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This license ("License") contains rights and restrictions associated with use of the accompanying software. Read the License carefully before utilizing the software. By using the software you agree to be bound by the terms and conditions of this license.

  1. Limited License Grant. David Griffiths ("The author") grants to you ("Licensee") a nonexclusive, nontransferable, worldwide, royalty-free license to use this The Lake Applet software (the "Software"). Licensee agrees that it shall not use the Software for computer operations of any critical nature.
  2. Source Code Whilst the author may occasionally make source code available, it is NOT in the public domain and the author retains full copyright over it. UNDER NO CIRCUMSTANCES may software be sold containing code derived from this source code without David Griffiths giving his explicit permission.
  3. Restrictions. The Software is copyrighted and title to all copies is retained by the author. Licensee shall not make copies of Software, other than a single copy of Software in machine-readable format for back-up or archival purposes and, if applicable, Licensee may print one copy of on-line documentation, in which event all proprietary rights notices on Software and on-line documentation shall be reproduced and applied to all copies. Unless enforcement of this provision is prohibited by applicable law, Licensee shall not modify, decompile, disassemble, decrypt, extract, or otherwise reverse engineer Software. Software may not be transferred, leased, assigned, or sublicensed, in whole or in part.
  6. Termination. Licensee may terminate this License at any time by destroying all copies of Software including any documentation. This License will terminate immediately without notice from David Griffiths if Licensee fails to comply with any provision of this License. Upon termination, Licensee must destroy all copies of Software.
  7. Severability. If any of the above provisions are held to be in violation of applicable law, void, or unenforceable in any jurisdiction, then such provisions are herewith waived to the extent necessary for the License to be otherwise enforceable in such jurisdiction, However, if in the author's opinion deletion of any provisions of the License by operation of this paragraph unreasonably compromises the rights or liabilities of the author, David Griffiths reserves the right to terminate the License and refund the fee paid by Licensee as Licensee's sole and exclusive remedy.
  8. Integration. This Agreement is the entire agreement between Licensee and David Griffiths relating to Software and: (i) supersedes all prior or contemporaneous oral or written communications, proposals and representations with respect to its subject matter; and (ii) prevails over any conflicting or additional terms of any quote, order, acknowledgment, or similar communication between the parties during the term of this Agreement. No modification to the Agreement will be binding, unless in writing and signed by a duly authorized representative of each party.


...upon choosing this product. Not only will it improve your health, and enhance your general spirituality, it will also clean the bath, cook you breakfast, take care of the children, end armed conflict and invigorate the look of your web page.


You should be careful to check that your unzipping program has named the files correctly. Some DOS programs will name according to the old 8.3 format, rename .class files "*.cla".

The Gallery Example

NB: If you cannot see an applet above, then you may need to extract more files from the .ZIP archive before reading this page.

The code which produces the above is:

<applet code=lake name=lake1 width=250 height=250>
<param name=image value="scenic.jpg">
<param name=href 

<img src="sunset_button.jpg" 
<img src="city_button.jpg"
<img src="scenic_button.jpg" 
<img src="clouds_button.jpg"
<input type=checkbox value="Rocking on" 
<input type=checkbox value="Underwater on" 

Paying for the Applet

There is NOTHING to pay. The applet is completely free. However, if you make a donation ($5 - $10?) to Ty Hafan, Children's Hospice of Wales, which is a charitable appeal formed to build, equip and run a Children's Hospice in Wales to provide care for terminally ill children, you can consider your applet well-and-truly registered. Click here for details on how to make a donation. They now have an excellent new OnLine donation page. In just a few minutes you can change a few old, crinkly, dirty little bank notes into a nice warm glow...

New features in version 4.0

The Dummy's Guide

If you get lost following these instructions, then there is an online "Dummy's Guide" at I shall continue to update this guide to cover any steps that people find problematical.

Using lake in a web page (With FrontPage 98)

  1. Create a (temporary) directory for the files (e.g. c:\lake)

  2. Unzip all of the files into the directory

  3. Start FrontPage 98

  4. Open the appropriate web

  5. Change to the folder in the web that contains the page which will contain the lake

  6. Choose "File/Import" from the menu

  7. When the "Import" dialog appears, click the "Add File" button.

  8. Change the "Open File" dialog to the lake directory (e.g. c:\lake)

  9. Select all of the files in the directory (you can do this by clicking the first file, then holding down the "CTRL" key and clicking each of the other files in sequence)

  10. Click the "Open" button to close the "Open File" dialog.

  11. Click the "OK" button to start the import of the files.

  12. The files should now appear in the contents of the FrontPage folder.

  13. Double-click the page that you want to insert a lake in.

  14. Once the page opens, move the cursor to the place on it where you want the lake to appear.

  15. Choose "Insert/Image..." from the menu

  16. When the "Image" dialog appears, change to the folder containing the file you want to appear at the back of the lake. Click this file once and note down (on a piece of paper) the value which appears in the "URL" field.

  17. Now click the "OK" button. The image will now be inserted into page. But it will not yet be rippling.

  18. Right-click the image and choose "Image properties" from the menu.

  19. When the "Image Properties" dialog appears, switch to the "Appearance" tab.

  20. In the size section you should have values for the "Width" and "Height" of the image. Note these down on the same piece of paper that you noted the "URL" value on.

  21. Click the "Cancel" button.

  22. Delete the image you have just inserted. You should be able to do this by just clicking the "Delete" key.

  23. Choose "Insert/Advanced/Java Applet" from the menu.

  24. In "Applet Source" enter "lake"

  25. In the section labelled "Applet Parameters" click on the "Add..." button.

  26. Enter "image" in the "Name" field

  27. Go to the "Value" field and enter the "URL" value that you previously wrote down on the piece of paper.

  28. Click the "OK" button.

  29. You should now be back in the "Java Applet Properties" dialog. In the "Size" section, click the mouse in the "Width" field.

  30. Replace the current value with the "Width" value that you noted on the piece of paper.

  31. Now click your mouse in the "Height" property.

  32. VERY IMPORTANT: You should now enter a value that is 1.8 times the value for the height that you noted down on the piece of paper. So, for instance, if you originally noted down a value of "100", you should enter 180 into this field.

  33. Click the "OK" button. You should now have a large "J" on the page.

  34. To see the applet running, click on the "Preview" tab at the bottom of the page.

  35. You have set up lake to run with a single "image" parameter. You can add other parameters by amending the properties of the applet (by right-clicking the applet in the editor view and then choosing "Applet properties"). For a full list of the parameters that can be used, see below.

Using lake in a web page (HTML editors)

To include lake in a web page, you should copy all class files into the same directory as the web page and then insert an <APPLET...> tag into the page, e.g.

<applet code="lake" width= height=>
  <param name="image" value="sunset.jpg"> 
  <param name="href" 

Each of the "PARAM" tags passes a value to the applet. The examples shown here are the "image" parameter and the "href" parameter. In general the "PARAM" tag has the following format:


Note that in Communicator 4.5 you will need to insert the tags in one at a time. Do this by choosing "Insert/HTML Tag..." from the menu for the <applet...> tag, then each of the <param...> tags and so on. For a full list of the parameters that can be passed to lake, see below.

Parameters that can be passed to lake

The following parameters can be passed to the lake:

The IMAGE parameter

JPG or GIF file that you want to reflect.

<applet code=lake width=250 height=250>
<param name=image value="scenic.jpg">

The OVERLAY parameter

The JPG or GIF file that you want to appear over the animated image. Quite frequently an overlay would be a GIF file, so that parts of it can be made transparent and allow the lake image to show through.

<applet code=lake width=250 height=250>
<param name=image value="scenic.jpg">
<param name=overlay value="dglogo.gif">

The HORIZON parameter

The HORIZON parameter allows you to have a visual horizon within the image. This is useful in situations where the image already has water and a horizon in it. In this example the original example is placed next to the lake version. Notice how the applet is exactly the same size as the original image. This is because it is animating part of the image, rather than reflecting it.

<img src="horizon.jpg" width=250 height=183 align=left>
<applet code=lake width=250 height=183>
<param name=image value="horizon.jpg">
<param name=horizon value="96">

The HREF parameter

The URL to link to when the applet is clicked. By default this is .

<applet code=lake width=250 height=250>
<param name=image value="scenic.jpg">
<param name=href value="">

The TARGET parameter

This is the name of the frame you want any linked page to appear in.

<applet code=lake width=250 height=250>
<param name=image value="scenic.jpg">
<param name=href value="">
<param name=target value="newframe">

The UNDERWATER parameter

TRUE if the image is to appear reflected on the underside of the water.

<applet code=lake width=250 height=250>
<param name=image value="scenic.jpg">
<param name=underwater value="true">

The ROCKING parameter

Set to TRUE if you want the boat rocking.

If you set the "ROCKING" parameter to "TRUE" then you almost certainly need to reduce the height of the applet.

<applet code=lake width=250 height=220>
<param name=image value="scenic.jpg">
<param name=rocking value="true">

Sizing and other matters

You will need to set the height of the applet by trial and error. Start off with the height equal to about 1.8 * height of original image. The only exception to this rule is if you are using the "Horizon" parameter, in which case you should set the image to the size of the image being used.

If you can still see a gap appearing at the bottom of the applet as the waves move backwards and forwards, then you should reduce the height a little.

I'd suggest you put the lake.class file in the same directory as the page on which it will appear. If you want to move it elsewhere then use the "CODEBASE" option to point to the appropriate directory.

Some implementations of Java will not allow you to put the .class file in one subdirectory and the image file in another. If the try it might cause a security exception.

Using it with JavaScript

How does the example applet above communicate with the images and controls around it?

Well for a start, if you are not using at least version 4 of Netscape or Internet Explorer, it won't be reacting at all. So if clicking on the images and the checkbox are either having no effect or producing an error, that will probably be the reason.

The HTML source for the above is:

<applet code=lake name=lake1 width=250 height=250>
<param name=image value="scenic.jpg">
<param name=href 

<img src="sunset_button.jpg" 
<img src="city_button.jpg"
<img src="scenic_button.jpg" 
<img src="clouds_button.jpg"
<input type=checkbox value="Rocking on" 
<input type=checkbox value="Underwater on" 

There are two important points to note in this code. Firstly, the <applet...> tag has been given a "name" attribute. Secondly, the different image and checkbox controls call methods as if the applet were a form or a text box on the web page. In fact the applet has become part of the browser's object model.

So - what are lake's methods?

setImageValue(var x)

setImageValue changes the image that is currently being reflected in the lake. The variable x should the name of a JPG or GIF file accessible by the applet.

setOverlayValue(var x)

setOverlayValue sets the filename of the overlay image.

setTargetValue(var x)

setTargetValue sets the target frame of the applet's "href" parameter.

setHRefValue(var x)

setHRefValue sets the hyperlink destination for when the applet is clicked.

setSpeedValue(var x)

setSpeedValue sets the animation speed (1 - 100).

setHorizonValue(var x)

setHorizonValue sets the level of the horizon (1 - height of image).

setRockingValue(var x)

setRockingValue sets whether the applet is rocking or not. The value passed should be either "true" or "false".


toggleRocking sets the rocking on and off alternately.

setUnderwaterValue(var x)

setUnderwaterValue sets whether the image is viewed from underwater or not. The value passed should be either "true" or "false".


toggleUnderwater sets underwater viewing on and off alternately.


Blank applet

If the applet remains blank when it is run off the server and never shows the image, the chances are there are problems with the image. If the image is too large then it may not be able to create the animation in memory. On the other hand, it may be that the image is not accessible. Have you spelt the image filename correctly in the

<param name=image...>
line? Again you will need to check the case and also the file permissions.

Gap at the bottom

If you make the applet too large then you will notice a blank strip appear at the bottom of it as the waves lap backwards and forwards. The solution is to make the applet a bit smaller...

Positioning the horizon

On an artistic note, it is not a good idea to use an image that already has a horizon. If you look across the surface of a lake you will not see the horizon reflected in the surface. The best solution is to cut the image *at* the horizon.

It's turned upside-down!

Do not use transparent GIFs with the applet's "image" parameter. There is no problem using transparent GIFs for the overlay parameter - in fact this is recommended. You can usually tell if a transparent GIF has been used because the top half of the applet will have parts which appear to be upside down.

Why won't the applet work off my hard disk?

Some web browsers have trouble opening applets straight from a hard disk. I have noticed this happen with Internet Explorer 3 and Netscape 4. Once you have loaded the class file and the web page onto your web site you should find it works OK.

Why doesn't it open when I double-click it?

Don't! This is an applet, it is intended for use within web pages. You can't open it directly. If you try, it won't harm your computer, but neither will it show you the applet. The only way you will be able to see the applet is by inserting it into a web page (using these instructions) and then opening the web page.

Why does my web page say "Class Format Error"?

Class files are binary files, just like image files are. Binary files contain more information than text (also known as ASCII) files do. If you transfer class files as if they were ASCII files then they will lose this extra information and will become corrupted. How do you transfer class files as binary files? You should transfer them in the same way that you transfer image files.

Why does my web page say "Class Not Found"?

This is a very common problem. It may be because of one of the following:

  1. You have not put the class file onto the web site
  2. You are not calling the file with the correct name (rename to use the same combination of upper- and lower-case letters as your class file)
  3. Your transfer program has changed the name. This does happen. Some programs will shorten the ".class" extension to ".cla". Other will change the case of the letters to either all uppercase or all lowercase. See if you can change the options on the transfer program to stop it doing this.
  4. You have include a "codebase=…" clause inside your <applet…> code in your web page. "codebase=…" tells the browser to look some place else for the applet file.
  5. Some other reason I haven't thought of :-)

Examples from the Web

Site of the Week

Peter Searle's collection of lake applets is one of the largest I've seen. The thing I like about them is that the photograph for each one is very simple.

The Lake Applet Ring

A terribly nice bloke by the name of Bruce Jodoin has started a "Lake applet ring" at, to help provide links between lake sites on the web, as well as tutorials, a forum, some tea, a little sympathy and a lot advice for anyone having trouble getting it to work. He also has many, many, many lake examples.

Bruce's site is particularly recommended.



Personal Home Pages



Linking to my site

If you use this applet then it would be nice if you gave me a link by copying the image:

(this is the file "dglogo.gif" in the .zip archive) into the same directory as your web page and then pasting the following into your page.

    <a href="" target="_top">
    <img src="dglogo.gif"
          width=88 height=31 border=0></a>

It will put a little button on your page that will link through to my Java Spigots page.

It is only a request: feel free to omit it.

Additional Usage Notes

There are additional notes available for this applet at The Lake Applet: Notes

Transferring files

Remember that if you are transferring the .class file to another machine with FTP, you should set the 'binary' mode on. Failure to do so will corrupt the file and give rise to a "Class Format" error.

Contacting Me

If you still have trouble getting the applet to work and you have tried all of the possible solutions listed above, then feel to contact me, remembering to include:

  1. A precise description of the problem (do you just get a grey rectangle, or an error message etc. etc.)

  2. The URL of the page containing the applet (that's the actual page - not just the front page on your site)

These two pieces of information will make it a lot easier for me to solve the problem. I cannot guarantee that I will be able to respond to all messages (there's only so many hours in the day...) but sending the URL of a page that doesn't work will greatly increase the chances of getting an answer.

Remember to keep a look out at my web site for new applets.

David Griffiths,


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Last updated: Thursday 17 May 2001