test(render): visual permutation grids for points, labels, polygons

Adds 2x2 visual tests mirroring the circle one, for the other elements whose render
paths split by backend / as_points, so divergence or breakage across paths is visible:

- points:   (no color / continuous) x (matplotlib / datashader)
- labels:   (fill / as_points)       x (matplotlib / datashader)
- polygons: (geometry / as_points)   x (matplotlib / datashader)

Colorbars disabled and marker sizes bumped so panels stay non-degenerate; each panel is
titled with its (mode x backend) combination. New baselines to be generated from CI.

Author: timtreis

tests/pl/test_render_labels.py

@@ -40,6 +40,19 @@ def _annotate_labels_with_outline_columns(sdata: SpatialData) -> SpatialData:
 
 
 class TestLabels(PlotTester, metaclass=PlotTesterMeta):
+    def test_plot_labels_render_permutations(self, sdata_blobs: SpatialData):
+        """2x2 of (fill / as_points) x (matplotlib / datashader); fill is backend-invariant, as_points should match."""
+        panels = [
+            ("fill · matplotlib", {"method": "matplotlib"}),
+            ("fill · datashader", {"method": "datashader"}),
+            ("as_points · matplotlib", {"as_points": True, "size": 150, "method": "matplotlib"}),
+            ("as_points · datashader", {"as_points": True, "size": 150, "method": "datashader"}),
+        ]
+        _, axs = plt.subplots(2, 2, figsize=(8, 8))
+        for ax, (title, kw) in zip(axs.ravel(), panels, strict=True):
+            sdata_blobs.pl.render_labels("blobs_labels", color="channel_0_sum", colorbar=False, **kw).pl.show(ax=ax)
+            ax.set_title(title, fontsize=8)
+
     def test_plot_can_render_labels(self, sdata_blobs: SpatialData):
         sdata_blobs.pl.render_labels(element="blobs_labels").pl.show()
 

tests/pl/test_render_points.py

@@ -48,6 +48,19 @@
 
 
 class TestPoints(PlotTester, metaclass=PlotTesterMeta):
+    def test_plot_points_render_permutations(self, sdata_blobs: SpatialData):
+        """2x2 of (no color / continuous color) x (matplotlib / datashader); columns should look alike."""
+        panels = [
+            ("no color · matplotlib", {"method": "matplotlib"}),
+            ("no color · datashader", {"method": "datashader"}),
+            ("color · matplotlib", {"color": "instance_id", "method": "matplotlib", "colorbar": False}),
+            ("color · datashader", {"color": "instance_id", "method": "datashader", "colorbar": False}),
+        ]
+        _, axs = plt.subplots(2, 2, figsize=(8, 8))
+        for ax, (title, kw) in zip(axs.ravel(), panels, strict=True):
+            sdata_blobs.pl.render_points("blobs_points", size=200, **kw).pl.show(ax=ax)
+            ax.set_title(title, fontsize=8)
+
     def test_plot_can_render_points(self, sdata_blobs: SpatialData):
         sdata_blobs.pl.render_points(element="blobs_points").pl.show()
 

tests/pl/test_render_shapes.py

@@ -71,6 +71,20 @@ def test_plot_circle_render_permutations(self, monkeypatch):
             sdata.pl.render_shapes("circ", **kw).pl.show(ax=ax)
             ax.set_title(title, fontsize=8)
 
+    def test_plot_polygon_render_permutations(self, sdata_blobs_shapes_annotated: SpatialData):
+        """2x2 of (geometry / as_points) x (matplotlib / datashader) for polygons; columns should look alike."""
+        panels = [
+            ("geometry · matplotlib", {"method": "matplotlib"}),
+            ("geometry · datashader", {"method": "datashader"}),
+            ("as_points · matplotlib", {"as_points": True, "size": 150, "method": "matplotlib"}),
+            ("as_points · datashader", {"as_points": True, "size": 150, "method": "datashader"}),
+        ]
+        annotated = sdata_blobs_shapes_annotated
+        _, axs = plt.subplots(2, 2, figsize=(8, 8))
+        for ax, (title, kw) in zip(axs.ravel(), panels, strict=True):
+            annotated.pl.render_shapes("blobs_polygons", color="value", colorbar=False, **kw).pl.show(ax=ax)
+            ax.set_title(title, fontsize=8)
+
     def test_plot_can_render_circles(self, sdata_blobs: SpatialData):
         sdata_blobs.pl.render_shapes(element="blobs_circles").pl.show()