DirectWrite

DirectWrite is a text-layout and glyph-rendering API by Microsoft. It was designed to replace GDI/GDI+ and Uniscribe for screen-oriented rendering and was shipped with Windows 7 and Windows Server 2008 R2, as well as Windows Vista and Windows Server 2008 (with Platform Update installed^[1] and Platform Update Supplement for Windows Vista and for Windows Server 2008(KB2117917)^[2] & KB2505189^[3] update installed.

Microsoft has fixed many DirectWrite bugs in Windows 7 through Windows 7 Service Pack 1(SP1)^[4] and KB2505438 update^[5].

Features

• Comprehensive support for Unicode, with over 20 scripts providing layout and rendering of every language supported in Windows. DirectWrite supports measuring, drawing, and hit-testing of multi-format text. Supported Unicode features include BIDI, line breaking, surrogates, UVS, language-guided script itemization, number substitution, and glyph shaping.

• Sub-pixel ClearType text rendering with bi-directional antialiasing which can interoperate with GDI/GDI+, Direct2D/Direct3D and any application-specific technology. When using with Direct2D, text rendering can be hardware-accelerated or can use WARP software rasterizer when hardware acceleration is not available. It is, however, unable to render aliased (or bi-level) text.

• Supports advanced typographic features of OpenType, such as stylistic alternates and swashes, which were never supported in GDI and WinForms.

• Provides a low-level glyph rendering API for those who employ proprietary text layout and Unicode-to-glyph processing.

Supported scripts

Arabic Armenian Bengali Bopomofo ‡ Braille

Canadian aboriginal syllabics Cherokee Chinese Simplified Chinese Traditional Cyrillic ‡ Coptic

Devanagari Ethiopic Georgian ‡ Glagolitic Greek Gujarati Gurmukhi

Hebrew Japanese Kannada Khmer Korean Lao Latin

Malayalam Mongolian Myanmar New Tai Lue ‡ Ogham Oriya

’Phags-pa ‡ Runic Sinhala Syriac

Tai Le Tamil Telugu Thaana Thai Tibetan Yi

‡ No default system font provided in Windows. Braille, Ogham, and Runic are supported by Segoe UI Symbol.

External links

• MSDN: Introducing DirectWrite

References

1. ^ http://blogs.msdn.com/directx/archive/2009/09/10/windows-7-transition-pack-for-windows-vista.aspx
2. ^ http://support.microsoft.com/kb/2117917
3. ^ http://support.microsoft.com/kb/2505189
4. ^ http://www.microsoft.com/downloads/en/details.aspx?FamilyID=c3202ce6-4056-4059-8a1b-3a9b77cdfdda
5. ^ http://support.microsoft.com/kb/2505438