash arrays and dash phases and how they would be interpreted:

[] 0                      No dash, one solid line
[3] 0                     3 unit dash, 3 unit gap, 3 unit dash, 3 unit gap, ...
[3] 1                     2 unit dash, 3 unit gap, 3 unit dash, 3 unit gap, ...
[2 1] 0                   2 unit dash, 1 unit gap, 2 unit dash, 1 unit gap, ...
[3 5] 6                   2 unit gap, 3 unit dash, 5 unit gap, 3 unit dash, ...
[2 3] 6                   1 unit dash, 3 unit gap, 2 unit dash, 3 unit gap, ...

See: PDF1.7 s8.4.3.6

Attributes

array[R]

The dash array.

phase[R]

The dash phase.

Public Class Methods

new(array = [], phase = 0) click to toggle source

Inititalizes the line dash pattern with the given array and phase.

The argument phase must be non-negative and the numbers in the array must be non-negative and must not all be zero.

# File lib/hexapdf/content/graphics_state.rb, line 186
def initialize(array = [], phase = 0)
  if phase < 0 || (!array.empty? &&
    array.inject(0) {|m, n| m < 0 ? m : (n < 0 ? -1 : m + n) } <= 0)
    raise ArgumentError, "Invalid line dash pattern: #{array.inspect} #{phase.inspect}"
  end
  @array = array.freeze
  @phase = phase
end
normalize(array, phase = 0) click to toggle source

Returns the arguments normalized to a valid LineDashPattern instance.

If array is 0, the default line dash pattern representing a solid line will be used. If it is a single number, it will be converted into an array holding that number.

# File lib/hexapdf/content/graphics_state.rb, line 165
def self.normalize(array, phase = 0)
  case array
  when LineDashPattern then array
  when Array then new(array, phase)
  when 0 then new
  when Numeric then new([array], phase)
  else
    raise ArgumentError, "Unknown line dash pattern: #{array} / #{phase}"
  end
end

Public Instance Methods

==(other) click to toggle source

Returns true if the other line dash pattern is the same as this one.

# File lib/hexapdf/content/graphics_state.rb, line 196
def ==(other)
  other.kind_of?(self.class) && other.array == array && other.phase == phase
end
to_operands() click to toggle source

Converts the LineDashPattern object to an array of operands for the associated PDF content operator.

# File lib/hexapdf/content/graphics_state.rb, line 202
def to_operands
  [@array, @phase]
end