#!/usr/bin/env ruby -w require 'Qt' class MyWidget < Qt::MainWindow def initialize() super @canvas = Qt::Canvas.new(640, 480) rect = Qt::CanvasRectangle.new(10, 10, 50, 50, @canvas) rect.setBrush(Qt::Brush.new(Qt::green)) rect.setPen(Qt::Pen.new(Qt::red)) rect.show @canvas_view = Qt::CanvasView.new(@canvas, self) self.setCentralWidget(@canvas_view) @canvas.update end end a = Qt::Application.new(ARGV) w = MyWidget.new w.show a.setMainWidget(w) a.exec() exit