Canvas

参考

• http://gwtcanvasdemo.appspot.com/

• http://www.dev-articles.com/article/Gwt-canvas-a-small-example-400001

• http://www.giantflyingsaucer.com/blog/?p=2338

• http://lexaux.blogspot.com/2009/08/gwt-canvas-widget-drawing-in-browser.html