The Golden Fibonacci Ratio (#69)


#1

A PDF version “translate” from Christian N.'s Postscript Code.
( http://www.ruby-talk.org/cgi-bin/scat.rb/ruby/ruby-talk/182741 )

(puts “Usage #$0 filename”; exit(1)) unless ARGV[0]

require ‘pdf/writer’

pdf = PDF::Writer.new
pdf.translate_axis(100, 100)
s = 400
colors = [0.7, 0.5, 0.3].map { |e| Color::GrayScale.from_fraction(e) }
phi = (Math.sqrt(5) - 1 ) / 2

def box(i, pdf)
pdf.move_to(0,0).line_to(i,0).line_to(i,i).line_to(0,i).close_fill
pdf.move_to(0,0).line_to(i,0).line_to(i,i).line_to(0,i).close_stroke
end

style = pdf.stroke_style?

10.times do |i|
pdf.fill_color(colors[i % colors.size])
pdf.stroke_color(Color::RGB::Black)
box(s, pdf)
pdf.stroke_color(Color::RGB.from_fraction(0.8, 0.4, 0))
pdf.ellipse2_at(0, s, s, s, 0, -90).stroke
pdf.translate_axis(s, s)
pdf.rotate_axis(90)
pdf.scale_axis(phi, phi)
style.width /= phi
pdf.stroke_style!(style)
end

pdf.save_as(ARGV[0])

END