Add get_name, get_full_name, get_glyph_index, and glyph_count functions

OpenFontFormat/OpenFont.py

@@ -445,7 +445,10 @@ def parse_cmap_subtable(f: BinaryIO, platformID: PlatformID) -> CmapSubtable:
 	
 	assert False, format
 
-class EncodingID(ABE): pass
+class EncodingID(ABE):
+	@abstractmethod
+	def get_code_point(self, char: str) -> Optional[int]:
+		assert False, f"Unimplemented: get_code_point for {repr(self)}"
 
 class UnicodeEncodingID(EncodingID, Enum):
 	Unicode_1_0 = 0
@@ -456,6 +459,14 @@ class UnicodeEncodingID(EncodingID, Enum):
 	UnicodeVariationSequences = 5
 	UnicodeFull = 6
 
+	def __str__(self) -> str:
+		return self._name_
+	
+	def get_code_point(self, char: str) -> int | None:
+		return ord(char) # TODO: Actually validate that the codepoint is within range of these different versions of Unicode Encoding
+		match self:
+			case _: assert False, self
+
 class MacintoshEncodingID(EncodingID, Enum):
 	Roman = 0
 
@@ -478,6 +489,15 @@ class WindowsEncodingID(EncodingID, Enum):
 	def __str__(self) -> str:
 		return self._name_
 	
+	def get_code_point(self, char: str) -> int | None:
+		match self:
+			case self.UnicodeBMP:
+				code_point = ord(char)
+				if 0 <= code_point <= 0xFFFF: return code_point
+				return None
+			case self.UnicodeFull: return ord(char)
+			case _: assert False, self
+
 @dataclass
 class CustomEncodingID(EncodingID):
 	encodingID: int
@@ -6261,3 +6281,44 @@ def parse_open_font_file(f: BinaryIO) -> OpenFontFile:
 def open_font_file(file_path: str) -> OpenFontFile: # as in `open (verb) font file (noun)`, not OpenFontFile
 	with open(file_path, 'rb') as f:
 		return parse_open_font_file(f)
+
+def get_name(font: OpenFontFile, nameID: NameID) -> str:
+	assert isinstance(font.naming_table, NameTable_Format_0)
+
+	for nameRecord in font.naming_table.nameRecord:
+		if nameRecord.nameID == nameID:
+			return nameRecord.string
+		
+	assert False, f"Name not found: {nameID}"
+
+def get_full_name(font: OpenFontFile) -> str:
+	return get_name(font, PredefinedNameID.FULL_NAME)
+
+def get_glyph_index(font: OpenFontFile, char: str) -> int:
+	for encoding_record in font.character_to_glyph_mapping.encodingRecords:
+		code_point = encoding_record.encodingID.get_code_point(char)
+		if code_point is not None:
+			match encoding_record.subtable:
+				case CmapSubtable_Format_4(
+					segCountX2=segCountX2,
+					endCode=end_code,
+					startCode=start_code,
+					idDelta=id_delta,
+					idRangeOffset=id_range_offset,
+					glyphIdArray=glyph_id_array):
+					for i, (start, end) in enumerate(zip(start_code, end_code)):
+						if start <= code_point <= end:
+							if start == end == 0xFFFF: return 0
+							if id_range_offset[i] == 0: return (id_delta[i]+code_point)%0xFFFF
+							index = glyph_id_array[code_point-start+id_range_offset[i]//2+i-segCountX2//2]
+							if index == 0: return 0
+							return (index+id_delta[i])%0xFFFF
+				case CmapSubtable_Format_12(groups=groups):
+					for group in groups:
+						if group.startCharCode <= code_point <= group.endCharCode:
+							assert False, (group, code_point)
+				case _: assert False, encoding_record.subtable.__class__
+	return 0
+
+def glyph_count(font: OpenFontFile) -> int:
+	return font.maximum_profile.numGlyphs