Re: Compositing managers spec
Carsten Haitzler (The Rasterman) <[email protected]>
| Newsgroups | gmane.comp.gnome.wm-spec |
|---|---|
| Organization | You expect me to be organized? |
| Message-ID | <[email protected]> |
On Tue, 5 Feb 2008 14:23:47 +0100 Lubos Lunak <[email protected]> babbled: > On Saturday 02 of February 2008, Carsten Haitzler wrote: > > a lot of apps will update their window by drawing all the parts that > > change. if they do not double-buffer theme selves they will draw directly > > to the front-buffer. this means that to draw a button that goes from light > > red to deep pink and looks pressed-in, it may very easily draw a new base > > color, then draw the lines surrounding the box to make it look indented, > > then redraw the label in the middle. in theory this can easily be half a > > dozen or more damage events for the same region. if the CM simply draws on > > every damage event - u'll get lots of extra compositing going on. if its > > smart it will queue updates and wait until all damage events have been read > > then update. if it gets really smart it may even delay a bit then as more > > damage events may be on their way but not in the buffers yet. it may also > > wait until vsync > > > > sometimes such extra delays that are artificially added beyond draining all > > damage events could lead to bad sync. situations - eg - video players. they > > will update the whole video at once anyway. so for apps hat are "smart" > > about drawing and double-buffer themselves, and care about getting updates > > up ASAP - set a property. for "legacy" or "stupid' apps - the CM can play > > some heuristics games by adding small delays to gathering all damage events > > to make sure it queues up as many as it can for 1 on-screen update to > > improve smoothness of screen updates as much as possible. > > There is _NET_WM_SYNC_REQUEST, which is a way to detect when the client has > finished doing a repaint. It is unfortunately bound to ConfigureNotify > events, but I think that's not a real problem in practice. we could recycle that - didn't think of that actually. > -- > Lubos Lunak > KDE developer > -------------------------------------------------------------- > SUSE LINUX, s.r.o. e-mail: [email protected] , [email protected] > Lihovarska 1060/12 tel: +420 284 028 972 > 190 00 Prague 9 fax: +420 284 028 951 > Czech Republic http//www.suse.cz > _______________________________________________ > wm-spec-list mailing list > [email protected] > http://mail.gnome.org/mailman/listinfo/wm-spec-list > -- ------------- Codito, ergo sum - "I code, therefore I am" -------------- The Rasterman (Carsten Haitzler) [email protected]