fix: Backlog/move pyside2 specific flag (#581)

apps/connect/release_notes.md

@@ -2,6 +2,7 @@
 
 ## Upcoming
 
+* [changed] Move deprecated HighDPI settings into PySide2 specific codepath.
 * [fix] Fix ctrl+c interrupt behaviour when launching connect through the commandline. It will now properly exit the application.
 * [fix] Remove obsolete pkg_resources import which lead to errors when launching through the commandline
 

apps/connect/source/ftrack_connect/__main__.py

@@ -113,21 +113,20 @@ def main_connect(arguments=None):
             )
             raise SystemExit(1)
 
-    # If under X11, make Xlib calls thread-safe.
-    # http://stackoverflow.com/questions/31952711/threading-pyqt-crashes-with-unknown-request-in-queue-while-dequeuing
-
-    if os.name == 'posix' and is_pyside2:
+    if is_pyside2:
+        # These HighDPI settings are deprecated and enabled by default in PySide6.
         QtCore.QCoreApplication.setAttribute(
-            QtCore.Qt.ApplicationAttribute.AA_X11InitThreads
+            QtCore.Qt.AA_EnableHighDpiScaling, True
         )
-
-    # Ensure support for highdpi
-    QtCore.QCoreApplication.setAttribute(
-        QtCore.Qt.AA_EnableHighDpiScaling, True
-    )
-    QtCore.QCoreApplication.setAttribute(
-        QtCore.Qt.ApplicationAttribute.AA_UseHighDpiPixmaps, True
-    )
+        QtCore.QCoreApplication.setAttribute(
+            QtCore.Qt.ApplicationAttribute.AA_UseHighDpiPixmaps, True
+        )
+        # If under X11, make Xlib calls thread-safe.
+        # http://stackoverflow.com/questions/31952711/threading-pyqt-crashes-with-unknown-request-in-queue-while-dequeuing
+        if os.name == 'posix':
+            QtCore.QCoreApplication.setAttribute(
+                QtCore.Qt.ApplicationAttribute.AA_X11InitThreads
+            )
 
     # Construct global application.