Special Information about using PNG image files

The Portable Network Graphics format (see this page for more information about PNG) has become a popular alternative to the GIF format for distributing images on the Web. Unfortunately, only more recent versions of the Java runtime used by common browsers have the capability to decode PNG files. If you do not have control over the browser or Java runtime version employed by your audience, and if you want to use PNG files, the information on this page may be of help.

This page documents the use of a freely available, open source project (web site) produced library that can be used in conjuntion with AniS to enable the use of PNG-formatted image files by browsers running older (and newer) versions of Java.

Note that the current sixlegs png.jar file is NOT compatible with AniS -- they rearranged the "packages" inside the jar file. You must use the older version!!

Here's what you need to do:

1. Get an updated copy of the AniS code from this link and un-zip the contents into a base directory on your server.
2. Get a copy of the older release of the Chris Nokleberg's PNG decoder from this link. Do this:
   • Unzip or untar the contents into a temporary directory,
   • Find the "png.jar" file and
   • Copy the "png.jar" file into the same "base" directory as you put the AniS code.
3. Finally, do all three of the following:
   • Use the archive= attribute in the applet tag of your HTML:
     <applet archive="aniscode.jar,png.jar" code="AniS.class" height=500 width=700>
   • Include a new parameter in your HTML to indicate that this mode should be used:
     <param name="enable_png" value="true">
   • Make sure that your image filenames end with .png -- for example: myimage0.png, myimage1.png...

Note that if you want to put the JAR files into a different directory than your HTML, you need to use the codebase= directive (see main AniS page for more info).

To see an example, click this link.

Caveat: The png.jar file is about 61K bytes in size -- nearly 3 times the size of the AniS jar file. This means there will be some impact on the download/start-up for your users. That is why we set up the use in this way...so that the png.jar file would not be downloaded to the browser unless it was needed.