Re: Accessibility issues of GUI interface in Linux

[Martin McCormick <martin dc cis okstate edu>]

	The question I have always had about X Windows is what kind of
traffic goes through the Ethernet or serial cable during a session?  If
the screen displays a menu or some other text, did the server send it
as text with font and formatting information such as is done in a
well-designed html document or does it send a video raster with pixels
turned on in the shapes of the text like a facsimile transmission.

	If it is a bit map or raster, we have exactly the same mess as
in Windows.  If it sends most text as ASCII with VT100-style codes to
give it color and place it in the correct part of the screen, then
there is reason to hope.

	I would expect that there should be a combination of modes to
allow for free-form graphics such as pictures as well as methods for
handling text.  Being able to send text as text helps far more than
those who are blind.  There is about a 10 to 1 reduction in traffic
when sending a 4,000-char block of text compared with sending a
picture of a page.  This also effects storage and the ability to
retrieve data based on key words.  

	Knowing how X works will tell us where the real trouble is
because text that turns in to pictures makes the decoding process much
less accurate and more computationally intensive than just sending the
text.

	What, then, do the raw data look like when a UNIX system is
speaking X with a remote system or servicing a X login on the local
system?

Martin McCormick