这个例子演示了如何使用QPainter的转换和缩放特性来简化绘图. 值得学习的: 定时器事件ID检查: 在定时器事件中检查定时器id是比较好的实践. QPainter抗锯齿: We call QPainter::setRenderHint() with QPainter::Antialiasing to turn on antialiasing. This makes drawing of diagonal lines much smoother. 画笔的平移/缩放: p->translate(
在Web GIS迅猛发展的今天,使用浏览器来进行交互以其方便性.快捷性被广大用户所推崇,那么在传输格式方面,都已比較简单的JSON或者WKT来解决网络带宽带来的数据压力. 在ArcGIS10.2版本号,已经提供了Geometry与JSON的相互转换.并且在现实业务中.Geometry与WKT的相互转换也比較多见.比如在ArcSDE环境中,用户能够使用Esri或者原生提供的函数来进行转换. SQL> select sde.st_astext(shape) from city where objec
Once upon a time there was a greedy King who ordered his chief Architect to build a wall around the King's castle. The King was so greedy, that he would not listen to his Architect's proposals to build a beautiful brick wall with a perfect shape and