From dfc01b7be339d9517202ef43424a7d26fdd9767f Mon Sep 17 00:00:00 2001
From: Knut Nergaard <knut.nergaard@gmail.com>
Date: Thu, 5 Dec 2024 11:46:30 +0100
Subject: [PATCH 01/10] Add type annotation and correct errors.

---
 Lib/fontParts/base/component.py | 133 ++++++++++++++++++--------------
 1 file changed, 77 insertions(+), 56 deletions(-)

diff --git a/Lib/fontParts/base/component.py b/Lib/fontParts/base/component.py
index 755e28ae..90af01d3 100644
--- a/Lib/fontParts/base/component.py
+++ b/Lib/fontParts/base/component.py
@@ -1,3 +1,6 @@
+from __future__ import annotations
+from typing import TYPE_CHECKING, cast, Any, Iterator, List, Optional, Tuple, Union
+
 from fontTools.misc import transform
 from fontParts.base import normalizers
 from fontParts.base.errors import FontPartsError
@@ -13,6 +16,24 @@
 )
 from fontParts.base.compatibility import ComponentCompatibilityReporter
 from fontParts.base.deprecated import DeprecatedComponent, RemovedComponent
+from fontParts.base.annotations import (
+    PairType,
+    PairCollectionType,
+    QuadrupleType,
+    SextupleType,
+    SextupleCollectionType,
+    IntFloatType,
+    PenType,
+    PointPenType,
+)
+
+if TYPE_CHECKING:
+    from fontParts.base.point import BasePoint
+    from fontParts.base.bPoint import BaseBPoint
+    from fontParts.base.segment import BaseSegment
+    from fontParts.base.glyph import BaseGlyph
+    from fontParts.base.layer import BaseLayer
+    from fontParts.base.font import BaseFont
 
 
 class BaseComponent(
@@ -24,9 +45,9 @@ class BaseComponent(
     DeprecatedComponent,
     RemovedComponent,
 ):
-    copyAttributes = ("baseGlyph", "transformation")
+    copyAttributes: Tuple[str, str] = ("baseGlyph", "transformation")
 
-    def _reprContents(self):
+    def _reprContents(self) -> List[str]:
         contents = [
             f"baseGlyph='{self.baseGlyph}'",
             f"offset='({self.offset[0]}, {self.offset[1]})'",
@@ -44,14 +65,14 @@ def _reprContents(self):
 
     _glyph = None
 
-    glyph = dynamicProperty("glyph", "The component's parent glyph.")
+    glyph: dynamicProperty = dynamicProperty("glyph", "The component's parent glyph.")
 
-    def _get_glyph(self):
+    def _get_glyph(self) -> Optional[BaseGlyph]:
         if self._glyph is None:
             return None
         return self._glyph()
 
-    def _set_glyph(self, glyph):
+    def _set_glyph(self, glyph: Optional[BaseGlyph]) -> None:
         if self._glyph is not None:
             raise AssertionError("glyph for component already set")
         if glyph is not None:
@@ -60,18 +81,18 @@ def _set_glyph(self, glyph):
 
     # Layer
 
-    layer = dynamicProperty("layer", "The component's parent layer.")
+    layer: dynamicProperty = dynamicProperty("layer", "The component's parent layer.")
 
-    def _get_layer(self):
+    def _get_layer(self) -> Optional[BaseLayer]:
         if self._glyph is None:
             return None
         return self.glyph.layer
 
     # Font
 
-    font = dynamicProperty("font", "The component's parent font.")
+    font: dynamicProperty = dynamicProperty("font", "The component's parent font.")
 
-    def _get_font(self):
+    def _get_font(self) -> Optional[BaseFont]:
         if self._glyph is None:
             return None
         return self.glyph.font
@@ -82,31 +103,29 @@ def _get_font(self):
 
     # baseGlyph
 
-    baseGlyph = dynamicProperty(
+    baseGlyph: dynamicProperty = dynamicProperty(
         "base_baseGlyph", "The name of the glyph the component references."
     )
 
-    def _get_base_baseGlyph(self):
+    def _get_base_baseGlyph(self) -> Optional[str]:
         value = self._get_baseGlyph()
         # if the component does not belong to a layer,
         # it is allowed to have None as its baseGlyph
-        if value is None and self.layer is None:
-            pass
-        else:
-            value = normalizers.normalizeGlyphName(value)
-        return value
+        if value is None or self.layer is None:
+            return value
+        return normalizers.normalizeGlyphName(value)
 
-    def _set_base_baseGlyph(self, value):
+    def _set_base_baseGlyph(self, value: str) -> None:
         value = normalizers.normalizeGlyphName(value)
         self._set_baseGlyph(value)
 
-    def _get_baseGlyph(self):
+    def _get_baseGlyph(self) -> Optional[str]:
         """
         Subclasses must override this method.
         """
         self.raiseNotImplementedError()
 
-    def _set_baseGlyph(self, value):
+    def _set_baseGlyph(self, value: str) -> None:
         """
         Subclasses must override this method.
         """
@@ -114,26 +133,26 @@ def _set_baseGlyph(self, value):
 
     # transformation
 
-    transformation = dynamicProperty(
+    transformation: dynamicProperty = dynamicProperty(
         "base_transformation", "The component's transformation matrix."
     )
 
-    def _get_base_transformation(self):
+    def _get_base_transformation(self) -> SextupleType[float]:
         value = self._get_transformation()
         value = normalizers.normalizeTransformationMatrix(value)
         return value
 
-    def _set_base_transformation(self, value):
+    def _set_base_transformation(self, value: SextupleCollectionType[IntFloatType]) -> None:
         value = normalizers.normalizeTransformationMatrix(value)
         self._set_transformation(value)
 
-    def _get_transformation(self):
+    def _get_transformation(self) -> SextupleType[float]:
         """
         Subclasses must override this method.
         """
         self.raiseNotImplementedError()
 
-    def _set_transformation(self, value):
+    def _set_transformation(self, value: SextupleCollectionType[IntFloatType]) -> None:
         """
         Subclasses must override this method.
         """
@@ -141,25 +160,25 @@ def _set_transformation(self, value):
 
     # offset
 
-    offset = dynamicProperty("base_offset", "The component's offset.")
+    offset: dynamicProperty = dynamicProperty("base_offset", "The component's offset.")
 
-    def _get_base_offset(self):
+    def _get_base_offset(self) -> PairType[IntFloatType]:
         value = self._get_offset()
         value = normalizers.normalizeTransformationOffset(value)
         return value
 
-    def _set_base_offset(self, value):
+    def _set_base_offset(self, value: PairCollectionType[IntFloatType]) -> None:
         value = normalizers.normalizeTransformationOffset(value)
         self._set_offset(value)
 
-    def _get_offset(self):
+    def _get_offset(self) -> PairType[IntFloatType]:
         """
         Subclasses may override this method.
         """
         sx, sxy, syx, sy, ox, oy = self.transformation
         return ox, oy
 
-    def _set_offset(self, value):
+    def _set_offset(self, value: PairCollectionType[IntFloatType]) -> None:
         """
         Subclasses may override this method.
         """
@@ -169,25 +188,25 @@ def _set_offset(self, value):
 
     # scale
 
-    scale = dynamicProperty("base_scale", "The component's scale.")
+    scale: dynamicProperty = dynamicProperty("base_scale", "The component's scale.")
 
-    def _get_base_scale(self):
+    def _get_base_scale(self) -> PairType[float]:
         value = self._get_scale()
         value = normalizers.normalizeComponentScale(value)
         return value
 
-    def _set_base_scale(self, value):
+    def _set_base_scale(self, value: PairCollectionType[IntFloatType]) -> None:
         value = normalizers.normalizeComponentScale(value)
         self._set_scale(value)
 
-    def _get_scale(self):
+    def _get_scale(self) -> PairType[float]:
         """
         Subclasses may override this method.
         """
         sx, sxy, syx, sy, ox, oy = self.transformation
         return sx, sy
 
-    def _set_scale(self, value):
+    def _set_scale(self, value: PairCollectionType[IntFloatType]) -> None:
         """
         Subclasses may override this method.
         """
@@ -201,7 +220,7 @@ def _set_scale(self, value):
 
     # index
 
-    index = dynamicProperty(
+    index: dynamicProperty = dynamicProperty(
         "base_index",
         (
             "The index of the component within the "
@@ -209,7 +228,7 @@ def _set_scale(self, value):
         ),
     )
 
-    def _get_base_index(self):
+    def _get_base_index(self) -> Optional[int]:
         glyph = self.glyph
         if glyph is None:
             return None
@@ -217,11 +236,13 @@ def _get_base_index(self):
         value = normalizers.normalizeIndex(value)
         return value
 
-    def _set_base_index(self, value):
+    def _set_base_index(self, value: int) -> None:
         glyph = self.glyph
         if glyph is None:
             raise FontPartsError("The component does not belong to a glyph.")
         value = normalizers.normalizeIndex(value)
+        if value is None:
+            raise ValueError("Value cannot be None.")
         componentCount = len(glyph.components)
         if value < 0:
             value = -(value % componentCount)
@@ -229,14 +250,14 @@ def _set_base_index(self, value):
             value = componentCount
         self._set_index(value)
 
-    def _get_index(self):
+    def _get_index(self) -> Optional[int]:
         """
         Subclasses may override this method.
         """
         glyph = self.glyph
         return glyph.components.index(self)
 
-    def _set_index(self, value):
+    def _set_index(self, value: int) -> None:
         """
         Subclasses must override this method.
         """
@@ -246,13 +267,13 @@ def _set_index(self, value):
     # Pens
     # ----
 
-    def draw(self, pen):
+    def draw(self, pen: PenType) -> None:
         """
         Draw the component with the given Pen.
         """
         self._draw(pen)
 
-    def _draw(self, pen, **kwargs):
+    def _draw(self, pen: PenType, **kwargs: Any) -> None:
         """
         Subclasses may override this method.
         """
@@ -261,13 +282,13 @@ def _draw(self, pen, **kwargs):
         adapter = PointToSegmentPen(pen)
         self.drawPoints(adapter)
 
-    def drawPoints(self, pen):
+    def drawPoints(self, pen: PointPenType) -> None:
         """
         Draw the contour with the given PointPen.
         """
         self._drawPoints(pen)
 
-    def _drawPoints(self, pen, **kwargs):
+    def _drawPoints(self, pen: PointPenType, **kwargs: Any) -> None:
         """
         Subclasses may override this method.
         """
@@ -289,7 +310,7 @@ def _drawPoints(self, pen, **kwargs):
     # Transformation
     # --------------
 
-    def _transformBy(self, matrix, **kwargs):
+    def _transformBy(self, matrix: SextupleCollectionType[IntFloatType], **kwargs: Any) -> None:
         """
         Subclasses may override this method.
         """
@@ -301,13 +322,13 @@ def _transformBy(self, matrix, **kwargs):
     # Normalization
     # -------------
 
-    def round(self):
+    def round(self) -> None:
         """
         Round offset coordinates.
         """
         self._round()
 
-    def _round(self):
+    def _round(self) -> None:
         """
         Subclasses may override this method.
         """
@@ -316,7 +337,7 @@ def _round(self):
         y = normalizers.normalizeVisualRounding(y)
         self.offset = (x, y)
 
-    def decompose(self):
+    def decompose(self) -> None:
         """
         Decompose the component.
         """
@@ -325,7 +346,7 @@ def decompose(self):
             raise FontPartsError("The component does not belong to a glyph.")
         self._decompose()
 
-    def _decompose(self):
+    def _decompose(self) -> None:
         """
         Subclasses must override this method.
         """
@@ -337,7 +358,7 @@ def _decompose(self):
 
     compatibilityReporterClass = ComponentCompatibilityReporter
 
-    def isCompatible(self, other):
+    def isCompatible(self, other: BaseComponent) -> Tuple[bool, ComponentCompatibilityReporter]:
         """
         Evaluate interpolation compatibility with **other**. ::
 
@@ -354,7 +375,7 @@ def isCompatible(self, other):
         """
         return super(BaseComponent, self).isCompatible(other, BaseComponent)
 
-    def _isCompatible(self, other, reporter):
+    def _isCompatible(self, other: BaseComponent, reporter: ComponentCompatibilityReporter) -> None:
         """
         This is the environment implementation of
         :meth:`BaseComponent.isCompatible`.
@@ -364,7 +385,7 @@ def _isCompatible(self, other, reporter):
         component1 = self
         component2 = other
         # base glyphs
-        if component1.baseName != component2.baseName:
+        if component1.baseGlyph != component2.baseGlyph:
             reporter.baseDifference = True
             reporter.warning = True
 
@@ -372,7 +393,7 @@ def _isCompatible(self, other, reporter):
     # Data Queries
     # ------------
 
-    def pointInside(self, point):
+    def pointInside(self, point: PairCollectionType[IntFloatType]) -> bool:
         """
         Determine if point is in the black or white of the component.
 
@@ -381,7 +402,7 @@ def pointInside(self, point):
         point = normalizers.normalizeCoordinateTuple(point)
         return self._pointInside(point)
 
-    def _pointInside(self, point):
+    def _pointInside(self, point: PairCollectionType[IntFloatType]) -> bool:
         """
         Subclasses may override this method.
         """
@@ -391,18 +412,18 @@ def _pointInside(self, point):
         self.draw(pen)
         return pen.getResult()
 
-    bounds = dynamicProperty(
+    bounds: dynamicProperty = dynamicProperty(
         "base_bounds",
         ("The bounds of the component: " "(xMin, yMin, xMax, yMax) or None."),
     )
 
-    def _get_base_bounds(self):
+    def _get_base_bounds(self) -> QuadrupleType[float]:
         value = self._get_bounds()
         if value is not None:
             value = normalizers.normalizeBoundingBox(value)
         return value
 
-    def _get_bounds(self):
+    def _get_bounds(self) -> QuadrupleType[float]:
         """
         Subclasses may override this method.
         """

From c8d1a8ec6b5775d7873a54c14aadc83075a89ae4 Mon Sep 17 00:00:00 2001
From: knutnergaard <knutnergaard@users.noreply.github.com>
Date: Thu, 5 Dec 2024 10:47:10 +0000
Subject: [PATCH 02/10] Format fixes by ruff

---
 Lib/fontParts/base/component.py | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/Lib/fontParts/base/component.py b/Lib/fontParts/base/component.py
index 90af01d3..bbec6a1c 100644
--- a/Lib/fontParts/base/component.py
+++ b/Lib/fontParts/base/component.py
@@ -142,7 +142,9 @@ def _get_base_transformation(self) -> SextupleType[float]:
         value = normalizers.normalizeTransformationMatrix(value)
         return value
 
-    def _set_base_transformation(self, value: SextupleCollectionType[IntFloatType]) -> None:
+    def _set_base_transformation(
+        self, value: SextupleCollectionType[IntFloatType]
+    ) -> None:
         value = normalizers.normalizeTransformationMatrix(value)
         self._set_transformation(value)
 
@@ -310,7 +312,9 @@ def _drawPoints(self, pen: PointPenType, **kwargs: Any) -> None:
     # Transformation
     # --------------
 
-    def _transformBy(self, matrix: SextupleCollectionType[IntFloatType], **kwargs: Any) -> None:
+    def _transformBy(
+        self, matrix: SextupleCollectionType[IntFloatType], **kwargs: Any
+    ) -> None:
         """
         Subclasses may override this method.
         """
@@ -358,7 +362,9 @@ def _decompose(self) -> None:
 
     compatibilityReporterClass = ComponentCompatibilityReporter
 
-    def isCompatible(self, other: BaseComponent) -> Tuple[bool, ComponentCompatibilityReporter]:
+    def isCompatible(
+        self, other: BaseComponent
+    ) -> Tuple[bool, ComponentCompatibilityReporter]:
         """
         Evaluate interpolation compatibility with **other**. ::
 
@@ -375,7 +381,9 @@ def isCompatible(self, other: BaseComponent) -> Tuple[bool, ComponentCompatibili
         """
         return super(BaseComponent, self).isCompatible(other, BaseComponent)
 
-    def _isCompatible(self, other: BaseComponent, reporter: ComponentCompatibilityReporter) -> None:
+    def _isCompatible(
+        self, other: BaseComponent, reporter: ComponentCompatibilityReporter
+    ) -> None:
         """
         This is the environment implementation of
         :meth:`BaseComponent.isCompatible`.

From fd426e3661b5a1849a6c5dbaae9a35f0f1176538 Mon Sep 17 00:00:00 2001
From: Knut Nergaard <knut.nergaard@gmail.com>
Date: Thu, 5 Dec 2024 11:51:01 +0100
Subject: [PATCH 03/10] Delete unused imports.

---
 Lib/fontParts/base/component.py | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/Lib/fontParts/base/component.py b/Lib/fontParts/base/component.py
index 90af01d3..12a83fa4 100644
--- a/Lib/fontParts/base/component.py
+++ b/Lib/fontParts/base/component.py
@@ -1,5 +1,5 @@
 from __future__ import annotations
-from typing import TYPE_CHECKING, cast, Any, Iterator, List, Optional, Tuple, Union
+from typing import TYPE_CHECKING, Any, List, Optional, Tuple
 
 from fontTools.misc import transform
 from fontParts.base import normalizers
@@ -8,7 +8,6 @@
     BaseObject,
     TransformationMixin,
     InterpolationMixin,
-    PointPositionMixin,
     SelectionMixin,
     IdentifierMixin,
     dynamicProperty,
@@ -28,9 +27,6 @@
 )
 
 if TYPE_CHECKING:
-    from fontParts.base.point import BasePoint
-    from fontParts.base.bPoint import BaseBPoint
-    from fontParts.base.segment import BaseSegment
     from fontParts.base.glyph import BaseGlyph
     from fontParts.base.layer import BaseLayer
     from fontParts.base.font import BaseFont

From 40abe55c0914adf1fd4597103699bcfbaf696a74 Mon Sep 17 00:00:00 2001
From: Knut Nergaard <knut.nergaard@gmail.com>
Date: Thu, 5 Dec 2024 20:15:57 +0100
Subject: [PATCH 04/10] Add/improve documentation and make other slight
 changes.

---
 Lib/fontParts/base/component.py | 466 +++++++++++++++++++++++++++-----
 1 file changed, 393 insertions(+), 73 deletions(-)

diff --git a/Lib/fontParts/base/component.py b/Lib/fontParts/base/component.py
index dad33ebc..5e5ee063 100644
--- a/Lib/fontParts/base/component.py
+++ b/Lib/fontParts/base/component.py
@@ -2,6 +2,8 @@
 from typing import TYPE_CHECKING, Any, List, Optional, Tuple
 
 from fontTools.misc import transform
+from fontTools.pens.pointInsidePen import PointInsidePen
+from fontTools.pens.boundsPen import BoundsPen
 from fontParts.base import normalizers
 from fontParts.base.errors import FontPartsError
 from fontParts.base.base import (
@@ -41,6 +43,12 @@ class BaseComponent(
     DeprecatedComponent,
     RemovedComponent,
 ):
+    """Represent the basis for a component object.
+
+    This object provides a reference to another glyph, allowing it to be
+    inserted as part of an outline.
+
+    """
     copyAttributes: Tuple[str, str] = ("baseGlyph", "transformation")
 
     def _reprContents(self) -> List[str]:
@@ -61,7 +69,23 @@ def _reprContents(self) -> List[str]:
 
     _glyph = None
 
-    glyph: dynamicProperty = dynamicProperty("glyph", "The component's parent glyph.")
+    glyph: dynamicProperty = dynamicProperty(
+        "glyph",
+        """Get or set the component's parent glyph object.
+
+        The value must be a :class:`BaseGlyph` instance or :obj:`None`.
+
+        :return: The :class:`BaseGlyph` instance containing the component
+            or :obj:`None`.
+        :raises AssertionError: If attempting to set the glyph when it
+            has already been set.
+
+        Example::
+
+            >>> glyph = component.glyph
+
+        """,
+    )
 
     def _get_glyph(self) -> Optional[BaseGlyph]:
         if self._glyph is None:
@@ -77,7 +101,21 @@ def _set_glyph(self, glyph: Optional[BaseGlyph]) -> None:
 
     # Layer
 
-    layer: dynamicProperty = dynamicProperty("layer", "The component's parent layer.")
+    layer: dynamicProperty = dynamicProperty(
+        "layer",
+        """Get the component's parent layer object.
+
+        This property is read-only.
+
+        :return: The :class:`BaseLayer` instance containing the component
+            or :obj:`None`.
+
+        Example::
+
+            >>> layer = component.layer
+
+        """,
+    )
 
     def _get_layer(self) -> Optional[BaseLayer]:
         if self._glyph is None:
@@ -86,7 +124,21 @@ def _get_layer(self) -> Optional[BaseLayer]:
 
     # Font
 
-    font: dynamicProperty = dynamicProperty("font", "The component's parent font.")
+    font: dynamicProperty = dynamicProperty(
+        "font",
+        """Get the component's parent font object.
+
+        This property is read-only.
+
+        :return: The :class:`BaseFont` instance containing the component
+            or :obj:`None`.
+
+        Example::
+
+            >>> font = component.font
+
+        """,
+    )
 
     def _get_font(self) -> Optional[BaseFont]:
         if self._glyph is None:
@@ -100,15 +152,26 @@ def _get_font(self) -> Optional[BaseFont]:
     # baseGlyph
 
     baseGlyph: dynamicProperty = dynamicProperty(
-        "base_baseGlyph", "The name of the glyph the component references."
+        "base_baseGlyph",
+        """Get or set the name of the glyph referenced by the component.
+
+        The value must be a :class:`str`.
+
+        :return: A :class:`str` representing the name of the base glyph,
+            or :obj:`None` if the component does not belong to a layer.
+        :raise ValueError: If value is None when the component is part of a layer.
+
+        """,
     )
 
     def _get_base_baseGlyph(self) -> Optional[str]:
         value = self._get_baseGlyph()
         # if the component does not belong to a layer,
         # it is allowed to have None as its baseGlyph
-        if value is None or self.layer is None:
+        if value is None and self.layer is None:
             return value
+        if value is None:
+            raise ValueError(f"Value cannot be None when layer is '{self.layer}'.")
         return normalizers.normalizeGlyphName(value)
 
     def _set_base_baseGlyph(self, value: str) -> None:
@@ -116,21 +179,55 @@ def _set_base_baseGlyph(self, value: str) -> None:
         self._set_baseGlyph(value)
 
     def _get_baseGlyph(self) -> Optional[str]:
-        """
-        Subclasses must override this method.
+        """Get the name of the glyph referenced by the native component.
+
+        This is the environment implementation of the :attr:`BaseComponent.baseGlyph`
+        property getter.
+
+        :return: A :class:`str` representing the name of the base glyph,
+            or :obj:`None` if the component does not belong to a layer. The value
+            will be normalized with :func:`normalizers.normalizeGlyphName`.
+        :raises NotImplementedError: If the method has not been overridden by a
+            subclass.
+
+        .. important::
+
+            Subclasses must override this method.
+
         """
         self.raiseNotImplementedError()
 
     def _set_baseGlyph(self, value: str) -> None:
-        """
-        Subclasses must override this method.
+        """Set the name of the glyph referenced by the native component.
+
+        This is the environment implementation of the :attr:`BaseComponent.baseGlyph`
+        property setter.
+
+        :param value: The name of the glyph to set as a :class:`str`. The value
+            will have been normalized
+         with :func:`normalizers.normalizeGlyphName`.
+        :raises NotImplementedError: If the method has not been overridden by a
+            subclass.
+
+        .. important::
+
+            Subclasses must override this method.
+
         """
         self.raiseNotImplementedError()
 
     # transformation
 
     transformation: dynamicProperty = dynamicProperty(
-        "base_transformation", "The component's transformation matrix."
+        "base_transformation",
+        """Get or set the component's transformation matrix.
+
+        The value must be a :ref:`type-transformation`.
+
+        :return: A :ref:`type-transformation` value representing the
+            transformation matrix of the component.
+
+        """
     )
 
     def _get_base_transformation(self) -> SextupleType[float]:
@@ -145,20 +242,54 @@ def _set_base_transformation(
         self._set_transformation(value)
 
     def _get_transformation(self) -> SextupleType[float]:
-        """
-        Subclasses must override this method.
+        """Get the native component's transformation matrix.
+
+        This is the environment implementation of the
+        :attr:`BaseComponent.transformation` property getter.
+
+        :return: A :ref:`type-transformation` value representing the
+            transformation matrix of the component. The value will be
+            normalized with :func:`normalizers.normalizeTransformationMatrix`.
+        :raises NotImplementedError: If the method has not been overridden by a
+            subclass.
+
+        .. important::
+
+            Subclasses must override this method.
+
         """
         self.raiseNotImplementedError()
 
     def _set_transformation(self, value: SextupleCollectionType[IntFloatType]) -> None:
-        """
-        Subclasses must override this method.
+        """Set the native component's transformation matrix.
+
+        This is the environment implementation of the
+        :attr:`BaseComponent.transformation` property setter.
+
+        :param value: The :ref:`type-transformation` to set. The value will have
+            been normalized with :func:`normalizers.normalizeTransformationMatrix`.
+        :raises NotImplementedError: If the method has not been overridden by a
+            subclass.
+
+        .. important::
+
+            Subclasses must override this method.
+
         """
         self.raiseNotImplementedError()
 
     # offset
 
-    offset: dynamicProperty = dynamicProperty("base_offset", "The component's offset.")
+    offset: dynamicProperty = dynamicProperty(
+        "base_offset",
+        """Get or set the component's offset.
+
+        The value must be a :ref:`type-coordinate.`
+
+        :return: A :ref:`type-coordinate.` representing the offset of the component.
+
+        """
+    )
 
     def _get_base_offset(self) -> PairType[IntFloatType]:
         value = self._get_offset()
@@ -170,15 +301,36 @@ def _set_base_offset(self, value: PairCollectionType[IntFloatType]) -> None:
         self._set_offset(value)
 
     def _get_offset(self) -> PairType[IntFloatType]:
-        """
-        Subclasses may override this method.
+        """Get the native component's offset.
+
+        This is the environment implementation of the :attr:`BaseComponent.offset`
+        property getter.
+
+        :return: A :ref:`type-coordinate.` representing the offset of the component.
+            The value will be normalized
+            with :func:`normalizers.normalizeTransformationOffset`.
+
+        .. note::
+
+            Subclasses may override this method.
+
         """
         sx, sxy, syx, sy, ox, oy = self.transformation
         return ox, oy
 
     def _set_offset(self, value: PairCollectionType[IntFloatType]) -> None:
-        """
-        Subclasses may override this method.
+        """Set the native component's offset.
+
+        This is the environment implementation of the :attr:`BaseComponent.offset`
+        property setter.
+
+        :param value: The offset to set as a :ref:`type-coordinate.`. The value will
+            have been normalized with :func:`normalizers.normalizeTransformationOffset`.
+
+        .. note::
+
+            Subclasses may override this method.
+
         """
         sx, sxy, syx, sy, ox, oy = self.transformation
         ox, oy = value
@@ -186,7 +338,18 @@ def _set_offset(self, value: PairCollectionType[IntFloatType]) -> None:
 
     # scale
 
-    scale: dynamicProperty = dynamicProperty("base_scale", "The component's scale.")
+    scale: dynamicProperty = dynamicProperty(
+        "base_scale",
+        """Get or set the component's scale.
+
+        The value must be a :class:`list` or :class:`tuple` of two :class:`int`
+        or :class:`float` items representing the ``(x, y)`` scale of the component.
+
+        :return: A :class:`tuple` of two :class:`float` items representing the
+            ``(x, y)`` scale of the component.
+
+        """
+    )
 
     def _get_base_scale(self) -> PairType[float]:
         value = self._get_scale()
@@ -198,15 +361,38 @@ def _set_base_scale(self, value: PairCollectionType[IntFloatType]) -> None:
         self._set_scale(value)
 
     def _get_scale(self) -> PairType[float]:
-        """
-        Subclasses may override this method.
+        """Get the native component's scale.
+
+        This is the environment implementation of the :attr:`BaseComponent.scale`
+        property getter.
+
+        :return: A :class:`tuple` of two :class:`float` items representing the
+            ``(x, y)`` scale of the component. The value will have been normalized
+            with :func:`normalizers.normalizeComponentScale`.
+
+        .. note::
+
+            Subclasses may override this method.
+
         """
         sx, sxy, syx, sy, ox, oy = self.transformation
         return sx, sy
 
     def _set_scale(self, value: PairCollectionType[IntFloatType]) -> None:
-        """
-        Subclasses may override this method.
+        """Set the native component's scale.
+
+        This is the environment implementation of the :attr:`BaseComponent.scale`
+        property setter.
+
+        :param value: The scale to set as a :class:`list` or :class:`tuple`
+            of :class:`int` or :class:`float` items representing the ``(x, y)``
+            scale of the component. The value will have been normalized
+            with :func:`normalizers.normalizeComponentScale`.
+
+        .. note::
+
+            Subclasses may override this method.
+
         """
         sx, sxy, syx, sy, ox, oy = self.transformation
         sx, sy = value
@@ -220,10 +406,17 @@ def _set_scale(self, value: PairCollectionType[IntFloatType]) -> None:
 
     index: dynamicProperty = dynamicProperty(
         "base_index",
-        (
-            "The index of the component within the "
-            "ordered list of the parent glyph's components."
-        ),
+        """Get or set the index of the contour.
+
+        The value must be an :class:`int`
+
+        :return: An :class:`int` representing the index of the component within
+            the ordered list of parent glyph's components, or :obj:`None` if the
+            component does not belong to a glyph.
+        :raise FontPartsError: If attempting to set the index while the
+            component does not belong to a glyph.
+
+        """
     )
 
     def _get_base_index(self) -> Optional[int]:
@@ -240,7 +433,7 @@ def _set_base_index(self, value: int) -> None:
             raise FontPartsError("The component does not belong to a glyph.")
         value = normalizers.normalizeIndex(value)
         if value is None:
-            raise ValueError("Value cannot be None.")
+            return
         componentCount = len(glyph.components)
         if value < 0:
             value = -(value % componentCount)
@@ -249,15 +442,39 @@ def _set_base_index(self, value: int) -> None:
         self._set_index(value)
 
     def _get_index(self) -> Optional[int]:
-        """
-        Subclasses may override this method.
+        """Get the index of the native contour.
+
+        This is the environment implementation of the :attr:`BaseComponent.index`
+        property getter.
+
+        :return: An :class:`int` representing the index of the component within
+            the ordered list of parent glyph's components, or :obj:`None` if the
+            component does not belong to a glyph. The value will be normalized
+            with :func:`normalizers.normalizeIndex`.
+
+        .. note::
+
+            Subclasses may override this method.
+
         """
         glyph = self.glyph
         return glyph.components.index(self)
 
     def _set_index(self, value: int) -> None:
-        """
-        Subclasses must override this method.
+        """Set the index of the native contour.
+
+        This is the environment implementation of the :attr:`BaseComponent.index`
+        property setter.
+
+        :param value: The index to set as an :class:`int`. The value will have been
+            normalized with :func:`normalizers.normalizeIndex`.
+        :raises NotImplementedError: If the method has not been overridden by a
+            subclass.
+
+        .. important::
+
+            Subclasses must override this method.
+
         """
         self.raiseNotImplementedError()
 
@@ -266,14 +483,27 @@ def _set_index(self, value: int) -> None:
     # ----
 
     def draw(self, pen: PenType) -> None:
-        """
-        Draw the component with the given Pen.
+        """Draw the component with the given pen.
+
+        :param pen: The :class:`fontTools.pens.basePen.AbstractPen` with which
+            to draw the componnet.
+
         """
         self._draw(pen)
 
     def _draw(self, pen: PenType, **kwargs: Any) -> None:
-        """
-        Subclasses may override this method.
+        r"""Draw the native component with the given pen.
+
+        This is the environment implementation of :meth:`BaseComponent.draw`.
+
+        :param pen: The :class:`fontTools.pens.basePen.AbstractPen` with which
+            to draw the componnet.
+        :param \**kwargs: Additional keyword arguments.
+
+        .. note::
+
+            Subclasses may override this method.
+
         """
         from fontTools.ufoLib.pointPen import PointToSegmentPen
 
@@ -281,14 +511,27 @@ def _draw(self, pen: PenType, **kwargs: Any) -> None:
         self.drawPoints(adapter)
 
     def drawPoints(self, pen: PointPenType) -> None:
-        """
-        Draw the contour with the given PointPen.
+        """Draw the component with the given point pen.
+
+        :param pen: The :class:`fontTools.pens.pointPen.AbstractPointPen` with
+            which to draw the componnet.
+
         """
         self._drawPoints(pen)
 
     def _drawPoints(self, pen: PointPenType, **kwargs: Any) -> None:
-        """
-        Subclasses may override this method.
+        r"""Draw the native component with the given point pen.
+
+        This is the environment implementation of :meth:`BaseComponent.draw`.
+
+        :param pen: The :class:`fontTools.pens.pointPen.AbstractPointPen` with
+            which to draw the componnet.
+        :param \**kwargs: Additional keyword arguments.
+
+        .. note::
+
+            Subclasses may override this method.
+
         """
         # The try: ... except TypeError: ...
         # handles backwards compatibility with
@@ -311,8 +554,18 @@ def _drawPoints(self, pen: PointPenType, **kwargs: Any) -> None:
     def _transformBy(
         self, matrix: SextupleCollectionType[IntFloatType], **kwargs: Any
     ) -> None:
-        """
-        Subclasses may override this method.
+        r"""Transform the component according to the given matrix.
+
+        This is the environment implementation of :meth:`BaseComponent.transformBy`.
+
+        :param matrix: The :ref:`type-transformation` to apply. The value will
+             be normalized with :func:`normalizers.normalizeTransformationMatrix`.
+        :param \**kwargs: Additional keyword arguments.
+
+        .. note::
+
+            Subclasses may override this method.
+
         """
         t = transform.Transform(*matrix)
         transformation = t.transform(self.transformation)
@@ -323,14 +576,22 @@ def _transformBy(
     # -------------
 
     def round(self) -> None:
-        """
-        Round offset coordinates.
+        """Round the compnent's offset coordinates.
+
+        This applies to :attr:`offset`
+
         """
         self._round()
 
     def _round(self) -> None:
-        """
-        Subclasses may override this method.
+        """Round the native compnent's offset coordinates.
+
+        This is the environment implementation of :meth:`BaseComponent.round`.
+
+        .. note::
+
+            Subclasses may override this method.
+
         """
         x, y = self.offset
         x = normalizers.normalizeVisualRounding(x)
@@ -338,17 +599,24 @@ def _round(self) -> None:
         self.offset = (x, y)
 
     def decompose(self) -> None:
-        """
-        Decompose the component.
-        """
+        """Decompose the component."""
         glyph = self.glyph
         if glyph is None:
             raise FontPartsError("The component does not belong to a glyph.")
         self._decompose()
 
     def _decompose(self) -> None:
-        """
-        Subclasses must override this method.
+        """Decompose the native component.
+
+        This is the environment implementation of :meth:`BaseComponent.decompose`.
+
+        :raises NotImplementedError: If the method has not been overridden by a
+            subclass.
+
+        .. important::
+
+            Subclasses must override this method.
+
         """
         self.raiseNotImplementedError()
 
@@ -361,8 +629,16 @@ def _decompose(self) -> None:
     def isCompatible(
         self, other: BaseComponent
     ) -> Tuple[bool, ComponentCompatibilityReporter]:
-        """
-        Evaluate interpolation compatibility with **other**. ::
+        """Evaluate interpolation compatibility with another component.
+
+        :param other: The other :class:`BaseComponent` instance to check
+            compatibility with.
+        :return: A :class:`tuple` where the first element is a :class:`bool`
+            indicating compatibility, and the second element is
+            a :class:`fontParts.base.compatibility.ComponentCompatibilityReporter`
+            instance.
+
+        Example::
 
             >>> compatible, report = self.isCompatible(otherComponent)
             >>> compatible
@@ -371,20 +647,24 @@ def isCompatible(
             [Warning] Component: "A" + "B"
             [Warning] Component: "A" has name A | "B" has name B
 
-        This will return a ``bool`` indicating if the component is
-        compatible for interpolation with **other** and a
-        :ref:`type-string` of compatibility notes.
         """
         return super(BaseComponent, self).isCompatible(other, BaseComponent)
 
     def _isCompatible(
         self, other: BaseComponent, reporter: ComponentCompatibilityReporter
     ) -> None:
-        """
-        This is the environment implementation of
-        :meth:`BaseComponent.isCompatible`.
+        """Evaluate interpolation compatibility with another native component.
+
+        This is the environment implementation of :meth:`BaseComponent.isCompatible`.
+
+        :param other: The other :class:`BaseComponent` instance to check
+            compatibility with.
+        :param reporter: An object used to report compatibility issues.
+
+        .. note::
+
+            Subclasses may override this method.
 
-        Subclasses may override this method.
         """
         component1 = self
         component2 = other
@@ -398,27 +678,56 @@ def _isCompatible(
     # ------------
 
     def pointInside(self, point: PairCollectionType[IntFloatType]) -> bool:
-        """
-        Determine if point is in the black or white of the component.
+        """Check if `point` lies inside the filled area of the component.
+
+        :param point: The point to check as a :ref:`type-coordinate`.
+        :return: :obj:`True` if `point` is inside the filled area of the
+            glyph, :obj:`False` otherwise.
+
+        Example::
+
+            >>> glyph.pointInside((40, 65))
+            True
 
-        point must be an (x, y) tuple.
         """
         point = normalizers.normalizeCoordinateTuple(point)
         return self._pointInside(point)
 
     def _pointInside(self, point: PairCollectionType[IntFloatType]) -> bool:
-        """
-        Subclasses may override this method.
-        """
-        from fontTools.pens.pointInsidePen import PointInsidePen
+        """Check if `point` lies inside the filled area of the native component.
+
+        This is the environment implementation of :meth:`BaseComponent.pointInside`.
+
+        :param point: The point to check as a :ref:`type-coordinate`. The value will
+            have been normalized with :func:`normalizers.normalizeCoordinateTuple`.
+        :return: :class:`bool`.
 
+        .. note::
+
+            Subclasses may override this method.
+
+        """
         pen = PointInsidePen(glyphSet=self.layer, testPoint=point, evenOdd=False)
         self.draw(pen)
         return pen.getResult()
 
     bounds: dynamicProperty = dynamicProperty(
         "base_bounds",
-        ("The bounds of the component: " "(xMin, yMin, xMax, yMax) or None."),
+        """Get the bounds of the component.
+
+        This property is read-only.
+
+        :return: A :class:`tuple` of four :class:`int` or :class:`float` values
+            in the form ``(x minimum, y minimum, x maximum, y maximum)``
+            representing the bounds of the component, or :obj:`None` if the
+            component is empty.
+
+        Example::
+
+            >>> component.bounds
+            (10, 30, 765, 643)
+
+        """,
     )
 
     def _get_base_bounds(self) -> QuadrupleType[float]:
@@ -428,11 +737,22 @@ def _get_base_bounds(self) -> QuadrupleType[float]:
         return value
 
     def _get_bounds(self) -> QuadrupleType[float]:
-        """
-        Subclasses may override this method.
-        """
-        from fontTools.pens.boundsPen import BoundsPen
+        """Get the bounds of the component.
 
+        This is the environment implementation of the :attr:`BaseComponent.bounds`
+        property getter.
+
+       :return: A :class:`tuple` of four :class:`int` or :class:`float` values
+            in the form ``(x minimum, y minimum, x maximum, y maximum)``
+            representing the bounds of the component, or :obj:`None` if the
+            component is empty. The value will be normalized
+            with :func:`normalizers.normalizeBoundingBox`.
+
+        .. note::
+
+            Subclasses may override this method.
+
+        """
         pen = BoundsPen(self.layer)
         self.draw(pen)
         return pen.bounds

From 8f8179501a43a47f0287a7e648e7c727e2e0e271 Mon Sep 17 00:00:00 2001
From: Knut Nergaard <knut.nergaard@gmail.com>
Date: Thu, 5 Dec 2024 20:46:28 +0100
Subject: [PATCH 05/10] Resolve `mypy` errors.

---
 Lib/fontParts/base/base.py      | 3 +--
 Lib/fontParts/base/component.py | 2 +-
 Lib/fontParts/base/contour.py   | 2 +-
 Lib/fontParts/base/font.py      | 2 +-
 Lib/fontParts/base/glyph.py     | 2 +-
 Lib/fontParts/base/layer.py     | 2 +-
 Lib/fontParts/base/segment.py   | 2 +-
 7 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/Lib/fontParts/base/base.py b/Lib/fontParts/base/base.py
index 6172c128..a0b6da74 100644
--- a/Lib/fontParts/base/base.py
+++ b/Lib/fontParts/base/base.py
@@ -241,8 +241,7 @@ def __repr__(self) -> str:
             contentString = ""
         return f"<{self.__class__.__name__}{contentString} at {id(self)}>"
 
-    @classmethod
-    def _reprContents(cls) -> List[str]:
+    def _reprContents(self) -> List[str]:
         """Provide a list of strings for inclusion in :meth:`BaseObject.__repr__.
 
         :return: A :class:`list` of :class:`str` items.
diff --git a/Lib/fontParts/base/component.py b/Lib/fontParts/base/component.py
index 5e5ee063..763b0604 100644
--- a/Lib/fontParts/base/component.py
+++ b/Lib/fontParts/base/component.py
@@ -627,7 +627,7 @@ def _decompose(self) -> None:
     compatibilityReporterClass = ComponentCompatibilityReporter
 
     def isCompatible(
-        self, other: BaseComponent
+        self, other: BaseComponent, cls=None
     ) -> Tuple[bool, ComponentCompatibilityReporter]:
         """Evaluate interpolation compatibility with another component.
 
diff --git a/Lib/fontParts/base/contour.py b/Lib/fontParts/base/contour.py
index 8d513f5f..041bea4a 100644
--- a/Lib/fontParts/base/contour.py
+++ b/Lib/fontParts/base/contour.py
@@ -488,7 +488,7 @@ def _transformBy(
     compatibilityReporterClass = ContourCompatibilityReporter
 
     def isCompatible(
-        self, other: BaseContour
+        self, other: BaseContour, cls=None
     ) -> Tuple[bool, ContourCompatibilityReporter]:
         """Evaluate interpolation compatibility with another contour.
 
diff --git a/Lib/fontParts/base/font.py b/Lib/fontParts/base/font.py
index 37f67ca8..0899ef0a 100644
--- a/Lib/fontParts/base/font.py
+++ b/Lib/fontParts/base/font.py
@@ -2058,7 +2058,7 @@ def _interpolate(
 
     compatibilityReporterClass = FontCompatibilityReporter
 
-    def isCompatible(self, other: BaseFont) -> Tuple[bool, FontCompatibilityReporter]:
+    def isCompatible(self, other: BaseFont, cls=None) -> Tuple[bool, FontCompatibilityReporter]:
         """Evaluate interpolation compatibility with another font.
 
         This method will return a :class:`bool` indicating if the font is
diff --git a/Lib/fontParts/base/glyph.py b/Lib/fontParts/base/glyph.py
index 13b02a7a..f5530694 100644
--- a/Lib/fontParts/base/glyph.py
+++ b/Lib/fontParts/base/glyph.py
@@ -2795,7 +2795,7 @@ def _checkPairs(
                 reporter.warning = True
             reporterObject.append(compatibility)
 
-    def isCompatible(self, other: BaseGlyph) -> Tuple[bool, GlyphCompatibilityReporter]:
+    def isCompatible(self, other: BaseGlyph, cls=None) -> Tuple[bool, GlyphCompatibilityReporter]:
         """Evaluate interpolation compatibility with another glyph.
 
         :param other: The other :class:`BaseGlyph` instance to check
diff --git a/Lib/fontParts/base/layer.py b/Lib/fontParts/base/layer.py
index 6b008105..a4059e27 100644
--- a/Lib/fontParts/base/layer.py
+++ b/Lib/fontParts/base/layer.py
@@ -1106,7 +1106,7 @@ def _interpolate(
 
     compatibilityReporterClass = LayerCompatibilityReporter
 
-    def isCompatible(self, other: BaseLayer) -> Tuple[bool, LayerCompatibilityReporter]:
+    def isCompatible(self, other: BaseLayer, cls=None) -> Tuple[bool, LayerCompatibilityReporter]:
         """Evaluate interpolation compatibility with another layer.
 
         :param other: The other :class:`BaseLayer` instance to check
diff --git a/Lib/fontParts/base/segment.py b/Lib/fontParts/base/segment.py
index d0267513..5737c581 100644
--- a/Lib/fontParts/base/segment.py
+++ b/Lib/fontParts/base/segment.py
@@ -614,7 +614,7 @@ def _transformBy(self, matrix: SextupleCollectionType[IntFloatType], **kwargs: A
     compatibilityReporterClass = SegmentCompatibilityReporter
 
     def isCompatible(
-        self, other: BaseSegment
+        self, other: BaseSegment, cls=None
     ) -> Tuple[bool, SegmentCompatibilityReporter]:
         """Evaluate interpolation compatibility with another segment.
 

From 778a2323a7252193e5446c6b698d8f4cfba4a85d Mon Sep 17 00:00:00 2001
From: knutnergaard <knutnergaard@users.noreply.github.com>
Date: Thu, 5 Dec 2024 19:47:35 +0000
Subject: [PATCH 06/10] Format fixes by ruff

---
 Lib/fontParts/base/component.py | 27 ++++++++++++++-------------
 Lib/fontParts/base/font.py      |  4 +++-
 Lib/fontParts/base/glyph.py     |  4 +++-
 Lib/fontParts/base/layer.py     |  4 +++-
 4 files changed, 23 insertions(+), 16 deletions(-)

diff --git a/Lib/fontParts/base/component.py b/Lib/fontParts/base/component.py
index 763b0604..14f584bf 100644
--- a/Lib/fontParts/base/component.py
+++ b/Lib/fontParts/base/component.py
@@ -49,6 +49,7 @@ class BaseComponent(
     inserted as part of an outline.
 
     """
+
     copyAttributes: Tuple[str, str] = ("baseGlyph", "transformation")
 
     def _reprContents(self) -> List[str]:
@@ -227,7 +228,7 @@ def _set_baseGlyph(self, value: str) -> None:
         :return: A :ref:`type-transformation` value representing the
             transformation matrix of the component.
 
-        """
+        """,
     )
 
     def _get_base_transformation(self) -> SextupleType[float]:
@@ -288,7 +289,7 @@ def _set_transformation(self, value: SextupleCollectionType[IntFloatType]) -> No
 
         :return: A :ref:`type-coordinate.` representing the offset of the component.
 
-        """
+        """,
     )
 
     def _get_base_offset(self) -> PairType[IntFloatType]:
@@ -348,7 +349,7 @@ def _set_offset(self, value: PairCollectionType[IntFloatType]) -> None:
         :return: A :class:`tuple` of two :class:`float` items representing the
             ``(x, y)`` scale of the component.
 
-        """
+        """,
     )
 
     def _get_base_scale(self) -> PairType[float]:
@@ -416,7 +417,7 @@ def _set_scale(self, value: PairCollectionType[IntFloatType]) -> None:
         :raise FontPartsError: If attempting to set the index while the
             component does not belong to a glyph.
 
-        """
+        """,
     )
 
     def _get_base_index(self) -> Optional[int]:
@@ -739,18 +740,18 @@ def _get_base_bounds(self) -> QuadrupleType[float]:
     def _get_bounds(self) -> QuadrupleType[float]:
         """Get the bounds of the component.
 
-        This is the environment implementation of the :attr:`BaseComponent.bounds`
-        property getter.
+         This is the environment implementation of the :attr:`BaseComponent.bounds`
+         property getter.
 
-       :return: A :class:`tuple` of four :class:`int` or :class:`float` values
-            in the form ``(x minimum, y minimum, x maximum, y maximum)``
-            representing the bounds of the component, or :obj:`None` if the
-            component is empty. The value will be normalized
-            with :func:`normalizers.normalizeBoundingBox`.
+        :return: A :class:`tuple` of four :class:`int` or :class:`float` values
+             in the form ``(x minimum, y minimum, x maximum, y maximum)``
+             representing the bounds of the component, or :obj:`None` if the
+             component is empty. The value will be normalized
+             with :func:`normalizers.normalizeBoundingBox`.
 
-        .. note::
+         .. note::
 
-            Subclasses may override this method.
+             Subclasses may override this method.
 
         """
         pen = BoundsPen(self.layer)
diff --git a/Lib/fontParts/base/font.py b/Lib/fontParts/base/font.py
index 0899ef0a..75002d68 100644
--- a/Lib/fontParts/base/font.py
+++ b/Lib/fontParts/base/font.py
@@ -2058,7 +2058,9 @@ def _interpolate(
 
     compatibilityReporterClass = FontCompatibilityReporter
 
-    def isCompatible(self, other: BaseFont, cls=None) -> Tuple[bool, FontCompatibilityReporter]:
+    def isCompatible(
+        self, other: BaseFont, cls=None
+    ) -> Tuple[bool, FontCompatibilityReporter]:
         """Evaluate interpolation compatibility with another font.
 
         This method will return a :class:`bool` indicating if the font is
diff --git a/Lib/fontParts/base/glyph.py b/Lib/fontParts/base/glyph.py
index f5530694..dc6c9a81 100644
--- a/Lib/fontParts/base/glyph.py
+++ b/Lib/fontParts/base/glyph.py
@@ -2795,7 +2795,9 @@ def _checkPairs(
                 reporter.warning = True
             reporterObject.append(compatibility)
 
-    def isCompatible(self, other: BaseGlyph, cls=None) -> Tuple[bool, GlyphCompatibilityReporter]:
+    def isCompatible(
+        self, other: BaseGlyph, cls=None
+    ) -> Tuple[bool, GlyphCompatibilityReporter]:
         """Evaluate interpolation compatibility with another glyph.
 
         :param other: The other :class:`BaseGlyph` instance to check
diff --git a/Lib/fontParts/base/layer.py b/Lib/fontParts/base/layer.py
index a4059e27..081e81eb 100644
--- a/Lib/fontParts/base/layer.py
+++ b/Lib/fontParts/base/layer.py
@@ -1106,7 +1106,9 @@ def _interpolate(
 
     compatibilityReporterClass = LayerCompatibilityReporter
 
-    def isCompatible(self, other: BaseLayer, cls=None) -> Tuple[bool, LayerCompatibilityReporter]:
+    def isCompatible(
+        self, other: BaseLayer, cls=None
+    ) -> Tuple[bool, LayerCompatibilityReporter]:
         """Evaluate interpolation compatibility with another layer.
 
         :param other: The other :class:`BaseLayer` instance to check

From b30b8836dc6e3d8e42ae6cd537021f36e16e4dfc Mon Sep 17 00:00:00 2001
From: Knut Nergaard <knut.nergaard@gmail.com>
Date: Thu, 5 Dec 2024 23:36:44 +0100
Subject: [PATCH 07/10] =?UTF-8?q?Resp=C3=B8ve=20`mypy`=20errors=20related?=
 =?UTF-8?q?=20to=20`base.reference`.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 Lib/fontParts/base/bPoint.py    |  8 ++++----
 Lib/fontParts/base/base.py      |  2 +-
 Lib/fontParts/base/component.py | 11 ++++++-----
 Lib/fontParts/base/contour.py   |  5 +++--
 Lib/fontParts/base/groups.py    |  5 +++--
 Lib/fontParts/base/layer.py     |  5 +++--
 Lib/fontParts/base/lib.py       |  9 +++++----
 Lib/fontParts/base/point.py     |  6 +++---
 Lib/fontParts/base/segment.py   |  6 +++---
 9 files changed, 31 insertions(+), 26 deletions(-)

diff --git a/Lib/fontParts/base/bPoint.py b/Lib/fontParts/base/bPoint.py
index 0fa173e5..20e05005 100644
--- a/Lib/fontParts/base/bPoint.py
+++ b/Lib/fontParts/base/bPoint.py
@@ -1,5 +1,5 @@
 from __future__ import annotations
-from typing import TYPE_CHECKING, Any, List, Optional
+from typing import TYPE_CHECKING, Any, Callable, List, Optional, Union
 from fontTools.misc import transform
 
 from fontParts.base.base import (
@@ -59,7 +59,7 @@ def __eq__(self, other):
     # this class should not be used in hashable
     # collections since it is dynamically generated.
 
-    __hash__ = None
+    __hash__ = None  # type: ignore[assignment]
 
     # -------
     # Parents
@@ -126,7 +126,7 @@ def _get_base_nextSegment(self) -> Optional[BaseSegment]:
 
     # Contour
 
-    _contour: Optional[BaseContour] = None
+    _contour: Optional[Callable[[], BaseContour]] = None
 
     contour = dynamicProperty(
         "contour",
@@ -151,7 +151,7 @@ def _get_contour(self) -> Optional[BaseContour]:
             return None
         return self._contour()
 
-    def _set_contour(self, contour: Optional[BaseContour]) -> None:
+    def _set_contour(self, contour: Optional[Union[BaseContour, Callable[[], BaseContour]]]) -> None:
         if self._contour is not None:
             raise AssertionError("contour for bPoint already set")
         if contour is not None:
diff --git a/Lib/fontParts/base/base.py b/Lib/fontParts/base/base.py
index a0b6da74..e355e166 100644
--- a/Lib/fontParts/base/base.py
+++ b/Lib/fontParts/base/base.py
@@ -1631,7 +1631,7 @@ def raiseNotImplementedError(self):
         pass
 
 
-def reference(obj: Callable[[], Any]) -> Callable[[], Any]:
+def reference(obj: Any) -> Callable[[], Any]:
     """
     This code returns a simple function that returns the given object.
     This is a backwards compatibility function that is under review (see issue #749).
diff --git a/Lib/fontParts/base/component.py b/Lib/fontParts/base/component.py
index 763b0604..0e5f791b 100644
--- a/Lib/fontParts/base/component.py
+++ b/Lib/fontParts/base/component.py
@@ -1,5 +1,5 @@
 from __future__ import annotations
-from typing import TYPE_CHECKING, Any, List, Optional, Tuple
+from typing import TYPE_CHECKING, Any, Callable, List, Optional, Tuple, Union
 
 from fontTools.misc import transform
 from fontTools.pens.pointInsidePen import PointInsidePen
@@ -67,7 +67,7 @@ def _reprContents(self) -> List[str]:
 
     # Glyph
 
-    _glyph = None
+    _glyph: Optional[Callable[[], BaseGlyph]] = None
 
     glyph: dynamicProperty = dynamicProperty(
         "glyph",
@@ -92,7 +92,7 @@ def _get_glyph(self) -> Optional[BaseGlyph]:
             return None
         return self._glyph()
 
-    def _set_glyph(self, glyph: Optional[BaseGlyph]) -> None:
+    def _set_glyph(self, glyph: Optional[Union[BaseGlyph, Callable[[], BaseGlyph]]]) -> None:
         if self._glyph is not None:
             raise AssertionError("glyph for component already set")
         if glyph is not None:
@@ -431,9 +431,10 @@ def _set_base_index(self, value: int) -> None:
         glyph = self.glyph
         if glyph is None:
             raise FontPartsError("The component does not belong to a glyph.")
-        value = normalizers.normalizeIndex(value)
-        if value is None:
+        index = normalizers.normalizeIndex(value)
+        if index is None:
             return
+        value = index
         componentCount = len(glyph.components)
         if value < 0:
             value = -(value % componentCount)
diff --git a/Lib/fontParts/base/contour.py b/Lib/fontParts/base/contour.py
index 041bea4a..2533baa5 100644
--- a/Lib/fontParts/base/contour.py
+++ b/Lib/fontParts/base/contour.py
@@ -3,6 +3,7 @@
     TYPE_CHECKING,
     cast,
     Any,
+    Callable,
     Iterator,
     List,
     Optional,
@@ -105,7 +106,7 @@ def copyData(self, source: BaseContourType) -> None:
 
     # Glyph
 
-    _glyph = None
+    _glyph: Optional[Callable[[], BaseGlyph]] = None
 
     glyph: dynamicProperty = dynamicProperty(
         "glyph",
@@ -130,7 +131,7 @@ def _get_glyph(self) -> Optional[BaseGlyph]:
             return None
         return self._glyph()
 
-    def _set_glyph(self, glyph: Optional[BaseGlyph]) -> None:
+    def _set_glyph(self, glyph: Optional[Union[BaseGlyph, Callable[[], BaseGlyph]]]) -> None:
         if self._glyph is not None:
             raise AssertionError("glyph for contour already set")
         if glyph is not None:
diff --git a/Lib/fontParts/base/groups.py b/Lib/fontParts/base/groups.py
index d35e7590..798f7dca 100644
--- a/Lib/fontParts/base/groups.py
+++ b/Lib/fontParts/base/groups.py
@@ -7,6 +7,7 @@
     List,
     Optional,
     Tuple,
+    Union,
 )
 from collections.abc import MutableMapping
 
@@ -63,7 +64,7 @@ def _reprContents(self) -> List[str]:
 
     # Font
 
-    _font = None
+    _font: Optional[Callable[[], BaseFont]] = None
 
     font: dynamicProperty = dynamicProperty(
         "font",
@@ -89,7 +90,7 @@ def _get_font(self) -> Optional[BaseFont]:
             return None
         return self._font()
 
-    def _set_font(self, font: Optional[BaseFont]) -> None:
+    def _set_font(self, font: Optional[Union[BaseFont, Callable[[], BaseFont]]]) -> None:
         if self._font is not None and self._font != font:
             raise AssertionError("font for groups already set and is not same as font")
         if font is not None:
diff --git a/Lib/fontParts/base/layer.py b/Lib/fontParts/base/layer.py
index a4059e27..ad60e970 100644
--- a/Lib/fontParts/base/layer.py
+++ b/Lib/fontParts/base/layer.py
@@ -9,6 +9,7 @@
     List,
     Optional,
     Tuple,
+    Union,
 )
 import collections
 
@@ -673,7 +674,7 @@ def copyData(self, source: BaseLayer) -> None:
 
     # Font
 
-    _font = None
+    _font: Optional[Callable[[], BaseFont]] = None
 
     font: dynamicProperty = dynamicProperty(
         "font",
@@ -698,7 +699,7 @@ def _get_font(self) -> Optional[BaseFont]:
             return None
         return self._font()
 
-    def _set_font(self, font: Optional[BaseFont]) -> None:
+    def _set_font(self, font: Optional[Union[BaseFont, Callable[[], BaseFont]]]) -> None:
         if self._font is not None:
             raise AssertionError("font for layer already set")
         if font is not None:
diff --git a/Lib/fontParts/base/lib.py b/Lib/fontParts/base/lib.py
index 9f4efbb7..69727566 100644
--- a/Lib/fontParts/base/lib.py
+++ b/Lib/fontParts/base/lib.py
@@ -6,6 +6,7 @@
     Iterator,
     List,
     Optional,
+    Union,
 )
 from collections.abc import MutableMapping
 
@@ -64,7 +65,7 @@ def _reprContents(self) -> List[str]:
 
     # Glyph
 
-    _glyph: Optional[BaseGlyph] = None
+    _glyph: Optional[Callable[[], BaseGlyph]] = None
 
     glyph: dynamicProperty = dynamicProperty(
         "glyph",
@@ -91,7 +92,7 @@ def _get_glyph(self) -> Optional[BaseGlyph]:
             return None
         return self._glyph()
 
-    def _set_glyph(self, glyph: Optional[BaseGlyph]) -> None:
+    def _set_glyph(self, glyph: Optional[Union[BaseGlyph, Callable[[], BaseGlyph]]]) -> None:
         if self._font is not None:
             raise AssertionError("font for lib already set")
         if self._glyph is not None and self._glyph() != glyph:
@@ -102,7 +103,7 @@ def _set_glyph(self, glyph: Optional[BaseGlyph]) -> None:
 
     # Font
 
-    _font: Optional[BaseFont] = None
+    _font: Optional[Callable[[], BaseFont]] = None
 
     font: dynamicProperty = dynamicProperty(
         "font",
@@ -131,7 +132,7 @@ def _get_font(self) -> Optional[BaseFont]:
             return self.glyph.font
         return None
 
-    def _set_font(self, font: Optional[BaseFont]) -> None:
+    def _set_font(self, font: Optional[Union[BaseFont, Callable[[], BaseFont]]]) -> None:
         if self._font is not None and self._font() != font:
             raise AssertionError("font for lib already set and is not same as font")
         if self._glyph is not None:
diff --git a/Lib/fontParts/base/point.py b/Lib/fontParts/base/point.py
index b32a2558..5724ca1b 100644
--- a/Lib/fontParts/base/point.py
+++ b/Lib/fontParts/base/point.py
@@ -1,5 +1,5 @@
 from __future__ import annotations
-from typing import TYPE_CHECKING, Any, Optional, Union, Tuple
+from typing import TYPE_CHECKING, Any, Callable, Optional, Union, Tuple
 
 from fontTools.misc import transform
 from fontParts.base.base import (
@@ -66,7 +66,7 @@ def _reprContents(self) -> list[str]:
 
     # Contour
 
-    _contour: Optional[BaseContour] = None
+    _contour: Optional[Callable[[], BaseContour]] = None
 
     contour: dynamicProperty = dynamicProperty(
         "contour",
@@ -91,7 +91,7 @@ def _get_contour(self) -> Optional[BaseContour]:
             return None
         return self._contour()
 
-    def _set_contour(self, contour: Optional[BaseContour]) -> None:
+    def _set_contour(self, contour: Optional[Union[BaseContour, Callable[[], BaseContour]]]) -> None:
         if self._contour is not None:
             raise AssertionError("contour for point already set")
         if contour is not None:
diff --git a/Lib/fontParts/base/segment.py b/Lib/fontParts/base/segment.py
index 5737c581..5a12202b 100644
--- a/Lib/fontParts/base/segment.py
+++ b/Lib/fontParts/base/segment.py
@@ -1,5 +1,5 @@
 from __future__ import annotations
-from typing import TYPE_CHECKING, Any, Generator, List, Optional, Tuple
+from typing import TYPE_CHECKING, Any, Callable, Generator, List, Optional, Tuple, Union
 
 from fontParts.base.errors import FontPartsError
 from fontParts.base.base import (
@@ -61,7 +61,7 @@ def _reprContents(self) -> List[str]:
 
     # Contour
 
-    _contour: Optional[BaseContour] = None
+    _contour: Optional[Callable[[], BaseContour]] = None
 
     contour: dynamicProperty = dynamicProperty(
         "contour",
@@ -86,7 +86,7 @@ def _get_contour(self) -> Optional[BaseContour]:
             return None
         return self._contour()
 
-    def _set_contour(self, contour: Optional[BaseContour]) -> None:
+    def _set_contour(self, contour: Optional[Union[BaseContour, Callable[[], BaseContour]]]) -> None:
         if self._contour is not None:
             raise AssertionError("contour for segment already set")
         if contour is not None:

From fde1ca208f664f33b16c8d92976a757ea1b85d7c Mon Sep 17 00:00:00 2001
From: knutnergaard <knutnergaard@users.noreply.github.com>
Date: Thu, 5 Dec 2024 22:37:32 +0000
Subject: [PATCH 08/10] Format fixes by ruff

---
 Lib/fontParts/base/bPoint.py    | 4 +++-
 Lib/fontParts/base/component.py | 4 +++-
 Lib/fontParts/base/contour.py   | 4 +++-
 Lib/fontParts/base/groups.py    | 4 +++-
 Lib/fontParts/base/layer.py     | 4 +++-
 Lib/fontParts/base/lib.py       | 8 ++++++--
 Lib/fontParts/base/point.py     | 4 +++-
 Lib/fontParts/base/segment.py   | 4 +++-
 8 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/Lib/fontParts/base/bPoint.py b/Lib/fontParts/base/bPoint.py
index 20e05005..525a3448 100644
--- a/Lib/fontParts/base/bPoint.py
+++ b/Lib/fontParts/base/bPoint.py
@@ -151,7 +151,9 @@ def _get_contour(self) -> Optional[BaseContour]:
             return None
         return self._contour()
 
-    def _set_contour(self, contour: Optional[Union[BaseContour, Callable[[], BaseContour]]]) -> None:
+    def _set_contour(
+        self, contour: Optional[Union[BaseContour, Callable[[], BaseContour]]]
+    ) -> None:
         if self._contour is not None:
             raise AssertionError("contour for bPoint already set")
         if contour is not None:
diff --git a/Lib/fontParts/base/component.py b/Lib/fontParts/base/component.py
index f054e2ed..f8f1d6d3 100644
--- a/Lib/fontParts/base/component.py
+++ b/Lib/fontParts/base/component.py
@@ -93,7 +93,9 @@ def _get_glyph(self) -> Optional[BaseGlyph]:
             return None
         return self._glyph()
 
-    def _set_glyph(self, glyph: Optional[Union[BaseGlyph, Callable[[], BaseGlyph]]]) -> None:
+    def _set_glyph(
+        self, glyph: Optional[Union[BaseGlyph, Callable[[], BaseGlyph]]]
+    ) -> None:
         if self._glyph is not None:
             raise AssertionError("glyph for component already set")
         if glyph is not None:
diff --git a/Lib/fontParts/base/contour.py b/Lib/fontParts/base/contour.py
index 2533baa5..1f11c503 100644
--- a/Lib/fontParts/base/contour.py
+++ b/Lib/fontParts/base/contour.py
@@ -131,7 +131,9 @@ def _get_glyph(self) -> Optional[BaseGlyph]:
             return None
         return self._glyph()
 
-    def _set_glyph(self, glyph: Optional[Union[BaseGlyph, Callable[[], BaseGlyph]]]) -> None:
+    def _set_glyph(
+        self, glyph: Optional[Union[BaseGlyph, Callable[[], BaseGlyph]]]
+    ) -> None:
         if self._glyph is not None:
             raise AssertionError("glyph for contour already set")
         if glyph is not None:
diff --git a/Lib/fontParts/base/groups.py b/Lib/fontParts/base/groups.py
index 798f7dca..1ad554ff 100644
--- a/Lib/fontParts/base/groups.py
+++ b/Lib/fontParts/base/groups.py
@@ -90,7 +90,9 @@ def _get_font(self) -> Optional[BaseFont]:
             return None
         return self._font()
 
-    def _set_font(self, font: Optional[Union[BaseFont, Callable[[], BaseFont]]]) -> None:
+    def _set_font(
+        self, font: Optional[Union[BaseFont, Callable[[], BaseFont]]]
+    ) -> None:
         if self._font is not None and self._font != font:
             raise AssertionError("font for groups already set and is not same as font")
         if font is not None:
diff --git a/Lib/fontParts/base/layer.py b/Lib/fontParts/base/layer.py
index 8c365a0f..480bc146 100644
--- a/Lib/fontParts/base/layer.py
+++ b/Lib/fontParts/base/layer.py
@@ -699,7 +699,9 @@ def _get_font(self) -> Optional[BaseFont]:
             return None
         return self._font()
 
-    def _set_font(self, font: Optional[Union[BaseFont, Callable[[], BaseFont]]]) -> None:
+    def _set_font(
+        self, font: Optional[Union[BaseFont, Callable[[], BaseFont]]]
+    ) -> None:
         if self._font is not None:
             raise AssertionError("font for layer already set")
         if font is not None:
diff --git a/Lib/fontParts/base/lib.py b/Lib/fontParts/base/lib.py
index 69727566..7f27652d 100644
--- a/Lib/fontParts/base/lib.py
+++ b/Lib/fontParts/base/lib.py
@@ -92,7 +92,9 @@ def _get_glyph(self) -> Optional[BaseGlyph]:
             return None
         return self._glyph()
 
-    def _set_glyph(self, glyph: Optional[Union[BaseGlyph, Callable[[], BaseGlyph]]]) -> None:
+    def _set_glyph(
+        self, glyph: Optional[Union[BaseGlyph, Callable[[], BaseGlyph]]]
+    ) -> None:
         if self._font is not None:
             raise AssertionError("font for lib already set")
         if self._glyph is not None and self._glyph() != glyph:
@@ -132,7 +134,9 @@ def _get_font(self) -> Optional[BaseFont]:
             return self.glyph.font
         return None
 
-    def _set_font(self, font: Optional[Union[BaseFont, Callable[[], BaseFont]]]) -> None:
+    def _set_font(
+        self, font: Optional[Union[BaseFont, Callable[[], BaseFont]]]
+    ) -> None:
         if self._font is not None and self._font() != font:
             raise AssertionError("font for lib already set and is not same as font")
         if self._glyph is not None:
diff --git a/Lib/fontParts/base/point.py b/Lib/fontParts/base/point.py
index 5724ca1b..e6e35699 100644
--- a/Lib/fontParts/base/point.py
+++ b/Lib/fontParts/base/point.py
@@ -91,7 +91,9 @@ def _get_contour(self) -> Optional[BaseContour]:
             return None
         return self._contour()
 
-    def _set_contour(self, contour: Optional[Union[BaseContour, Callable[[], BaseContour]]]) -> None:
+    def _set_contour(
+        self, contour: Optional[Union[BaseContour, Callable[[], BaseContour]]]
+    ) -> None:
         if self._contour is not None:
             raise AssertionError("contour for point already set")
         if contour is not None:
diff --git a/Lib/fontParts/base/segment.py b/Lib/fontParts/base/segment.py
index 5a12202b..3cdbaaa7 100644
--- a/Lib/fontParts/base/segment.py
+++ b/Lib/fontParts/base/segment.py
@@ -86,7 +86,9 @@ def _get_contour(self) -> Optional[BaseContour]:
             return None
         return self._contour()
 
-    def _set_contour(self, contour: Optional[Union[BaseContour, Callable[[], BaseContour]]]) -> None:
+    def _set_contour(
+        self, contour: Optional[Union[BaseContour, Callable[[], BaseContour]]]
+    ) -> None:
         if self._contour is not None:
             raise AssertionError("contour for segment already set")
         if contour is not None:

From cb0d9472cd49c2dde3ef6edd69c4b4803cf0d447 Mon Sep 17 00:00:00 2001
From: Knut Nergaard <knut.nergaard@gmail.com>
Date: Fri, 6 Dec 2024 00:19:30 +0100
Subject: [PATCH 09/10] Add annotation of `self` in `Interpolatable` protocol.

---
 Lib/fontParts/base/annotations.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/Lib/fontParts/base/annotations.py b/Lib/fontParts/base/annotations.py
index 11908339..836fb12d 100644
--- a/Lib/fontParts/base/annotations.py
+++ b/Lib/fontParts/base/annotations.py
@@ -54,8 +54,8 @@
 class Interpolatable(Protocol):
     """Represent a protocol for interpolatable types."""
 
-    def __add__(self, other: InterpolatableType) -> InterpolatableType: ...
+    def __add__(self: InterpolatableType, other: InterpolatableType) -> InterpolatableType: ...
 
-    def __sub__(self, other: InterpolatableType) -> InterpolatableType: ...
+    def __sub__(self: InterpolatableType, other: InterpolatableType) -> InterpolatableType: ...
 
-    def __mul__(self, other: TransformationType) -> InterpolatableType: ...
+    def __mul__(self: InterpolatableType, other: TransformationType) -> InterpolatableType: ...

From a43d5882fff85b80bab381ceb48ae16b2a7051ce Mon Sep 17 00:00:00 2001
From: knutnergaard <knutnergaard@users.noreply.github.com>
Date: Thu, 5 Dec 2024 23:19:52 +0000
Subject: [PATCH 10/10] Format fixes by ruff

---
 Lib/fontParts/base/annotations.py | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/Lib/fontParts/base/annotations.py b/Lib/fontParts/base/annotations.py
index 836fb12d..a02df1ee 100644
--- a/Lib/fontParts/base/annotations.py
+++ b/Lib/fontParts/base/annotations.py
@@ -54,8 +54,14 @@
 class Interpolatable(Protocol):
     """Represent a protocol for interpolatable types."""
 
-    def __add__(self: InterpolatableType, other: InterpolatableType) -> InterpolatableType: ...
+    def __add__(
+        self: InterpolatableType, other: InterpolatableType
+    ) -> InterpolatableType: ...
 
-    def __sub__(self: InterpolatableType, other: InterpolatableType) -> InterpolatableType: ...
+    def __sub__(
+        self: InterpolatableType, other: InterpolatableType
+    ) -> InterpolatableType: ...
 
-    def __mul__(self: InterpolatableType, other: TransformationType) -> InterpolatableType: ...
+    def __mul__(
+        self: InterpolatableType, other: TransformationType
+    ) -> InterpolatableType: ...