fix(gamescope): DPI Re-architecture For GameScope Compatability

Signed-off-by: Collecting <collecting@noreply.localhost>

src/citron/main.cpp

@@ -6089,96 +6089,71 @@ void VolumeButton::ResetMultiplier() {
 #endif
 
 static void SetHighDPIAttributes() {
+    const bool is_gamescope = !qgetenv("GAMESCOPE_WIDTH").isEmpty() || qgetenv("XDG_CURRENT_DESKTOP") == "gamescope";
+
 #ifdef _WIN32
-    // For Windows, we want to avoid scaling artifacts on fractional scaling ratios.
+    // Windows logic: Set policy globally.
-    // This is done by setting the optimal scaling policy for the primary screen.
+    // removed the 'temp QApplication' here because in Qt 6 it locks the DPI logic
+    // before our environment overrides in main() can take effect.
+    QGuiApplication::setHighDpiScaleFactorRoundingPolicy(
+        Qt::HighDpiScaleFactorRoundingPolicy::Round);
 
-    // Create a temporary QApplication.
-    int temp_argc = 0;
-    char** temp_argv = nullptr;
-    QApplication temp{temp_argc, temp_argv};
-
-    // Get the current screen geometry.
-    const QScreen* primary_screen = QGuiApplication::primaryScreen();
-    if (primary_screen == nullptr) {
-        return;
-    }
-
-    const QRect screen_rect = primary_screen->geometry();
-    const int real_width = screen_rect.width();
-    const int real_height = screen_rect.height();
-    const float real_ratio = primary_screen->logicalDotsPerInch() / 96.0f;
-
-    // Recommended minimum width and height for proper window fit.
-    // Any screen with a lower resolution than this will still have a scale of 1.
-    constexpr float minimum_width = 1350.0f;
-    constexpr float minimum_height = 900.0f;
-
-    const float width_ratio = std::max(1.0f, real_width / minimum_width);
-    const float height_ratio = std::max(1.0f, real_height / minimum_height);
-
-    // Get the lower of the 2 ratios and truncate, this is the maximum integer scale.
-    const float max_ratio = std::trunc(std::min(width_ratio, height_ratio));
-
-    if (max_ratio > real_ratio) {
-        QApplication::setHighDpiScaleFactorRoundingPolicy(
-            Qt::HighDpiScaleFactorRoundingPolicy::Round);
-    } else {
-        QApplication::setHighDpiScaleFactorRoundingPolicy(
-            Qt::HighDpiScaleFactorRoundingPolicy::Floor);
-    }
-#else
-    // Other OSes should be better than Windows at fractional scaling.
-    QApplication::setHighDpiScaleFactorRoundingPolicy(
-        Qt::HighDpiScaleFactorRoundingPolicy::PassThrough);
-#endif
-
-    // Set the DPI awareness for better scaling on Windows
-#ifdef _WIN32
-    // Enable Per Monitor DPI Awareness for Windows 8.1+
     SetProcessDPIAware();
 
-    // For Windows 10+, use Per Monitor v2 DPI Awareness
-    // This provides better scaling for multi-monitor setups
     HMODULE shcore = LoadLibrary(L"shcore.dll");
     if (shcore) {
         typedef HRESULT(WINAPI* SetProcessDpiAwarenessFunc)(int);
         SetProcessDpiAwarenessFunc setProcessDpiAwareness =
             (SetProcessDpiAwarenessFunc)GetProcAddress(shcore, "SetProcessDpiAwareness");
         if (setProcessDpiAwareness) {
-            // PROCESS_PER_MONITOR_DPI_AWARE_V2 = 2
+            setProcessDpiAwareness(2); // PROCESS_PER_MONITOR_DPI_AWARE_V2
-            setProcessDpiAwareness(2);
         }
         FreeLibrary(shcore);
     }
+#else
+    if (is_gamescope) {
+        // Force 1:1 pixel mapping for Steam Deck to prevent bloated windows.
+        QGuiApplication::setHighDpiScaleFactorRoundingPolicy(
+            Qt::HighDpiScaleFactorRoundingPolicy::Floor);
+    } else {
+        // Standard Linux desktops handle fractional scaling better via PassThrough
+        QGuiApplication::setHighDpiScaleFactorRoundingPolicy(
+            Qt::HighDpiScaleFactorRoundingPolicy::PassThrough);
+    }
 #endif
 }
 
 int main(int argc, char* argv[]) {
     // 1. Detect Gamescope/Steam Deck hardware
-    const bool is_gamescope = qgetenv("XDG_CURRENT_DESKTOP") == "gamescope" ||
+    const bool is_gamescope = !qgetenv("GAMESCOPE_WIDTH").isEmpty() ||
-                             !qgetenv("GAMESCOPE_WIDTH").isEmpty() ||
+                             qgetenv("XDG_CURRENT_DESKTOP") == "gamescope" ||
                              !qgetenv("STEAM_DECK").isEmpty();
 
     if (is_gamescope) {
         // Kill the SteamOS scaling requests before they can bloat the UI
         QGuiApplication::setDesktopSettingsAware(false);
-        QGuiApplication::setHighDpiScaleFactorRoundingPolicy(Qt::HighDpiScaleFactorRoundingPolicy::Floor);
 
         // Force 1:1 pixel ratio
         qputenv("QT_ENABLE_HIGHDPI_SCALING", "0");
         qputenv("QT_SCALE_FACTOR", "1");
         qputenv("QT_SCREEN_SCALE_FACTORS", "1");
         qputenv("QT_AUTO_SCREEN_SCALE_FACTOR", "0");
+
+        // Steam Deck has a high physical DPI. Hard-coding 96 DPI prevents text
+        // from being oversized in dialogs like "About" or "Updater".
         qputenv("QT_FONT_DPI", "96");
 
+        // FORCE X11 backend: Qt 6 scaling overrides are reliably respected under XCB in Gamescope.
+        // Wayland mode in Gamescope often ignores scaling overrides for child windows.
+        qputenv("QT_QPA_PLATFORM", "xcb");
+
         // Ensure Gamescope compositor handles Citron menus correctly
         QCoreApplication::setAttribute(Qt::AA_DontUseNativeMenuBar);
         QCoreApplication::setAttribute(Qt::AA_DontUseNativeDialogs);
         qputenv("QT_WAYLAND_SHELL_INTEGRATION", "xdg-shell");
     }
 
-    // 2. NOW setup AppImage environment
+    // 2. Setup AppImage environment
     const bool is_appimage = !qgetenv("APPIMAGE").isEmpty();
     if (is_appimage) {
         qputenv("QT_WAYLAND_DISABLE_EXPLICIT_SYNC", "1");
@@ -6231,6 +6206,7 @@ int main(int argc, char* argv[]) {
     QGuiApplication::setDesktopFileName(QStringLiteral("org.citron_emu.citron"));
 #endif
 
+    // Call policy attributes BEFORE creating the real QApplication instance
     SetHighDPIAttributes();
 
 #if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
@@ -6252,21 +6228,16 @@ int main(int argc, char* argv[]) {
 
 #ifdef _WIN32
     // On Windows, updates are applied by the helper script after the app exits.
-    // If we find a staging directory here, it means the helper script failed.
-    // Clean it up to avoid confusion.
     std::filesystem::path staging_path = app_dir / "update_staging";
     if (std::filesystem::exists(staging_path)) {
         try {
             std::filesystem::remove_all(staging_path);
-        } catch (...) {
+        } catch (...) {}
-            // Ignore cleanup errors
-        }
     }
 #else
-    // On Linux, apply staged updates at startup as before
+    // On Linux, apply staged updates at startup
     if (Updater::UpdaterService::HasStagedUpdate(app_dir)) {
         if (Updater::UpdaterService::ApplyStagedUpdate(app_dir)) {
-            // Show a simple message that update was applied
             QMessageBox::information(nullptr, QObject::tr("Update Applied"),
                                      QObject::tr("Citron has been updated successfully!"));
         }
@@ -6279,10 +6250,7 @@ int main(int argc, char* argv[]) {
 #endif
 
 
-    // Workaround for QTBUG-85409, for Suzhou numerals the number 1 is actually \u3021
+    // Workaround for QTBUG-85409
-    // so we can see if we get \u3008 instead
-    // TL;DR all other number formats are consecutive in unicode code points
-    // This bug is fixed in Qt6, specifically 6.0.0-alpha1
 #if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
     const QLocale locale = QLocale::system();
     if (QStringLiteral("\u3008") == locale.toString(1)) {
@@ -6314,8 +6282,7 @@ int main(int argc, char* argv[]) {
     QObject::connect(&app, &QGuiApplication::applicationStateChanged, &main_window,
                      &GMainWindow::OnAppFocusStateChanged);
 
-    int result = app.exec();
+    return app.exec();
-    return result;
 }
 
 void GMainWindow::OnCheckForUpdates() {