tir, 05.10.2004 kl. 21.15 skrev Owen Taylor: > On Tue, 2004-10-05 at 11:34 +1000, Steffen Kluge wrote: > > Hi, > > I've just got to ask this, please forgive me if it is only marginally > > on-topic for this list. > > > > Back when I started using X11 (late 80's, Ultrix, X11R3), turning on > > save-unders and backing store was an essential performance tuning step, > > that drastically improved the perceived "speed" of the desktop (e.g. > > disappearing menus exposed the underlying window instantly, without it > > having to be re-drawn). > > > > I've used save-unders and backing store ever since. Which also means > > that ever since starting to use RH desktops I had to turn it on > > manually, by editing the X command line in [gx]dm.conf. All RH and FC > > desktops I've used so far disable backing store (and at the same time > > save-unders - the two seem to be inextricably linked) by default. > > > > Why is that so? I have to admit that with modern hardware the perceived > > speed-up is small and may even be entirely based on self-suggestion. > > However, I'd like to understand the pros and cons of turning on backing > > store with modern X servers and on modern hardware. > > Well, the biggest problem with backing store is that it is per-window > not per *toplevel* window. In X, toplevel windows can have subwindows > (try xwininfo -tree). > > In certain circumstances, X can end up storing huge amounts of entirely > useless pixel data for subwindows because it mistakes them for > obscured toplevels. > > Save unders are broken because they are just a quick hack that works > by turning on backing store for the windows under the popup. > > The COMPOSITE extension is a much better way of doing backing stored > windows. It's slightly more expensive than classic save unders because > it saves the entire window, not just the obscured parts, but it's > a lot more robust, and allows doing a lot more (previews in your pager, > alpha transparency, etc.) We'll probably have it on by default by > the FC5 timescale. > > Regards, > Owen > > > ______________________________________________________________________ > -- > > Fedora-desktop-list@xxxxxxxxxx > http://www.redhat.com/mailman/listinfo/fedora-desktop-list That's a looong wait. About a year or so... But, yes, i'm really looking foreward to it :P -- Fedora-desktop-list@xxxxxxxxxx http://www.redhat.com/mailman/listinfo/fedora-desktop-list
