readme.txt

gif can source. display gif picture

GIFCanvas - Copyright (C) 1998-99 by Bill Giel & KC Multimedia and Design
Group, Inc. All Rights reserved. http://www.kcmultimedia.com
[e-mail]

Version: 1.4 (March 19, 1999)
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License
-------
GIFCanvas is neither freeware or shareware. If you have received this
distribution as part of a "no-cost" evaluation, you may not redistribute
the package in any form, and may only use the files contained herein 
for in-house testing and evaluation purposes on a single development 
computer. You may not decompile, disassemble or reverse-engineer 
GIFCanvas's class files. By installing the distribution zip on a 
computer, you agree to the terms described in license.html. Please
review the license.html document for full details.

For further information concerning licensing for other purposes, please
contact [e-mail]

Changes
-------
Version 1.4 - Added support for Local Color Tables in GIF89a, and support
              for static GIF87a. March 19, 1999
Version 1.3 - Segregated GIF parsing from GIFCanvas class, to permit
              greater flexibility in using the package. Optimized methods
              for size, resulting in slightly smaller package. Revised
              documentation. Version 1.3 API is backward compatible
              with apps built using previous versions. August 4, 1998
Version 1.2 - Added new constructor to accept a byte array, added methods
              to set/get the current frame number. June 12, 1998
Version 1.1 - Changes to support image "disposal" options specified in
              the GIF89A specification. April 29, 1998

Installation
------------
The zip distribution should be unzipped to any subdirectory or folder
that will contain the GIFCanvas package, along with the sample images
and GCTest.class application.

Use a zip utility that supports case-sensitive, long filenames. Be sure
to unpack the zip using the "Use Folder Names" or "Use Directory Names"
to ensure that the proper directory tree required to run the package 
test is created within your installation directory.

You can also extract the zip using JDK's JAR tool, if you do not have a
suitable zip utility, or are unable to run one on your platform.

Running the GIF Canvas Tester
-----------------------------

GCTest.class is a small, standalone Java application that can be used to
preview Animated GIF's using the GIFCanvas package. GCTest can run under
either Java 1.02 and Java 1.1 and has been tested with both.

1. Open a DOS or console window on your desktop.

2. Make your installation directory (the one with the file GCTest.class)
the current working directory.

3. You can run the test with either the Java Developer's Kit (JDK) or
the Java Runtime Environment (JRE.)

With the JDK, the startup command might look like either of these:

Windows:

d:\jdk1.1.5\bin\java GCTest <imagename>

UNIX:

/usr/local/jdk1.1.5/bin java GCTest <imagename>

With the JRE, it is a little different:

Windows:

d:\jre1.1.5\bin\jre -cp .;d:\jre1.1.5\lib\rt.jar GCTest <imagename>

UNIX:

/usr/local/jre1.1.5/bin/jre -cp .:/usr/local/jre1.1.5/lib/rt.jar GCTest <imagename>


Notes:

- Substitute your own path for the JDK or JRE in the above examples.

- <imagename> refers to a gif file that you wish to view. A number of
examples are provided (test1.gif, test2.gif, etc.) and should be in the
images directory of the distribution.

- If you are using the JDK, either clear any CLASSPATH environment
settings prior to issuing the above JDK commands, or at least be sure
that the current CLASSPATH is consistent with the Java version that you
invoke with the command.

Running the Applet Demos
------------------------
Simply open the file "applet.html" or "applet2.html" with a java-capable
browser.

Test Platforms
--------------
GIFCanvas 1.1 (Java 1.02 Compatible) has been tested under Windows 95,
and Windows NT 4.0 with JRE 1.1.5 and both JDK 1.1.5 and JDK 1.02
java runtimes, and MS JVIEW. The GIFCanvas Demo Applet (at our website) 
has been tested with Navigator 4.04, 4.05/JDK 1.1, MSIE 4.01, MSIE 3.02 
with Java Update, and JDK 1.02 and 1.1.5 appletviewers.

GIFCanvas has also been tested on SPARC/Solaris 2.5.1 using both JDK
1.02 and 1.1.5 Java runtimes. The demo applet at our website has been
tested on the SPARC with both JDK appletviewers, and Navigator 4.04
standard edition.

Limitations
-----------

- GIFCanvas has been torture tested with multiple instances of "real-
world" GIF images (including an 87-frame image,) and run continuously
for 8 hours on an NT 4.0 Workstation, 300Mhz Pentium II with 128Mb Ram.
Memory consumption was typical for a small Java application, and very
stable. The only problems noted were start-up delays typical to threaded
Java apps if the CPU usage was pushed to 100%  with other CPU-heavy
processes. However, extended 100% CPU usage is an unusual condition in
most cases.

- Java 1.02 suffers from an occasional image-rendering bug that we have
seen in other applications as well. Portions of some GIF images simply
do not display, or display incorrectly. The problem can sometimes be
resolved by importing the image into a different graphics editor and
resaving the file, varying the pallette. or by ensuring that the GIF 
is saved in interlaced format. 99% of GIF files display correctly, but
occasionally one will be created that does not. Before deploying any
image for public use, it should be tested with GCTest to ensure that all
frames display correctly. (Example GIF test1.gif demonstrates this
problem. The top 5 pixel rows of frame no. 1 are never painted. This
only occurs in Java 1.02. Java 1.1 displays the image correctly using
the same class files.)

Credits
-------
For permission to use their ad banners in our demo, we extend our thanks
to Alchemy Mindworks Inc., creators of Graphics Workshop for Windows, and
the GIF Construction Set. If you are a graphics pro, working on the Windows
platform and building animated GIF's, visit their website:

http://www.mindworkshop.com/alchemy/alchemy.html