[compiz] Question about extending screengrabs

[Danny Baumann]

Hi,

> Wouldn't it be better to add this kind of functionality through
> different interface than the current screen grab interface? We can
> always expose the current screen grabs through a new interface if we
> want that.
> 
> I'm not sure exactly how this interface should look like but seems like
> it would makes sense to be able to not just check if some state is
> present but also be able to prevent a state from being entered.
> 
> E.g. instead of the rotate plugin checking for some "showdesktop" state,
> the showdesktop plugin could check for a "rotate" state and prevent it
> from being entered while being in "showdesktop" state.
> 
> What do you think? Do you think that extending the screen grab interface
> is the best way to do this anyhow?

I'm not sure if we would gain a lot from that. The idea sounds very
nice, but thinking about it I have the impression that such an interface
would be much more complicated than what we have now.

I can think of two use cases for the whole checking:

- A plugin wants to check if other plugins are active which could be
disturbing ... otherScreenGrabExist is perfectly suited for that by
whitelisting non-disturbing plugins.

- A plugin wants to check if certain actions are related to a certain
plugin (e.g. a viewport change causes a move) ... that's why I proposed
the screenGrabExist function

While your proposal sounds really nice, it only would change the
checking order (rotate checks for other plugins vs. other plugins check
for rotate). In both cases, all plugins need to be aware of the name of
other plugins which could disturb them. That's why I see no big gain
from another interface replacing the screen grab interface.

BTW: As I mentioned viewport changes - wouldn't it be a good idea to
pass the information if a window movement is caused by a viewport change
to moveWindow or into a member of the CompScreen structure?

Just my 0,02$ ;-)

Regards,

Danny