功能强大稳定的地图缩放功能类，可以用于放大缩小指定地理坐标范围的地图-Powerful and stable map zoom feature class can be used to zoom the map specifies the scope of the geographical coordinates

programs in open gl

图像缩放的源码，相当强大，之得一看,建议下载-it is a masig piature