Re: [AD] X-windows screen updates

[Michael Bukin <M.A.Bukin@xxxxxxxxxx>]

"Eric Botcazou" <ebotcazou@xxxxxxxxxx> writes:

> > I discovered that direct drawing to the screen is slower because
> > the screen is updated every time someting is drawn onto it. I think that
> > we can use the acquire_screen / release_screen functions to tell the
> > X-windows driver not to update the screen (acquire_screen = stop
> > updating the screen, release_screen = update the screen and go back to
> > usual behaviour).
> 
> That's exactly the way the DirectDraw windowed driver (and soon the GDI
> driver) works.

It updates the whole screen, or it uses dirty rectangles?  If double
buffering is used, then performance will be worse for programs that
use dirty rectangles for updating screen.  If dirty rectangles are
used, then good dirty-rectangles API (allowing several DR lists at
once) should be added to the library, and it can be used in all
windowed drivers.

-- 
Michael Bukin