LED Sign 3.1

Updated: August 11, 1996
If you were using a Java-enabled browser, you would see an animated scrolling text sign that looks like this:

Self-test and demonstration Page

PLEASE!

If you don't read anything else, read the section This is a packaged applet.

About LED Sign V3.1

In Spring 1996, Darrick Browne, the original author of LED Sign, announced that he would no longer support the applet. I had given Darrick some code snippets and suggestions, for which he credited me in the sources (thanks, Darrick!). Since I make active use of LED Sign at my site, I decided to take the code and run with it. This is my first release of LED Sign. If you are interested in what I have done since version 2.7, see Changes since V2.7.

Support Notice

My time is devoted primarily to the O'Reilly WebSite Web Server. I get an enormous amount of email, and I read a dozen or so usenet newsgroups and mailing lists. Bottom line is that I cannot provide technical support for this package. I hope you can understand. Darrick has provided a reasonably complete set of documentation files, to which I have added to make them represent V3.1. Like Darrick, I will delete any email I receive asking for technical support. If you have questions about how to set up an applet, check the java site at http://www.javasoft.com/. If you have other problems, I would suggest checking the usenet newsgroups comp.lang.java.*.
I will continue to improve LED Sign so if you have any bug reports or suggestions, please let me know.

Features

Script controlled, multiple scripts may be chained together
Colored text (red, orange, yellow, green, cyan, blue, purple, and white)
Variable fonts, transitions, and LED size
Displays the current time/date
Scripts may be fed through server-side include processor for additional dynamics
URL links - takes you to another page if you click on the sign while a certain message is being displayed
Separate border color when current message has a URL link
Frame/Window targets on URL links - Use LED Sign with your frames and windows

Usability

This applet was designed to be "user friendly". Everything you see the sign displaying is run entirely by a script. LED Sign will provide errors and warnings in the Java console of your browser to help make the setup easier and quicker.
More on the Script Feature.
Here is the Demo script that the sign above is running.

Flexibility

The LED applet also has a large amount of flexibility. The size, size of border, color of border, size of the LED's, and even the font that the sign uses are all configurable. The size and border parameters can be easily set in the applet "command line" in the HTML. The font is specified by a data file that contains the shape for each letter. The font data file can have as many or few characters as needed. If a character is used in the message but is not in the font data file, then it will be substituted by a space.
More on fonts .
More on configurability .

Examples of LED Sign

Here are some sites that use LED Sign on their pages.

Download LED Sign V3.1

PLEASE! Read the insallation document INSTALL.txt. This is a packaged applet, something you probably haven't yet seen. Installing it requires you to make some decisions about where you are going to store globally named classes and packages.

Download the ZIP file LEDSign31.zip, or the
Unix tar/gz file LEDSign31.tar.gz
If you are running Win95/NT you might need WinZip95 6.0a to unzip and untar the archive. WinZip will retain the long filenames which are needed for the applet to work.
The LED Sign V3.1 distribution comes with all source code, pre-compiled binaries, Symantec Cafe' project files, example scripts, fonts, and the HTML documentation you see here.

This is a packaged applet

This is probably the first applet you have seen that is packaged using a globally unique package name (per the Sun recommendations). The name of the package is com.dc3.applet.LEDSign. This may drive you crazy at first. Get used to it. If Java keeps growing in use and the vision is realized, it will be important that applet and utility class names don't clash.

When you unarchived/unzipped this, it created a directory hierarchy of com/dc3/applet/ledsign/. This correponds to the package name of this applet, com.dc3.applet.LEDSign. The CODEBASE parameter in your APPLET tags must specify the URL of the root directory that contains the com directory! This is analogous to the CLASSPATH used when developing (it should also contain this root).

I know this is going to be a pain, but don't shoot the messenger (me). This is the way things are going to be soon anyway. If others follow the Sun recommendations for class packaging, you'll end up with a unified directory hierarchy for classes from anywhere.

If you want some more details, see the INSTALL.TXT document that comes with this kit.

Using the ZIP container

This package contains an uncompressed ZIP file whch contains all of the LED Sign classes, in their proper directory path hierarchy for the package name. As of Netscape 3.0b7, you can specify the archive="<URL path>" parameter in the <APPLET> tag. This causes the browser to read the ZIP file and get its classes from there. This permits the applet classes to be loaded much faster.

LED Font V1.1

Check out this cool program by W. Scott Dillman. LED Font will turn any of your windows TrueType fonts into new LED Sign fonts. So now you can use Arial, Times, Courier, etc., on LED Sign! It's super easy! If you use LED Font and like it. Please drop Scott Dillman a line and thank him for the great job he did. He deserves it! Also, stop over and check out Scott's Homepage.
YES! I have Windows 3.1/95/NT and I want to download LED Font V1.1!

Questions???

Check the LEDSign FAQ.

Self-Test and Demonstration

I have included a fairly thorough self-test and demonstration page. Try it out!

Known bugs

Changing the delay parameter does not take effect immediately. This is clearly a multi-thread synchronization problem. I just discovered it and will fix it as soon as I get a chance.

Changes since V2.7

Added separate border color(s) which are used when the current message has a URL link associated with it. The default colors produce a 3-D blue border (the well-known color for hyperlinked text).
Added new parameter smooth_leds to draw the LEDs in sizes 3 and 4 as real circles. This is a bit slower, but much prettier. It's quite usable with the newer JIT engines that come with Netscape 3.0b6 and later, and Internet Explorer 2.0B3 and later.
Added Chain directive to the script language, allowing one script to chain to another.
Brightened up the default red LED color somewhat. It was too dim on "accurate" color displays.
Darkened the "off" LED color somewhat. It was too light on "accurate" color displays.
Corrected the suggested value of the 'ht' parameter warning (written to Java console) when not set to the pixel height of the selected font.
Turned applet into a Java "package" called com.dc3.applet.LEDSign. This follows the Java standard for package names, and will prevent name clashes in the future.
Additional cleanup of error handling, replacing lots of tested ifs with structured exceptions. Some of this was required to get the chain directive to work and to prevent nullPointerException from being thrown when the script finished. There is more work to do on this, but the applet is substantially more robust in this regard now.
Trim trailing whitespace from numbers when reading font files. The LEDFont utility was leaving trailing blanks on dimensions, which caused exceptions.