[ossrp-control] Re: What Is A Screen Reader?

I like the definition with a couple of qualifications--ones that may
have been intended but omitted for the purpose of simplification and
brevity.
 
The visual display is not the only source of semantic meaning for a
screen reader.  Often, this has been the case, thus necessitating the
need for an off screen model that intercepts and interprets drawing of
text to the screen, capturing it when it still is characters rather than
a picture of text.  Fortunately, however, graphical operating systems
have increasingly made use of underlying object models with interfaces
that may be tapped by screen readers and other applications.  
 
Under Windows, these have mostly been COM (Component Object Model)
technologies, e.g., the building blocks of Microsoft Word, Excel, and
Internet Explorer.  In such cases, the underlying semantic meaning may
be more abstract than its visual representation, and a screen reader can
choose to represent its meaning in ways that are better optimized for
modes of perception other than sight, e.g., audio or braille.  This is,
as I understand it, the primary mechanism by which the open source
screen reader will seek to retrieve semantic meaning (not COM
necessarily, but an underlying, probably .NET-based object model).  A
good analogy here is HTML and cascading style sheets, where underlying
content and physical  presentation are separated as much as possible,
thus permitting rendering by various types of browsers and devices.
 
A second qualification to the definition below is that some visual
presentation is essentially decorative in nature and does not convey
semantic meaning that a screen reader needs to render.  A screen reader
should err on the side of making all possible information availble in
case it does contain useful meaning to the blind user, but the goal
should not be comprehensive mimicking of visual expression for the sake
of a supposed equality that is thereby established.  Unless one is
specifically involved in graphical arts, which would be difficult to
ever make truly nonvisually accessible, the purpose of a computer is
primarily functional rather than expressive in nature.  As such, the
goal of a screen reader, in my opinion, should be competitive
productivity by all reasonable, nonvisual means.  This sometimes
involves strategies that maximize use of semantic meaning by other
modalities in significantly different ways than more indirect attempts
to convey the visual interface that sighted users experience.
 
Regards,
Jamal
-----Original Message-----
From: ossrp-control-bounce@xxxxxxxxxxxxx
[mailto:ossrp-control-bounce@xxxxxxxxxxxxx] On Behalf Of Will Pearson
Sent: Saturday, April 30, 2005 9:59 PM
To: ossrp-control@xxxxxxxxxxxxx; uvip@xxxxxxxxxxxxxxx
Subject: [ossrp-control] What Is A Screen Reader?


Hi,
 
I thought I'd share my, rather academic, view of what a screen reader
is.  It offers a little glimmer into what screen readers could
potentially do, and some of the pitfalls that the current crop of screen
readers have fallen into.  All this is from the viewpoint of human
computer interaction, psychology and communications theory.
 
OK.  So, what is a screen reader?  Well, it's actually a lot more than
people often assume it is.  It's not just something that grabs the text
from the screen and reads it to you, well, at least it shouldn't be, it
is in fact the interface by which user and machine communicate semantic
meaning, relating to thoughts, concepts, actions and states.
 
So, how did I arrive at this view?  As some of you may know, I've been
researching into semantics and their role in software interfaces for a
while now.  During this time, it's become apparent that software
interfaces are just intended to communicate semantic meaning, but as
we're not capable of extr sensory perception and telepathy with the
computer, we need some way to indicate our thoughts, concepts, actions,
etc. to the computer, and vice versa.  The way this is visually done is
by placing elements on the screen, such as icons, buttons, etc. and
having their shape, colour, position on screen and relationships to one
another act as encoding channels by which the semantic meaning is
conveyed.  Users then just point to an object, conveying the semantics
of which element they would like to interact with, and either click it
or select an action to perform on it from a menu.  All this is just a
form of physical encoding of the semantic meaning between user and
machine and vice versa.
 
So, as a screen reader is a replacement for the visual interface, it's
role is simply to act as an interface between user and machine and
convey the semantic meaning generated by the machine.  However, there's
a nasty twist, and that is that a screen reader has to get the semantic
meaning that it is to communicate to the user from somewhere.  As the
screen reader has no access to the internals of the machine, it's only
available source of semantics that the machine wishes to convey is the
visual interface, which uses encoding techniques such as colour, shape,
position and spatial relationship to convey it's semantics.  So, a
screen reader should really be about extracting the semantics from the
visual display and encoding them in a non-visual form suitable for a
blind user, and this is where current screen readers fall down.  To
maintain accurate and efficient communication with the user, all the
semantics that are conveyed visually need to be conveyed to the user.
This includes things like spatial positioning and spatial relationships
between interface elements, things that are currently lost to the user
when they are using one of the current screen readers.  If this were to
happen, then the number of errors, and according back-tracks and
reissuing of commands that go along with errors, would decrease, and
screen reader users would be more efficient beasts.
 
I haven't gone into design specifics, as they're for another day, and
these can dramatically affect efficiency as well, but that's my thoughts
of what a screen reader should be doing.  In focusing on the semantics,
then it's likely that through the use of semantic translation access to
all those difficult accessibility problems could be increased.
 
Will

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