Re: Can GTK+ make use of XSHM extension from MIT

["Tristan Van Berkom" <tvb gnome org>]

On Jan 11, 2008 11:01 PM, Bin Chen <binary chen gmail com> wrote:

> > Gdk does all image operations in 32-bits, N800/N810 display is 16-bit.
> > Whether you use SHM or not can be of less concern than this from the
> > performance point of view.
>
> OK, so your point is because the convert process must be done on every
> operation, so the performance will be bad? But I think if the XSHM is
> used, at least the transfer overhead will be cut, right?


What are you using to compose the image ? if you are doing direct
pixel operations on the permanent GdkImage that you created
and occasionally tell the X server to update a window based on
your shared image, this should be fast.

Data transfers over unix sockets generally go:
   while (not finished writing and no errors)
      write (8kb chunks of remaining data);

If you are using shared memory, then you still need to wake up
the X server process for it to copy the data internally in its own
process - unless these are really huge images, you are not
gaining much by using XSHM.

Its really hard to say what will be optimal for your situation
without a little more context on what you want to achieve.

Cheers,
                       -Tristan