We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Default to QT_QPA_PLATFORM=xcb on Linux/Wayland
If we detect a linux box running on wayland, we should force Qt to use the xcb platform as the wayland backend doesn't work properly with moderngl.

This maybe a good way to detect wayland:
```
XDG_SESSION_TYPE=wayland
```

Relevant discussions:
- https://github.com/abey79/vsketch/issues/353
- https://discord.com/channels/550302843777712148/696045774970028062/1072436292798926868

--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `vpype_viewer/qtviewer/__init__.py`
Content:
```
1 from .viewer import *
2
```
--- END FILES ---

Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.

Here is an example:

```diff
diff --git a/examples/server_async.py b/examples/server_async.py
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -313,4 +313,4 @@
 
 
 if __name__ == "__main__":
-    asyncio.run(run_async_server("."), debug=True)
+    asyncio.run(run_async_server(), debug=True)
diff --git a/examples/server_sync.py b/examples/server_sync.py
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -313,5 +313,5 @@
 
 
 if __name__ == "__main__":
-    server = run_sync_server(".")
+    server = run_sync_server()
     server.shutdown()

```

diff --git a/vpype_viewer/qtviewer/__init__.py b/vpype_viewer/qtviewer/__init__.py
--- a/vpype_viewer/qtviewer/__init__.py
+++ b/vpype_viewer/qtviewer/__init__.py
@@ -1 +1,18 @@
+def _check_wayland():
+    """Fix QT env variable on Wayland-based systems.
+
+    See https://github.com/abey79/vpype/issues/596
+    """
+    import os
+    import sys
+
+    if sys.platform.startswith("linux"):
+        if os.environ.get("XDG_SESSION_TYPE", "") == "wayland":
+            if "QT_QPA_PLATFORM" not in os.environ:
+                os.environ["QT_QPA_PLATFORM"] = "xcb"
+
+
+_check_wayland()
+
+
 from .viewer import *

{"golden_diff": "diff --git a/vpype_viewer/qtviewer/__init__.py b/vpype_viewer/qtviewer/__init__.py\n--- a/vpype_viewer/qtviewer/__init__.py\n+++ b/vpype_viewer/qtviewer/__init__.py\n@@ -1 +1,18 @@\n+def _check_wayland():\n+    \"\"\"Fix QT env variable on Wayland-based systems.\n+\n+    See https://github.com/abey79/vpype/issues/596\n+    \"\"\"\n+    import os\n+    import sys\n+\n+    if sys.platform.startswith(\"linux\"):\n+        if os.environ.get(\"XDG_SESSION_TYPE\", \"\") == \"wayland\":\n+            if \"QT_QPA_PLATFORM\" not in os.environ:\n+                os.environ[\"QT_QPA_PLATFORM\"] = \"xcb\"\n+\n+\n+_check_wayland()\n+\n+\n from .viewer import *\n", "issue": "Default to QT_QPA_PLATFORM=xcb on Linux/Wayland\nIf we detect a linux box running on wayland, we should force Qt to use the xcb platform as the wayland backend doesn't work properly with moderngl.\r\n\r\nThis maybe a good way to detect wayland:\r\n```\r\nXDG_SESSION_TYPE=wayland\r\n```\r\n\r\nRelevant discussions:\r\n- https://github.com/abey79/vsketch/issues/353\r\n- https://discord.com/channels/550302843777712148/696045774970028062/1072436292798926868\n", "before_files": [{"content": "from .viewer import *\n", "path": "vpype_viewer/qtviewer/__init__.py"}], "after_files": [{"content": "def _check_wayland():\n    \"\"\"Fix QT env variable on Wayland-based systems.\n\n    See https://github.com/abey79/vpype/issues/596\n    \"\"\"\n    import os\n    import sys\n\n    if sys.platform.startswith(\"linux\"):\n        if os.environ.get(\"XDG_SESSION_TYPE\", \"\") == \"wayland\":\n            if \"QT_QPA_PLATFORM\" not in os.environ:\n                os.environ[\"QT_QPA_PLATFORM\"] = \"xcb\"\n\n\n_check_wayland()\n\n\nfrom .viewer import *\n", "path": "vpype_viewer/qtviewer/__init__.py"}]}