Xvfb(1) - NetBSD Manual Pages

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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 was 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.   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.


BUILDING

       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



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



X Version 11		   Release 6.3				1





XVFB(1)							  XVFB(1)


	   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().

       -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 exper-
	   iment 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.


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  for-
	   mat.	  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  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



X Version 11		   Release 6.3				2





XVFB(1)							  XVFB(1)


	       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 6.3				3