Add button in toolbar to toggle grid

src/plopp/backends/matplotlib/canvas.py

@@ -746,6 +746,12 @@ def toggle_logy(self):
         """
         self.yscale = 'log' if self.yscale == 'linear' else 'linear'
 
+    def toggle_grid(self):
+        """
+        Toggle the visibility of the grid.
+        """
+        self.grid = not self.grid
+
     def has_user_xlabel(self) -> bool:
         """
         Return ``True`` if the user has set an x-axis label.

src/plopp/backends/matplotlib/figure.py

@@ -2,6 +2,8 @@
 # Copyright (c) 2024 Scipp contributors (https://github.com/scipp)
 from __future__ import annotations
 
+from functools import partial
+
 from matplotlib.axes import Axes
 from matplotlib.figure import Figure as MplFigure
 
@@ -137,7 +139,7 @@ def __init__(self, View, *args, **kwargs):
         self.interactive = True
         self.toolbar = make_toolbar_canvas2d(view=self.view)
 
-        self._setup_linked_home_buttons()
+        self._setup_linked_buttons()
 
         self.left_bar = VBar([self.toolbar])
         self.right_bar = VBar()
@@ -158,31 +160,38 @@ def _make_children(self):
             self.bottom_bar,
         ]
 
-    def _setup_linked_home_buttons(self):
+    def _setup_linked_buttons(self):
         """
-        Link home buttons across all Plopp figures sharing this matplotlib figure.
+        Link some buttons buttons across all Plopp figures sharing this matplotlib
+        figure (e.g. the 'home' or 'grid' buttons).
         This is needed when multiple Plopp figures are created from matplotlib axes
         that belong to the same figure, e.g. subplots.
         """
-        if not hasattr(self.fig, '_plopp_home_data'):
-            self.fig._plopp_home_data = {'callbacks': {}, 'toolbars': {}}
-        data = self.fig._plopp_home_data
+        keys = ('home', 'grid')
+        if not hasattr(self.fig, '_plopp_buttons_data'):
+            self.fig._plopp_buttons_data = {
+                'callbacks': {key: {} for key in keys},
+                'toolbars': {},
+            }
+        data = self.fig._plopp_buttons_data
         axes_id = id(self.ax)
-        # Store the original callback.
+        # Store the original callbacks
         # We use a dict to make sure that for repeated use of the same axes via
         # successive figure creations, we do not grow the list of callbacks
         # indefinitely.
-        data['callbacks'][axes_id] = self.toolbar['home'].callback
+        for key in keys:
+            data['callbacks'][key][axes_id] = self.toolbar[key].callback
         data['toolbars'][axes_id] = self.toolbar
 
         # Create a linked callback that calls ALL original callbacks
-        def linked_home():
-            for callback in data['callbacks'].values():
+        def linked_home(key):
+            for callback in data['callbacks'][key].values():
                 callback()
 
         # Update all toolbars (including this one) to use the linked callback
         for toolbar in data['toolbars'].values():
-            toolbar['home'].callback = linked_home
+            for key in keys:
+                toolbar[key].callback = partial(linked_home, key)
 
 
 class StaticFigure(MplBaseFig):

src/plopp/widgets/toolbar.py

@@ -63,10 +63,15 @@ def autoscale_axes() -> None:
         view.autoscale()
         view.canvas.draw()
 
+    def grid() -> None:
+        view.canvas.toggle_grid()
+        view.canvas.draw()
+
     return Toolbar(
         tools={
             "home": tools.HomeTool(autoscale_axes, tooltip="Autoscale axes range"),
             "panzoom": tools.PanZoomTool(view.canvas.panzoom),
+            "grid": tools.GridTool(grid, value=view.canvas.grid),
             "save": tools.SaveTool(view.canvas.download_figure),
         }
     )

src/plopp/widgets/tools.py

@@ -152,6 +152,9 @@ def value(self) -> str | None:
 HomeTool = partial(ButtonTool, icon='home')
 """Return home tool."""
 
+GridTool = partial(ToggleTool, icon='th', tooltip='Toggle grid visibility')
+"""Toggle grid visibility tool."""
+
 SaveTool = partial(ButtonTool, icon='save', tooltip='Save figure')
 """Save figure to png tool."""