issues with X Window

[Paolo Molaro <lupus lettere unipd it>]

There are several issues for an eyes-free access to the X Windows System
that need to be discussed:
1) The low-level protocol
2) The window manager
3) The applications and the toolkits thay are bulit upon

1) The low level protocol
The applications that run on an X Window System use the X protocol
to send to the server commands such as draw this line here, draw this 
string there etc.
This is useless from the visually impaired point of view because
there is no context or structure: these are low-level commands that
are impossibile to translate to speech or audio output.
This means that blind users will not be able to use all of
the applications that run in X.

2) The window manager
Because the X server provides only for low-level access, there is 
the need for another program that handles the windows and their
decorations (the title bar, the close button, etc.).
The window manager handles also the focus changes between windows
and the position of the window on the desktop.
Different window managers use different focus policies: the policy
suited for blind access is usually called "Click to focus": this means
that to change focus from one window to another you have to click
with the mouse. This isn't so bad because you can use keyboard 
shortcuts to do the same. The important bit of information is that
the focus windows doesn't change if you accidentally move the mouse.
The problem with the other window manager functions (moving a
window, changing desktop, closing a window) is that the user needs
an audio feedback: this can be easily done by an external program
if the window manager supports the Gnome window manager hints.
Anyway, there are at least a couple of window managers in
development that use the Gtk+ library and so can be easily adapted to
work with GSpeech.

3) The applications
The applications that work in an X Window enviroment can use the
low-level X protocol or a toolkit that provides high-level
interfaces. The former are not accessible for the blind.
There are many different toolkits for X Window.
The issues here is that there will be very few applications
developed with the blind user in mind, no matter what, so the
accessibility features must be built into the toolkit. This way
the applications don't need changes (they need to be well designed,
though, but that is required even for sighted people:-).
Currently, the toolkits that provide the features needed for
blind access are Xt/Motif and Gtk+.

These issues and the implementation of GSpeech will be presented
in a talk at the Atlanta Linux Showcase in October.

lupus

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