Linux Accessibility HOWTO - Michael De La Rue (ebook smartphone .txt) 📗

Linux Accessibility HOWTO

Michael De La Rue

Sharon Snider

v3.1, June 21, 2002

Revision History

Revision v3.1 2002-06-21 Revised by: sds

Updated and converted to DocBook XML.

Revision v3.0 2001-10-25 Revised by: sds

Updated and converted to DocBook SGML.

Revision v2.11 1997-03-28 Revised by: mdlr

Last Linuxdoc revision.

The Linux Accessibility HOWTO covers the use of adaptive technologies that

are available for the Linux operating system, as well as the software

applications and hardware devices that can be installed to make Linux

accessible to users with disabilities. The information provided targets

specific groups of individuals with similar disabilities.

Table of Contents

Introduction

1.1. Distribution Policy

The Linux Operating System

2.1. Assistive Technologies Available for Linux

2.2. Usability

Visual Impairments

3.1. Technologies for the Visually Impaired

Hearing Impaired

4.1. Assistive Technologies for the Hearing Impaired

Physically Disabled

5.1. Keyboard Navigation

5.2. Assistive Technologies for the Physically Disabled

5.3. Additional Resources

Cognitive, Language, and Other Impairments

6.1. Assistive Technologies for Cognitive, Language and Other Impairments

Developing Accessible Applications

Other Helpful Information

Acknowledgments

Introduction

The purpose of this HOWTO is to introduce the tools, applications, and

configuration utilities that are available to Linux users who are disabled.

The information provided targets groups of individuals with the following

disabilities:

* Visually Impaired

* Hearing Impaired

* Physically Disabled

* Cognitive, Language, and Other Impairments

Please send any comments, or contributions via e-mail to [mailto:

snidersd@us.ibm.com] Sharon Snider. This document will be updated regularly

with new contributions and suggestions.

1.1. Distribution Policy

The Access-HOWTO may be distributed, at your choice, under either the terms

of the GNU Public License version 2 or later or the standard Linux

Documentation Project (LDP) terms. These licenses should be available from

the LDP Web site: [http://www.linuxdoc.org/docs.html] http://www.linuxdoc.org

/docs.html. Please note that since the LDP terms do not allow modification

(other than translation), modified versions can be assumed to be distributed

under the GPL.

ViaVoice® is a registered trademark of International Business Machines

Corporation.

The Linux Operating System

The Linux operating system has many software applications and utilities that

run in the non-graphical environment. The graphical user interface (GUI),

which is often referred to as X Windows, is clearly separate from the

underlying non-graphical, text-only environment. One major reason that a

visually impaired individual can use Linux is that network connectivity is

built in to the operating system and provides full access to the Internet

from the non-graphical interface. All visible text on the screen can be

translated using a screen reader and speech synthesizer.

Over the past few years many improvements have been made to the GUI, and many

of the desktops now provide features and enhancements designed for

accessibility. In the following sections you will find information on the

tools, utilities, and applications that are available to assist users in

configuring their desktop environment.

2.1. Assistive Technologies Available for Linux

Assistive technologies are computer hardware devices and software

applications that provide individuals with impairments access to the

information and applications on a computer. Although there are not many

commercial applications available specifically for Linux accessibility, there

are free software applications that can make the computer more accessible.

Detailed information on assistive technologies that are available has been

listed in this document based on the type of disability.

2.2. Usability

Linux has the advantage over Windows that a large majority of Linux software

has been developed for the console. Although many programs are now being

developed for the GUI, programs continue to be written for the non-graphical,

text-based environment. Linux originated as a programmer's operating system

and, for the physically disabled, this means that it is easy to build and

customize programs to suit an individual's needs.

The windowing system used by Linux (X11) includes many programming tools that

enable further modification and customization of the GUI. KDE and GNOME have

included many accessibility and usability features in their latest releases

and are continuing to test, upgrade, and enhance the graphical environment.

The following are links to KDE and GNOME's accessibility and usability

projects:

* KDE Accessibility Project - [http://accessibility.kde.org/] http://

accessibility.kde.org/.

* GNOME Accessibility Project - [http://developer.gnome.org/projects/gap/]

http://developer.gnome.org/projects/gap/.

* KDE Usability Project - [http://usability.kde.org/] http://

usability.kde.org/.

* GNOME Usability Project - [http://developer.gnome.org/projects/gup/]

http://developer.gnome.org/projects/gup/. Visual Impairments

There are two categories of visual impairments. Individuals who are partially

sighted (for example, blurred vision, near and far-sightedness, color

blindness) and those who are totally blind. Assistive technologies are

available for the Linux operating system for visually impaired users, and

many of the software packages are free.

3.1. Technologies for the Visually Impaired

The following is a list of assistive technologies for visually impaired

users:

3.1.1. Screen Readers

Screen readers are software applications that are installed on the computer

to provide translation of the information on the computer screen to an audio

output format. The translation is passed to the speech synthesizer and the

words are spoken out loud. Currently, fully functional screen readers are

only available for Linux in console mode. This section describes some of the

most common screen readers.

* Emacspeak is the complete Audio Desktop is an excellent non-graphical,

text based interface for users who are visually impaired. This application can be used as a screen reader in conjunction with a hardware synthesizer or IBM ViaVoice® Run-time text-to-speech application. More information and software packages of are available at: [http:// www.cs.cornell.edu/home/raman/emacspeak/] http://www.cs.cornell.edu/home/ raman/emacspeak/. The Emacspeak HOWTO [http://www.ibiblio.org/pub/Linux/ docs/HOWTO/] http://www.ibiblio.org/pub/Linux/docs/HOWTO/ includes a tutorial and installation guide.

* Jupiter Speech System is a screen reader for Linux in console mode. A

user guide and software packages are available at: [http://www.eklhad.net /linux/jupiter/] http://www.eklhad.net/linux/jupiter/.

* Screader is a screen reader for Linux in console mode that works with the

Festival software speech synthesizer and the Accent hardware synthesizer. Information and downloads are available at: [http://www.euronet.nl/~acj/ eng-screader.html] http://www.euronet.nl/~acj/eng-screader.html.

* Speaker is a new plugin for the Konqueror file manager and Web browser.

Speaker provides Text to Speech using the Festival speech system or IBM ViaVoice. Downloads are available at: [http://dogma.freebsd-uk.eu.org/ ~grrussel/speaker.html] http://dogma.freebsd-uk.eu.org/~grrussel/ speaker.html.

* Speakup is a screen review package for the Linux operating system. It

requires a hardware speech synthesizer, such as the DecTalk Express. An installation boot disk and packages are available at: [http:// www.linux-speakup.org/] http://www.linux-speakup.org/ that allow a visually impaired user to install the Linux operating system.

* ZipSpeak is a talking mini-distribution of Linux. More information and

software packages are available at: [http://www.linux-speakup.org/ zipspeak.html] http://www.linux-speakup.org/zipspeak.html.

3.1.2. Speech Synthesizers

Speech synthesizers can be a hardware device or a text to speech (TTS)

software application that creates the sounds necessary to provide speech

output. Hardware synthesizers are available for the Linux operating system;

however, they can be very expensive and must be compatible with the screen

reader application in order to function properly. The alternative is to

download and install a software synthesizer such as IBM's ViaVoice or

Festival and configure the application to a compatible screen reader, such as

Emacspeak.

3.1.2.1. Hardware Speech Synthesizers

A hardware speech synthesizer is a device that is connected to the computer's

serial or parallel port and translates the text to a spoken output. Normally

there are Braille labels on all controls to indicate the off and on position,

and volume control. Hardware synthesizers also have the ability to speak in

different tones that can be setup to indicate various parts of a document or

text. Some models will provide a connection for headphones. The following is

a list of speech synthesizers that are supported on the Linux operating

system and can be used with Emacspeak:

* Accent SA and Apollo 2 ([http://polio.dyndns.org/chip/vss.html] http://

polio.dyndns.org/chip/vss.html)

* DECTalk Express ([http://www.4access.com/synthesizers.asp] http://

www.4access.com/synthesizers.asp)

* DoubleTalk ([http://www.rcsys.com] http://www.rcsys.com)

3.1.2.2. Software Speech Synthesizers

A software speech synthesizer is an application that translates the text on

the screen to speech output and provides speech synthesis, so that the screen

reader application can read information out loud to the user.

* Festival is a general, multi-lingual speech synthesis system developed at

the Center for Speech Technology Research (CSTR). It offers a full TTS system with various application program interfaces, as well as an environment for development and research of speech synthesis techniques. Mbrola or FestVox are needed to complete the Festival installation. Software packages and installation instructions are available at: [http:/ /www.cstr.ed.ac.uk/projects/festival/] http://www.cstr.ed.ac.uk/projects/ festival/.

* Mbrola is a speech synthesizer that can be used with a TTS application,

such as, Festival to provide speech output. More information is available at: [http://tcts.fpms.ac.be/synthesis/mbrola.html] http://tcts.fpms.ac.be /synthesis/mbrola.html.

3.1.3. Screen Magnifiers

Screen magnifiers enable users that are partially sighted to view selected

areas of the screen in a manner similar to using a magnifying glass.

* GMag is a screen magnifier for X Windows. It provides continuous

magnification while you work, as well as the option to change the contrast of images at run-time. More information and downloads are available at: [http://projects.prosa.it/gmag/] http://projects.prosa.it/ gmag/.

* Puff is a screen magnifier for users who need a high magnification of

text and graphics in X Windows. Puff follows the focus of the mouse or pointer and enlarges the portion of the screen under the cursor. In order for Puff to run properly on Linux the source code needs to be modified. This application is not a good option for inexperienced users. The software packages and source code modification instructions are available at: [http://trace.wisc.edu/world/computer_access/unix/unixshare.html] http://trace.wisc.edu/world/computer_access/unix/unixshare.html.

* SVGATextmode enlarges or reduces the font size for users who perfer to

work in console mode. The normal text screen that Linux provides is 80 characters across and 25 vertically. After SVGATextmode is installed, the text can be displayed much larger. One example would be 50 characters across and 15 vertically. The program does not offer the ablitity to zoom in and out, but the user can re-size when necessary. The most current download is available at: [http://freshmeat.net/projects/svgatextmode/] http://freshmeat.net/projects/svgatextmode/. Do not run try to run SVGATextmode from an X Windows terminal. You must be in console mode for the display to function properly.

* UnWindows is a collection of programs that