Identifying Writing System Information within a Font

As mentioned earlier, Windows can not determine an intended writing system or language based solely on the glyphs contained in a font. Before giving the user or application writing system options, Windows must know which writing systems a font covers.

Fortunately, fonts contain a great deal of information about their glyphs: in well-designed fonts you'll find hinting instructions, metrics, language information, attachment points for diacritical marks, underline and strikethrough information, and more. Fonts are comprised of many data structures, commonly referred to as tables, each containing specific information.

Language information about a font is stored in the "OS/2" table of the font. This table contains a variety of information about typeface weight, superscripts, strikeouts, ascender/descender values, PANOSE classification, licensing info, and more. For more information about the structure of TrueType Font Files, see the TrueType 1.0 Font File Specification (available on MSDN).

Writing systems covered by the glyphs in a font can be specified according to the Unicode script ranges covered by the font, or the codepages covered by the font. A font manufacturer sets script ranges and/or codepages by setting the appropriate bits of the ulCodePageRange fields or the ulUnicodeRange fields in the OS/2 table of the font. Multiple ranges can be specified for a single font. This encoding can not be changed by the user.

ulUnicodeRange bit settings (OS/2 table)

Bit	Description
0	Basic Latin
1	Latin-1 Supplement
2	Latin Extended-A
3	Latin Extended-B
4	IPA Extensions
5	Spacing Modifier Letters
6	Combining Diacritical Marks
7	Basic Greek
8	Greek Symbols And Coptic
9	Cyrillic
10	Armenian
11	Basic Hebrew
12	Hebrew Extended (A and B blocks combined)
13	Basic Arabic
14	Arabic Extended
15	Devanagari
16	Bengali
17	Gurmukhi
18	Gujarati
19	Oriya
20	Tamil
21	Telugu
22	Kannada
23	Malayalam
24	Thai
25	Lao
26	Basic Georgian
27	Georgian Extended
28	Hangul Jamo
29	Latin Extended Additional
30	Greek Extended
31	General Punctuation
32	Superscripts And Subscripts
33	Currency Symbols
34	Combining Diacritical Marks For Symbols
35	Letterlike Symbols
36	Number Forms
37	Arrows
38	Mathematical Operators
39	Miscellaneous Technical
40	Control Pictures
41	Optical Character Recognition
42	Enclosed Alphanumerics
43	Box Drawing
44	Block Elements
45	Geometric Shapes
46	Miscellaneous Symbols
47	Dingbats
48	CJK Symbols And Punctuation
49	Hiragana
50	Katakana
51	Bopomofo
52	Hangul Compatibility Jamo
53	CJK Miscellaneous
54	Enclosed CJK Letters And Months
55	CJK Compatibility
56	Hangul
57	Hangul Supplementary-A
58	Hangul Supplementary-B
59	CJK Unified Ideographs
60	Private Use Area
61	CJK Compatibility Ideographs
62	Alphabetic Presentation Forms
63	Arabic Presentation Forms-A
64	Combining Half Marks
65	CJK Compatibility Forms
66	Small Form Variants
67	Arabic Presentation Forms-B
68	Halfwidth And Fullwidth Forms
69	Specials
70–127	Reserved for Unicode SubRanges

ulCodePageRange bit settings (OS/2 table)

Bit	Codepage	Description
0	1252	Latin 1
1	1250	Latin 2: Eastern Europe
2	1251	Cyrillic
3	1253	Greek
4	1254	Turkish
5	1255	Hebrew
6	1256	Arabic
7	1257	Windows Baltic
8–16		Reserved for Alternate ANSI
17	874	Thai
18	932	JIS/Japan
19	936	Chinese: Simplified chars--PRC and Singapore
20	949	Korean Wansung
21	950	Chinese: Traditional chars--Taiwan and Hong Kong SAR, China
22–29		Reserved for Alternate ANSI & OEM
30		Macintosh Character Set (Standard Roman)
31		Symbol Character Set
32-47		Reserved for OEM
48	869	IBM Greek
49	866	MS-DOS Russian
50	865	MS-DOS Nordic
51	864	Arabic
52	863	MS-DOS Canadian French
53	862	Hebrew
54	861	MS-DOS Icelandic
55	860	MS-DOS Portuguese
56	857	IBM Turkish
57	855	IBM Cyrillic; primarily Russian
58	852	Latin 2
59	775	MS-DOS Baltic
60	737	Greek; former 437 G
61	708	Arabic; ASMO 708
62	850	WE/Latin 1
63	437	US