refactor: update SubShape class to use generic type for improved type safety

Author: ya7010

src/tppt/pptx/shape/__init__.py

@@ -58,19 +58,22 @@ def text_frame(self) -> "TextFrame":
         return TextFrame(self._pptx.text_frame)
 
 
-class SubShape(PptxConvertible[PptxSubshape]):
-    def __init__(self, pptx_shape: PptxSubshape) -> None:
-        self._pptx: PptxSubshape = pptx_shape
+_GenericPptxSubshape = TypeVar("_GenericPptxSubshape", bound=PptxSubshape)
+
+
+class SubShape(PptxConvertible[_GenericPptxSubshape]):
+    def __init__(self, pptx_shape: _GenericPptxSubshape) -> None:
+        self._pptx: _GenericPptxSubshape = pptx_shape
 
     @property
     def part(self) -> XmlPart:
         return self._pptx.part
 
-    def to_pptx(self) -> PptxSubshape:
+    def to_pptx(self) -> _GenericPptxSubshape:
         return self._pptx
 
     @classmethod
-    def from_pptx(cls, pptx_obj: PptxSubshape) -> Self:
+    def from_pptx(cls, pptx_obj: _GenericPptxSubshape) -> Self:
         return cls(pptx_obj)
 
 

src/tppt/pptx/text/text_frame.py

@@ -1,17 +1,16 @@
-from typing import Self
-
 from pptx.enum.text import MSO_AUTO_SIZE, MSO_VERTICAL_ANCHOR
 from pptx.text.text import TextFrame as PptxTextFrame
 from pptx.util import Length as PptxLength
 
-from tppt.pptx.converter import PptxConvertible, to_pptx_length
+from tppt.pptx.converter import to_pptx_length
+from tppt.pptx.shape import SubShape
 from tppt.pptx.text.paragraph import Paragraph
 from tppt.types._length import EnglishMetricUnits, Length, LiteralLength, to_emu
 
 
-class TextFrame(PptxConvertible[PptxTextFrame]):
+class TextFrame(SubShape[PptxTextFrame]):
     def __init__(self, pptx_obj: PptxTextFrame) -> None:
-        self._pptx = pptx_obj
+        super().__init__(pptx_obj)
 
     def add_paragraph(self) -> Paragraph:
         return Paragraph(self._pptx.add_paragraph())
@@ -96,10 +95,3 @@ def word_wrap(self) -> bool | None:
     @word_wrap.setter
     def word_wrap(self, value: bool | None) -> None:
         self._pptx.word_wrap = value
-
-    def to_pptx(self) -> PptxTextFrame:
-        return self._pptx
-
-    @classmethod
-    def from_pptx(cls, pptx_obj: PptxTextFrame) -> Self:
-        return cls(pptx_obj)