Merge pull request #26055 from meeseeksmachine/auto-backport-of-pr-26052-on-v3.7.x

QuLogic · web-flow · commit 5958e32761c6 · 2023-06-05T19:38:12.000-04:00
Backport PR #26052 on branch v3.7.x (Improve Qt compatibility)
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
@@ -48,20 +48,28 @@ jobs:
             python-version: 3.8
             extra-requirements: '-r requirements/testing/extra.txt'
             CFLAGS: "-fno-lto"  # Ensure that disabling LTO works.
+            # https://github.com/matplotlib/matplotlib/pull/26052#issuecomment-1574595954
+            pyqt6-ver: '!=6.5.1'
             # https://bugreports.qt.io/projects/PYSIDE/issues/PYSIDE-2346
             pyside6-ver: '!=6.5.1'
           - os: ubuntu-20.04
             python-version: 3.9
             extra-requirements: '-r requirements/testing/extra.txt'
+            # https://github.com/matplotlib/matplotlib/pull/26052#issuecomment-1574595954
+            pyqt6-ver: '!=6.5.1'
             # https://bugreports.qt.io/projects/PYSIDE/issues/PYSIDE-2346
             pyside6-ver: '!=6.5.1'
           - os: ubuntu-20.04
             python-version: '3.10'
             extra-requirements: '-r requirements/testing/extra.txt'
+            # https://github.com/matplotlib/matplotlib/pull/26052#issuecomment-1574595954
+            pyqt6-ver: '!=6.5.1'
             # https://bugreports.qt.io/projects/PYSIDE/issues/PYSIDE-2346
             pyside6-ver: '!=6.5.1'
           - os: ubuntu-20.04
             python-version: '3.11'
+            # https://github.com/matplotlib/matplotlib/pull/26052#issuecomment-1574595954
+            pyqt6-ver: '!=6.5.1'
             # https://bugreports.qt.io/projects/PYSIDE/issues/PYSIDE-2346
             pyside6-ver: '!=6.5.1'
           - os: macos-latest
diff --git a/lib/matplotlib/backends/backend_qt.py b/lib/matplotlib/backends/backend_qt.py
@@ -113,8 +113,10 @@ def _create_qApp():
         # of Qt is not instantiated in the process
         if QT_API in {'PyQt6', 'PySide6'}:
             other_bindings = ('PyQt5', 'PySide2')
+            qt_version = 6
         elif QT_API in {'PyQt5', 'PySide2'}:
             other_bindings = ('PyQt6', 'PySide6')
+            qt_version = 5
         else:
             raise RuntimeError("Should never be here")
 
@@ -130,11 +132,11 @@ def _create_qApp():
                     'versions may not work as expected.'
                 )
                 break
-        try:
-            QtWidgets.QApplication.setAttribute(
-                QtCore.Qt.AA_EnableHighDpiScaling)
-        except AttributeError:  # Only for Qt>=5.6, <6.
-            pass
+        if qt_version == 5:
+            try:
+                QtWidgets.QApplication.setAttribute(QtCore.Qt.AA_EnableHighDpiScaling)
+            except AttributeError:  # Only for Qt>=5.6, <6.
+                pass
         try:
             QtWidgets.QApplication.setHighDpiScaleFactorRoundingPolicy(
                 QtCore.Qt.HighDpiScaleFactorRoundingPolicy.PassThrough)
@@ -148,10 +150,8 @@ def _create_qApp():
         app.lastWindowClosed.connect(app.quit)
         cbook._setup_new_guiapp()
 
-    try:
-        app.setAttribute(QtCore.Qt.AA_UseHighDpiPixmaps)  # Only for Qt<6.
-    except AttributeError:
-        pass
+        if qt_version == 5:
+            app.setAttribute(QtCore.Qt.AA_UseHighDpiPixmaps)
 
     return app
 
@@ -529,9 +529,6 @@ class FigureManagerQT(FigureManagerBase):
     def __init__(self, canvas, num):
         self.window = MainWindow()
         super().__init__(canvas, num)
-        self.window.closing.connect(
-            # The lambda prevents the event from being immediately gc'd.
-            lambda: CloseEvent("close_event", self.canvas)._process())
         self.window.closing.connect(self._widgetclosed)
 
         if sys.platform != "darwin":
@@ -576,6 +573,7 @@ def full_screen_toggle(self):
             self.window.showFullScreen()
 
     def _widgetclosed(self):
+        CloseEvent("close_event", self.canvas)._process()
         if self.window._destroying:
             return
         self.window._destroying = True
