Qt快捷屏幕截图

QPixmap QScreen::grabWindow(WId window, 
                            int x = 0, 
                            int y = 0, 
                            int width = -1, 
                            int height = -1)

QScreen *screen = QGuiApplication::primaryScreen();
screen->grabWindow(0).save("screen_shot.jpg", "jpg"); // 0值为整个电脑屏幕WId

QPixmap QWidget::grab(const QRect &rectangle = QRect(QPoint(0, 0), 
                      QSize(-1, -1)))

QWidget widget;
widget.grab().save("screen_shot.jpg", "jpg");