add support for PySide2, matplotlib#5971

Signed-off-by: Thorsten Liebig <[email protected]>

Author: thliebig

lib/matplotlib/backends/qt_compat.py

@@ -13,10 +13,11 @@
 QT_API_PYQT = 'PyQt4'       # API is not set here; Python 2.x default is V 1
 QT_API_PYQTv2 = 'PyQt4v2'   # forced to Version 2 API
 QT_API_PYSIDE = 'PySide'    # only supports Version 2 API
-QT_API_PYQT5 = 'PyQt5'       # use PyQt5 API; Version 2 with module shim
+QT_API_PYQT5 = 'PyQt5'      # use PyQt5 API; Version 2 with module shim
+QT_API_PYSIDE2 = 'PySide2'  # Version 2 API with module shim
 
 ETS = dict(pyqt=(QT_API_PYQTv2, 4), pyside=(QT_API_PYSIDE, 4),
-           pyqt5=(QT_API_PYQT5, 5))
+           pyqt5=(QT_API_PYQT5, 5), pyside2=(QT_API_PYSIDE2, 5))
 # ETS is a dict of env variable to (QT_API, QT_MAJOR_VERSION)
 # If the ETS QT_API environment variable is set, use it, but only
 # if the varible if of the same major QT version.  Note that
@@ -64,7 +65,7 @@
         # A different backend was specified, but we still got here because a Qt
         # related file was imported. This is allowed, so lets try and guess
         # what we should be using.
-        if "PyQt4" in sys.modules or "PySide" in sys.modules:
+        if "PyQt4" in sys.modules or ("PySide" in sys.modules and not "PySide2" in sys.modules):
             # PyQt4 or PySide is actually used.
             QT_API = rcParams['backend.qt4']
         else:
@@ -154,13 +155,24 @@ def _getSaveFileName(*args, **kwargs):
         # QtCore did not get imported, fall back to pyside
         QT_API = QT_API_PYSIDE
 
+
+if QT_API == QT_API_PYSIDE2:
+    try:
+        from PySide2 import QtCore, QtGui, QtWidgets, __version__
+        _getSaveFileName = QtWidgets.QFileDialog.getSaveFileName
+    except ImportError:
+        # tried PySide2, failed, fall back to PySide
+        QT_API = rcParams['backend.qt4']
+        QT_RC_MAJOR_VERSION = 4
+        QT_API = QT_API_PYSIDE
+
 if QT_API == QT_API_PYSIDE:  # try importing pyside
     try:
         from PySide import QtCore, QtGui, __version__, __version_info__
     except ImportError:
         raise ImportError(
-            "Matplotlib qt-based backends require an external PyQt4, PyQt5,\n"
-            "or PySide package to be installed, but it was not found.")
+            "Matplotlib qt-based backends require an external PyQt4, PyQt5, PySide,\n"
+            "or PySide2 package to be installed, but it was not found.")
 
     if __version_info__ < (1, 0, 3):
         raise ImportError(

lib/matplotlib/rcsetup.py

@@ -243,7 +243,7 @@ def validate_backend(s):
 
 
 validate_qt4 = ValidateInStrings('backend.qt4', ['PyQt4', 'PySide', 'PyQt4v2'])
-validate_qt5 = ValidateInStrings('backend.qt5', ['PyQt5'])
+validate_qt5 = ValidateInStrings('backend.qt5', ['PyQt5', 'PySide2'])
 
 
 def validate_toolbar(s):

setupext.py

@@ -2207,8 +2207,18 @@ def __init__(self, *args, **kwargs):
         BackendQtBase.__init__(self, *args, **kwargs)
         self.callback = backend_qt4_internal_check
 
+def backend_pyside2_internal_check(self):
+    try:
+        from PySide2 import __version__
+        from PySide2 import QtCore
+    except ImportError:
+        raise CheckFailed("PySide2 not found")
+    else:
+        BackendAgg.force = True
+        return ("Qt: %s, PySide2: %s" %
+                (QtCore.__version__, __version__))
 
-def backend_qt5_internal_check(self):
+def backend_pyqt5_internal_check(self):
     try:
         from PyQt5 import QtCore
     except ImportError:
@@ -2223,6 +2233,22 @@ def backend_qt5_internal_check(self):
         BackendAgg.force = True
         return ("Qt: %s, PyQt: %s" % (self.convert_qt_version(qt_version), pyqt_version_str))
 
+def backend_qt5_internal_check(self):
+    successes = []
+    failures = []
+    try:
+        successes.append(backend_pyside2_internal_check(self))
+    except CheckFailed as e:
+        failures.append(str(e))
+
+    try:
+        successes.append(backend_pyqt5_internal_check(self))
+    except CheckFailed as e:
+        failures.append(str(e))
+
+    if len(successes) == 0:
+        raise CheckFailed('; '.join(failures))
+    return '; '.join(successes + failures)
 
 class BackendQt5(BackendQtBase):
     name = "qt5agg"