- From: mark novak <menovak@facstaff.wisc.edu>
- Date: Thu, 14 Oct 1999 09:15:39 -0500
- To: schwer@us.ibm.com, i3@w3.org
- Cc: w3c-wai-ua@w3.org
see comment below at MN: At 6:00 PM 10/12/99, schwer@us.ibm.com wrote: >Ian, > >The following are techniques 1.1 through 1.6 as transcribed at the User Agent >Working group meeting: > >Technique 1.1 > >Operating system and application frameworks provide standard mechanisms for >providing navigation control to your application for standard input devices. In >the case of Windows, OS/2, the X Windows System, and MacOS,GUI applications are >provided this information through the messaging queue through the window >manager. In the case of non-GUI applications, the compiler run time libraries >provide standard mechanisms for recieving keyboard input in the case of desktop >operating systems. Should you use an application framework such as the >Microsoft >Foundation Classes, the framework used must support the same standard input >mechanisms. > >When implementing custom GUI controls do so using the standard input mechanisms >defined above. Examples of not supporting the standard input devices are: > >- Do not communicate directly with the device such as directly opening the >keyboard device driver in Windows. This may result in sytem messaging >circumvention. It is often the case that the windowing system needs to change >the form and method for processing standard input mechanisms for proper >application coexistence within the user interface framework. > >- Do not implement your own input queue handler. Devices for mobility access, >such as those that support serial >keys, use the standard input queue to control applications. > >Technique 1.2 > >When providing input control to document elements in your user agent >ensure that >you follow the techniques defined in technique section 1.1. Any output >resulting >from user actions should use the techniques defined in technique 1.6. > >Technique 1.3 > >When creating or using installation software ensure that it is navigable using >the techniques 1.1 and 1.6. Installation >software includes normal program update mechanisms included during normal >program operation. > >Technique 1.4 > >When creating the user agent software, including installation and >deinstallation, ensure that it can be configured >using techniques 1.1 and 1.6. > >Technique 1.5 > >Ensure that the user can access user agent documentation using the User Agent >Accessibility Guidelines. A way to do this in Windows would be to create help >files in HTML so that you can use a Windows browser designed to meet the User >Agent Accessibility Guidelines. This HTML source would also need to follow the >Web Content Accessibility Guidelines. > >Technique 1.6 > >Operating system and application frameworks provide standard mechanisms for the >use of standard output devices. In the case of common desktop operating >systems, >such as Windows, OS/2, and MacOS standard API are provided for writing to the >display and the multimedia subsystems. > >It is important to also support standard output notification of sound such as >those found in the Windows control panel for sounds. Windows maps accessibility >features to respond to the event caused by generation of these specific system >sounds. Accessibility features such as show sounds would flash the screen, as >appropriate, in response to events that would cause these sounds to play. This >enables the deaf user to user your application in the absence of sound. MN: Rich, I think you've confused ShowSounds and SoundSentry, and /or the description for which you were trying to use. Please check the appendix of the techniques doc., and adjust accordingly. >When implementing standard output you would not want to: > >- Render text in the form of bitmap before transferring to the screen. Screen >Readers intercept text drawing calls to create a text representation of the >screen, called an offscreen model, which is read to the user. Common operating >system 2D graphics engines and drawing libraries provide functions for drawing >text to the screen. Examples of this are the Graphics Device Interface >(GDI) for >Windows, Graphics Programming Interface (GPI) for OS/2, and for the X Windows >System or Motif it is the X library (XLIB). > >- Provide your own mechanism for generating pre-defined system sounds. > >- When using a device do not use the device driver directly. Screen readers are >designed to monitor what is drawn on the screen by hooking drawing calls at >different points in the of the drawing process. By calling the display driver >directly you may be drawing to the display below the point at which a screen >reader for the blind >is intercepting the drawing call. > >- Do not draw directly to the video frame buffer. This circumvents the >interception point at which a screen reader hooks the display calls. > > >Rich Schwerdtfeger >Lead Architect, IBM Special Needs Systems >EMail/web: schwer@us.ibm.com http://www.austin.ibm.com/sns/rich.htm > >"Two roads diverged in a wood, and I - >I took the one less traveled by, and that has made all the difference.", Frost
Received on Thursday, 14 October 1999 10:16:17 UTC