xserver/hw/kdrive/ephyr

Xephyr README
=============


What Is It ?
============

Xephyr is a a kdrive server that outputs to a window on a pre-existing
'host' X display. Think Xnest but with support for modern extensions
like composite, damage and randr.

Unlike Xnest which is an X proxy, i.e.  limited to the
capabilities of the host X server, Xephyr is a real X server which
uses the host X server window as "framebuffer" via fast SHM XImages.

It also has support for 'visually' debugging what the server is
painting.


How To Use
==========

You probably want to run like;

Xephyr :1 -ac -screen 800x600 &

Then set DISPLAY=:1 and run whatever X apps you like.

Use 'xrandr' to change to orientation/size.

There is a '-parent' switch which works just like Xnest's ( for use
with things like matchbox-nest - http://matchbox.handhelds.org ).

There is also a '-host-cursor' switch to set 'cursor acceleration' -
The host's cursor is reused. This is only really there to aid
debugging by avoiding server paints for the cursor. Performance
improvement is negligible.

Send a SIGUSR1 to the server ( eg kill -USR1 `pidof Xephyr` ) to
toggle the debugging mode. In this mode red rectangles are painted to
screen areas getting painted before painting the actual content. The
delay between this can be altered by setting a XEPHYR_PAUSE env var to
a value in microseconds.


Caveats
=======

 - Depth is limited to being the same as the host.
   *Update* As of 8/11/2004. Xephyr can now do 8bpp & 16bpp
            on 24bpp host.

 - Rotated displays are currently updated via full blits. This
   is slower than a normal oprientated display. Debug mode will
   therefore not be of much use rotated.

 - The '-host-cursor' cursor is static in its appearance.

 - The build gets a warning about 'nanosleep'. I think the various '-D'
   build flags are causing this. I haven't figured as yet how to work
   around it. It doesn't appear to break anything however.

 - Keyboard handling is basic but works.

 - Mouse button 5 probably won't work.





Matthew Allum <mallum@o-hand.com> 2004