PutImage vs BackgroundPixmap (was Re: Open Shared Memory and Render Pictures)

[Thomas Lübking]

On Sat, Aug 06, 2016 at 09:03:04PM +0900, Carsten Haitzler wrote:

>no. this is just how it goes. because everything is async, the compositor/wm
>has resized the window, then some small time later the client gets a
>configurenotify event, then client renders some update, then sends to x, then x
>tells compositor of a new damage, compositor gets event goes "ooh time to
>draw", compositor draws, talks to x again to display...

Though the dealbreaker is usually just the clients re-layouting, maybe
sometimes broken XSYNC implementations.
Less the roundtrip itself (which tends to be << 16ms ;-)

The solution to this is usually lazy updates by allowing for internal scaling
or padding (if your client has significant payload here) - or anything
else to make the client resize faster.

@Michael, try resizing xterm. If that's slow, there's a problem in the
mechanism. If not, it's just the client.

Cheers,
Thomas