FormProcessRoi *form = new FormProcessRoi(this);
//只能用指针,不能实例化为对象
//Qt::NonModal 不阻塞
//Qt::WindowModal 阻塞父窗口,所有祖先窗口及其子窗口
//Qt::ApplicationModal 阻塞整个应用程序
form->setWindowModality(Qt::ApplicationModal); //设置阻塞类型
form->setAttribute(Qt::WA_ShowModal, true); //属性设置 true:模态 false:非模态
form->setWindowFlags(Qt::WindowMinMaxButtonsHint | Qt::WindowCloseButtonHint | Qt::Dialog);
form->show();