nanogui: Blitting
Subject:
Re: Blitting
From:
Alan Cox ####@####.####
Date:
4 Jan 2000 21:26:49 -0000
Message-Id: <E125bIV-0003Pr-00@the-village.bc.nu>
> > You're confusing current screen refresh with scrollback. Anything
> > drawn on an 80x24 screen needs to be saved for refresh.
>
> Agreed. I'm not going to tackle this quite yet, as my device/use won't
> use VT switching, I'll add it in later when I'm in the "adding toys"
> stage :)
Most X terminal applications store an ascii grid with end markers. The end markers are
used for cut/paste to know if a line wrapped or is a real newline.
Its generally faster to redraw the relevant bits (common optimisation - dont redraw the
large empty white areas). The redrawing thing has a lot to do with the nature of PC
video - its cheap to write, expensive to read as you stall the CPU for the bus on a read
but writes are buffered.
Alan
