composite and smooth moving (double buffering?)

[Thomas Lübking]

Am Mittwoch, 5. Oktober 2005 03:26 schrieb Anders Storsveen:
> When I enable composite and try to drag the konqueror window around
> fast, the window will move very smooth, although very slow to, but
> that's another issue (probably nvidia's rendr acceleration that is slow
> right?).
rather xaa composite implementation (i.e cache limitation?, try to reduce 
resolution and/or bpp) or because you didn't activate the
Option     "RenderAccel" "true"
(btw, randr but rend_e_r)
also it might be that the "nvidia" driver (nVidias CSS stuff) is faster than 
the "nv" driver that comes with X

> However, this smooth moving, which only happens to qt apps, why is this?
hää? toolkit doesn't matter here (i.e. xterm is as smooth as konsole or 
gnome-terminal) - what exactly do you mean by run "not smooth"?
however, i guess it's rather a matter of the window size
also gtk1 apps run ARGB, i.e. they eat more cache space for the alpha channel 
- try to run it exporting XLIB_SKIP_ARGB_VISUALS="1"

> Could someone please explain this to me, also how it works :)
basically the window content is rendered into an offscreen buffer, redirected 
into an application (the compmgr, probably kompmgr for kde) and there used to 
draw a fullsize picture onto the root window.
the compmgr then can do funny things on this (like adding translucency or 
shadows etc.)

Thomas
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