Text can be positioned and scaled arbitrarily on the canvas, rendered using any font that is installed on your system.

#!/usr/local/bin/macruby

framework 'cocoa'
require 'rubygems'
require 'hotcocoa/graphics'
include HotCocoa
include Graphics

# set up the canvas and font
canvas = Canvas.new :type => :image, :filename => 'spiro.png', :size => [400,400]
canvas.background(Color.beige)
canvas.fill(Color.black)
canvas.font('Book Antiqua')
canvas.fontsize(12)
canvas.translate(200,200)

# rotate, draw text, repeat
for frame in 1..180
    canvas.push
    canvas.rotate((frame*2) + 120)
    canvas.translate(70,0)
    canvas.text("Going ...", 80, 0)
    canvas.rotate(frame * 6)
    canvas.text("Around and", 20, 0)
    canvas.pop
end

# save the canvas
canvas.save