From: John Maclean <info@...>
Date: 2006-01-16T00:08:15+09:00
Subject: "Programming Ruby", ed. 2, P747. Script generated different image to book's example

Chaps,

Please find below a script taken from "Programming Ruby", ed. 2, P747. Its intention is to "show off" the abilities of Tk and widgets. The  script works but generates a different image to that shown in the book. What results do you guys have? I would be interested to know.

#!/usr/bin/ruby 
require 'tk'
include Math

TkRoot.new do |root|
  title "Curves"
  geometry "400x400"
  TkCanvas.new(root) do |canvas|
    width 400
    height 400
    pack('side' => 'top' , 'fill' => 'both' , 'expand' => 'yes' )
      points = [ ]
      10.upto(30) do |scale|
        (0.0).step(2*PI,0.1) do |i|
          new_x = 5*scale*sin(i) + 200 + scale*sin(i*2)
          new_y = 5*scale*cos(i) + 200 + scale*cos(i*6)
          points << [ new_x, new_y ]
          f = scale/5.0
          r = (Math.sin(f)+1)*127.0
          g = (Math.cos(2*f)+1)*127.0
          b = (Math.sin(3*f)+1)*127.0

          col = sprintf("#%02x%02x%02x", r.to_i, g.to_i, b.to_i)
          if points.size ==3
            TkcLine.new(canvas,
                        points[0],[0], points[0],[1],
                        points[1],[0], points[1],[1],
                        points[2],[0], points[2],[1],
                        'smooth' => 'on',
                        'width' => 7,
                        'fill'      => col,
                        'capstyle'  => 'round')
             points.shift
           end
         end
       end
     end
   end
   Tk.mainloop

#errors generated
jayeola@tp20$ /usr/lib/ruby/1.8/tk.rb:2313: warning: redefine encoding=
/usr/lib/ruby/1.8/tk.rb:2316: warning: redefine encoding

-- 
John Maclean
MSc (DIC)
07739 171 531