使用到的类QScreen;
window DPI可调范围为125%--250%和硬件有关系;
/96的目的是将int转成 1.0/1.25/1.5
double nn = QApplication::primaryScreen()->logicalDotsPerInch() / 96;QList<QScreen*> listScreen = QGuiApplication::screens();if (listScreen[0]) {connect(listScreen[0], &QScreen::availableGeometryChanged, this, &screen::slot_availableGeometryChanged);connect(listScreen[0], &QScreen::physicalDotsPerInchChanged, this, &screen::slot_physicalDotsPerInchChanged);connect(listScreen[0], &QScreen::logicalDotsPerInchChanged, this, &screen::slot_logicalDotsPerInchChanged);connect(listScreen[0], &QScreen::virtualGeometryChanged, this, &screen::slot_virtualGeometryChanged);connect(listScreen[0], &QScreen::physicalSizeChanged, this, &screen::slot_physicalSizeChanged);}