feat: add back and forward buttons

src/plopp/backends/matplotlib/canvas.py

@@ -690,6 +690,14 @@ def panzoom(self, value: Literal['pan', 'zoom'] | None):
         elif value is None:
             self.reset_mode()
 
+    def back(self):
+        """Navigate to the previous view in the pan and zoom history."""
+        self.fig.canvas.toolbar.back()
+
+    def forward(self):
+        """Navigate to the next view in the pan and zoom history."""
+        self.fig.canvas.toolbar.forward()
+
     def download_figure(self):
         """
         Save the figure to a PNG file via a pop-up dialog.

src/plopp/widgets/toolbar.py

@@ -66,6 +66,8 @@ def autoscale_axes() -> None:
     return Toolbar(
         tools={
             "home": tools.HomeTool(autoscale_axes, tooltip="Autoscale axes range"),
+            "back": tools.BackTool(view.canvas.back),
+            "forward": tools.ForwardTool(view.canvas.forward),
             "panzoom": tools.PanZoomTool(view.canvas.panzoom),
             "save": tools.SaveTool(view.canvas.download_figure),
         }

src/plopp/widgets/tools.py

@@ -152,6 +152,12 @@ def value(self) -> str | None:
 HomeTool = partial(ButtonTool, icon='home')
 """Return home tool."""
 
+BackTool = partial(ButtonTool, icon='arrow-left', tooltip='Back to previous view')
+"""Return tool for navigating to the previous view."""
+
+ForwardTool = partial(ButtonTool, icon='arrow-right', tooltip='Forward to next view')
+"""Return tool for navigating to the next view."""
+
 SaveTool = partial(ButtonTool, icon='save', tooltip='Save figure')
 """Save figure to png tool."""
 

tests/backends/matplotlib/mpl_canvas_test.py

@@ -167,3 +167,22 @@ def test_home_button_rescales_all_axes_sharing_a_figure():
     p0.toolbar['home'].callback()
 
     assert p1.canvas.yrange == pytest.approx(expected)
+
+
+@pytest.mark.parametrize("ndim", [1, 2])
+def test_back_and_forward_buttons_navigate_view_history(ndim):
+    da = data_array(ndim=ndim)
+    p = da.plot()
+    toolbar = p.canvas.fig.canvas.toolbar
+
+    original_range = p.canvas.xrange
+    toolbar.push_current()
+    zoomed_range = (10.0, 20.0)
+    p.canvas.xrange = zoomed_range
+    toolbar.push_current()
+
+    p.toolbar['back'].click()
+    assert p.canvas.xrange == pytest.approx(original_range)
+
+    p.toolbar['forward'].click()
+    assert p.canvas.xrange == pytest.approx(zoomed_range)