[compiz] Thumbnail plugin

[David Reveman]

On Wed, 2007-01-24 at 17:25 +0100, Stjepan Glavina wrote:
> When hovering taskbar, gnome-panel/kicker change the property of the
> appropriate window ("_NET_WM_SHOW_THUMBNAIL").
> Thumbnail plugin checks for PropertyNotify events and shows/hides the
> thumbnail.

(I assume that you didn't want take this discussion off the list)

This discussion should eventually be moved to the wm-spec-list but
there's a few things I think we should try to decide here first.

1. Should one window only be allowed to show one thumbnail or should the
property be a list of thumbnails?

2. How is the position and scale of the thumbnail encoded. Is it:

data[0] = thumbnail window ID
data[1] = x
data[2] = y
data[3] = width
data[4] = height

x, y being relative to the client window position.

3. The compositing manager might have to do some work before it can
render the requested thumbnail(s) in a client window. The client
wouldn't want the window which contains thumbnails to be visible until
all thumbnails can be rendered properly. If the client sets the
thumbnail property prior to mapping the window, it allows the
compositing manager to delay any drawing of the client window until the
requested thumbnails can be rendered. Some of this might need to be
documented before it can be accepted as an addition to the EWMH spec.

4. What windows are valid in the thumbnail property? Any window in the
_NET_CLIENT_LIST root window property? Or should there be a new
_NET_THUMBNAIL_LIST property? Such a list means that the compositing
manager doesn't have to provide thumbnails for all available windows,
which makes sense for the current state where thumbnails for minimized
windows can't be rendered.

If someone can think of something else, please jump in.

- David