Implement frameon parameter and deprecate fig in show()

src/spatialdata_plot/pl/basic.py

@@ -2,8 +2,9 @@
 
 import contextlib
 import sys
+import warnings
 from collections import OrderedDict
-from collections.abc import Callable
+from collections.abc import Callable, Sequence
 from copy import deepcopy
 from pathlib import Path
 from typing import Any, Literal, cast
@@ -938,6 +939,15 @@ def show(
             show,
         )
 
+        if fig is not None and not isinstance(ax, Sequence):
+            warnings.warn(
+                "`fig` is being deprecated as an argument to `PlotAccessor.show` in spatialdata-plot. "
+                "To use a custom figure, create axes from it and pass them via `ax` instead: "
+                "`ax = fig.add_subplot(111)`.",
+                DeprecationWarning,
+                stacklevel=2,
+            )
+
         sdata = self._copy()
 
         # Evaluate execution tree for plotting
@@ -1242,6 +1252,8 @@ def _draw_colorbar(
                         raise IndexError("The number of titles must match the number of coordinate systems.") from e
                 ax.set_title(t)
                 ax.set_aspect("equal")
+                if fig_params.frameon is False:
+                    ax.axis("off")
 
             extent = get_extent(
                 sdata,

tests/pl/test_show.py

@@ -1,9 +1,13 @@
+import warnings
 from unittest.mock import patch
 
 import matplotlib
 import matplotlib.pyplot as plt
+import pytest
 import scanpy as sc
+from matplotlib.figure import Figure
 from spatialdata import SpatialData
+from spatialdata.transformations import Identity, set_transformation
 
 import spatialdata_plot  # noqa: F401
 from tests.conftest import DPI, PlotTester, PlotTesterMeta
@@ -25,6 +29,19 @@ class TestShow(PlotTester, metaclass=PlotTesterMeta):
     def test_plot_pad_extent_adds_padding(self, sdata_blobs: SpatialData):
         sdata_blobs.pl.render_images(element="blobs_image").pl.show(pad_extent=100)
 
+    def test_plot_frameon_false_single_panel(self, sdata_blobs: SpatialData):
+        """Visual test: frameon=False hides axes decorations on a single panel (regression for #204)."""
+        sdata_blobs.pl.render_images(element="blobs_image").pl.show(frameon=False)
+
+    def test_plot_frameon_false_multi_panel(self, sdata_blobs: SpatialData):
+        """Visual test: frameon=False hides axes decorations on all panels (regression for #204)."""
+        set_transformation(sdata_blobs["blobs_image"], Identity(), "second_cs")
+        sdata_blobs.pl.render_images(element="blobs_image").pl.show(frameon=False, title="")
+
+    def test_plot_no_decorations(self, sdata_blobs: SpatialData):
+        """Visual test: frameon=False + title='' produces just the plot content (regression for #204)."""
+        sdata_blobs.pl.render_images(element="blobs_image").pl.show(frameon=False, title="", colorbar=False)
+
     def test_no_plt_show_when_ax_provided(self, sdata_blobs: SpatialData):
         """plt.show() must not be called when the user supplies ax= (regression for #362)."""
         _, ax = plt.subplots()
@@ -40,3 +57,56 @@ def test_plt_show_when_ax_provided_and_show_true(self, sdata_blobs: SpatialData)
             sdata_blobs.pl.render_images(element="blobs_image").pl.show(ax=ax, show=True)
             mock_show.assert_called_once()
         plt.close("all")
+
+    def test_frameon_false_hides_axes_decorations(self, sdata_blobs: SpatialData):
+        """frameon=False should turn off axes decorations (regression for #204)."""
+        ax = sdata_blobs.pl.render_images(element="blobs_image").pl.show(frameon=False, return_ax=True, show=False)
+        assert not ax.axison
+        plt.close("all")
+
+    def test_frameon_none_keeps_axes_decorations(self, sdata_blobs: SpatialData):
+        """Default frameon=None should keep axes decorations visible."""
+        ax = sdata_blobs.pl.render_images(element="blobs_image").pl.show(frameon=None, return_ax=True, show=False)
+        assert ax.axison
+        plt.close("all")
+
+    def test_title_empty_string_suppresses_title(self, sdata_blobs: SpatialData):
+        """title='' should suppress the default coordinate system title (regression for #204)."""
+        ax = sdata_blobs.pl.render_images(element="blobs_image").pl.show(title="", return_ax=True, show=False)
+        assert ax.get_title() == ""
+        plt.close("all")
+
+
+def test_fig_parameter_emits_deprecation_warning(sdata_blobs: SpatialData):
+    """Passing fig= should emit a DeprecationWarning (regression for #204)."""
+    fig = Figure()
+    with pytest.warns(DeprecationWarning, match="`fig` is being deprecated"):
+        sdata_blobs.pl.render_images(element="blobs_image").pl.show(fig=fig, show=False)
+    plt.close("all")
+
+
+def test_fig_parameter_default_no_warning(sdata_blobs: SpatialData):
+    """Not passing fig= should not emit a deprecation warning."""
+    with warnings.catch_warnings():
+        warnings.simplefilter("error", DeprecationWarning)
+        sdata_blobs.pl.render_images(element="blobs_image").pl.show(show=False)
+    plt.close("all")
+
+
+def test_fig_parameter_no_warning_with_ax_list(sdata_blobs: SpatialData):
+    """Passing fig= with a list of axes should not warn (fig is still required there)."""
+    set_transformation(sdata_blobs["blobs_image"], Identity(), "second_cs")
+    fig, axs = plt.subplots(1, 2)
+    with warnings.catch_warnings():
+        warnings.simplefilter("error", DeprecationWarning)
+        sdata_blobs.pl.render_images(element="blobs_image").pl.show(fig=fig, ax=list(axs), show=False)
+    plt.close("all")
+
+
+def test_frameon_false_multi_panel(sdata_blobs: SpatialData):
+    """frameon=False should apply to all panels in a multi-panel plot (regression for #204)."""
+    set_transformation(sdata_blobs["blobs_image"], Identity(), "second_cs")
+    axs = sdata_blobs.pl.render_images(element="blobs_image").pl.show(frameon=False, return_ax=True, show=False)
+    for ax in axs:
+        assert not ax.axison
+    plt.close("all")