Thu Mar 11 21:20:00 GMT 2004
Mostly curious - I fired off the email a bit quickly, I found some of
the answers in the contributors guide later on, rtfm would've been a
I've been following the Y-windows mailing list where they talked about
about an X compatibility layer, I was just considering how this would be
done. I doubt I'd have the time to implement it. Since I use cygwin/x a
lot seemed like a good template.
After a bit of hunting I found the miext/rootless code, I've been
struggling to understand the Objective C code using it though. I'd be
curious to read Torrey's draft on how it works (obviously I wouldn't
Harold L Hunt II wrote:
> Jeremy Wilkins wrote:
>> I'm curious about how the cygwin XWin server works?
> Curious, or interested in helping? If just curious, then please wait a
> few days or dig through the archives... I have described it in detail a
> few times. Perhaps the following answers will be all you need.
>> My understanding is it is similar to an X Server on linux but instead
>> of rendering to the graphics card framebuffer, it is rendered to an
>> offscreen surface and then bitblt'd to an on screen pixmap using
>> direct draw, or GDI if dd is unavailable.
> That is correct.
>> Does the MacOS X Xserver work in the same way?
>> Does this use a lot of existing code, eg from either vnc or xvfb servers?
> Yes, but not from vnc or xvfb. There is a generic layer written by
> Keith Packard called "fb" that draws to framebuffers using the cpu. This
> "fb" layer replaced the old "cfb" and "mfb" layers that did the same
> thing but were crufty and designed for the cpu being the constraint
> (think 1980's) rather than the buses to and from memory and other
> peripherals being the constraint (think today).
>> How does the rootless stuff work, does this just figure out where the
>> top level windows are and only bitblt those but into separate
> Well, that is sort of a dangerous question. There is the original
> "rootless" mode that Kensuke wrote a while back. That mode just keeps
> track of the top-level X11 windows and clips transfers to our single
> Win32 window to the region that is occupied by X11 windows, thus
> preventing the root window from being drawn. You will note that all of
> the X11 windows appear to float in the same plane when you use -rootless
> in the current versions of XWin.exe.
> There is also multi-window, but that is a little more complex in that it
> has an internal window manager and it creates a Win32 window for each
> top-level X11 window and provides management of those windows. This one
> does bitblt to particular Win32 windows, whereas the aforementioned
> rootless mode only had a single Win32 window.
>> I've read somewhere that there is some generic rootless code in the xc
>> tree, where abouts is this?
> That is in xc/programs/Xserver/miext/rootless. Kensuke's latest work
> has centered around getting this to work. He has a new window manager
> written that is more complete than the current multi-window window
> manager. However, there are still significant bugs in this
> implementation and we are not even building releases from the source
> tree with that code in it yet.
> Torrey Lyons just sent me a draft description of how miext/rootless
> works. Hopefully he will finish it soon so I can point you to it. It
> really is an interesting layer and it allows optimization of some simple
> cases that will have quite a large performance impact.
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