Merge pull request matplotlib#19894 from QuLogic/remove-qt4

API: Remove deprecated Qt4 backends

Author: tacaswell

doc/api/backend_qt_api.rst

@@ -6,16 +6,6 @@ to building the docs.
 .. redirect-from:: /api/backend_qt5agg_api
 .. redirect-from:: /api/backend_qt5cairo_api
 
-:mod:`matplotlib.backends.backend_qt4agg`
-=========================================
-
-.. module:: matplotlib.backends.backend_qt4agg
-
-:mod:`matplotlib.backends.backend_qt4cairo`
-===========================================
-
-.. module:: matplotlib.backends.backend_qt4cairo
-
 :mod:`matplotlib.backends.backend_qt5agg`
 =========================================
 

doc/api/next_api_changes/removals/19894-ES.rst

@@ -0,0 +1,15 @@
+Qt4-based backends
+~~~~~~~~~~~~~~~~~~
+The qt4agg and qt4cairo backends have been removed. Qt4 has reached its
+end-of-life in 2015 and there are no releases of either PyQt4 or PySide for
+recent versions of Python. Please use one of the Qt5 or Qt6 backends.
+
+``qt_compat.is_pyqt5``
+~~~~~~~~~~~~~~~~~~~~~~
+This function has been removed due to the release of PyQt6. The Qt version can
+be checked using ``QtCore.qVersion()``.
+
+``matplotlib.backends.qt_editor.formsubplottool``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+This module has been removed.  Use
+``matplotlib.backends.backend_qt5.SubplotToolQt`` instead.

doc/api/prev_api_changes/api_changes_3.3.0/deprecations.rst

@@ -609,8 +609,8 @@ accepted.
 Qt modifier keys
 ~~~~~~~~~~~~~~~~
 The ``MODIFIER_KEYS``, ``SUPER``, ``ALT``, ``CTRL``, and ``SHIFT``
-global variables of the :mod:`matplotlib.backends.backend_qt4agg`,
-:mod:`matplotlib.backends.backend_qt4cairo`,
+global variables of the ``matplotlib.backends.backend_qt4agg``,
+``matplotlib.backends.backend_qt4cairo``,
 :mod:`matplotlib.backends.backend_qt5agg` and
 :mod:`matplotlib.backends.backend_qt5cairo` modules are deprecated.
 

doc/devel/dependencies.rst

@@ -40,7 +40,6 @@ Matplotlib figures can be rendered to various user interfaces. See
 and the capabilities they provide.
 
 * Tk_ (>= 8.3, != 8.6.0 or 8.6.1) [#]_: for the Tk-based backends.
-* PyQt4_ (>= 4.6) or PySide_ (>= 1.0.3) [#]_: for the Qt4-based backends.
 * PyQt5_ or PySide2_: for the Qt5-based backends.
 * PyGObject_: for the GTK3-based backends [#]_.
 * wxPython_ (>= 4) [#]_: for the wx-based backends.
@@ -49,8 +48,6 @@ and the capabilities they provide.
 * Tornado_: for the WebAgg backend.
 
 .. _Tk: https://docs.python.org/3/library/tk.html
-.. _PyQt4: https://pypi.org/project/PyQt4
-.. _PySide: https://pypi.org/project/PySide
 .. _PyQt5: https://pypi.org/project/PyQt5
 .. _PySide2: https://pypi.org/project/PySide2
 .. _PyGObject: https://pygobject.readthedocs.io/en/latest/

examples/user_interfaces/embedding_in_qt_sgskip.py

@@ -15,12 +15,8 @@
 import numpy as np
 
 from matplotlib.backends.qt_compat import QtCore, QtWidgets
-if QtCore.qVersion() >= "5.":
-    from matplotlib.backends.backend_qt5agg import (
-        FigureCanvas, NavigationToolbar2QT as NavigationToolbar)
-else:
-    from matplotlib.backends.backend_qt4agg import (
-        FigureCanvas, NavigationToolbar2QT as NavigationToolbar)
+from matplotlib.backends.backend_qt5agg import (
+    FigureCanvas, NavigationToolbar2QT as NavigationToolbar)
 from matplotlib.figure import Figure
 
 

lib/matplotlib/__init__.py

@@ -1066,7 +1066,7 @@ def use(backend, *, force=True):
 
         - interactive backends:
           GTK3Agg, GTK3Cairo, MacOSX, nbAgg,
-          Qt4Agg, Qt4Cairo, Qt5Agg, Qt5Cairo,
+          Qt5Agg, Qt5Cairo,
           TkAgg, TkCairo, WebAgg, WX, WXAgg, WXCairo
 
         - non-interactive backends:

lib/matplotlib/backend_bases.py

@@ -99,7 +99,6 @@ def _safe_pyplot_import():
         if current_framework is None:
             raise  # No, something else went wrong, likely with the install...
         backend_mapping = {'qt5': 'qt5agg',
-                           'qt4': 'qt4agg',
                            'gtk3': 'gtk3agg',
                            'wx': 'wxagg',
                            'tk': 'tkagg',
@@ -1680,7 +1679,7 @@ class FigureCanvasBase:
         A high-level figure instance.
     """
 
-    # Set to one of {"qt5", "qt4", "gtk3", "wx", "tk", "macosx"} if an
+    # Set to one of {"qt5", "gtk3", "wx", "tk", "macosx"} if an
     # interactive framework is required, or None otherwise.
     required_interactive_framework = None
 
@@ -1756,7 +1755,7 @@ def _fix_ipython_backend2gui(cls):
             # don't break on our side.
             return
         rif = getattr(cls, "required_interactive_framework", None)
-        backend2gui_rif = {"qt5": "qt", "qt4": "qt", "gtk3": "gtk3",
+        backend2gui_rif = {"qt5": "qt", "gtk3": "gtk3",
                            "wx": "wx", "macosx": "osx"}.get(rif)
         if backend2gui_rif:
             if _is_non_interactive_terminal_ipython(ip):