http://javascript.ruanyifeng.com/htmlapi/canvas.html

贝塞尔曲线

http://www.cnblogs.com/doudougou/archive/2012/04/26/2472048.html

http://www.cnblogs.com/lhb25/archive/2011/04/12/1964343.html

http://www.cnblogs.com/tim-li/archive/2012/08/06/2580252.html

http://www.cnblogs.com/lixlib/archive/2012/12/17/2821338.html

http://www.cnbeta.com/articles/176994.htm

http://www.html5tricks.com/8-html5-canvas-animation.html

http://javascript.ruanyifeng.com/htmlapi/canvas.html

ctx.save

ctx.translate

ctx.rotate

ctx.drawImage

ctx.restore

canvas的使用