Python Console: Reduce the number of supported backends

Fixes #2471
Fixes #2348

- From now on we will only support Qt, Tk and MacOSX backends. I really
don't know how to support the other ones (i.e. Gtk and Wx), so I'm
removing support to set them in the interface.

spyderlib/config.py

@@ -253,10 +253,7 @@ def is_ubuntu():
               'qt/api': 'default',
               'pyqt/api_version': 2,
               'pyqt/ignore_sip_setapi_errors': False,
-              'matplotlib/backend/enabled': True,
-              'matplotlib/backend/value': 'MacOSX' if (sys.platform == 'darwin' \
-                                           and os.environ.get('QT_API') == 'pyside')\
-                                           else 'Qt4Agg',
+              'matplotlib/backend/value': 0,
               'umr/enabled': True,
               'umr/verbose': True,
               'umr/namelist': ['guidata', 'guiqwt'],
@@ -745,7 +742,7 @@ def is_ubuntu():
 # 2. If you want to *remove* options that are no longer needed in our codebase,
 #    you need to do a MAJOR update in version, e.g. from 3.0.0 to 4.0.0
 # 3. You don't need to touch this value if you're just adding a new option
-CONF_VERSION = '18.1.0'
+CONF_VERSION = '19.0.0'
 
 # XXX: Previously we had load=(not DEV) here but DEV was set to *False*.
 # Check if it *really* needs to be updated or not

spyderlib/plugins/externalconsole.py

@@ -318,29 +318,37 @@ def setup_page(self):
             pyqt_layout.addWidget(ignore_api_box)
             pyqt_group.setLayout(pyqt_layout)
             qt_layout.addWidget(pyqt_group)
-        
+
         # Matplotlib Group
-        mpl_group = QGroupBox(_("Matplotlib"))
-        mpl_backend_box = newcb('', 'matplotlib/backend/enabled', True)
-        mpl_backend_edit = self.create_lineedit(_("GUI backend:"),
-                                'matplotlib/backend/value',
-                                tip=_("Set the GUI toolkit used by <br>"
-                                      "Matplotlib to show figures "
-                                      "(default: Qt4Agg)"),
-                                alignment=Qt.Horizontal)
-        mpl_backend_box.toggled.connect(mpl_backend_edit.setEnabled)
-        mpl_backend_layout = QHBoxLayout()
-        mpl_backend_layout.addWidget(mpl_backend_box)
-        mpl_backend_layout.addWidget(mpl_backend_edit)
-        mpl_backend_edit.setEnabled(
-                                self.get_option('matplotlib/backend/enabled'))
+        mpl_group = QGroupBox(_("Graphics"))
+        mpl_label = QLabel(_("Decide which backend to use to display graphics. "
+                              "If unsure, please select the <b>Qt</b> "
+                              "backend.<br><br>"
+                              "<b>Note:</b> We support a very limited amount "
+                              "of backends in our Python consoles. If you "
+                              "prefer to work with a different one, please use "
+                              "an IPython console."))
+        mpl_label.setWordWrap(True)
+
+        backends = [("Qt", 0)]
+        if programs.is_module_installed('_tkinter'):
+            backends.append( ("Tkinter", 1) )
+        if sys.platform == 'darwin':
+            backends.append( ("Mac OSX", 2) )
+        backends = tuple(backends)
+
+        mpl_backend_box = self.create_combobox( _("Backend:")+"   ", backends,
+                                       'matplotlib/backend/value',
+                                       tip=_("This option will be applied the "
+                                             "next time a console is opened."))
+
         mpl_installed = programs.is_module_installed('matplotlib')
-
         mpl_layout = QVBoxLayout()
-        mpl_layout.addLayout(mpl_backend_layout)
+        mpl_layout.addWidget(mpl_label)
+        mpl_layout.addWidget(mpl_backend_box)
         mpl_group.setLayout(mpl_layout)
         mpl_group.setEnabled(mpl_installed)
-        
+
         # ETS Group
         ets_group = QGroupBox(_("Enthought Tool Suite"))
         ets_label = QLabel(_("Enthought Tool Suite (ETS) supports "
@@ -786,10 +794,7 @@ def start(self, fname, wdir=None, args='', interact=False, debug=False,
             else:
                 pythonstartup = self.get_option('pythonstartup', None)
             monitor_enabled = self.get_option('monitor/enabled')
-            if self.get_option('matplotlib/backend/enabled'):
-                mpl_backend = self.get_option('matplotlib/backend/value')
-            else:
-                mpl_backend = None
+            mpl_backend = self.get_option('matplotlib/backend/value')
             ets_backend = self.get_option('ets_backend')
             qt_api = self.get_option('qt/api')
             if qt_api not in ('pyqt', 'pyside'):

spyderlib/widgets/externalshell/pythonshell.py

@@ -467,8 +467,9 @@ def create_process(self):
 
         # External modules options
         env.append('ETS_TOOLKIT=%s' % self.ets_backend)
-        if self.mpl_backend:
-            env.append('MATPLOTLIB_BACKEND=%s' % self.mpl_backend)
+        if self.mpl_backend is not None:
+            backends = {0: 'Qt4Agg', 1: 'TkAgg', 2: 'MacOSX'}
+            env.append('MATPLOTLIB_BACKEND=%s' % backends[self.mpl_backend])
         if self.qt_api:
             env.append('QT_API=%s' % self.qt_api)
         env.append('COLORIZE_SYS_STDERR=%s' % self.colorize_sys_stderr)

spyderlib/widgets/externalshell/sitecustomize.py

@@ -596,9 +596,9 @@ def __init__(self, namelist=None, pathlist=None):
         if namelist is None:
             namelist = []
         spy_modules = ['sitecustomize', 'spyderlib', 'spyderplugins']
-        mpl_modules = ['matplotlib', 'tkinter', 'Tkinter', 'gtk']
+        mpl_modules = ['matplotlib', 'tkinter', 'Tkinter']
         self.namelist = namelist + spy_modules + mpl_modules
-        
+
         if pathlist is None:
             pathlist = []
         self.pathlist = pathlist