xshape+xcomposite

[Keith Packard]

On Sun, 2006-01-22 at 18:15 +0000, chinlu chinawa wrote:
> Hi,
> 
> Sorry to bother again asking about development in
> here, but don't know anywhere else where to ask
> questions such like this, since for example xfree does
> not ship xcomposite.

this is a developer list, so your questions are welcome.

> The thing is I'm not capable to use xshape any longer.
> I think there might be any reason for which xshape
> stopped from working when using argb visuals. 

There shouldn't be any connection between ARGB visuals and the shape
extension; they should work fine together, although I haven't tested
them myself.

> I guess
> this extension doesn't support them at all, haven't
> tried but I think if I set up a non-argb mask for it,
> an depth mistmatch error will come up, cose my app has
> previously asked for an argb visual.

Masks used with the shape extension must be depth 1; the shape extension
can only deal with boolean masks.

> I used to set up the hand pixmap-cursor for the mouse
> once over my xshaped window, and it would respect
> image's transparency or shape, but don't know how this
> should be done now, hopefully someone can tell the
> proper way of doing it.

With the newer version of Shape, you can set an Input region separately
from the output region, permitting you to control the appearance of
cursors separately from the drawn area of the window, this would allow
you to have nearly transparent pixels not be included in the cursor
region.
 
> Another question is in regards of xcomposite itself,
> I've noticed it doesn't do anything if I set up an
> override-redirected window as I used to do with xfree,
> I mean, it doesn't render or composite any shadows. 

That's purely a function of the compositing manager; feel free to do
whatever you like with that code.

> I've been looking at xcompmgr sources, and I'm
> thinking about implementing the needed part on my app,
> so it would have shaped shadows coming from image's
> alpha channel (as you can see in the images show
> above). Is this alright? would it be problematic if
> this app is run into another
> server which's got already a composite manager
> running? 

Unfortunately, only one application can be in charge of this drawing, so
you'll have to modify the compositing manager itself.

There are a few people thinking about how to create pluggable
compositing modules so we could make this more flexible.

> I'm also asking myself whether an xfree server will
> allow to be
> compiled with xcomposite support, and how much
> difficult it could be
> for anyone, if possible.

You might ask on the XFree86 mailing lists about this; I'm not sure what
their plans are with respect to these new extensions.

-- 
keith.packard at intel.com
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