fixup! add the toolctx() context manager to simplify temporary retool() calls

masque/library.py

@@ -1068,20 +1068,22 @@ class ILibrary(ILibraryView, MutableMapping[str, 'Pattern'], metaclass=ABCMeta):
         Returns:
             A set containing the names of all deleted patterns
         """
+        parent_graph = self.parent_graph()
+        empty = {name for name, pat in self.items() if pat.is_empty()}
         trimmed = set()
-        while empty := {name for name, pat in self.items() if pat.is_empty()}:
+        while empty:
+            parents = set()
             for name in empty:
                 del self[name]
-
+                for parent in parent_graph[name]:
-            for pat in self.values():
+                    del self[parent].refs[name]
-                for name in empty:
+                parents |= parent_graph[name]
-                    # Second pass to skip looking at refs in empty patterns
-                    if name in pat.refs:
-                        del pat.refs[name]
 
             trimmed |= empty
             if not repeat:
                 break
+
+            empty = {parent for parent in parents if self[parent].is_empty()}
         return trimmed
 
     def delete(

masque/shapes/polygon.py

@@ -20,7 +20,7 @@ class Polygon(Shape):
     A polygon, consisting of a bunch of vertices (Nx2 ndarray) which specify an
        implicitly-closed boundary, and an offset.
 
-    Note that the setter for `Polygon.vertices` may creates a copy of the
+    Note that the setter for `Polygon.vertices` creates a copy of the
       passed vertex coordinates.
 
     A `normalized_form(...)` is available, but can be quite slow with lots of vertices.
@@ -379,8 +379,9 @@ class Polygon(Shape):
     def normalized_form(self, norm_value: float) -> normalized_shape_tuple:
         # Note: this function is going to be pretty slow for many-vertexed polygons, relative to
         #   other shapes
-        offset = self.vertices.mean(axis=0) + self.offset
+        meanv = self.vertices.mean(axis=0)
-        zeroed_vertices = self.vertices - offset
+        zeroed_vertices = self.vertices - meanv
+        offset = meanv + self.offset
 
         scale = zeroed_vertices.std()
         normed_vertices = zeroed_vertices / scale