慣れればProcessing並に楽ちんに使えるかも。

require 'osx/cocoa'
include OSX

class HelloView < OSX::NSView
　def drawRect(rect)
　　string = NSString.stringWithUTF8String("こんにちは")
　　string.drawAtPoint_withAttributes([30,50], nil)
　end
end

if __FILE__ == $0
　application = NSApplication.sharedApplication

　window = NSWindow.alloc.
　　objc_send(:initWithContentRect, [200, 200, 150, 100],
　　　　　　　:styleMask, 15, :backing, 2, :defer, 0)

　view = HelloView.alloc.initWithFrame([0, 0, 150, 100])
　window.setContentView(view)

　window.makeKeyAndOrderFront(nil)
　window.orderFrontRegardless()

　trap('SIGINT') { $stderr.puts "bye." ; exit 0 }

　application.run
end