Automatically set glyph class in subclassed BaseVariantFactory

README.md

@@ -454,17 +454,14 @@ import itertools
 from glyphsynth.lib.variants import BaseVariantExportFactory
 
 # Factory to create variants of AMTComboGlyph
-class VariantFactory(BaseVariantExportFactory[AMTComboGlyph]):
+class AMTVariantFactory(BaseVariantExportFactory[AMTComboGlyph]):
 
     # Width of resulting matrix
     MATRIX_WIDTH = len(COLORS)
 
     # Top-level padding and space between glyph variants
     SPACING = UNIT / 10
 
-    # Glyph subclass from which to generate variants
-    glyph_cls = AMTComboGlyph
-
     # Generate variants of colors and letter combinations
     def get_params_variants(self) -> Generator[AMTComboParams, None, None]:
         for color, letter1, letter2 in itertools.product(
@@ -477,4 +474,4 @@ class VariantFactory(BaseVariantExportFactory[AMTComboGlyph]):
             )
 ```
 
-The fully-qualified class name of `VariantFactory` can be passed as an argument to `glyphsynth-export`. This will result in a folder structure containing each variant individually, as well as the variant matrix and each individual row/column.
+The fully-qualified class name of `AMTVariantFactory` can be passed as an argument to `glyphsynth-export`. This will result in a folder structure containing each variant individually, as well as the variant matrix and each individual row/column.

glyphsynth/lib/variants.py

@@ -16,6 +16,7 @@
     VArrayGlyph,
 )
 
+from ..core._utils import extract_type_param
 from ..core.export import ExportSpec
 
 __all__ = [
@@ -29,7 +30,7 @@ class BaseVariantFactory[GlyphT: BaseGlyph]:
     Encapsulates a BaseGlyph subclass and parameter variants.
     """
 
-    glyph_cls: type[GlyphT]
+    _glyph_cls: type[GlyphT]
     """
     BaseGlyph subclass to instantiate.
     """
@@ -69,13 +70,22 @@ def get_variants(self) -> Generator[GlyphT, None, None]:
         """
         for params in self.get_params_variants():
             glyph_id = _derive_glyph_id(params)
-            yield self.glyph_cls(glyph_id=glyph_id, params=params)
+            yield self._glyph_cls(glyph_id=glyph_id, params=params)
 
     def get_params_variants(self) -> Generator[BaseParams, None, None]:
         """
         Override to yield parameter variants to export.
         """
-        yield self.glyph_cls.get_params_cls()()
+        yield self._glyph_cls.get_params_cls()()
+
+    def __init_subclass__(cls):
+        """
+        Populate _glyph_cls with the parameterized class.
+        """
+        glyph_cls = extract_type_param(cls, BaseGlyph)
+        assert glyph_cls is not None
+
+        cls._glyph_cls = glyph_cls
 
 
 class BaseVariantExportFactory[GlyphT: BaseGlyph](BaseVariantFactory[GlyphT]):

test/conftest.py

@@ -8,7 +8,7 @@
 from glyphsynth.lib.alphabet.minimal import UNIT
 from glyphsynth.lib.arrays import HArrayGlyph, VArrayGlyph
 
-logging.basicConfig(level=logging.DEBUG)
+logging.basicConfig(level=logging.INFO)
 
 OUTPUT_PATH = Path(os.getcwd()) / "test" / "__out__"
 SPACING: float = UNIT / 10

test/lib/test_matrix.py

@@ -46,10 +46,9 @@ def draw(self):
         letter2.rotate(180)
 
 
-class VariantFactory(BaseVariantExportFactory[AMTComboGlyph]):
+class AMTVariantFactory(BaseVariantExportFactory[AMTComboGlyph]):
     MATRIX_WIDTH = len(COLORS)
     SPACING = UNIT / 10
-    glyph_cls = AMTComboGlyph
 
     # generate variants of colors and letter combinations
     def get_params_variants(self) -> Generator[AMTComboParams, None, None]:
@@ -87,5 +86,5 @@ def test_matrix(output_dir: Path):
 
 
 def test_variants(output_dir: Path):
-    for spec in VariantFactory():
+    for spec in AMTVariantFactory():
         write_glyph(output_dir / spec.path, spec.glyph)