Reject legend_loc='on data' loudly in pl.show() (#649)

Author: timtreis

src/spatialdata_plot/pl/basic.py

@@ -1147,6 +1147,9 @@ def show(
             legend_fontoutline = legend_params.get("fontoutline", legend_fontoutline)
             na_in_legend = legend_params.get("na_in_legend", na_in_legend)
 
+        if legend_loc == "on data":
+            raise ValueError("legend_loc='on data' is not supported in spatialdata-plot.")
+
         legend_params_obj = LegendParams(
             legend_fontsize=legend_fontsize,
             legend_fontweight=legend_fontweight,

src/spatialdata_plot/pl/render.py

@@ -1153,12 +1153,6 @@ def _draw_channel_legend(
         palette_dict[entry.channel_name] = entry.color_hex
 
     legend_loc = legend_params.legend_loc
-    if legend_loc == "on data":
-        logger.warning(
-            "legend_loc='on data' is not supported for channel legends (no scatter coordinates); "
-            "falling back to 'right margin'."
-        )
-        legend_loc = "right margin"
 
     categories = pd.Categorical(list(palette_dict))