question about 8bit pseudocolor support by xpra

[Ward Braspenning]

Hello,

I need 8 bit pseudocolor for some x apps who use it (don't have code of these apps to change it) to get blinking colors.
But I don't get xpra working with depth = 8 bit.

When I (on a Red Hat 7.2) test 'xpra start' (v.16.2-r11889) as root with DefaultDepth? and Depth 8 in /root/.xpra/xorg.conf.d/Screen, I get following error in file
':0.log':

File "window_bindings.pyx", line 604, in xpra.x11.bindings.window_bindings.X11WindowBindings.ensure_XComposite_support (xpra/x11/bindings/window_bindings.c:5406):

...
File "window_bindings.pyx", line 426, in xpra.x11.bindings.window_bindings.X11WindowBindings.ensure_extension_support (xpra/x11/bindings/window_bindings.c:2342)
ValueError?: X11 extension Composite not available
...

See attachments for the necessary files.

I'm pretty sure it is a restriction in the x(dummy) server:

From source code package xorg-x11-server-Xorg, v 1.17.2, file composite/compext.c, fu CompositeExtensionInit?:
...
Composite on 8bpp pseudocolor root windows appears to fail, so
just disable it on anything pseudocolor for safety.

for (vis = pScreen->visuals; vis->vid != pScreen->rootVisual; vis++);
if ((vis->class | DynamicClass?) == PseudoColor?)

return;

...

Xvnc, on the other hand, does support 8-bit pseudocolor.
My questions are:

• Is there a way to get 8 bit pseudocolor working with xpra that i overlook?
  • And do have the 'xpra'-developers an idea of what is necessary to get the 'composite' extension working with 8 bit pseudocolor. Or better to ask this on the Xorg team?

I don't know enough of it, but if Xvnc gets 8 bit pseudolor working, the I think it should also be possible to implement this for X + Composite extension. Xvnc must also use something Composite like, no?

Thanks in advance if you have the time and effort to look into these questions.

[Ward Braspenning]

/etc/xpra/xpra.conf