X Version 11 (Release 6.1)
Xvfb(X1M)
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 is 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.
A secondary use is testing clients against unusual depths and screen
configurations.
Options
In addition to the normal server options described in the
Xsco(X1M)
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 the Files section.
-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.
If neither -shmem nor -fbdir is specified,
the framebuffer memory will be allocated with
malloc(3C).
-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.
The header file Xserver/mi/miline.h in the X
Development System includes public definitions used for
configuring basic pixelization aspects of the sample implementation
graphics routines provided in {mfb,mi,cfb*} at run-time.
Devices can configure the rendering of routines in mi,
mfb, and cfb*
by specifying a thin line bias to be applied to a particular screen
using the following function. The bias parameter is an OR'ing of
the appropriate OCTANT constants defined above to indicate which
octants to bias a line to prefer an axial step when the Bresenham
error term is exactly zero. The octants are mapped as follows:
\ | /
\ 3 | 2 /
\ | /
4 \ | / 1
\|/
-----------
/|\
5 / | \ 8
/ | \
/ 6 | 7 \
/ | \
Files
The following files are created if the -fbdir option is given:
framebuffer-directory/Xvfb_screenn
Memory mapped file containing screen n's framebuffer memory, one file
per screen. The file is in xwd format.
See also XWDFile.h, the X Window Dump File format
definition file.
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 /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 example.
References
X(X1M),
Xsco(X1M),
xwd(X1),
xwud(X1).
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 25 April 2004