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LibVNCServer: a library for easy implementation of a RDP/VNC server.
Copyright (C) 2001 Johannes E. Schindelin
What is it?
VNC is set of programs using the RFB (Remote Frame Buffer) protocol. They
are designed to "export" a frame buffer via net. It is already in wide use
for administration, but it is not that easy to make a server yourself.
This has been changed by LibVNCServer.
There are two examples included:
- example, a shared scribble sheet
- pnmshow, a program to show PNMs (pictures) over the net.
The examples are not too well documented, but easy straight forward and a
good starting point.
How to use
To make a server, you just have to initialise a server structure using the
function rfbDefaultScreenInit, like
rfbScreenInfoPtr rfbScreen =
You then can set hooks and io functions (see below).
You can use a blocking event loop, a background (pthread based) event loop,
or implement your own using the processEvents function.
Also, there is functionality included to draw a cursor (see below).
To start also an HTTP server (running on port 5800+display_number), you have
to set rfbScreen->httpdDir to a directory containing vncviewer.jar and
index.vnc (like the included "classes" directory).
Hooks and IO functions
Cursor handling
The rfbCursor structure consists mainly of a mask and a source. The mask
describes, which pixels are drawn for the cursor (a cursor needn't be
rectangular). The source describes, which colour those pixels should have.
The standard is an XCursor: a cursor with a foreground and a background
colour (stored in backRed and similar with a range from 0-0xffff). The
arrays "mask" and "source" consist of byte padded rows in MSB order (i.e. a
10x4 cursor's mask has 2x4 bytes, because 2 bytes are needed to hold 10 bits).
It is very easy to make a cursor like this:
char* cur=" "
" xx "
" x "
" ";
char* mask="xxxx"
"xxx ";
rfbCursorPtr c=rfbMakeXCursor(4,4,cur,mask);
You can even set "mask" to NULL in this call and LibVNCServer will calculate
a mask for you.
There is also an array named "richSource" for colourful cursors. They have
the same format as the frameBuffer.
LibVNCServer is based on Tridia VNC and OSXvnc, which in turn are based on
the original code from ORL/AT&T.
22 years ago
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.dfdf
For help with OSXvnc, please visit