用qt做的城市电子地图，可自动放大缩小，希望对初学QT编程的同门有帮助-Qt to do with electronic maps of cities, can be automatically enlarged or reduced, in the hope of learning programming QT help with the door

Industry of street lighting systems are growing rapidly and going to complex with rapid growth of industry and cities. -Industry of street lighting systems are growing rapidly and going to complex with rapid growth of industry