hw/vfb/man/Xvfb.man

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  29 .TH XVFB 1 __xorgversion__
  30 .SH NAME
  31 Xvfb \- virtual framebuffer X server for X Version 11
  32 .SH SYNOPSIS
  33 .B Xvfb
  34 [ option ] ...
  35 .SH DESCRIPTION
  36 .I Xvfb
  37 is an X server that can run on machines with no display hardware
  38 and no physical input devices.  It emulates a dumb framebuffer using
  39 virtual memory.
  40 .PP
  41 The primary use of this server was intended to be server testing.  The
  42 fb code for any depth can be exercised with this server
  43 without the need for real hardware that supports the desired depths.
  44 The X community has found many other novel uses for \fIXvfb\fP,
  45 including testing clients against unusual depths and screen
  46 configurations, doing batch processing with \fIXvfb\fP as a background
  47 rendering engine, load testing, as an aid to porting the X server to a
  48 new platform, and providing an unobtrusive way to run applications
  49 that don't really need an X server but insist on having one anyway.
  50 .SH OPTIONS
  51 .PP
  52 In addition to the normal server options described in the \fIXserver(1)\fP
  53 manual page, \fIXvfb\fP accepts the following command line switches:
  54 .TP 4
  55 .B "\-screen \fIscreennum\fP \fIWxHxD\fP"
  56 This option creates screen \fIscreennum\fP and sets its width, height,
  57 and depth to W, H, and D respectively.  By default, only screen 0 exists
  58 and has the dimensions 1280x1024x8.
  59 .TP 4
  60 .B "\-pixdepths \fIlist-of-depths\fP"
  61 This option specifies a list of pixmap depths that the server should
  62 support in addition to the depths implied by the supported screens.
  63 \fIlist-of-depths\fP is a space-separated list of integers that can
  64 have values from 1 to 32.
  65 .TP 4
  66 .B "\-fbdir \fIframebuffer-directory\fP"
  67 This option specifies the directory in which the memory mapped files
  68 containing the framebuffer memory should be created.
  69 See FILES.
  70 This option only exists on machines that have the mmap and msync system
  71 calls.
  72 .TP 4
  73 .B "\-shmem"
  74 This option specifies that the framebuffer should be put in shared memory.
  75 The shared memory ID for each screen will be printed by the server.
  76 The shared memory is in xwd format.
  77 This option only exists on machines that support the System V shared memory
  78 interface.
  79 .PP
  80 If neither \fB\-shmem\fP nor \fB\-fbdir\fP is specified,
  81 the framebuffer memory will be allocated with malloc().
  82 .TP 4
  83 .B "\-linebias \fIn\fP"
  84 This option specifies how to adjust the pixelization of thin lines.
  85 The value \fIn\fP is a bitmask of octants in which to prefer an axial
  86 step when the Bresenham error term is exactly zero.  See the file
  87 Xserver/mi/miline.h for more information.  This option is probably only useful
  88 to server developers to experiment with the range of line pixelization
  89 possible with the fb code.
  90 .TP 4
  91 .B "\-blackpixel \fIpixel-value\fP, \-whitepixel \fIpixel-value\fP"
  92 These options specify the black and white pixel values the server should use.
  93 .SH FILES
  94 The following files are created if the \-fbdir option is given.
  95 .TP 4
  96 \fIframebuffer-directory\fP/Xvfb_screen<n>
  97 Memory mapped file containing screen n's framebuffer memory, one file
  98 per screen.  The file is in xwd format.  Thus, taking a full-screen
  99 snapshot can be done with a file copy command, and the resulting
 100 snapshot will even contain the cursor image.
 101 .SH EXAMPLES
 102 .TP 8
 103 Xvfb :1 -screen 0 1600x1200x32
 104 The server will listen for connections as server number 1, and screen 0
 105 will be depth 32 1600x1200.
 106 .TP 8
 107 Xvfb :1 -screen 1 1600x1200x16
 108 The server will listen for connections as server number 1, will have the
 109 default screen configuration (one screen, 1280x1024x8), and screen 1
 110 will be depth 16 1600x1200.
 111 .TP 8
 112 Xvfb -pixdepths 3 27 -fbdir /var/tmp
 113 The server will listen for connections as server number 0, will have the
 114 default screen configuration (one screen, 1280x1024x8),
 115 will also support pixmap
 116 depths of 3 and 27,
 117 and will use memory mapped files in /var/tmp for the framebuffer.
 118 .TP 8
 119 xwud -in /var/tmp/Xvfb_screen0
 120 Displays screen 0 of the server started by the preceding example.
 121 .SH "SEE ALSO"
 122 .PP
 123 X(__miscmansuffix__), Xserver(1), xwd(1), xwud(1), XWDFile.h
 124 .SH AUTHORS
 125 David P. Wiggins, The Open Group, Inc.