[BRLTTY] screen driver in brlapi

[Dave Mielke]

[quoted lines by Samuel Thibault on 2018/11/04 at 00:36 +0100]

>Ok, so we really have to read the whole screen before calling poll().

Not necessarily. It all depends on the paradigm. Let's say that brltty only
ever cared about the part of the screen being shown on the display. Then that's
the only bit that it'd need to read. If the display is moved then it could
immediately read (without polling) the new area, and then use poll() to watch
for a possible change.

Note that it's also best to poll vcsa, rather than vcsu, in order to catch
cursor motion, dimension changes, etc.

-- 
I believe the Bible to be the very Word of God: http://Mielke.cc/bible/
Dave Mielke            | 2213 Fox Crescent | WebHome: http://Mielke.cc/
EMail: Dave at Mielke.cc  | Ottawa, Ontario   | Twitter: @Dave_Mielke
Phone: +1 613 726 0014 | Canada  K2A 1H7   |