Upload
christopher-stevens
View
224
Download
2
Tags:
Embed Size (px)
Citation preview
Supplementary Character Support Supplementary Character Support in Microsoft Productsin Microsoft Products
Michael S. KaplanGlobalization Infrastructure and Font Technology
Windows International
Microsoft
24-26 March 2003 Prague, Czech Republic (IUC23)
What are supplementary characters?What are supplementary characters?
"a coded character representation for a single abstract character that consists of a sequence of two code units, where the first unit of the pair is a high surrogate and the second is a low surrogate"
24-26 March 2003 Prague, Czech Republic (IUC23)
High/low surrogate?High/low surrogate?
High: U+D800 - U+DBFFLow: U+DC00 - U+DFFFTerminology:
– "surrogate pair" preferred over "surrogate character“
See http://www.trigeminal.com/16to32AndBack.asp
24-26 March 2003 Prague, Czech Republic (IUC23)
Conversion example #1Conversion example #1 Example #1:
– The first character in the Surrogate range (D800, DC00) as UTF-32:
1. D800: binary 1101100000000000 (lower ten bits: 0000000000)
2. DC00: binary 1101110000000000 (lower ten bits: 0000000000)
3. Concatenate 0000000000+0000000000 = x0000
4. Add x10000
Result: U+10000. This makes sense, since the first character in the Surrogate range follows immediately after the last character in the 16-bit Unicode range (U+FFFF)
24-26 March 2003 Prague, Czech Republic (IUC23)
Conversion example #2Conversion example #2 Example #2.
– You have a Unicode character such as U+2040A (a CJK character in Plane 2) and wish to encode it in UTF-16
1. Subtract x10000 - Result: 1040A 2. Split into two ten-bit pieces: 0001000001 0000001010 3. Add 1101100000000000 (D800) to the high 10
bits piece (0001000001) - Result: 1101100001000001 (D841)
4. Add 1101110000000000 (DC00) to the low 10 bits piece (0000001010) - Result: 1101110000001010 (DC0A)
Your surrogate pair: D841, DC0A
24-26 March 2003 Prague, Czech Republic (IUC23)
UTF-8 conversionsUTF-8 conversions
Illegal conversions: six-byte UTF-8 (two surrogate code points of UTF-16, converted separately)
legal conversions: four-byte UTF-8 (one UTF-32 code point)
CESU-8 is the the inverse of the above
24-26 March 2003 Prague, Czech Republic (IUC23)
UTF-8 exampleUTF-8 example Unicode surrogate pair: aaaabbbbbbcccccc, zzzzyyyyyyxxxxxx
becomes incorrect UTF-8 total 6 bytes: 1110aaaa 10bbbbbb 10cccccc 1110zzzz 10yyyyyy 10xxxxxx
Instead, you should take a Unicode surrogate pair:
110110wwwwzzzzyy, 110111yyyyxxxxxx
and convert it to UTF-8 totaling 4 bytes (below, uuuuu is defined as = wwww+1):
11110uuu 10uuzzzz 10yyyyyy 10xxxxxx
24-26 March 2003 Prague, Czech Republic (IUC23)
Encoding choices for MSEncoding choices for MS UTF-16, mostly Occasionally UTF-8 Even more occasionally, UTF-32
REASONS: There was obviously an existing, well-tested set of APIs
that support UCS-2, which is a subset of UTF-16. A completely new API set was not required. A move to UTF-32 would require twice as much space
for all characters. A move to UTF-8 would require even more than twice as
much space in many cases.
24-26 March 2003 Prague, Czech Republic (IUC23)
The products...The products... Mostly the new generation of products:
– Windows 2000/XP– Office XP (some support in Office 2000)– Visual Studio.Net– .NET’s Common Language Runtime (CLR)
Most (all) of these products supported Unicode already– a little bit of extra work needed for supplementary
characters– usually just UTF-8 changes were needed
24-26 March 2003 Prague, Czech Republic (IUC23)
Windows 2000Windows 2000
Uniscribe support for renderingEach surrogate pair is a single graphemeAPIs like CharPrev/CharNext not changedNo specific surrogate font/IMEMust be turned on:http://msdn.microsoft.com/library/en-us/intl/unicode_192r.asp
24-26 March 2003 Prague, Czech Republic (IUC23)
Windows XPWindows XP*.* from Windows 2000Turned on by default!GDI+ support for rendering Font CMAP extensionsLots of UTF-8 issues fixedNo specific surrogate font/IME (yet)Extensions to fallback fonts [limited]:
HKLM\Software\Microsoft\Windows NT\CurrentVersion\LanguagePack\SurrogateFallback\Plane1HKLM\Software\Microsoft\Windows NT\CurrentVersion\LanguagePack\SurrogateFallback\Plane2HKLM\Software\Microsoft\Windows NT\CurrentVersion\LanguagePack\SurrogateFallback\Plane3(etc.)
24-26 March 2003 Prague, Czech Republic (IUC23)
Other system componentsOther system components
MLangInternet Explorer
http://i18nWithVB.com/surrogate_ime/IIS 5.0/6.0
24-26 March 2003 Prague, Czech Republic (IUC23)
The downlevel storyThe downlevel story
No good support for Unicode, let alone supplementary characters
Uniscribe/RichEdit does improve the downlevel story for display purposes
Officially, no support on Win9x
24-26 March 2003 Prague, Czech Republic (IUC23)
The Office suiteThe Office suite
WordFrontpageExcel/AccessOutlookRichEdit 4.0
24-26 March 2003 Prague, Czech Republic (IUC23)
Office - Specific FeaturesOffice - Specific Features
Insertion/Deletion of text - All Cursor movement - All Font linking/fallback - All (Word's is best) UTF-8 issues fixed - All Enhanced word breaking - All (Word/RichEdit) Vertical text - Word/PowerPoint/Publisher/RichEdit Direct entry (Alt+nnnnnn, hhhhh + Alt+x) -
Word/RichEdit
24-26 March 2003 Prague, Czech Republic (IUC23)
CHS/CHT/CHP OfficeCHS/CHT/CHP Office
The product and the langpacks support an extended Unicode IME that handles supplementary characters
An Extension B font is also included
24-26 March 2003 Prague, Czech Republic (IUC23)
.NET CLR/Visual Studio.NET.NET CLR/Visual Studio.NET
String class and globalization namespaceStringInfoGetTextElementEnumerator
– Handles supplementary characters– Also handles composite characters
GDI+VS IDE support
24-26 March 2003 Prague, Czech Republic (IUC23)
SQL ServerSQL Server
Past - no support (for Unicode, even!)Present - surrogate "safe" (neutral)Future - surrogate “aware”
24-26 March 2003 Prague, Czech Republic (IUC23)
Items not [currently] supportedItems not [currently] supported
Character MapGraph 10Outlook 10 mail headersFonts/IMEs“Collations” for supplementary characters
24-26 March 2003 Prague, Czech Republic (IUC23)
Collation plan for Collation plan for supplementary characters in supplementary characters in
the UCA?the UCA? All Plane-1 (non-ideographic) characters sort after all the
other non-ideographic scripts but before the ideographs. All Plane 2 (ideographic) characters will be sorted after all
the ideographs on the BMP. All Plane 3-14 (currently not assigned) will be treated like
any other unassigned characters. Plane 14 language tags will be treated as if they were
unassigned. All characters encoded in Plane 15-16 (private use) will be
sorted after all other characters.
24-26 March 2003 Prague, Czech Republic (IUC23)
Questions?Questions?
24-26 March 2003 Prague, Czech Republic (IUC23)
Supplementary Character Support in Microsoft
Products
Don’t forget to fill out your evals!