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<TITLE> Xvfb - virtual framebuffer X server for X Version 11 </TITLE>
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XVFB(1)							  XVFB(1)


NAME
       Xvfb - virtual framebuffer X server for X Version 11

SYNOPSIS
       Xvfb [ option ] ...

DESCRIPTION
       Xvfb  is an X server that can run on machines with no dis
       play hardware and no physical input devices.  It	 emulates
       a dumb framebuffer using virtual memory.

       The  primary  use  of this server is intended to be server
       testing.	 The mfb or cfb code for any depth can	be  exer
       cised  with this server without the need for real hardware
       that supports the desired depths.

       A secondary use is testing clients against unusual  depths
       and screen configurations.

OPTIONS
       In  addition to the normal server options described in the
       Xserver(1) manual page, Xvfb accepts the following command
       line switches:

       -screen screennum WxHxD
	   This	 option	 creates  screen  screennum  and sets its
	   width, height, and depth to W, H, and D  respectively.
	   By  default,	 only  screen 0 exists and has the dimen
	   sions 1280x1024x8.

       -pixdepths list-of-depths
	   This option specifies a list of pixmap depths that the
	   server  should  support  in	addition  to  the  depths
	   implied by the supported screens.  list-of-depths is a
	   space-separated  list of integers that can have values
	   from 1 to 32.

       -fbdir framebuffer-directory
	   This option specifies the directory in which the  mem
	   ory	mapped	files  containing  the framebuffer memory
	   should be  created.	 See  FILES.   This  option  only
	   exists on machines that have the mmap and msync system
	   calls.

       -shmem
	   This option specifies that the framebuffer  should  be
	   put	in  shared memory.  The shared memory ID for each
	   screen will be printed by the server.  The shared mem
	   ory	is  in	xwd  format.   This option only exists on
	   machines that  support  the	System	V  shared  memory
	   interface.

       If neither -shmem nor -fbdir is specified, the framebuffer
       memory will be allocated with malloc().



X Version 11		   Release 6.1				1





XVFB(1)							  XVFB(1)


       -linebias n
	   This option specifies how to adjust	the  pixelization
	   of thin lines.  The value n is a bitmask of octants in
	   which to prefer an axial step when the Bresenham error
	   term	    is	  exactly    zero.     See    the    file
	   Xserver/mi/miline.h for more information.

FILES
       The following files are created if the  -fbdir  option  is
       given.

       framebuffer-directory/Xvfb_screen&lt;n&gt;
	   Memory  mapped  file containing screen n's framebuffer
	   memory, one file per screen.	 The file is in xwd  for
	   mat.

EXAMPLES
       Xvfb :1 -screen 0 1600x1200x32
	       The  server  will listen for connections as server
	       number 1, and screen 0 will be depth 32 1600x1200.

       Xvfb :1 -screen 1 1600x1200x16
	       The  server  will listen for connections as server
	       number 1, will have the default screen  configura
	       tion  (one screen, 1280x1024x8), and screen 1 will
	       be depth 16 1600x1200.

       Xvfb -pixdepths 3 27 -fbdir /usr/tmp
	       The server will listen for connections  as  server
	       number  0, will have the default screen configura
	       tion (one screen, 1280x1024x8), will also  support
	       pixmap  depths  of  3  and 27, and will use memory
	       mapped files in /usr/tmp for the framebuffer.

       xwud -in /usr/tmp/Xvfb_screen0
	       Displays screen 0 of the	 server	 started  by  the
	       preceding example.

SEE ALSO
       X(1), Xserver(1), xwd(1), xwud(1), XWDFile.h

AUTHORS
       David P. Wiggins, X Consortium, Inc.














X Version 11		   Release 6.1				2


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