iOS截图实现

支持拖动大小 取消、保存、确定 // 四角拖拽点,可以不要 dragBtn1 = [self createDragButtonWithPosition:dragPos1]; dragBtn2 = [self createDragButtonWithPosition:dragPos2]; dragBtn3 = [self createDragButtonWithPosition:dragPos3]; dragBtn4 = [self createDragButtonWithPosition:dragPos4];