Fast cell rendering: render_shapes/labels(as_points=True) + axis-aligned extent

src/spatialdata_plot/pl/basic.py

@@ -64,13 +64,15 @@
     _expand_color_panels,
     _get_cs_contents,
     _get_elements_to_be_rendered,
+    _get_extent_fast,
     _get_valid_cs,
     _get_wanted_render_elements,
     _maybe_set_colors,
     _mpl_ax_contains_elements,
     _prepare_cmap_norm,
     _prepare_params_plot,
     _set_outline,
+    _validate_as_points_size,
     _validate_graph_render_params,
     _validate_image_render_params,
     _validate_label_render_params,
@@ -332,6 +334,8 @@ def render_shapes(
         colorbar_params: dict[str, object] | None = None,
         datashader_reduction: _DsReduction | None = None,
         transfunc: Callable[[float], float] | None = None,
+        as_points: bool = False,
+        size: float | int = 1.0,
     ) -> sd.SpatialData:
         """
         Render shapes elements in SpatialData.
@@ -448,6 +452,8 @@ def render_shapes(
         sd.SpatialData
             A copy of the SpatialData object with the rendering parameters stored in its plotting tree.
         """
+        if as_points:
+            _validate_as_points_size(size)
         panel_param_dicts = _expand_color_panels(
             self._sdata,
             color,
@@ -515,6 +521,8 @@ def render_shapes(
                     ds_reduction=param_values["ds_reduction"],
                     colorbar=param_values["colorbar"],
                     colorbar_params=param_values["colorbar_params"],
+                    as_points=as_points,
+                    size=size,
                     panel_key=panel_key,
                 )
                 n_steps += 1
@@ -953,6 +961,9 @@ def render_labels(
         table_layer: str | None = None,
         gene_symbols: str | None = None,
         transfunc: Callable[[float], float] | None = None,
+        as_points: bool = False,
+        size: float | int = 1.0,
+        method: str | None = None,
     ) -> sd.SpatialData:
         """
         Render labels elements in SpatialData.
@@ -1038,12 +1049,18 @@ def render_labels(
             in another column of ``var``. Mimics scanpy's ``gene_symbols`` parameter.
         transfunc : Callable[[float], float] | None, optional
             Optional transformation applied to the continuous color vector before normalization and colormap mapping.
+        method : str | None, optional
+            Backend for ``as_points`` centroids: ``'matplotlib'`` or ``'datashader'``. When ``None``,
+            matplotlib is used unless there are more than ~500k centroids. Datashader is skipped (with a
+            warning) when the colouring cannot be aggregated (e.g. labels with no color column).
 
         Returns
         -------
         sd.SpatialData
             A copy of the SpatialData object with the rendering parameters stored in its plotting tree.
         """
+        if as_points:
+            _validate_as_points_size(size)
         panel_param_dicts = _expand_color_panels(
             self._sdata,
             color,
@@ -1101,6 +1118,9 @@ def render_labels(
                     zorder=n_steps,
                     colorbar=param_values["colorbar"],
                     colorbar_params=param_values["colorbar_params"],
+                    as_points=as_points,
+                    size=size,
+                    method=method,
                     panel_key=panel_key,
                 )
                 n_steps += 1
@@ -1812,15 +1832,16 @@ def _draw_colorbar(
                 empty_shape_elements = [
                     name
                     for name in wanted_elements
-                    if name in sdata.shapes and not sdata.shapes[name]["geometry"].apply(lambda g: not g.is_empty).any()
+                    if name in sdata.shapes and sdata.shapes[name]["geometry"].is_empty.all()
                 ]
                 if empty_shape_elements:
                     raise ValueError(
                         f"Cannot render shape element(s) {empty_shape_elements} in coordinate system {cs!r}: "
                         "all geometries are empty. Drop the element or restore at least one non-empty geometry."
                     )
 
-            extent = get_extent(
+            # fast path for axis-aligned transforms; identical result, falls back to get_extent otherwise
+            extent = _get_extent_fast(
                 sdata,
                 coordinate_system=cs,
                 has_images=has_images and wants_images,