[OpenJDK 2D-Dev] Questions about the X11 backend

Clemens Eisserer linuxhippy at gmail.com
Sat May 3 12:31:48 UTC 2008


I've (again) some questions about the X11 pipeline, just a few words
would be really helpful:

1.) When looking at X11SurfaceData.c, there are several notes that
this provides support for the software-loops to work directly on the
native data, e.g.:
> This file contains support code for loops using the SurfaceData
> interface to talk to an X11 drawable from native code.
I wonder where, and what the required mechanisms are to allow this working?

I commented out all blit-"loops"-registrations in X11XPMBlit(Bg)Loops
and although slow, everything seems still to work ... amazing :)

2.) In X11SurfaceData.java the pipeline-setup quite confuses me:
Whats lazy pipe, and why is it set for everything if x11txpipe is null?
Is "sg2d.loops = getRenderLoops(sg2d);" only there to be overridden if
the rendering mode changes?

3.) Why is there a javaGC and a cachedGC in _X11SDOps?

4.) Is DGA still used? I see quite a lot #ifdef's for missing MITSHM
and DGA, but I wonder wether there are still systems without MITSHM,
and the other way round for DGA.

Thanks for your patience and help, lg Clemens

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