Allow using QtWebEngine in the main calibre application as well

bypy/init_env.py

@@ -34,6 +34,7 @@ dlls = [
     'Widgets',
     # 'Multimedia',
     'OpenGL',
+    'OpenGLWidgets',
     'Quick',
     'QuickWidgets',
     'Qml',
@@ -88,6 +89,8 @@ PYQT_MODULES = (
     'QtSensors',
     'QtSvg',
     'QtWidgets',
+    'QtOpenGL',
+    'QtOpenGLWidgets',
     'QtWebEngine',
     'QtWebEngineCore',
     'QtWebEngineWidgets',

src/calibre/gui2/__init__.py

@@ -1077,6 +1077,9 @@ class Application(QApplication):
         # Allow import of webengine after construction of QApplication on new
         # enough PyQt
         QApplication.setAttribute(Qt.ApplicationAttribute.AA_ShareOpenGLContexts)
+        # this import is needed to have Qt call qt_registerDefaultPlatformBackingStoreOpenGLSupport
+        from qt.core import QOpenGLWidget
+        del QOpenGLWidget
         if iswindows:
             self.windows_app_uid = None
             if windows_app_uid: