Re: How to create layered windows or widgets?

[Skee Lin <skee lin gmail com>]

Tristan Van Berkom 写道:
> On Jan 24, 2008 12:16 AM, Skee Lin <skee lin gmail com
> <mailto:skee lin gmail com>> wrote:
>
>     Tristan Van Berkom 写道:
>     > On Jan 23, 2008 7:03 AM, Skee Lin <skee lin gmail com
>     <mailto:skee lin gmail com>
>     > <mailto: skee lin gmail com <mailto:skee lin gmail com>>> wrote:
>     >
>     > Hi everybody,
>     > I'm trying to create a transparent window to show some
>     > informations, and
>     > it's always on top.
>     > Does anybody know how to let the mouse messages through? For
>     instance,
>     > when I click on the window, I actually click on the desktop(if
>     > there are
>     > no other windows).
>     >
>     >
>     > I think you can accomplish this with
>     gdk_window_shape_combine_mask ()
>     >
>     >
>     http://library.gnome.org/devel/gdk/unstable/gdk-Windows.html#gdk-window-shape-combine-mask
>     <http://library.gnome.org/devel/gdk/unstable/gdk-Windows.html#gdk-window-shape-combine-mask>
>     >
>     > Cheers,
>     > -Tristan
>     >
>     I really appreciate the helpful reply from Tristan. However, there is
>     another problem that does irregular window occupy much cup time?
>     I want to create a window to show lyrics of songs. User can move the
>     window by clicking on the text while clicking on the other areas
>     will be
>     send to lower window. I think cairo can convert the text to pixmap
>     mask,
>     but I'm afraid the nonstop changing of the shape will occupy much
>     cpu time.
>     Maybe I need to describe my problem more simply: How to show a window
>     and let all clicking messages through, just like the window is not
>     exist?
>     Any information would be appreciated.**
>
>
> Your use case is particular, you said you want the *Desktop* also to
> recieve
> mouse clicks, and other applications too.
>
> You definitely can accomplish this with layered windows in YOUR app,
> but once you eat up the gdk events from the X server, I dont know how
> you can send them back to the underlying random window.
>
> It might be possible already, anything is surely is possible if you hack
> the X server to do it ;-)
>
> Cheers,
> -Tristan
>
I'll write a demo this weekend. And if gdk_window_shape_combine_mask
doesn't fit my application, I will try to implement it by using Xlib.

Thank you very much for your helpful reply.