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 display hardware and
       no physical input devices.  It emulates a dumb framebuffer using  virtual
       memory.

       The primary use of this server was intended to be server testing.  The fb
       code for any depth can be exercised with this server without the need for
       real  hardware  that  supports  the  desired depths.  The X community has
       found many other novel uses for Xvfb, including testing  clients  against
       unusual  depths  and  screen  configurations, doing batch processing with
       Xvfb as a background rendering engine, load testing, as an aid to porting
       the  X  server to a new platform, and providing an unobtrusive way to run
       applications that don't really need an X server but insist on having  one
       anyway.

OPTIONS
       In addition to the normal server options described in the Xserver(1) man‐
       ual 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 dimensions 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 memory mapped files
           containing the framebuffer memory  should  be  created.   See  FILES.
           This option only exists on machines that have the mmap and msync sys‐
           tem 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 memory 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().

       -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.  This option is probably
           only useful to server developers to experiment with the range of line
           pixelization possible with the fb code.

       -blackpixel pixel-value, -whitepixel pixel-value
           These  options  specify  the  black and white pixel values the server
           should use.

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

       framebuffer-directory/Xvfb_screen<n>
           Memory mapped file containing screen n's framebuffer memory, one file
           per  screen.   The file is in xwd format.  Thus, taking a full-screen
           snapshot can be done with a file  copy  command,  and  the  resulting
           snapshot will even contain the cursor image.

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 configuration (one screen, 1280x1024x8),
               and screen 1 will be depth 16 1600x1200.

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

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

SEE ALSO
       X(7), Xserver(1), xwd(1), xwud(1), XWDFile.h

AUTHORS
       David P. Wiggins, The Open Group, Inc.



X Version 11                   xorg-server 1.12.4                        XVFB(1)