NAME¶
directvnc - a vnc client for the linux framebuffer device
SYNOPSIS¶
directvnc server:display [options]
DESCRIPTION¶
DirectVNC is a client implementing the remote framebuffer protocol (rfb)
which is used by VNC servers. If a VNC server is running on a machine you can
connect to it using this client and have the contents of its display shown on
your screen. Keyboard and mouse events are sent to the server, so you can
basically control a VNC server remotely. There are servers (and other clients)
freely available for all operating systems.
What makes DirectVNC different from other unix vnc clients is that it uses the
linux framebuffer device through the DirectFB library which enables it to run
on anything that has a framebuffer without the need for a running X server.
This includes embedded devices. DirectFB even uses acceleration features of
certain graphics cards. Thus a lot of configuration can be done by creating
the library specific configuration file /etc/directfbrc or the
program-specific configuration file /etc/directfbrc.directvnc. See
directfbrc(5) or find out all about DirectFB here:
www.directfb.org
DirectVNC basically provides a very thin VNC client for unix framebuffer
systems.
QUITTING¶
Hitting <ctrl-q> exits the viewer.
OPTIONS¶
- -h, --help
- display help output and exit
- -v, --version
- output version information and exit
- -p, --password
- password string to be passed to the server for
authentication. Use this with care!
- -b, --bpp
- the bits per pixel to be used by the client. Currently only
16 and 24 bpp are available.
- -e --encodings
- DirectVNC supports several different compression methods to
encode screen updates; this option specifies a set of them to use in order
of preference. Encodings are specified separated with spaces, and must
thus be enclosed in quotes if more than one is specified. Available
encodings, in default order for a remote connection, are "copyrect
tight hextile zlib corre rre raw". For a local connection (to the
same machine), the default order to try is "raw copyrect tight
hextile zlib corre rre". Raw encoding is always assumed as a last
option if no other encoding can be used for some reason.
- -f --pollfrequency
- time in ms to wait between polls for screen updates when no
events are to be processed. This reduces cpu and network load. Default is
50 ms.
- -s, --shared (default)
- Don't disconnect already connected clients.
- -n, --noshared
- Disconnect already connected clients.
- -n, --nolocalcursor
- Disable local cursor tracking By default, and if the server
is capable of the SoftCursor encoding, mouse movements do not generate
framebuffer updates and the cursor state is kept locally. This removes
mouse pointer lag and lets the connection appear faster.
- -c --compresslevel level
- Use specified compression level (0..9) for
"tight" and "zlib" encodings (only usable with servers
capable of those encodings). Level 1 uses minimum of CPU time and achieves
weak compression ratios, while level 9 offers best compression but is slow
in terms of CPU time consumption on the server side. Use high levels with
very slow network connections, and low levels when working over high-speed
LANs. It's not recommended to use compression level 0, reasonable choices
start from the level 1.
- -q --quality level
- Use the specified image quality level (0..9) for
"tight" encoding (only usable with servers capable of those
encodings). Specifying this option allows "tight" encoder to use
lossy JPEG compression. Quality level 0 denotes bad image quality but very
impressive compression ratios, while level 9 offers very good image
quality at lower compression ratios. Note that "tight" encoder
uses JPEG to encode only those screen areas that look suitable for lossy
compression, so quality level 0 does not always mean unacceptable image
quality.
- -m --modmap PATH
- Path to the modmap (subset of X-style) file to load. With
this option, it is possible to set an alternative keyboard layout, with
ability to support non-latin characters such as Cyrillic. A plain text
file, containing a subset of xmodmap(1) syntax (only keycode expressions
are recognized with up to four KEYSYMNAMEs) can be converted into the
format that directvnc understands, and can be loaded upon directvnc
startup with this option. See directvnc-kbmapping(7).
LIMITATIONS¶
At the moment, it is still necessary to use the --bpp command line option to set
color depth. When negotiating with the remote VNC server side, color depth
supplied by the server will be used. It is therefore necessary to make sure
(at least in the present) that screen color depth (default, or set in the
DirectFB configuration file), color depth supplied at the command line, and
remote VNC server color depth all match.
SEE ALSO¶
directfbrc(5),
directvnc-kbmapping(7),
directvnc-xmapconv(1),
xmodmap(1)
AUTHORS¶
Till Adam, Dimitry Golubovsky, Malte S. Stretz, Loris Boillet and others, based
on AT&T and tightvnc VNC implementations.