Allow to scale GUI on high DPI screens

src/blackgui/guiapplication.cpp

@@ -85,6 +85,7 @@ namespace BlackGui
     {
         this->addWindowModeOption();
         this->addWindowResetSizeOption();
+        this->addWindowScaleSizeOption();
 
         // notify when app goes down
         connect(qGuiApp, &QGuiApplication::lastWindowClosed, this, &CGuiApplication::gracefulShutdown);
@@ -117,9 +118,7 @@ namespace BlackGui
 
     void CGuiApplication::addWindowModeOption()
     {
-        m_cmdWindowMode = QCommandLineOption(QStringList() << "w" << "window",
+        m_cmdWindowMode = QCommandLineOption({"w", "window"}, QCoreApplication::translate("main", "Windows: (n)ormal, (f)rameless, (t)ool."), "windowtype");
-                                             QCoreApplication::translate("main", "Windows: (n)ormal, (f)rameless, (t)ool."),
-                                             "windowtype");
         this->addParserOption(m_cmdWindowMode);
     }
 
@@ -129,6 +128,14 @@ namespace BlackGui
         this->addParserOption(m_cmdWindowSizeReset);
     }
 
+    void CGuiApplication::addWindowScaleSizeOption()
+    {
+        // just added here to display it in help
+        // parseScaleFactor() is used since it is needed upfront (before application is created)
+        m_cmdWindowScaleSize = QCommandLineOption("scale", QCoreApplication::translate("main", "Scale: number."), "scalevalue");
+        this->addParserOption(m_cmdWindowScaleSize);
+    }
+
     void CGuiApplication::addWindowStateOption()
     {
         m_cmdWindowStateMinimized =  QCommandLineOption({{"m", "minimized"}, QCoreApplication::translate("main", "Start minimized in system tray.")});
@@ -259,7 +266,7 @@ namespace BlackGui
         else
         {
             QApplication::setAttribute(Qt::AA_EnableHighDpiScaling); // DPI support
-            QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps); //HiDPI pixmaps
+            QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps); // HiDPI pixmaps
             const QString sf = QString::number(scaleFactor, 'f', 2);
             qputenv("QT_SCALE_FACTOR", sf.toLatin1());
         }
@@ -371,6 +378,22 @@ namespace BlackGui
         return html;
     }
 
+    qreal CGuiApplication::parseScaleFactor(int argc, char *argv[])
+    {
+        for (int i = 1; i < argc; ++i)
+        {
+            if (qstrcmp(argv[i], "--scale") == 0 || qstrcmp(argv[i], "-scale") == 0)
+            {
+                if (i + 1 >= argc) { return -1.0; } // no value
+                const QString factor(argv[i + 1]);
+                bool ok;
+                qreal f = factor.toFloat(&ok);
+                return ok ? f : -1.0;
+            }
+        }
+        return -1.0;
+    }
+
     bool CGuiApplication::cmdLineErrorMessage(const QString &errorMessage, bool retry) const
     {
         const QString helpText(beautifyHelpMessage(m_parser.helpText()));

src/blackgui/guiapplication.h

@@ -93,9 +93,12 @@ namespace BlackGui
         //! CMD line arguments
         void addWindowModeOption();
 
-        //! CMD line arguments
+        //! CMD line arguments (reset size store)
         void addWindowResetSizeOption();
 
+        //! CMD line arguments (scale size on DPI screens)
+        void addWindowScaleSizeOption();
+
         //! Window state
         Qt::WindowState getWindowState() const;
 
@@ -234,6 +237,9 @@ namespace BlackGui
         //! Uses the high DPI support?
         static bool isUsingHighDpiScreenSupport();
 
+        //! Parse scale factor if any
+        static qreal parseScaleFactor(int argc, char *argv[]);
+
     signals:
         //! Style sheet changed
         void styleSheetsChanged();
@@ -276,8 +282,9 @@ namespace BlackGui
         int m_minWidthChars  = -1; //!< min. width characters (based on current font metrics)
         int m_minHeightChars = -1; //!< min. height characters (based on current font metrics)
         QCommandLineOption m_cmdWindowStateMinimized { "empty" }; //!< window state (minimized)
-        QCommandLineOption m_cmdWindowMode { "empty" };           //!< window mode (flags: frameless ...)
+        QCommandLineOption m_cmdWindowMode      { "empty" };      //!< window mode (flags: frameless ...)
-        QCommandLineOption m_cmdWindowSizeReset { "empty" };      //!< window size resizing
+        QCommandLineOption m_cmdWindowSizeReset { "empty" };      //!< window size reset
+        QCommandLineOption m_cmdWindowScaleSize { "empty" };      //!< window scale size
         CStyleSheetUtility m_styleSheetUtility {{}, this};        //!< style sheet utility
         bool m_uiSetupCompleted = false;                          //!< ui setup completed
         bool m_saveMainWidgetState = true;                        //!< save/restore main widget's state

src/swiftcore/main.cpp

@@ -26,7 +26,7 @@ using namespace BlackGui;
 int main(int argc, char *argv[])
 {
     //! [SwiftApplicationDemo]
-    CGuiApplication::highDpiScreenSupport();
+    CGuiApplication::highDpiScreenSupport(CGuiApplication::parseScaleFactor(argc, argv));
     QApplication qa(argc, argv);
     Q_UNUSED(qa); // init of qa is required, but qa not used
     CGuiApplication a(CApplicationInfo::swiftCore(), CApplicationInfo::PilotClientCore, CIcons::swiftCore24());

src/swiftdata/main.cpp

@@ -24,7 +24,7 @@ using namespace BlackGui;
 
 int main(int argc, char *argv[])
 {
-    CGuiApplication::highDpiScreenSupport();
+    CGuiApplication::highDpiScreenSupport(CGuiApplication::parseScaleFactor(argc, argv));
     QApplication qa(argc, argv);
     Q_UNUSED(qa);
     CGuiApplication a(CApplicationInfo::swiftMappingTool(), CApplicationInfo::MappingTool, CIcons::swiftDatabase48());

src/swiftguistandard/main.cpp

@@ -23,7 +23,7 @@ using namespace BlackCore;
 int main(int argc, char *argv[])
 {
     //! [SwiftApplicationDemo]
-    CGuiApplication::highDpiScreenSupport();
+    CGuiApplication::highDpiScreenSupport(CGuiApplication::parseScaleFactor(argc, argv));
     QApplication qa(argc, argv);
     Q_UNUSED(qa); // application init needed
     CSwiftGuiStdApplication a; // application with contexts

src/swiftlauncher/main.cpp

@@ -30,12 +30,12 @@ using namespace BlackCore::Db;
 int main(int argc, char *argv[])
 {
     //! [SwiftApplicationDemo]
-    CGuiApplication::highDpiScreenSupport();
+    CGuiApplication::highDpiScreenSupport(CGuiApplication::parseScaleFactor(argc, argv));
     QApplication qa(argc, argv); // needed
     Q_UNUSED(qa);
     CGuiApplication a(CApplicationInfo::swiftLauncher(), CApplicationInfo::Laucher, CIcons::swiftLauncher1024());
     a.addVatlibOptions(); // so it can be passed (hand over) to started applications
-    a.addParserOption({{"i", "installer"}, QCoreApplication::translate("main", "Installer setup.") });
+    a.addParserOption({{"i", "installer"}, QCoreApplication::translate("main", "Installer setup.")});
     if (!a.parseAndSynchronizeSetup()) { return EXIT_FAILURE; }
     a.useWebDataServices(BlackCore::CWebReaderFlags::AllSwiftDbReaders, CDatabaseReaderConfigList::forLauncher());
     if (!a.start())