[maemo-developers] Can GTK+ make use of XSHM extension from MIT

[From: Bin Chen]

On Jan 11, 2008 9:54 PM, Tristan Van Berkom <tvb at gnome.org> wrote:
> On Jan 10, 2008 11:38 PM, Bin Chen <binary.chen at gmail.com> wrote:
>
> [...]
> > Ok, let me make the things clear, the content in a gdk window includes
> > many widgets, such as label, entry, button. But from the perspective of
> > X server, this widgets are just bitmaps with the states updated by GTK+,
> > right?
>
> A kind of mix of the above, generally many widgets draw to the same
> GdkWindow yes, for the X server this is only one Window.
>
>
> > Xshm will accelerate the client to server transfer for type of Image and
> > Pixmap, but the GTK+ use XCopyArea to update the bitmap, can XCopyArea
> > can benefit from the Xshm?
>
> Yes XCopyArea will do a different proceedure depending if you are using
> an XSHM Image or not.
>
>
> > In more detail, I am using gdk_draw_image to draw an image to a gdk
> > drawable, will this benefit the Xshm?
>
> Assuming the Images were created as shared memory segments then
> yes they will be transfered as shared memory, this can be faster than
> using unix sockets for _large_ images (for smaller images its probably
> the same considering there has to be task switching/locking involved
> anyway when updating a window from an image).
>
Thanks for your reply, but I wonder how the Xlib or GDK knows the
image is drawing in a shared memory segment? In detail can you show me
some pseudo code to how to do it?

Thanks a lot.

Bin