仿QQ截图，实时显示选取区域起始位置和选取区域的大小，可动态调整选取区域的大小及移动选取区域的位置，保存截图、复制、取消操作和设为桌面背景-Imitation QQ screenshots, real-time display selection area starting position and the size of the selected area, dynamically adjust the size of the selected area and move the locati