Compositor woes

[Brian J. Tarricone]

Bob Snyder wrote:

> I am trying to get shadows and transparency to work, and I am getting 
> confusing symptoms.
>
> I have 4.2.0, compiled with from the graphic installer, and with the 
> compositor enabled. This is confirmed by looking at config.log for 
> xfwm4 which says "  $ ./configure --enable-compositor....".

Also check the output to make sure it found libXcomposite, among other 
things.  There should be some output like:

checking for xrender... yes
checking RENDER_CFLAGS... -I/usr/X11R6/include
checking RENDER_LIBS... -lXrender -lX11 -lXext
checking for XRRUpdateConfiguration in -lXrandr... yes
checking for X11/extensions/Xrandr.h... yes
checking for xcomposite >= 1.0 xfixes xdamage... yes
checking COMPOSITOR_CFLAGS... -DXTHREADS -D_REENTRANT -DXUSE_MTSAFE_API 
-I/usr/X11R6/include
checking COMPOSITOR_LIBS... -lXcomposite -lXdamage -lXfixes -lX11

You can check this manually by running:
$ pkg-config xcomposite --modversion
If that prints out an error, it means pkg-config can't find 
xcomposite.pc, and you'll need to set your PKG_CONFIG_PATH env var 
appropriately before running the installer.

Olivier, would you be opposed to adding a condition to xfwm4's 
configure.ac such that, if --enable-compositor is specified, and 
pkg-config fails to find the required libs, configure actually fails?  
Assuming I'm correct about the problem here, I've seen this question pop 
up on the order of 10-15 times in #xfce alone, and this isn't the first 
time I've seen it here, IIRC.  I think it's safe to assume that, if the 
user specifically passes --enable-compositor, they'll want to know 
up-front if it's not going to work.

> My video card is nvidia GeForce4 MX 440, X server is the open source 
> 'nv' driver.

Agreed with what someone else said - if you want reasonable performance 
with transparency, you should use the binary 'nvidia' driver, and set:
Option "RenderAccel" "enable"
in your xorg.conf (Device section, IIRC).  The XRender speed of 'nv' is 
better than it used to be, but 'nvidia' still blows it away.

    -brian