Class NavigationToolbar2Tk

lib/matplotlib/backends/_backend_tk.py:660–967

class NavigationToolbar2Tk(NavigationToolbar2, tk.Frame):
    def __init__(self, canvas, window=None, *, pack_toolbar=True):
        """
        Parameters
        ----------
        canvas : `FigureCanvas`
            The figure canvas on which to operate.
        window : tk.Window
            The tk.Window which owns this toolbar.
        pack_toolbar : bool, default: True
            If True, add the toolbar to the parent's pack manager's packing
            list during initialization with ``side="bottom"`` and ``fill="x"``.
            If you want to use the toolbar with a different layout manager, use
            ``pack_toolbar=False``.
        """

        if window is None:
            window = canvas.get_tk_widget().master
        tk.Frame.__init__(self, master=window, borderwidth=2,
                          width=int(canvas.figure.bbox.width), height=50)
        # Avoid message_label expanding the toolbar size, and in turn expanding the
        # canvas size.
        # Without pack_propagate(False), when the user defines a small figure size
        # (e.g. 2x2):
        # 1. Figure size that is bigger than the user's expectation.
        # 2. When message_label is refreshed by mouse enter/leave, the canvas
        #    size will also be changed.
        self.pack_propagate(False)

        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}.png")),
                    toggle=callback in ["zoom", "pan"],
                    command=getattr(self, callback),
                )
                if tooltip_text is not None:
                    add_tooltip(button, tooltip_text)

        self._label_font = tkinter.font.Font(root=window, size=10)

        # This filler item ensures the toolbar is always at least two text
        # lines high. Otherwise the canvas gets redrawn as the mouse hovers
        # over images because those use two-line messages which resize the
        # toolbar.
        label = tk.Label(master=self, font=self._label_font,
                         text='\N{NO-BREAK SPACE}\n\N{NO-BREAK SPACE}')
        label.pack(side=tk.RIGHT)

        self.message = tk.StringVar(master=self)
        self._message_label = tk.Label(master=self, font=self._label_font,
                                       textvariable=self.message,
                                       justify=tk.RIGHT)