1XVFB(1) General Commands Manual XVFB(1)
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6 Xvfb - virtual framebuffer X server for X Version 11
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9 Xvfb [ option ] ...
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12 Xvfb is an X server that can run on machines with no display hardware
13 and no physical input devices. It emulates a dumb framebuffer using
14 virtual memory.
15 The primary use of this server was intended to be server testing. The
17 fb code for any depth can be exercised with this server without the
18 need for real hardware that supports the desired depths. The X commu‐
19 nity has found many other novel uses for Xvfb, including testing
20 clients against unusual depths and screen configurations, doing batch
21 processing with Xvfb as a background rendering engine, load testing, as
22 an aid to porting the X server to a new platform, and providing an un‐
23 obtrusive way to run applications that don't really need an X server
24 but insist on having one anyway.
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27 In addition to the normal server options described in the Xserver(1)
28 manual page, Xvfb accepts the following command line switches:
29 -screen screennum WxHxD
31 This option creates screen screennum and sets its width, height,
32 and depth to W, H, and D respectively. By default, only screen 0
33 exists and has the dimensions 1280x1024x24.
34 -pixdepths list-of-depths
36 This option specifies a list of pixmap depths that the server
37 should support in addition to the depths implied by the supported
38 screens. list-of-depths is a space-separated list of integers that
39 can have values from 1 to 32.
40 -fbdir framebuffer-directory
42 This option specifies the directory in which the memory mapped
43 files containing the framebuffer memory should be created. See
44 FILES. This option only exists on machines that have the mmap and
45 msync system calls.
46 -shmem
48 This option specifies that the framebuffer should be put in shared
49 memory. The shared memory ID for each screen will be printed by
50 the server. The shared memory is in xwd format. This option only
51 exists on machines that support the System V shared memory inter‐
52 face.
53 If neither -shmem nor -fbdir is specified, the framebuffer memory will
55 be allocated with malloc().
56 -linebias n
58 This option specifies how to adjust the pixelization of thin lines.
59 The value n is a bitmask of octants in which to prefer an axial
60 step when the Bresenham error term is exactly zero. See the file
61 Xserver/mi/miline.h for more information. This option is probably
62 only useful to server developers to experiment with the range of
63 line pixelization possible with the fb code.
64 -blackpixel pixel-value, -whitepixel pixel-value
66 These options specify the black and white pixel values the server
67 should use.
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70 The following files are created if the -fbdir option is given.
71 framebuffer-directory/Xvfb_screen<n>
73 Memory mapped file containing screen n's framebuffer memory, one
74 file per screen. The file is in xwd format. Thus, taking a full-
75 screen snapshot can be done with a file copy command, and the re‐
76 sulting snapshot will even contain the cursor image.
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79 Xvfb :1 -screen 0 1600x1200x24
80 The server will listen for connections as server number 1, and
81 screen 0 will be depth 24 1600x1200.
82 Xvfb :1 -screen 1 1600x1200x16
84 The server will listen for connections as server number 1,
85 screen 0 will have the default screen configuration
86 (1280x1024x24), and screen 1 will be depth 16 1600x1200.
87 Xvfb -pixdepths 3 27 -fbdir /var/tmp
89 The server will listen for connections as server number 0, will
90 have the default screen configuration (one screen,
91 1280x1024x24), will also support pixmap depths of 3 and 27, and
92 will use memory mapped files in /var/tmp for the framebuffer.
93 xwud -in /var/tmp/Xvfb_screen0
95 Displays screen 0 of the server started by the preceding exam‐
96 ple.
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99 X(7), Xserver(1), xwd(1), xwud(1), XWDFile.h
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102 David P. Wiggins, The Open Group, Inc.
103X Version 11 xorg-server 1.20.11 XVFB(1)