Fix Wayland work-around for COSMIC, and add to the PyPI entry point

cq_editor/__main__.py

@@ -1,11 +1,22 @@
+import os
 import sys
 import argparse
 
 from PyQt5.QtWidgets import QApplication
 
 NAME = "CQ-editor"
 
-# need to initialize QApp here, otherewise svg icons do not work on windows
+# Reorder QT_QPA_PLATFORM so Qt reaches a Wayland plugin only after everything
+# else has failed to load, defaulting to xcb. OCCT does not yet support Wayland.
+if sys.platform == "linux":
+    # Desktops such as COSMIC export QT_QPA_PLATFORM="wayland;xcb" session-wide,
+    # we want to respect this config as far as possible, without using wayland.
+    plugins = (os.environ.get("QT_QPA_PLATFORM") or "xcb").split(";")
+    os.environ["QT_QPA_PLATFORM"] = ";".join(
+        sorted(plugins, key=lambda plugin: plugin.startswith("wayland"))
+    )
+
+# need to initialize QApp here, otherwise svg icons do not work on windows
 app = QApplication(sys.argv, applicationName=NAME)
 
 from .main_window import MainWindow

cq_editor/widgets/occt_widget.py

@@ -220,6 +220,7 @@ def _get_window_win(self, wid):
 
     def _get_window_linux(self, wid):
 
+        # X11 only as OCCT currently doesn't have wayland support
         from OCP.Xw import Xw_Window
 
         return Xw_Window(self.display_connection, int(wid))

run.py

@@ -1,11 +1,6 @@
 import sys
-import os
 import faulthandler
 
-# OCP's Xw_Window requires an X11 window ID, so we force XCB so winId() is valid under Wayland/XWayland.
-if sys.platform == "linux" and "QT_QPA_PLATFORM" not in os.environ:
-    os.environ["QT_QPA_PLATFORM"] = "xcb"
-
 # PyInstaller with console=False sets sys.stdout/stderr to None on Windows
 if sys.stdout is None:
     sys.stdout = open("nul", "w")