<p><strong>GIS (Geographical Information System) is a computer support system that represents data using maps. It helps people access, display and analyse data that has geographic content and meaning. For those not familiar with GIS, it u

显示3D灰色图像，主要通过BitBlt绘制两次来实现，用GetSysColor函数获取系统定义的颜色值-Display 3D gray image, mainly through BitBlt drawn twice to achieve with GetSysColor function to get the system-defined color values