Uniscribe is the Microsoft Windows set of services for rendering Unicode-encoded text, supporting complex text layout. It is implemented in the dynamic link library USP10.DLL. Uniscribe has been released with Windows 2000 and Internet Explorer 5.0. In addition, the Windows CE platform has supported Uniscribe since version 5.0.
"USP" is an initialism for Unicode Scripts Processor. Its features include:
Although Uniscribe continues to be maintained as of 2021, its intended replacement DirectWrite, which has more features, has been introduced with Windows 7.
Below are listed some common versions of usp10.dll, as well as the methods by which they are distributed.
Features are added according only the "major.minor" part of the version number, the third part in the full version number is used for system target identification numbers for which the DLL was ported by Microsoft, and the last part is the build number on each target system version (which may change within regular system/software updates). Some hotfixes provide upgrades only for specific applications (notably in the Office installation directory), and not suited for use in the Windows system directory (whose version of the DLL should never be updated and is often protected by the system):
File sizes may vary depending on specific localizations of the DLL (depending on the target system or application for which it was compiled); those given here are for the US-English localization.
|Version number||File Size||File Date||Software Bundled by||New feature of this version|
|10.0.14393.0||79,360 bytes (x64)||2016-08-02||Windows 10 Anniversary Update||?|
|1.626.7601.23259||627,712 bytes (x86)||2015-11-03||?||?|
|1.626.7601.19054||627,712 bytes (x86)||2015-11-03||?||?|
|10.0.10240.16834||626,688 bytes (x64)||2015-07-10||Windows 10||Universal Shaping Engine support for Unicode 7.0 complex scripts|
|1.626.7601.18454 (Windows 7 GDR)||626,688 bytes (x86)
801,280 bytes (x64)
|2014-04-25||KB2957509  – Windows 7, Windows Server 2008 R2, Windows Vista, Windows Server 2008, Windows Server 2003||Security update|
|1.626.7601.22666 (Windows 7 LDR)||626,688 bytes (x86)|
801,792 bytes (x64)
|6.3.9431.0||76,288 bytes||2013-06-16||Windows 8.1 (preview)||?|
|1.626.7601.22171||626,688 bytes (x86)||2012-11-22||?||?|
||2012-11-22||KB2786400 ||An update is available that changes the default settings of the shaping behavior for Arabic text rendering in Windows 7 and Windows Server 2008 R2.|
||2010-11-20||Windows 7 SP1 x64 (RTM)||?|
||Windows 7 SP1 x86 (RTM)|
||2010-09-30||Windows 7 SP1 (RC)||Restore support for unassigned code points|
||2010-09-21||PowerPoint Viewer 2010 (SP1) KB2460050 ||?|
||2010-01-07||Microsoft Office 2010 (RTM)||Support PR-37: Clarification of the Use of Zero Width Joiner in Indic Scripts; This version supports OpenType on Windows XP.|
||2009-08-04||Microsoft Office 2010 (Beta)||?|
||2009-07-14||Windows 7 (RTM)||?|
||2009-04-22||Windows 7 RC||?|
||2010-07-11||Microsoft Office 2007 (SP2) Security Update KB2288621 ||MS10-063: Description of the security update for the 2007 Office suites: September 14, 2010|
||2010-04-16||Windows Server 2008 SP2, Windows Vista SP2 Security Update KB981322 ||MS10-063: Description of the security update for Windows Unicode Scripts Processor: September 14, 2010|
||2009-04-11||Windows Server 2008 SP2, Windows Vista SP2||?|
||2008-01-19||Windows Server 2008 (RTM), Windows Vista SP1, VOLTSupplementalFiles (July 2008), MS VOLT 1.3  (released July 31, 2008), SIL FieldWorks, Keyman Desktop 7.1||Supports newer OpenType table features; improved support for ligatures and contextual shapes in Indic scripts with simpler fonts|
||2007-04-18||Windows Server "Longhorn" (Beta 3)||?|
|2007-04-19 02:15:55 UTC||Windows Vista Hotfix KB936176||FIX: incorrect rendering of fully decomposed characters in NFD form encoded in sequences with more than 2 characters (affects 114 Latin characters decomposed in sequences of 3 codes)|
|2006-11-02 09:44:03 UTC||Windows Vista Ultimate (RTM)||DirectX 10? WDDM?|
||2006-10-13||Microsoft Office 2007 Ultimate (RTM)||Supports Oriya and Kannada scripts|
||2006-06-17||Windows Vista (Beta 2)||DirectX 9?|
||2006-03-13||Microsoft Office 2007 (Beta 2)||OpenType typographic features?|
|2006-01-04||Windows Vista (Beta 1)||Microsoft VOLT 1.2 |
||2005-08-17||Microsoft Office 12 Professional (Beta 1)||OpenType typographic features?|
||?||Third-party software||Supports Mongolian script|
||?||Hotfix for SIL fonts||FIX : Combining mark sequences in Latin script may be incorrectly rendered|
||2005-01-07||Microsoft Sinhala Enabling Pack for XP 0.42||Supports Sinhala script|
|2004-10-22||Third-party software||Microsoft Visual OpenType Layout Tool (VOLT) 1.1.225 update|
|2004-10-22||Third-party software||Supports Malayalam script; VOLTSupplementalFiles (Nov 2004); rendering improvement up to 3 diacritics with CGJ|
|2004-02-04||Microsoft Office 2003 (fix), SIL FieldWorks (Speech Tools Phonology Assistant 3.0.1)||?|
|2004-04-15||Microsoft Office 2003, Google Earth|
|?||Paratext 6||Supports Tibetan script.|
|?||MS VOLT 1.1.206||Supports Khmer script|
|?||VOLTSupplementalFiles (Aug 2002)||?|
|2005-03-30||Windows Server 2003 (SP1)||FIX?|
|2003-03-25||Windows Server 2003||Support for DirectX, GDI+ and newer display driver model|
|2010-04-16||Windows XP (SP3) Security Update KB981322 ||MS10-063: Description of the security update for Windows Unicode Scripts Processor: September 14, 2010|
|2008-04-14||Windows XP Build 5512 (SP3)||FIX?|
|2007-06-26||Windows XP (SP2) Hotfix KB939450 ||FIX: The GetCharacterPlacement function unexpectedly returns zero|
|2005-11-05||Windows XP (SP2) Hotfix KB910466 ||FIX: You may receive a "MEM_BAD_POINTER" error message on a computer that is running Windows XP with Service Pack 2|
|2004-08-12||Windows XP Build 2180 (SP2)||Supports Bengali and Malayalam scripts; supports complex Latin (for Vietnamese); FIX: ligation of tone contours|
|2002-08-29||Windows XP Build 1106 (SP1)||?|
|2002-04-17||Internet Explorer 6.0.2800.1106 (SP1)||?|
|2001-08-17||Windows XP||Supports Thaana, Gujarati, Kannada, Gurmukhi (Punjabi), Syriac and Telugu scripts|
|2001-01-15||Microsoft Office XP (2002), Microsoft Word 2000 (SP1)||Fully supports Hebrew, Devanagari and Tamil scripts|
|2000-12-13||Internet Explorer 6 ||?|
|2003-06-19||Windows 2000 SP4 (?)||?|
||2001-09-25||Microsoft Windows Installer 2.0 Redistributable for Windows 95/98/Me KB827763||Needed for Microsoft viewers (which otherwise require 98SE at least) of Powerpoint 2003 (and later) presentations on Windows 95 and 98|
|2000-07-21||Windows 2000 SP1||Fully supports Arabic script|
|2000-06-08||Windows Me||Improved API for scripts with bidirectional and complex layouts; minimum support for Arabic and Hebrew scripts (no contextual letter forms, requires compatibility character mappings in fonts)|
|2000-04-26||Microsoft Global IME for Microsoft Office XP|
|1999-11-30||Internet Explorer 5.5 release, SP1 & SP2|
|1999-04-05||Windows 98 SE||First stable Uniscribe API; supports simple alphabetic scripts with decomposed diacritics (Latin, Greek, Cyrillic)|
|1999-01-28||Internet Explorer 5.01|
|1998-09-22||Third-party software||Multilanguage Text Layout and Complex Scripts (MTLCS) snapshot (early release for developers)|
Scripts with complex text layout have contextual and non-linear requirements to render their typography correctly. These requirements include: ligatures, where two consecutive characters are combined into one shape (Latin, Devanagari); reordering, where some characters are written before the letter they follow in pronunciation (Bengali, Sinhala, and other Indic scripts); and context-shaping, where some letters have to change shape depending on whether they occur in the beginning, middle, or the end of the word (Arabic, Mongolian).
Uniscribe uses several script-specific shaping engines for handling typography in supported complex scripts; these are implemented in addition to a generic engine for non-complex scripts (such as Latin or Cyrillic). The currently used engines include Indic (Bengali, Devanagari, Gujarati, Gurmukhi, Kannada, etc.), Arabic, Hangul, Hebrew, Khmer, Myanmar, and Thai/Lao variants.
The complexity of the Unicode standard and ambiguities in OpenType specification often result in incomplete or erroneous implementations of complex text layout. Script-specific shaping engines work on a case-by-case basis and do not consistently handle common features of OpenType fonts, which makes it difficult for OS programmers and font developers to support new scripts. Implementation errors are very hard or impossible to correct at a later stage without breaking up backward compatibility for existing documents and fonts, often requiring new OpenType layout features and a redesign of existing fonts and typography rendering engines.
In Windows 10, major refactoring work was done for Uniscribe to implement a generalized shaping model, the Universal Shaping Engine (USE). This engine is directly based on glyph properties defined in the Unicode standard, in the hope that any complex script with a suitable font would be supported without the time and effort required to create a dedicated shaping engine.
USE builds on a generalized "universal cluster model" developed for the Indic scripts, which models a superset of human writing systems. The engine classifies each character of a complex script into several categories, base classes and subclasses. For example, a provisional Indic classification includes general, syllabic and positional categories, further divided them into base (number, consonant, tone letter, dependent vowel, etc.), base vowel (independent vowel), number (Brahmi joining number), final, medial, and modifier consonants, medial consonants, as well as top, bottom, left and right consonants and vowels. Unicode symbol strings are converted into collection of USE classes using well-defined rules, making glyph composition a standard procedure and allowing inter-character interactions not possible with current language features defined in OpenType specifications.
The Universal Shaping Engine was presented at the OpenType Developer Meeting in 2014; a compatible approach has also been implemented by the open source HarfBuzz text shaper. As of 2020, the USE in Windows 10 handles a total of 70 complex scripts: Adlam, Ahom, Balinese, Batak, Bhaiksuki, Brahmi, Buginese, Buhid, Chakma, Cham, Chorasmian, Dives Akuru, Duployan, Egyptian Hieroglyphs, Elymaic, Grantha, Gunjala Gondi, Hanifi Rohingya, Hanunoo, Javanese, Kaithi, Kayah Li, Kharoshthi, Khitan Small Script, Khojki, Khudawadi, Lepcha, Limbu, Mahajani, Makasar, Mandaic, Manichaean, Marchen, Masaram Gondi, Medefaidrin, Meitei Mayek, Miao, Modi, Mongolian, Multani, Nandinagari, Newa, N’Ko, Nyiakeng Puachue Hmong, Pahawh Hmong, Phags-pa, Psalter Pahlavi, Rejang, Saurashtra, Sharada, Siddham, Sinhala, Sogdian, Old Sogdian, Soyombo, Sundanese, Syloti Nagri, Tagalog, Tagbanwa, Tai Le, Tai Tham (limited support), Tai Viet, Takri, Tibetan, Tifinagh, Tirhuta, Wancho, Yezidi, and Zanabazar Square.
Although Uniscribe has been available since Windows 2000, new versions of Uniscribe provided more functions to the system, namely, support for other writing systems. An earlier update of it supports the display of Arabic and Hebrew, then Thai and Vietnamese. Since Windows XP, more South Asian and Assyrian scripts are supported.