NonVisual Desktop Access
Encyclopedia
NonVisual Desktop Access (NVDA) is a free, open source, portable screen reader
for Microsoft Windows
. The project was started by Michael Curran in 2006. The latest stable version is 2011.3
NVDA is programmed in Python
. It currently takes advantage of video intercept techniques in favour of working with accessibility API
s such as Microsoft Active Accessibility
, IAccessible2
and the Java Access Bridge. It is licensed under the GNU General Public License
.
NVDA uses eSpeak
as its integrated speech synthesizer, and also supports SAPI
synthesizers. Output to Braille displays
is supported officially from Version 0.6p3.
, Notepad and Internet Explorer
. It supports the basic functions of Outlook Express
, Microsoft Word
2000/XP/2003 and Microsoft Excel
2000/XP/2003 . Support for the free office suites LibreOffice
and OpenOffice.org
requires the Java Access Bridge package. NVDA also supports Mozilla Firefox
(version 3 or higher). Firefox version 3 is the recommended web browser
for maximum barrier-free web browsing by the NVDA developers; several accessibility issues were introduced with version 4 of the browser, which will be fixed in the upcoming version 10 release.
Since early 2009, NVDA supports the WAI-ARIA standard for Accessible Rich Internet Applications, so that in the future, web applications can be better used by blind users.
Support for email
is provided with Mozilla Thunderbird
version 3 or higher.
With the 2010.1 release, NVDA supports 64-bit editions of Windows, the login screen and User Account Control
(UAC) screens, and has full support for Internet Explorer. It also has a newer version of the E-speak speech synthesizer
Release 2010.2, from October 2010, added greatly simplified object navigation; virtual buffers for Adobe Flash content; access to many previously inaccessible controls by retrieving text written to the screen; flat review of screen text; support for IBM Lotus Symphony documents; reporting of table row and column headers in Mozilla Firefox; and significantly improved user documentation.
The current release is 2011.1.1, which adds automatic reporting of new text output in mIRC, PuTTY, Tera Term and SecureCRT; support for global plugins; announcement of bullets and numbering in Microsoft Word; additional key bindings for braille displays, including keys to move to the next and previous line; support for several Baum, HumanWare and APH braille displays; and reporting of colors for some controls, including IBM Lotus Symphony text controls.
Screen reader
A screen reader is a software application that attempts to identify and interpret what is being displayed on the screen . This interpretation is then re-presented to the user with text-to-speech, sound icons, or a Braille output device...
for Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
. The project was started by Michael Curran in 2006. The latest stable version is 2011.3
NVDA is programmed in Python
Python (programming language)
Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Python claims to "[combine] remarkable power with very clear syntax", and its standard library is large and comprehensive...
. It currently takes advantage of video intercept techniques in favour of working with accessibility API
Application programming interface
An application programming interface is a source code based specification intended to be used as an interface by software components to communicate with each other...
s such as Microsoft Active Accessibility
Microsoft Active Accessibility
Microsoft Active Accessibility is an Application Programming Interface for user interface accessibility. MSAA was introduced as a platform add-on to Microsoft Windows 95 in 1997...
, IAccessible2
IAccessible2
IAccessible2 is a new accessibility API for Microsoft Windows applications. Initially developed by IBM under the codename Project Missouri, IAccessible2 has been placed under the aegis of the Free Standards Group, now part of the Linux Foundation...
and the Java Access Bridge. It is licensed under the GNU General Public License
GNU General Public License
The GNU General Public License is the most widely used free software license, originally written by Richard Stallman for the GNU Project....
.
NVDA uses eSpeak
ESpeak
eSpeak is a compact open source software speech synthesizer for Linux, Windows, and other platforms. It uses a formant synthesis method, providing many languages in a small size. Much of the programming for eSpeak's languages was based on information found on Wikipedia, with some subsequent...
as its integrated speech synthesizer, and also supports SAPI
Speech Application Programming Interface
The Speech Application Programming Interface or SAPI is an API developed by Microsoft to allow the use of speech recognition and speech synthesis within Windows applications. To date, a number of versions of the API have been released, which have shipped either as part of a Speech SDK, or as part...
synthesizers. Output to Braille displays
Refreshable Braille display
A refreshable Braille display or Braille terminal is an electro-mechanical device for displaying Braille characters, usually by means of raising dots through holes in a flat surface. Blind computer users, who cannot use a normal computer monitor, use it to read text output...
is supported officially from Version 0.6p3.
Integration
Besides general Windows functionality, NVDA works with WordPadWordPad
WordPad is a basic word processor that is included with almost all versions of Microsoft Windows from Windows 95 upwards. It is more advanced than Notepad but simpler than Microsoft Works Word Processor and Microsoft Word. It replaced Microsoft Write....
, Notepad and Internet Explorer
Internet Explorer
Windows Internet Explorer is a series of graphical web browsers developed by Microsoft and included as part of the Microsoft Windows line of operating systems, starting in 1995. It was first released as part of the add-on package Plus! for Windows 95 that year...
. It supports the basic functions of Outlook Express
Outlook Express
Outlook Express is an email and news client that is included with Internet Explorer versions 4.0 through 6.0. As such, it is also bundled with several versions of Microsoft Windows, from Windows 98 to Windows Server 2003, and is available for Windows 3.x, Windows NT 3.51, Windows 95 and Mac OS 9...
, Microsoft Word
Microsoft Word
Microsoft Word is a word processor designed by Microsoft. It was first released in 1983 under the name Multi-Tool Word for Xenix systems. Subsequent versions were later written for several other platforms including IBM PCs running DOS , the Apple Macintosh , the AT&T Unix PC , Atari ST , SCO UNIX,...
2000/XP/2003 and Microsoft Excel
Microsoft Excel
Microsoft Excel is a proprietary commercial spreadsheet application written and distributed by Microsoft for Microsoft Windows and Mac OS X. It features calculation, graphing tools, pivot tables, and a macro programming language called Visual Basic for Applications...
2000/XP/2003 . Support for the free office suites LibreOffice
LibreOffice
LibreOffice is a free and open source office suite developed by The Document Foundation as a fork of OpenOffice.org. It is largely compatible with other major office suites, including Microsoft Office, and available on a variety of platforms...
and OpenOffice.org
OpenOffice.org
OpenOffice.org, commonly known as OOo or OpenOffice, is an open-source application suite whose main components are for word processing, spreadsheets, presentations, graphics, and databases. OpenOffice is available for a number of different computer operating systems, is distributed as free software...
requires the Java Access Bridge package. NVDA also supports Mozilla Firefox
Mozilla Firefox
Mozilla Firefox is a free and open source web browser descended from the Mozilla Application Suite and managed by Mozilla Corporation. , Firefox is the second most widely used browser, with approximately 25% of worldwide usage share of web browsers...
(version 3 or higher). Firefox version 3 is the recommended web browser
Web browser
A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...
for maximum barrier-free web browsing by the NVDA developers; several accessibility issues were introduced with version 4 of the browser, which will be fixed in the upcoming version 10 release.
Since early 2009, NVDA supports the WAI-ARIA standard for Accessible Rich Internet Applications, so that in the future, web applications can be better used by blind users.
Support for email
Email
Electronic mail, commonly known as email or e-mail, is a method of exchanging digital messages from an author to one or more recipients. Modern email operates across the Internet or other computer networks. Some early email systems required that the author and the recipient both be online at the...
is provided with Mozilla Thunderbird
Mozilla Thunderbird
Mozilla Thunderbird is a free, open source, cross-platform e-mail and news client developed by the Mozilla Foundation. The project strategy is modeled after Mozilla Firefox, a project aimed at creating a web browser...
version 3 or higher.
With the 2010.1 release, NVDA supports 64-bit editions of Windows, the login screen and User Account Control
User Account Control
User Account Control is a technology and security infrastructure introduced with Microsoft's Windows Vista and Windows Server 2008 operating systems, with a more relaxed version also present in Windows 7 and Windows Server 2008 R2...
(UAC) screens, and has full support for Internet Explorer. It also has a newer version of the E-speak speech synthesizer
Release 2010.2, from October 2010, added greatly simplified object navigation; virtual buffers for Adobe Flash content; access to many previously inaccessible controls by retrieving text written to the screen; flat review of screen text; support for IBM Lotus Symphony documents; reporting of table row and column headers in Mozilla Firefox; and significantly improved user documentation.
The current release is 2011.1.1, which adds automatic reporting of new text output in mIRC, PuTTY, Tera Term and SecureCRT; support for global plugins; announcement of bullets and numbering in Microsoft Word; additional key bindings for braille displays, including keys to move to the next and previous line; support for several Baum, HumanWare and APH braille displays; and reporting of colors for some controls, including IBM Lotus Symphony text controls.