# encoding: utf-8
#
# Prawn's fill operators (<code>fill</code> and <code>fill_and_stroke</code>
# both accept a <code>:fill_rule</code> option. These rules determine which
# parts of the page are counted as "inside" vs. "outside" the path. There are
# two fill rules:
#
# * <code>:nonzero_winding_number</code> (default): a point is inside the path
# if a ray from that point to infinity crosses a nonzero "net number" of path
# segments, where path segments intersecting in one direction are counted as
# positive and those in the other direction negative.
#
# * <code>:even_odd</code>: A point is inside the path if a ray from that point
# to infinity crosses an odd number of path segments, regardless of direction.
#
# The differences between the fill rules only come into play with complex
# paths; they are identical for simple shapes.
#
require File.expand_path(File.join(File.dirname(__FILE__),
                                   %w[.. example_helper]))

filename = File.basename(__FILE__).gsub('.rb', '.pdf')
Prawn::Example.generate(filename) do
  pentagram = [[181, 95], [0, 36], [111, 190], [111, 0], [0, 154]]

  stroke_color 'ff0000'
  line_width 2

  text_box "Nonzero Winding Number", :at => [50, 215], :width => 170,
           :align => :center
  polygon(*pentagram.map { |x, y| [x+50, y] })
  fill_and_stroke

  text_box "Even-Odd", :at => [330, 215], :width => 170, :align => :center
  polygon(*pentagram.map { |x, y| [x+330, y] })
  fill_and_stroke(:fill_rule => :even_odd)
end
