https://www.baidu.com/s?wd=QT%20QMatrix&rsv_spt=1&rsv_iqid=0xe1e070ee0001f739&issp=1&f=8&rsv_bp=0&rsv_idx=2&ie=utf-8&tn=baiduhome_pg&rsv_enter=1&rsv_sug3=5&rsv_sug1=4&rsv_sug7=100&rsv_n=2&rsv_sug2=0&inputT=4522&rsv_sug4=4523
http://blog.csdn.net/hgcprg/article/details/53537106