Transcript Development of Accessible E-documents and Programs for

Development of Accessible Edocuments and Programs for
Visually Impaired
Using pc without visual control
0. What do you think?
• How can blind user controll the computer?
• Which input devices can he use (mouse?
Keyboard? something else?)
• Which input devices are not usable for
him?
• and what about output?
1. How to input (1)
• Blind users use only keyboard
• Standard Windows keyboard shortcuts
(almost all tasks in windows can be done
without the mouse)
• Keyboard shortcuts provided by
applications (CTRL+B: bold in wordpad,...)
2. How to input (2)
• Keyboard shortcuts provided by special
software (more info on next slides)
• Keys on special hardware devices (braille
displays)
• Users with partial seeing use also mouse
3. How to output
• Blind users: Speech and sounds
• Blind users: braille display
• Users with visual impairment: Magnified
screen
4. Speech and sounds
• Software synthesizers supporting some
communication protocol (MSSAPI, SSML)
• Integrated synthesis
• Special hardware synthesizers (Apollo,
Dectalk,...)
5. Braille display
• Special hardware connected via Universal Serial
Bus
• Contains braille cells (one cell = one braille
character)
• And control buttons (mouse emulation, cursor
adjustment,...)
• Is in different sizes (20, 24, 44, 70, 80 cells)
• Is very expensive (from 2000 to 10000 euro)
6. Magnified screen
• Used by users with visual impairment (not
blind users)
• Software magnification from 2 to 36 times
is used
7. 2 approaches to accessibility (1)
• Applications with speech and / or braille
output and magnification support
• Speech: often works only partially
• Reads text but not menu,...
• Magnification: only basic functionality (kind
of magnifying glass, font enlarging,...)
8. 2 approaches to accessibility (2)
Special applications (screen readers,
screen magnifiers)
Works in general (as a part of operating
system)
Applications with standard UI components:
are directly supported
Applications with special (third party) UI
components: can be supported
9. Screen reader: basic info
• Is a special software for blind computer
users
• Output: speech, sounds and braille
• Provides information about input devices
(typed characters, pressed shortcuts,...)
• Automatically provides information about
"important" parts of the screen
• Enables user to ask (by pressing shortcut)
for less important information
10. What is important and what not
(1)
• Yes: description of the object which received a
focus (listbox, edit, multiline edit, password edit,
checkbox, radio button,...)
• Yes: State of the focused object (checked, not
checked, grayed,...)
• Yes: Number of items in the focused object
(items in listbox/view, number of different states
of radio button,...)
• Yes: selection status (Which items in focused
listbox are now selected?)
11. What is important and what not
(2)
•
•
•
•
Font name, size and color:
in focused listbox object,
In multiline text edit
In edit box of standard find dialog (e.g. in
wordpad)
• Every minute information that the time on
system tray changed
• Content of status line in MS Word
• Title of focused (active) window
12. General rules - speech
• It is not good idea to automatically announce Long
speaking information (automatically read content of
multiline edit, automatically read whole selected text in
multiline edit, automatically say all selected items in file
list view)
• It is not good idea to automatically announce noninformative data (position of the focused control on the
screen, foreground and background color of focused
control,...)
• Screen reader users have no information about the look
of the window as a whole, so it is not good idea to
assume for example that the text to the left of input
control will be announced as a label.
13. General rules - braille display
• All rules from previous slide
• Braille displays provide better information
about screen positions of UI components
• It is good idea to provide shortened
descriptive strings of objects (listview=lw,
checkbox=chb,...)
14. Real example (Windows
explorer) (1)
• after opening:
• title of window is announced
• name of the focused object (tree view) is
announced
• Selected item is announced (My
Computer)
• State of the item (opened) is announced
• Number of subitems in the opened item
(10 items) is announced
15. Real example (Windows
explorer) (2)
• After down arrow:
• Level in the tree (level 2) is announced
• Name of the selected item (local disk...) is
announced
• State of the selected item (closed) is announced
• after tab key (switch to another UI component):
• Name and title (if exists) of newly focused object
(folder view list view) is announced
• State of selection in component (not selected) is
announced
• First item in component is announced
16. Real example
(foobar2000 settings)
• Two pictures on the next slides demonstrate a
somehow problematic user environment
• Can you name the problem and propose a
solution?
• Tab order is defined by numbers near
components
• The components without a number are not
reachable from the keyboard (are invisible for a
blind user)
17. Foobar2000 settings
(first instance)
18. Foobar2000 settings
(second instance)
19. Providing less important
information
• Screen readers provide many functions to
get less important information
• Title of focused window
• Textual content of focused window
• List of headings in document
• List of links on the web page
• ...
20. What is accessible
and what is not (1)
• Accessible object must be reachable from
the keyboard (for example toolbars are
not)
• Objects without textual description are
generally not accessible (icons without text
description, color chooser,...)
• Icons without text can be labelled with
textual information provided by user of
screen reader
21. What is accessible
and what is not (2)
• Are the tables accessible without special
processing?
• Is the multi column webpage accessible
without processing?
• How to make standard progress bar
accessible? Is it important to have
information from progress bar?
22. Some special functions of
screen readers
Mouse emulation:
• Many screen readers provide functionality to work with
mouse through keyboard
• Moving mouse pointer (and reading the text behind the
pointer)
• Left and right click and double click emulation
• Drag and drop emulation
Scripting:
• Better screen readers enables users to write scripts
associated with applications and improve accessibility
• Special functionality to optimize web browsing
23. Self voicing applications
• Standard applications with some kind of speech support
• Often provides only basic functionality
• Special working enviroments developed for visually
impaired users (emacspeak for linux, hpsio for dos,...)
• FireVox: speech plugin to Mozilla Firefox Browser
• Web anywhere: web browser screen reader written in
javascript (platform and browser independent)
• http://webanywhere.cs.washington.edu
24. Screen magnification
• Standard magnifying glass
• Enlarging part of screen or whole screen
• Tracking of changes on the invisible part of the
screen
• Static regions associated with hotkeys (e.g.
region fixed on window status line can be quickly
accessible)
• Smoothing edges of fonts and object borders
destroyed after magnification
• Color handling
25. Combination
• Many magnifiers have also basic speech
support
• Reading text behind the mouse
• Reading long chunks of texts (in
documents, on the web pages,...)
• Used mainly by users with very low vision
26. If you want to try (1)
• Mostly used screen reader in Slovakia: JAWS
for Windows (job access with speech)
• http://www.freedomscientific.com
• 40 minutes demo version (works again after
restart of the computer)
• Brilliant screen reader with good functionality
and support
• Speech and braille support
• Expensive (800 to 1000$)
27. If you want to try (2)
• NVDA (non visual desktop access)
• Open source screen reader with increasing
quality
• http://www.nvda-project.org
• Speech support (braille in development)
• Enough to perform standard everyday tasks
• Contains Slovak speech synthesis (e-speak
synthesizer)
• Internet browsing with Firefox 3
28. If you want to try (3)
• Magic: Mostly used screen magnifier in
Slovakia
• http://www.freedomscientific.com
• Good screen magnifier with functions
described on prior slides
• Expensive
• 40 minutes demo-version
29. If you want to try (4)
Desktop zoom:
• Free screen magnifier
• http://users.telenet.be/littlegems/MySoft/Desktop
Zoom/Index.html
• Zoom an area around the mouse, zoom a fixed
window or zoom the entire desktop
• View the entire screen as a thumbnail in the
right-bottom corner
• Follow the caret & menu items
• Change the colors to grey or inverse the colors
• Basic speech support