pseudo transparency


There is two methods that an application can use to achieve
"pseudo transparency".
One method, the E method, is to have a pixmap in memory and
to indicate the id of this pixmap with a root atom. The second
method is to use parental relativity.
Each method has some advantages I do not think that the wm-spec
should choose one of them. I think that it will be good that
the wm-spec support both.

One problem with parental relativity is that a priori the
application has to set the background of the frame window(s)
set by the window manager. It seems to me that this leads to
a bad hack. So I suggest to add a new window state:

  use the ParentRelative pixmap for its background. The window manager
  should set the frame window(s) background accordingly.

maybe the name is bad and also maybe it is better to have a
separated atom for this property. The advantage of using a state
is that an application can ask to set/unset this property.

About the E method. Here there is a de facto standard which
uses the ESETROOT_PMAP_ID and the _XROOTPMAP_ID atoms. Maybe,
this can be documented in the wm-spec? If I well understand
this method, applications should use the _XROOTPMAP_ID and
setroot programs should destroy the pixmap if
before setting the background with its own pixmap (and
then set _XROOTPMAP_ID and also ESETROOT_PMAP_ID if its
own pixmap can be destroyed). That's it?

Now one problem with the E method is that it may need
a lot of memory (this depends on the memory you have and
the size of your screen(s)). So, some environment/users
may prefer to do not use an E setroot compatible program.
But, in this case there is no way to know that the
background have changed.
So, if there is some plan to document the E method in the
wm-spec I suggest to add a weak form of the E method for
set root programs: a set root program may set _XROOTPMAP_ID
to None (or to ParentRelative) if the root background is not
keep in memory.


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]