render_shapes now has a scale parameter

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning][].
 ### Added
 
 -   Multipolygons are now handled correctly (#93)
+-   Can now scale shapes (#152)
 -   Can now plot columns from GeoDataFrame (#149)
 
 ### Fixed

src/spatialdata_plot/pl/basic.py

@@ -145,7 +145,7 @@ def render_shapes(
         elements: str | list[str] | None = None,
         color: str | None = None,
         groups: str | Sequence[str] | None = None,
-        size: float = 1.0,
+        scale: float = 1.0,
         outline: bool = False,
         outline_width: float = 1.5,
         outline_color: str | list[float] = "#000000ff",
@@ -171,7 +171,7 @@ def render_shapes(
         groups
             For discrete annotation in ``color``, select which values
             to plot (other values are set to NAs).
-        size
+        scale
             Value to scale circles, if present.
         outline
             If `True`, a thin border around points/shapes is plotted.
@@ -212,11 +212,12 @@ def render_shapes(
             na_color=na_color,  # type: ignore[arg-type]
             **kwargs,
         )
-        outline_params = _set_outline(size, outline, outline_width, outline_color)
+        outline_params = _set_outline(outline, outline_width, outline_color)
         sdata.plotting_tree[f"{n_steps+1}_render_shapes"] = ShapesRenderParams(
             elements=elements,
             color=color,
             groups=groups,
+            scale=scale,
             outline_params=outline_params,
             layer=layer,
             cmap_params=cmap_params,

src/spatialdata_plot/pl/render.py

@@ -102,7 +102,7 @@ def _render_shapes(
         shapes = gpd.GeoDataFrame(shapes, geometry="geometry")
         _cax = _get_collection_shape(
             shapes=shapes,
-            s=render_params.size,
+            s=render_params.scale,
             c=color_vector,
             render_params=render_params,
             rasterized=sc_settings._vector_friendly,

src/spatialdata_plot/pl/render_params.py

@@ -77,7 +77,7 @@ class ShapesRenderParams:
     palette: ListedColormap | str | None = None
     outline_alpha: float = 1.0
     fill_alpha: float = 0.3
-    size: float = 1.0
+    scale: float = 1.0
     transfunc: Callable[[float], float] | None = None
 
 

src/spatialdata_plot/pl/utils.py

@@ -185,7 +185,7 @@ def _get_collection_shape(
     Args:
     - shapes (list[GeoDataFrame]): List of geometrical shapes.
     - c: Color parameter.
-    - s (float): Size of the shape.
+    - s (float): Scale of the shape.
     - norm: Normalization for the color map.
     - fill_alpha (float, optional): Opacity for the fill color.
     - outline_alpha (float, optional): Opacity for the outline.
@@ -241,21 +241,30 @@ def assign_fill_and_outline_to_row(
         geom = row["geometry"]
         if geom.geom_type == "Polygon":
             row = row.to_dict()
-            row["geometry"] = mplp.Polygon(geom.exterior.coords, closed=True)
+            coords = np.array(geom.exterior.coords)
+            centroid = np.mean(coords, axis=0)
+            scaled_coords = [(centroid + (np.array(coord) - centroid) * s).tolist() for coord in geom.exterior.coords]
+            row["geometry"] = mplp.Polygon(scaled_coords, closed=True)
             assign_fill_and_outline_to_row(shapes, fill_c, outline_c, row, idx)
             rows.append(row)
 
         elif geom.geom_type == "MultiPolygon":
-            mp = _make_patch_from_multipolygon(geom)
-            for _, m in enumerate(mp):
+            # mp = _make_patch_from_multipolygon(geom)
+            for polygon in geom.geoms:
                 mp_copy = row.to_dict()
-                mp_copy["geometry"] = m
+                coords = np.array(polygon.exterior.coords)
+                centroid = np.mean(coords, axis=0)
+                scaled_coords = [(centroid + (coord - centroid) * s).tolist() for coord in coords]
+                mp_copy["geometry"] = mplp.Polygon(scaled_coords, closed=True)
                 assign_fill_and_outline_to_row(shapes, fill_c, outline_c, mp_copy, idx)
                 rows.append(mp_copy)
 
         elif geom.geom_type == "Point":
             row = row.to_dict()
-            row["geometry"] = mplp.Circle((geom.x, geom.y), radius=row["radius"])
+            scaled_radius = row["radius"] * s
+            row["geometry"] = mplp.Circle(
+                (geom.x, geom.y), radius=scaled_radius
+            )  # Circle is always scaled from its center
             assign_fill_and_outline_to_row(shapes, fill_c, outline_c, row, idx)
             rows.append(row)
 
@@ -576,7 +585,6 @@ def _prepare_cmap_norm(
 
 
 def _set_outline(
-    size: float,
     outline: bool = False,
     outline_width: float = 1.5,
     outline_color: str | list[float] = "#0000000ff",  # black, white

tests/pl/test_render_shapes.py

@@ -97,3 +97,6 @@ def test_plot_can_color_from_geodataframe(self, sdata_blobs: SpatialData):
             elements="blobs_polygons",
             color="value",
         ).pl.show()
+
+    def test_plot_can_scale_shapes(self, sdata_blobs: SpatialData):
+        sdata_blobs.pl.render_shapes(elements="blobs_circles", scale=0.5).pl.show()