XVFB(1)                     General Commands Manual                    XVFB(1)

       Xvfb - virtual framebuffer X server for X Version 11

       Xvfb [ option ] ...

       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
       mfb or cfb 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.

       To build Xvfb, put the following in your host.def and remake.

       #define BuildServer YES /* if you aren't already building other servers
       #define XVirtualFramebufferServer YES

       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 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 system calls.

           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

       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 cfb and mfb code.

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

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

           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.

       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 /usr/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 /usr/tmp for the framebuffer.

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

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

       David P. Wiggins, X Consortium, Inc.

X Version 11                      Release 6.3                          XVFB(1)