prawnpdf/prawn

# frozen_string_literal: true

require 'prawn/manual_builder'

Prawn::ManualBuilder::Chapter.new do
  title 'Stroke Dash Pattern'

  text do
    prose <<~TEXT
      This sets the dashed pattern for lines and curves. The (dash) length
      defines how long each dash will be.

      The <code>:space</code> option defines the length of the space between
      the dashes.

      The <code>:phase</code> option defines the start point of the sequence of
      dashes and spaces.

      Complex dash patterns can be specified by using an array with alternating
      dash/gap lengths for the first parameter (note that the
      <code>:space</code> option is ignored in this case).
    TEXT
  end

  example new_page: true do
    move_down 20
    dash([1, 2, 3, 2, 1, 5], phase: 6)
    stroke_horizontal_line 50, 500
    move_down 10
    dash([1, 2, 3, 4, 5, 6, 7, 8])
    stroke_horizontal_line 50, 500

    base_y = cursor - 10

    24.times do |i|
      length = (i / 4) + 1
      space = length # space between dashes same length as dash
      phase = 0 # start with dash

      case i % 4
      when 0 then base_y -= 10
      when 1 then phase = length # start with space between dashes
      when 2 then space = length * 0.5 # space between dashes half as long as dash
      when 3
        space = length * 0.5 # space between dashes half as long as dash
        phase = length # start with space between dashes
      end
      base_y -= 10

      dash(length, space: space, phase: phase)
      stroke_horizontal_line 50, 500, at: base_y - (2 * i)
    end
  end
end