gentoo-overlay/net-misc/tightvnc/files

TightVNC Java Viewer version 1.2.7

==================================



Copyright (C) 2001,2002 HorizonLive.com, Inc.  All Rights Reserved.

Copyright (C) 2001,2002 Constantin Kaplinsky.  All Rights Reserved.

Copyright (C) 1999 AT&T Laboratories Cambridge.  All Rights Reserved.



This software is distributed under the GNU General Public Licence as

published by the Free Software Foundation. See the file LICENCE.TXT for the

conditions under which this software is made available. TightVNC also

contains code from other sources. See the Acknowledgements section below, and

the individual files for details of the conditions under which they are made

available.





Compiling from the sources

==========================



To compile all the .java files to .class files, simply do:



	% make all



This will also generate a JAR (Java archive) file containing all the classes. 

Most JVM (Java Virtual Machine) implementations are able to use either a set

of .class files, or the JAR archive.





Installation

============



There are three basic ways to use TightVNC Java viewer:



  1. Running applet as part of TightVNC server installation.



     Both the Unix and Windows versions of TightVNC servers include small

     built-in HTTP server which can serve Java viewer to Web clients. This

     enables easy Web access to the shared desktop without need to install

     any software on the client computer. Unix and Windows versions of

     TightVNC servers are different in the way they store the .class and .jar

     files: the Unix server (Xvnc) is able to serve any set of files present

     in a particular directory, while the Windows server (WinVNC) has all the

     .class and .jar files inside the WinVNC executable file. Therefore, for

     Xvnc, it's enough to copy the files into a correct directory, but for

     WinVNC, the server binaries should be rebuild if the built-in Java

     viewer should be updated.



     To install the Java viewer under Xvnc, copy all the .class files, the

     .jar file and the .vnc files to an installation directory (e.g.

     /usr/local/vnc/classes):



         cp *.class *.jar *.vnc /usr/local/vnc/classes



     Also, make sure that the vncserver script is configured to point to the

     installation directory (see the Xvnc manual page for the description of

     the -httpd command-line option).



  2. Running applet hosted on a standalone Web server.



     Another possibility to use the Java viewer is to install it under a

     fully-functional HTTP server such as Apache or IIS. Obviously, this

     method requires running an HTTP server, and due to the Java security

     restrictions, it's also required that the server should be installed on

     the same machine which is running the TightVNC server. In this case,

     installation is simply copying the .class and .jar files into a

     directory that is under control of the HTTP server. Also, an HTML page

     should be created which will act as a the base document for the viewer

     applet (see an example named index.html in this distribution).



  3. Running the viewer as a standalone application.



     Finally, the Java viewer can be executed locally on the client machine,

     but this method requires installation of either JRE (Java Runtime

     Environment) or JDK (Java Development Kit). If all the .class files are

     in the current directory, the Java viewer can be executed like this,

     from the command line:



         java VncViewer HOST vnchost PORT 5900



     The parameters HOST and PORT are required, but there is a number of

     optional parameters as well (see the Parameters section below).



Parameters

==========



TightVNC Java viewer supports a number of parameters allowing you to

customize its behaviour. Most parameter names copy settings available from

the Options frame in the Java viewer. Both parameter names and their values

are case-insensitive, with one exception for the "PASSWORD" parameter. Here

is the full list of parameters supported in TightVNC Java viewer:



--> "HOST" (no GUI equivalent)



    Value: host name or IP address of the VNC server.

    Default: in applet mode, the host from which the applet was loaded.



    This parameter tells the viewer which server to connect to. Normally,

    it's not needed, because default Java security policy allow connections

    from applets to the only one host anyway, and that is the host from which

    the applet was loaded.



--> "PORT" (no GUI equivalent)



    Value: TCP port number on the VNC server.

    Default: none.



    This parameter is required in all cases. Note that this port is not the

    one used for HTTP connection from the browser, it is the port used for

    RFB connection. Usually, VNC servers use ports 58xx for HTTP connections,

    and ports 59xx for RFB connections. Thus, most likely, this parameter

    should be set to something like 5900, 5901 etc.



--> "PASSWORD"



    Value: session password in plan text.

    Default: none, ask user.



    DO NOT EVER USE THIS PARAMETER, unless you really know what you are

    doing. It's extremely dangerous from the security point of view. When

    this parameter is set, the viewer won't ever ask for a password.



--> "ENCPASSWORD"



    Value: encrypted session password in hex-ascii.

    Default: none, ask user.



    The same as the "PASSWORD" parameter but DES-encrypted using a fixed key.

    Its value should be represented in hex-ascii e.g. "494015f9a35e8b22".

    This parameter has higher priority over the "PASSWORD" parameter. DO NOT

    EVER USE THIS PARAMETER, unless you really know what you are doing. It's

    extremely dangerous from the security point of view, and encryption does

    not actually help here since the decryption key is always known.



--> "Encoding"



    Values: "Raw", "RRE", "CoRRE", "Hextile", "Zlib", "Tight".

    Default: "Tight".



    The preferred encoding. "Hextile" is a good choice for fast networks,

    while "Tight" is better suited for low-bandwidth connections. From the

    other side, the "Tight" decoder in TightVNC Java viewer seems to be more

    efficient than "Hextile" decoder so it's possible that this default

    setting can be ok for fast networks too.



--> "Compression level"



    Values: "Default", "1", "2", "3", "4", "5", "6", "7", "8", "9".

    Default: "Default". ;-)



    Use specified compression level for "Tight" and "Zlib" encodings. Level 1

    uses minimum of CPU time on the server but achieves weak compression

    ratios. Level 9 offers best compression but may be 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 higher-speed

    networks. The "Default" value means that the server's default compression

    level should be used.



--> "JPEG image quality"



    Values: "JPEG off", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9".

    Default: "6".



    Use the specified image quality level in "Tight" encoding. Quality level

    0 denotes bad image quality but very impressive compression ratios, while

    level 9 offers very good image quality at lower compression ratios. If

    the value is "JPEG off", the server will not use lossy JPEG compression

    in "Tight" encoding.



--> "Cursor shape updates"



    Values: "Enable", "Ignore", "Disable".

    Default: "Enable".



    Cursor shape updates is a protocol extension used to handle remote cursor

    movements locally on the client side, saving bandwidth and eliminating

    delays in mouse pointer movement. Note that current implementation of

    cursor shape updates does not allow a client to track mouse cursor

    position at the server side. This means that clients would not see mouse

    cursor movements if mouse was moved either locally on the server, or by

    another remote VNC client. Set this parameter to "Disable" if you always

    want to see real cursor position on the remote side. Setting this option

    to "Ignore" is similar to "Enable" but the remote cursor will not be

    visible at all. This can be a reasonable setting if you don't care about

    cursor shape and don't want to see two mouse cursors, one above another.



--> "Use CopyRect"



    Values: "Yes", "No".

    Default: "Yes".



    The "CopyRect" encoding saves bandwidth and drawing time when parts of

    the remote screen are moving around. Most likely, you don't want to

    change this setting.



--> "Restricted colors"



    Values: "Yes", "No".

    Default: "No".



    If set to "No", then 24-bit color format is used to represent pixel data. 

    If set to "Yes", then only 8 bits are used to represent each pixel. 8-bit

    color format can save bandwidth, but colors may look very inaccurate.



--> "Mouse buttons 2 and 3"



    Values: "Normal", "Reversed".

    Default: "Normal".



    If set to "Reversed", then right mouse button (button 2) will act as it

    was middle mouse button (button 3), and vice versa.



--> "View only"



    Values: "Yes", "No".

    Default: "No".



    If set to "Yes", then all keyboard and mouse events in the desktop window

    will be silently ignored and will not be passed to the remote side.



--> "Share desktop"



    Values: "Yes", "No".

    Default: "Yes".



    Share the connection with other clients on the same VNC server. The exact

    behaviour in each case depends on the server configuration.



--> "Open new window" (no GUI equivalent, applicable only in the applet mode)



    Values: "Yes", "No".

    Default: "No".



    Operate in a separate window. This makes possible resizing the desktop,

    and adds scroll bars when necessary. If the server supports variable

    desktop size, the window will resize automatically when remote desktop

    size changes.



--> "Show controls" (no GUI equivalent)



    Values: "Yes", "No".

    Default: "Yes".



    Set to "No" if you want to get rid of that button panel at the top.



--> "Offer relogin" (no GUI equivalent, not applicable in the applet mode)



    Values: "Yes", "No".

    Default: "Yes".



    If set to "No", the buttons "Login again" and "Close window" won't be

    shown on disconnects or after an error has occured.



--> "Show offline desktop" (no GUI equivalent)



    Values: "Yes", "No".

    Default: "No".



    If set to "Yes", the viewer would continue to display desktop even

    if the remote side has closed the connection. In this case, if the

    button panel is enabled, then the "Disconnect" button would be

    changed to "Hide desktop" after the connection is lost.



--> "Defer screen updates" (no GUI equivalent)



    Value: time in milliseconds.

    Default: "20".



    When updating the desktop contents after receiving an update from server,

    schedule repaint within the specified number of milliseconds. Small delay

    helps to coalesce several small updates into one drawing operation,

    improving CPU usage. Set this parameter to 0 to disable deferred updates.



--> "Defer cursor updates" (no GUI equivalent)



    Value: time in milliseconds.

    Default: "10".



    When updating the desktop after moving the mouse, schedule repaint within

    the specified number of milliseconds. This setting makes sense only when

    "Cursor shape updates" parameter is set to "Enable". Small delay helps to

    coalesce several small updates into one drawing operation, improving CPU

    usage. Set this parameter to 0 to disable deferred cursor updates.



--> "Defer update requests" (no GUI equivalent)



    Value: time in milliseconds.

    Default: "50".



    After processing an update received from server, wait for the specified

    number of milliseconds before requesting next screen update. Such delay

    will end immediately on every mouse or keyboard event if not in the "view

    only" mode. Small delay helps the server to coalesce several small

    updates into one framebuffer update, improving both bandwidth and CPU

    usage. Increasing the parameter value does not affect responsiveness on

    mouse and keyboard events, but causes delays in updating the screen when

    there is no mouse and keyboard activity on the client side.



--> "SocketFactory" (no GUI equivalent)



    Value: name of the class.

    Default: none.



    This option provides the way to define an alternate I/O implementation.

    The dynamically referenced class must implement a SocketFactory

    interface, and create a Socket, as configured by this parameter. See the

    source in the SocketFactory.class.





RECORDING VNC SESSIONS

======================



Current version of the TightVNC Java viewer is able to record VNC (RFB)

sessions in files for later playback. The data format in saved session files

is compatible with the rfbproxy program written by Tim Waugh. Most important

thing about session recording is that it's supported only if Java security

manager allows access to local filesystem. Typically, it would not work for

unsigned applets. To use this feature, either use TightVNC Java viewer as a

standalone application (Java Runtime Environment or Java Development Kit

should be installed), or as a signed applet. The code checks if it's possible

to support session recording, and if everything's fine, the new "Record"

button should appear in the button panel. Pressing this button opens new

window which controls session recording. The GUI is pretty self-explained.



Other important facts about session recording:



--> All sessions are recorded in the 24-bit color format. If you use

    restricted colors (8-bit format), it will be temporarly switched to

    24-bit mode during session recording.



--> All sessions are recorded with cursor shape updates turned off. This is

    necessary to represent remote cursor movements in recorded sessions.



--> Closing and re-opening the recording control window does not affect the

    recording. It's not necessary to keep that window open during recording a

    session.



--> Avoid using Zlib encoding when recording sessions. It's ok if you started

    recording BEFORE the connection to the VNC server has been established,

    but if you started recording during an active session, all Zlib sessions

    will be saved Raw-encoded (that is, without compression at all). Zlib

    decoding depends on the pixel data received earlier, thus saving the data

    received from the server at an arbitrary moment is not sufficient to

    decompress it correctly. And there is no way to say Zlib decoder to reset

    decompressor's state -- that's a limitation of the Zlib encoder. The

    viewer could re-compress raw pixel data again before saving Zlib-encoded

    sessions, but unfortunately Java API does not allow to flush zlib data

    streams making it impossible to save Zlib-encoded RFB pixel data without

    using native code.



--> Usually, Tight encoding is the most suitable one for session recording,

    but some of the issues described above for the Zlib encoding affect the

    Tight encoding as well. Unlike Zlib sessions, Tight-encoded sessions are

    always saved Tight-encoded, but the viewer has to re-compress parts of

    data to synchronize encoder's and decoder's zlib streams. And, due to

    Java zlib API limitations, zlib streams' states have to be reset on each

    compressed rectangle, causing compression ratios to be lower than in the

    original VNC session. If you want to achieve the best possible

    performance, turn recording on BEFORE connecting to the VNC server,

    otherwise CPU usage and compression ratios may be notably less efficient.





HINTS

=====



--> To refresh remote desktop in the view-only mode, press "r" or "R"

    on the keyboard.





ACKNOWLEDGEMENTS

================



This distribution contains Java DES software by Dave Zimmerman

<dzimm@widget.com> and Jef Poskanzer <jef@acme.com>.  This is:



    Copyright (c) 1996 Widget Workshop, Inc. All Rights Reserved.



    Permission to use, copy, modify, and distribute this software and its

    documentation for NON-COMMERCIAL or COMMERCIAL purposes and without fee

    is hereby granted, provided that this copyright notice is kept intact.

    

    WIDGET WORKSHOP MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE

    SUITABILITY OF THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT

    NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A

    PARTICULAR PURPOSE, OR NON-INFRINGEMENT. WIDGET WORKSHOP SHALL NOT BE

    LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING,

    MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.

    

    THIS SOFTWARE IS NOT DESIGNED OR INTENDED FOR USE OR RESALE AS ON-LINE

    CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS REQUIRING FAIL-SAFE

    PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR FACILITIES, AIRCRAFT

    NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL, DIRECT LIFE

    SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH THE FAILURE OF THE

    SOFTWARE COULD LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE

    PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH RISK ACTIVITIES").  WIDGET

    WORKSHOP SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF

    FITNESS FOR HIGH RISK ACTIVITIES.



    Copyright (C) 1996 by Jef Poskanzer <jef@acme.com>.  All rights

    reserved.



    Redistribution and use in source and binary forms, with or without

    modification, are permitted provided that the following conditions

    are met:

    1. Redistributions of source code must retain the above copyright

       notice, this list of conditions and the following disclaimer.

    2. Redistributions in binary form must reproduce the above copyright

       notice, this list of conditions and the following disclaimer in the

       documentation and/or other materials provided with the distribution.



    THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND

    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

    PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS

    BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

    CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR

    BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,

    WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR

    OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF

    ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.



    Visit the ACME Labs Java page for up-to-date versions of this and other

    fine Java utilities: http://www.acme.com/java/