The Ani(mation)S applet
Page 4 - Using overlays
4a. Simple overlays. In order to use overlays, you
must provide four pieces of information:
- The filename of the background image
- The labels for the overlaid fields
- The filename(s) for the overlay(s)
- The value of the color to use as transparent
In our example, we will use the previously shown images as the
overlays, and will put a satellite image up as the
background. The HTML for the applet looks like this:
<![CDATA[
<PARAM name="controls" value="overlay">
<PARAM name="overlay_labels" value="map,temperature,stream lines">
<PARAM name="overlay_filenames" value="TMAP.GIF, TSFC1.GIF, TSTR1.GIF">
<PARAM name="filenames" value="TIR1.GIF">
<PARAM name=transparency value="x00000000">
]]>
4b. Now let's animate the background. You need only add more
filenames>
<![CDATA[
<PARAM name="filenames" value="TIR1.GIF, TIR2.GIF, TIR3.GIF, TIR4.GIF">
]]>
In this case, we will also specify that the first overlay is an
animation, but the second and third are not. This is done
by using an ampersand between filenames that are to appear on
each frame:
<![CDATA[
<PARAM name="overlay_filenames" value="TSFC1.GIF & TSFC2.GIF
& TSFC3.GIF & TSFC4.GIF, TSTR1.GIF, TMAP.GIF">
]]>
Of course, we also should add some controls for the animation
(although this is not necessary):
<![CDATA[
<PARAM name="controls" value="startstop, overlay">
]]>
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If you would like more information, or have questions or
suggestions, please contact Tom Whittaker