NAME

       Xephyr - X server outputting to a window on a pre-existing X display

SYNOPSIS

       Xephyr [:display] [option ...]

DESCRIPTION

       Xephyr  is  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.

OPTIONS

       The server accepts all the standard options of Xserver(1) and the following additional options:

       -screen widthxheight
               sets the screen size.

       -parent id
               uses  existing  window  id  .   If  a -screen argument follows a -parent argument, this screen is
               embedded into the given window.

       -host-cursor
               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.

       -resizeable
               Allow the Xephyr window to be resized, even if not embedded into a parent window. By default, the
               Xephyr window has a fixed size.

       -no-host-grab
               Disable grabbing the keyboard and mouse.

SIGNALS

       Send a SIGUSR1 to the server (e.g. pkill -USR1 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 micro seconds.

CAVEATS

       • Rotated displays are currently updated via full blits. This is slower than a normal orientated 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 round it. It doesn't appear to break anything however.

       • Keyboard handling is basic but works.

       • Mouse button 5 probably won't work.

SEE ALSO

       X(7), Xserver(1)

AUTHOR

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