test(as_points): matched matplotlib/datashader visual pairs

Restructure the as_points visual tests into matplotlib+datashader pairs that
render identical params (shared helper) for shapes (no color), labels
(instance_id), and labels (categorical). Drop the old inconsistent/stale
baselines; all 6 will be regenerated from CI so the two backends are directly
comparable and look maximally similar.

Author: timtreis

tests/_images/Labels_can_render_labels_as_points.png

@@ -435,29 +435,34 @@ def test_plot_can_color_labels_by_gene_symbols(self, sdata_blobs: SpatialData):
             "blobs_labels", color="GeneA", table_name="table", gene_symbols="gene_symbol"
         ).pl.show()
 
-    def test_plot_can_render_labels_as_points(self, sdata_blobs: SpatialData):
-        """as_points draws one colored dot per label at its centroid instead of the mask."""
-        sdata_blobs.pl.render_labels("blobs_labels", color="instance_id", as_points=True, size=100).pl.show()
+    @staticmethod
+    def _as_points(sdata_blobs: SpatialData, method: str, color: str = "instance_id"):
+        # identical params for both backends, so the matplotlib and datashader baselines are comparable
+        return sdata_blobs.pl.render_labels("blobs_labels", color=color, as_points=True, method=method, size=600)
 
-    def test_plot_labels_as_points_respects_size(self, sdata_blobs: SpatialData):
-        """size sets the scatter marker area; larger size -> larger dots."""
-        sdata_blobs.pl.render_labels("blobs_labels", color="instance_id", as_points=True, size=600).pl.show()
-
-    def test_plot_labels_as_points_datashader(self, sdata_blobs: SpatialData):
-        """as_points with method='datashader' rasterizes the colored centroids instead of drawing markers."""
-        sdata_blobs.pl.render_labels(
-            "blobs_labels", color="instance_id", as_points=True, method="datashader", size=600
-        ).pl.show()
-
-    def test_plot_labels_as_points_datashader_categorical(self, sdata_blobs: SpatialData):
-        """Categorical-coloured as_points centroids datashade with a legend (color_source_vector path)."""
+    @staticmethod
+    def _add_categorical_color(sdata_blobs: SpatialData) -> str:
         max_col = sdata_blobs["table"].to_df().idxmax(axis=1)
         sdata_blobs["table"].obs["which_max"] = pd.Categorical(
             max_col, categories=sdata_blobs["table"].to_df().columns, ordered=True
         )
-        sdata_blobs.pl.render_labels(
-            "blobs_labels", color="which_max", as_points=True, method="datashader", size=600
-        ).pl.show()
+        return "which_max"
+
+    def test_plot_labels_as_points_matplotlib(self, sdata_blobs: SpatialData):
+        """as_points draws one colored dot per label at its centroid (matplotlib backend)."""
+        self._as_points(sdata_blobs, "matplotlib").pl.show()
+
+    def test_plot_labels_as_points_datashader(self, sdata_blobs: SpatialData):
+        """Same render via datashader; should look maximally similar to the matplotlib baseline."""
+        self._as_points(sdata_blobs, "datashader").pl.show()
+
+    def test_plot_labels_as_points_categorical_matplotlib(self, sdata_blobs: SpatialData):
+        """Categorical-coloured as_points with a legend (matplotlib backend)."""
+        self._as_points(sdata_blobs, "matplotlib", color=self._add_categorical_color(sdata_blobs)).pl.show()
+
+    def test_plot_labels_as_points_categorical_datashader(self, sdata_blobs: SpatialData):
+        """Same categorical render via datashader (color_source_vector + legend path)."""
+        self._as_points(sdata_blobs, "datashader", color=self._add_categorical_color(sdata_blobs)).pl.show()
 
 
 def test_raises_when_table_does_not_annotate_element(sdata_blobs: SpatialData):

tests/_images/Labels_labels_as_points_datashader.png

@@ -1108,17 +1108,18 @@ def test_plot_can_color_shapes_by_gene_symbols(self, sdata_blobs: SpatialData):
             "blobs_circles", color="GeneA", table_name="table", gene_symbols="gene_symbol"
         ).pl.show()
 
-    def test_plot_can_render_circles_as_points(self, sdata_blobs: SpatialData):
-        """as_points draws one dot per shape at its centroid instead of the geometry."""
-        sdata_blobs.pl.render_shapes("blobs_circles", as_points=True, size=100).pl.show()
+    @staticmethod
+    def _as_points(sdata_blobs: SpatialData, method: str):
+        # identical params for both backends, so the matplotlib and datashader baselines are comparable
+        return sdata_blobs.pl.render_shapes("blobs_circles", as_points=True, method=method, size=600)
 
-    def test_plot_shapes_as_points_respects_size(self, sdata_blobs: SpatialData):
-        """size sets the scatter marker area; larger size -> larger dots."""
-        sdata_blobs.pl.render_shapes("blobs_circles", as_points=True, size=600).pl.show()
+    def test_plot_shapes_as_points_matplotlib(self, sdata_blobs: SpatialData):
+        """as_points draws one dot per shape at its centroid (matplotlib backend)."""
+        self._as_points(sdata_blobs, "matplotlib").pl.show()
 
     def test_plot_shapes_as_points_datashader(self, sdata_blobs: SpatialData):
-        """as_points with method='datashader' rasterizes the centroids instead of drawing markers."""
-        sdata_blobs.pl.render_shapes("blobs_circles", as_points=True, method="datashader", size=600).pl.show()
+        """Same render via datashader; should look maximally similar to the matplotlib baseline."""
+        self._as_points(sdata_blobs, "datashader").pl.show()
 
 
 def test_gene_symbols_auto_detect_table(sdata_blobs: SpatialData):