On Fri, Nov 28, 2008 at 7:37 PM, Fred Kiefer <[EMAIL PROTECTED]> wrote: > [EMAIL PROTECTED] wrote: >>> The last of these is the most relevant part here. As I recall, when >>> we do a copy, we currently: >>> 1) Copy the relevant parts into the (client-side) buffer. >>> 2) Draw the new bits. >>> 3) Copy the buffer to the client. >> >> Doesn't it use a simple XCopyArea() which is done completely on the >> Server? >> > At least the xlib backend should be doing this, but I am unsure whether > there are paths where we don't hit this case. > >>> 1) Have a Picture per view. >>> 2) Use XRenderComposite to draw the old Picture onto itself with >>> translated coordinates. >>> 3) Draw the new parts in a new Picture. >>> 4) Copy this to the server. >>> 5) Render he new parts over the now-invalid parts of the old picture. >>> 6) Composite this into the parent view. >>> >>> This means you are transferring a lot less data and doing more on the >>> GPU. This is going to be particularly important on handheld devices, >>> where you will be moving much of the work from the ARM core to the GPU >>> core and freeing up the slow CPU to work on more important things. A >>> new X server can do all of these things in highly optimised CPU >>> routines if no GPU is available, but something similar can be done >>> with older parts of the X protocol. >> >> Well, I think you are requiring he Xrender extensions for older X11 >> servers. >> >> If they have this extension, I would suggest to switch to the cairo >> backend. That is already Xrender based. >> > > I fully agree with Nikolaus here. Handling Xrender ourselves is unneeded > hassle, > let cairo do this for us.
Irrespective of the scroll issue, exposing the view hierarchy to the backend would still be quite interesting: - we could have specialised backends using native widgets when available, for better integration with the host platform - we could have faster remote display as well (see NX) by being able to use local widgets and thus save on many round-trips -- Nicolas Roard "I love deadlines. I like the whooshing sound they make as they fly by." -- Douglas Adams _______________________________________________ Discuss-gnustep mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnustep
