circle.rb

require 'joyau/init'
require 'joyau/color'
require 'joyau/buffer_library'

require 'enumerator'

def draw_circle(x, y, radius, line_number,
                color, border_color, line_color, line_color2 = line_color)
  perimeter = (2 * Math::PI * radius).to_i

  raise ArgumentError, "line_number should be an Integer" unless
    line_number.is_a? Integer
  raise ArgumentError, "You cannot draw #{line_number} lines in this circle" if
    line_number > perimeter or line_number < 0

  painter = Joyau::Painter.new(Joyau::Buffer.actual)
  painter.drawFillCircle(x, y, radius, color)
  painter.drawCircle(x, y, radius, border_color)

  return if line_number.zero?
  
  step = 2 * Math::PI / line_number
  (0..(2 * Math::PI - step)).step(step) do |angle|
    abs = Math.cos(angle) * radius
    ord = Math.sin(angle) * radius
    
    painter.drawLine(x, y, (x + abs).to_i, (y + ord).to_i,
                     line_color, line_color2)
  end

  return
end

module CircleLibrary
  include Joyau::BufferLibrary

  @@buffers = {}

  COLOR = /rgb\((\d+), (\d+), (\d+)\)/
  @@regex = /^circle:(\d+):(\d+):#{COLOR}:#{COLOR}:#{COLOR}:#{COLOR}$/

  class << self
    def [](res_name)
      @@buffers[res_name] || create_buffer(res_name)
    end

    def create_buffer(res_name)
      datas = res_name.match(@@regex)

      unless datas
        raise(Joyau::InvalidRessourceName,
              "#{res_name} should match #{@@regex.inspect}")
      end

      radius, line_number = datas.captures
      rest = datas.captures[2..-1]
      
      radius = radius.to_i
      line_number = line_number.to_i
      buffer = Joyau::Buffer.new((radius + 1) * 2, (radius + 1) * 2)

      colors = []
      rest.each_slice(3) do |tab|
        colors << Joyau::Color.new(tab[0].to_i, tab[1].to_i, tab[2].to_i)
      end

      Joyau.draw(:buffer => buffer) do
        draw_circle(radius, radius, radius, line_number, *colors)
      end

      @@buffers[res_name] = buffer
      return buffer
    end
  end

  register_loader @@regex
end

Joyau.init(:gfx)

res_name =  "circle:50:15:rgb(255, 0, 0):rgb(0, 255, 0):rgb(0, 0, 255)"
res_name << ":rgb(255, 255, 255)"

sprite = Joyau::Sprite.from_res_name(res_name)
sprite.setPos(50, 50)

Joyau.draw do
  sprite.draw
end while Joyau.mayPlay

Joyau.stop