matplotlib · tacaswell · Apr 30, 2020 · Apr 8, 2020
diff --git a/doc/api/api_changes_3.3/deprecations.rst b/doc/api/api_changes_3.3/deprecations.rst
@@ -366,6 +366,16 @@ The ``Fil``, ``Fill``, ``Filll``, ``NegFil``, ``NegFill``, ``NegFilll``, and
 ``SsGlue`` classes in the :mod:`matplotlib.mathtext` module are deprecated.
 As an alternative, directly construct glue instances with ``Glue("fil")``, etc.
 
+NavigationToolbar2._init_toolbar
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Overriding this method to initialize third-party toolbars is deprecated.
+Instead, the toolbar should be initialized in the ``__init__`` method of the
+subclass (which should call the base-class' ``__init__`` as appropriate).  To
+keep back-compatibility with earlier versions of Matplotlib (which *required*
+``_init_toolbar`` to be overridden), a fully empty implementation (``def
+_init_toolbar(self): pass``) may be kept and will not trigger the deprecation
+warning.
+
 NavigationToolbar2QT.parent and .basedir
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 These attributes are deprecated.  In order to access the parent window, use

diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -2668,11 +2668,11 @@ def __str__(self):
 
 class NavigationToolbar2:
     """
-    Base class for the navigation cursor, version 2
+    Base class for the navigation cursor, version 2.
 
-    backends must implement a canvas that handles connections for
+    Backends must implement a canvas that handles connections for
     'button_press_event' and 'button_release_event'.  See
-    :meth:`FigureCanvasBase.mpl_connect` for more information
+    :meth:`FigureCanvasBase.mpl_connect` for more information.
 
     They must also define
 
@@ -2682,9 +2682,6 @@ class NavigationToolbar2:
       :meth:`set_cursor`
          if you want the pointer icon to change
 
-      :meth:`_init_toolbar`
-         create your toolbar widget
-
       :meth:`draw_rubberband` (optional)
          draw the zoom to rect "rubberband" rectangle
 
@@ -2695,6 +2692,12 @@ class NavigationToolbar2:
          you can change the history back / forward buttons to
          indicate disabled / enabled state.
 
+    and override ``__init__`` to set up the toolbar -- without forgetting to
+    call the base-class init.  Typically, ``__init__`` needs to set up toolbar
+    buttons connected to the `home`, `back`, `forward`, `pan`, `zoom`, and
+    `save_figure` methods and using standard icons in the "images" subdirectory
+    of the data path.
+
     That's it, we'll do the rest!
     """
 
@@ -2724,7 +2727,15 @@ def __init__(self, canvas):
         self._xypress = None  # location and axis info at the time of the press
         # This cursor will be set after the initial draw.
         self._lastCursor = cursors.POINTER
-        self._init_toolbar()
+
+        init = cbook._deprecate_method_override(
+            __class__._init_toolbar, self, allow_empty=True, since="3.3",
+            addendum="Please fully initialize the toolbar in your subclass' "
+            "__init__; a fully empty _init_toolbar implementation may be kept "
+            "for compatibility with earlier versions of Matplotlib.")
+        if init:
+            init()
+
         self._id_press = self.canvas.mpl_connect(
             'button_press_event', self._zoom_pan_handler)
         self._id_release = self.canvas.mpl_connect(
@@ -2787,6 +2798,7 @@ def home(self, *args):
         self.set_history_buttons()
         self._update_view()
 
+    @cbook.deprecated("3.3", alternative="__init__")
     def _init_toolbar(self):
         """
         This is where you actually build the GUI widgets (called by

diff --git a/lib/matplotlib/backends/_backend_tk.py b/lib/matplotlib/backends/_backend_tk.py
@@ -491,6 +491,29 @@ def __init__(self, canvas, window, *, pack_toolbar=True):
         # Avoid using self.window (prefer self.canvas.get_tk_widget().master),
         # so that Tool implementations can reuse the methods.
         self.window = window
+
+        tk.Frame.__init__(self, master=window, borderwidth=2,
+                          width=int(canvas.figure.bbox.width), height=50)
+
+        self._buttons = {}
+        for text, tooltip_text, image_file, callback in self.toolitems:
+            if text is None:
+                # Add a spacer; return value is unused.
+                self._Spacer()
+            else:
+                self._buttons[text] = button = self._Button(
+                    text,
+                    str(cbook._get_data_path(f"images/{image_file}.gif")),
+                    toggle=callback in ["zoom", "pan"],
+                    command=getattr(self, callback),
+                )
+                if tooltip_text is not None:
+                    ToolTip.createToolTip(button, tooltip_text)
+
+        self.message = tk.StringVar(master=self)
+        self._message_label = tk.Label(master=self, textvariable=self.message)
+        self._message_label.pack(side=tk.RIGHT)
+
         NavigationToolbar2.__init__(self, canvas)
         if pack_toolbar:
             self.pack(side=tk.BOTTOM, fill=tk.X)
@@ -547,51 +570,6 @@ def _Spacer(self):
         s.pack(side=tk.LEFT, padx=5)
         return s
 
-    def _init_toolbar(self):
-        xmin, xmax = self.canvas.figure.bbox.intervalx
-        height, width = 50, xmax-xmin
-        tk.Frame.__init__(self, master=self.window,
-                          width=int(width), height=int(height),
-                          borderwidth=2)
-
-        self.update()  # Make axes menu
-
-        self._buttons = {}
-        for text, tooltip_text, image_file, callback in self.toolitems:
-            if text is None:
-                # Add a spacer; return value is unused.
-                self._Spacer()
-            else:
-                self._buttons[text] = button = self._Button(
-                    text,
-                    str(cbook._get_data_path(f"images/{image_file}.gif")),
-                    toggle=callback in ["zoom", "pan"],
-                    command=getattr(self, callback),
-                )
-                if tooltip_text is not None:
-                    ToolTip.createToolTip(button, tooltip_text)
-
-        self.message = tk.StringVar(master=self)
-        self._message_label = tk.Label(master=self, textvariable=self.message)
-        self._message_label.pack(side=tk.RIGHT)
-
-    def _update_buttons_checked(self):
-        for name, mode in [("Pan", "PAN"), ("Zoom", "ZOOM")]:
-            button = self._buttons.get(name)
-            if button:
-                if self.mode.name == mode and not button.var.get():
-                    button.select()
-                elif self.mode.name != mode and button.var.get():
-                    button.deselect()
-
-    def pan(self, *args):
-        super().pan(*args)
-        self._update_buttons_checked()
-
-    def zoom(self, *args):
-        super().zoom(*args)
-        self._update_buttons_checked()
-
     def configure_subplots(self):
         toolfig = Figure(figsize=(6, 3))
         window = tk.Toplevel()

diff --git a/lib/matplotlib/backends/backend_gtk3.py b/lib/matplotlib/backends/backend_gtk3.py
@@ -451,43 +451,7 @@ class NavigationToolbar2GTK3(NavigationToolbar2, Gtk.Toolbar):
     def __init__(self, canvas, window):
         self.win = window
         GObject.GObject.__init__(self)
-        NavigationToolbar2.__init__(self, canvas)
-
-    @cbook.deprecated("3.3")
-    @property
-    def ctx(self):
-        return self.canvas.get_property("window").cairo_create()
-
-    def set_message(self, s):
-        self.message.set_label(s)
-
-    def set_cursor(self, cursor):
-        self.canvas.get_property("window").set_cursor(cursord[cursor])
-        Gtk.main_iteration()
-
-    def draw_rubberband(self, event, x0, y0, x1, y1):
-        # adapted from
-        # http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/189744
-        ctx = self.canvas.get_property("window").cairo_create()
-
-        # todo: instead of redrawing the entire figure, copy the part of
-        # the figure that was covered by the previous rubberband rectangle
-        self.canvas.draw()
 
-        height = self.canvas.figure.bbox.height
-        y1 = height - y1
-        y0 = height - y0
-        w = abs(x1 - x0)
-        h = abs(y1 - y0)
-        rect = [int(val) for val in (min(x0, x1), min(y0, y1), w, h)]
-
-        ctx.new_path()
-        ctx.set_line_width(0.5)
-        ctx.rectangle(*rect)
-        ctx.set_source_rgb(0, 0, 0)
-        ctx.stroke()
-
-    def _init_toolbar(self):
         self.set_style(Gtk.ToolbarStyle.ICONS)
 
         self._gtk_ids = {}
@@ -521,6 +485,42 @@ def _init_toolbar(self):
 
         self.show_all()
 
+        NavigationToolbar2.__init__(self, canvas)
+
+    @cbook.deprecated("3.3")
+    @property
+    def ctx(self):
+        return self.canvas.get_property("window").cairo_create()
+
+    def set_message(self, s):
+        self.message.set_label(s)
+
+    def set_cursor(self, cursor):
+        self.canvas.get_property("window").set_cursor(cursord[cursor])
+        Gtk.main_iteration()
+
+    def draw_rubberband(self, event, x0, y0, x1, y1):
+        # adapted from
+        # http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/189744
+        self.ctx = self.canvas.get_property("window").cairo_create()
+
+        # todo: instead of redrawing the entire figure, copy the part of
+        # the figure that was covered by the previous rubberband rectangle
+        self.canvas.draw()
+
+        height = self.canvas.figure.bbox.height
+        y1 = height - y1
+        y0 = height - y0
+        w = abs(x1 - x0)
+        h = abs(y1 - y0)
+        rect = [int(val) for val in (min(x0, x1), min(y0, y1), w, h)]
+
+        self.ctx.new_path()
+        self.ctx.set_line_width(0.5)
+        self.ctx.rectangle(rect[0], rect[1], rect[2], rect[3])
+        self.ctx.set_source_rgb(0, 0, 0)
+        self.ctx.stroke()
+
     def _update_buttons_checked(self):
         for name, active in [("Pan", "PAN"), ("Zoom", "ZOOM")]:
             button = self._gtk_ids.get(name)

diff --git a/lib/matplotlib/backends/backend_macosx.py b/lib/matplotlib/backends/backend_macosx.py
@@ -110,11 +110,10 @@ def close(self):
 class NavigationToolbar2Mac(_macosx.NavigationToolbar2, NavigationToolbar2):
 
     def __init__(self, canvas):
-        NavigationToolbar2.__init__(self, canvas)
-
-    def _init_toolbar(self):
+        self.canvas = canvas  # Needed by the _macosx __init__.
         _macosx.NavigationToolbar2.__init__(
             self, str(cbook._get_data_path('images')))
+        NavigationToolbar2.__init__(self, canvas)
 
     def draw_rubberband(self, event, x0, y0, x1, y1):
         self.canvas.set_rubberband(int(x0), int(y0), int(x1), int(y1))

diff --git a/lib/matplotlib/backends/backend_qt5.py b/lib/matplotlib/backends/backend_qt5.py
@@ -639,36 +639,12 @@ class NavigationToolbar2QT(NavigationToolbar2, QtWidgets.QToolBar):
 
     def __init__(self, canvas, parent, coordinates=True):
         """coordinates: should we show the coordinates on the right?"""
+        QtWidgets.QToolBar.__init__(self, parent)
+
         self._parent = parent
         self.coordinates = coordinates
         self._actions = {}  # mapping of toolitem method names to QActions.
-        QtWidgets.QToolBar.__init__(self, parent)
-        NavigationToolbar2.__init__(self, canvas)
-
-    @cbook.deprecated("3.3", alternative="self.canvas.parent()")
-    @property
-    def parent(self):
-        return self._parent
-
-    @cbook.deprecated(
-        "3.3", alternative="os.path.join(mpl.get_data_path(), 'images')")
-    @property
-    def basedir(self):
-        return str(cbook._get_data_path('images'))
-
-    def _icon(self, name, color=None):
-        if is_pyqt5():
-            name = name.replace('.png', '_large.png')
-        pm = QtGui.QPixmap(str(cbook._get_data_path('images', name)))
-        qt_compat._setDevicePixelRatio(pm, self.canvas._dpi_ratio)
-        if color is not None:
-            mask = pm.createMaskFromColor(QtGui.QColor('black'),
-                                          QtCore.Qt.MaskOutColor)
-            pm.fill(color)
-            pm.setMask(mask)
-        return QtGui.QIcon(pm)
 
-    def _init_toolbar(self):
         background_color = self.palette().color(self.backgroundRole())
         foreground_color = self.palette().color(self.foregroundRole())
         icon_color = (foreground_color
@@ -699,6 +675,31 @@ def _init_toolbar(self):
             labelAction = self.addWidget(self.locLabel)
             labelAction.setVisible(True)
 
+        NavigationToolbar2.__init__(self, canvas)
+
+    @cbook.deprecated("3.3", alternative="self.canvas.parent()")
+    @property
+    def parent(self):
+        return self._parent
+
+    @cbook.deprecated(
+        "3.3", alternative="os.path.join(mpl.get_data_path(), 'images')")
+    @property
+    def basedir(self):
+        return str(cbook._get_data_path('images'))
+
+    def _icon(self, name, color=None):
+        if is_pyqt5():
+            name = name.replace('.png', '_large.png')
+        pm = QtGui.QPixmap(str(cbook._get_data_path('images', name)))
+        qt_compat._setDevicePixelRatio(pm, qt_compat._devicePixelRatio(self))
+        if color is not None:
+            mask = pm.createMaskFromColor(QtGui.QColor('black'),
+                                          QtCore.Qt.MaskOutColor)
+            pm.fill(color)
+            pm.setMask(mask)
+        return QtGui.QIcon(pm)
+
     def edit_parameters(self):
         axes = self.canvas.figure.get_axes()
         if not axes:

diff --git a/lib/matplotlib/backends/backend_webagg_core.py b/lib/matplotlib/backends/backend_webagg_core.py
@@ -367,9 +367,10 @@ class NavigationToolbar2WebAgg(backend_bases.NavigationToolbar2):
         if name_of_method in _ALLOWED_TOOL_ITEMS
     ]
 
-    def _init_toolbar(self):
+    def __init__(self, canvas):
         self.message = ''
         self.cursor = 0
+        super().__init__(canvas)
 
     def set_message(self, message):
         if message != self.message:

diff --git a/lib/matplotlib/backends/backend_wx.py b/lib/matplotlib/backends/backend_wx.py
@@ -1104,22 +1104,6 @@ def _set_frame_icon(frame):
 class NavigationToolbar2Wx(NavigationToolbar2, wx.ToolBar):
     def __init__(self, canvas):
         wx.ToolBar.__init__(self, canvas.GetParent(), -1)
-        NavigationToolbar2.__init__(self, canvas)
-        self._idle = True
-        self.prevZoomRect = None
-        # for now, use alternate zoom-rectangle drawing on all
-        # Macs. N.B. In future versions of wx it may be possible to
-        # detect Retina displays with window.GetContentScaleFactor()
-        # and/or dc.GetContentScaleFactor()
-        self.retinaFix = 'wxMac' in wx.PlatformInfo
-
-    def get_canvas(self, frame, fig):
-        return type(self.canvas)(frame, -1, fig)
-
-    def _init_toolbar(self):
-        _log.debug("%s - _init_toolbar", type(self))
-
-        self._parent = self.canvas.GetParent()
 
         self.wx_ids = {}
         for text, tooltip_text, image_file, callback in self.toolitems:
@@ -1140,6 +1124,18 @@ def _init_toolbar(self):
 
         self.Realize()
 
+        NavigationToolbar2.__init__(self, canvas)
+        self._idle = True
+        self.prevZoomRect = None
+        # for now, use alternate zoom-rectangle drawing on all
+        # Macs. N.B. In future versions of wx it may be possible to
+        # detect Retina displays with window.GetContentScaleFactor()
+        # and/or dc.GetContentScaleFactor()
+        self.retinaFix = 'wxMac' in wx.PlatformInfo
+
+    def get_canvas(self, frame, fig):
+        return type(self.canvas)(frame, -1, fig)
+
     def zoom(self, *args):
         self.ToggleTool(self.wx_ids['Pan'], False)
         NavigationToolbar2.zoom(self, *args)