An application programming interface (API) is an interface implemented by a software program to enable interaction with other software.
The Speech Application Programming Interface or SAPI is an API developed by Microsoft to allow the use of speech synthesisers made by different manufacturers. You can install other SAPI versions, if you want. You have to look wheather this other version runs on your system on the download page.
The folowing table shows all Windowsversions supported by NVDA and which sapi versions they include:
| Windows version | Sapi Version |
|---|---|
| Windows 2000 | Sapi 4 |
| Windows xp | Sapi 5 |
| Windows Vista | Sapi 5.1 |
| Windows 7 | Sapi 5.1 |
Virtual Buffers are used to present complex documents in NVDA and other screen readers. Elements such as headings, paragraphs, tables and lists will be represented in such virtual Buffers. Buffers are named virtual because information about the object is only presented with the Screen reader and not on the screen. Examples for documents accessed by virtual buffers are HTML files in Firefox, Google Chrome, Internet explorer and the windows help (winhlp32) or reading PDFs in Adobe Reader. NVDA has got changed a lot in the future, so in the changes document you will read about old and new virtual buffers.
Microsoft Active Accessibility (MSAA) is an Application Programming Interface (API) for user interface accessibility. MSAA is designed to help Assistive Technology (AT) products with interact with standard and custom user interface (UI) elements of an application (or the operating system), as well as to access, identify, and manipulate an application's UI elements. AT products work with MSAA enabled applications in order to provide better access for individuals who have cognitive difficulties, impairments, or disabilities. One examples of AT products are screen readers for users with limited sight,.
User Information Automation is the further development of MSAA. They're are interfaces between both of them.
iaccessible is an accessibillity interface for Windows systems developed by IBM. IA2 is an alternative to the MSAA successor UI Automation
A video interceptor works like a driver that catches all information provided by the display card and passes all of them to a program like screen reader So the screen reader is able to show the data like on the screen. This enables the user to activate an object without knowing where it is in the hirarchical order or if the object isn't detected by the APIs. The disadvantage of this is that videointerceptors must be installed with administrator privileges. This makes a portable screenreader unusable
This is a method to get informations in relation to the screen without installing a display driver to the system. For example: the windows screen reader, System Access and in the Orca screen reader for linux packaged with gnome.
These are two examples for commercial screen readers. The developers orientate on their use of concept.
Modern keyboards have got besides the notepad and the numberpad an extended block. In this block you'll find 4 arrow keys and at the top of them is a block of 6 keys: Insert, delete, home, end, page up and page down. All of them can be found on the number pad, too. So there has to be a way to differenciate the keys on the numberpad and the extended pad. For example: If you want to make clear that the insert key on the extended pad is meant, you will say "extended insert" simply.
these settings change nvda's verbosity while reading objects. Here you can tell nvda (not) to read the type of an object or the position inside a list box.
If you are working in windows allways one object has the focus. This could be an edit field, a combo box, a checkbox etc.
This is the window you work in. If you read this document, the foreground window is your Internet browser probably.
Objects are everything which can be shown on the screen. Objects are for example edit fields, buttons, checkboxes, Links, program windows, etc.
the navigator implements a method for moving between objects inside an application. the current navigator object is the object which is displayed in the navigator.
The insertion pointer in an edit field is called the 'system cursor' because it can be moved with windows' built-in tools (arrow keys, page up, page down etc.) without using a screen reader. the review cursor is an nvda internal cursor. The user can navigate inside an object and read its content without moving the system cursor.
In the last few years webdisigners built dynamic content into their websites. This means that particular parts of the site get updates without reloading the whole website. I.E. Ebay auctions and share prices.
All objects not known by NVDA are named field or pane.
all editable objects within a web page (check boxes, combo boxes, edit fields, buttons) are summarized by this term.
With this function it is easier to move the mouse along axes of coordinates
After pressing the shortcut key alt+shift+numlock, a message box comes up to inform you that you are about to enable the keyboard mouse. Now you can:
you can speed up the mouse pointer movement by using the numpad keys together with the ctrl key. Using them together with the shift key will slow down the mouse pointer movement.
To get braille output while using the keyboard mouse, the following 3 conditions must be met: