Re: [OpenMap Users] psuedo animation (changing layers that are cached raster images on a timer)

From: Don Dietrick <>
Date: Thu, 15 Jul 2004 16:47:28 -0700

Hi Ben,

On Jul 13, 2004, at 7:12 PM, Ben Podoll wrote:

> I have a custom app that has a time slider at the bottom of and then a
> bunch of icons to turn on and off layers. It is coming along nicely,
> but...
> The first question (which may be very simple) is how to get the icons
> to turn on and off layers; I can't seem to find what the menu options
> under layers execute. (Forgive me if that is too simple of a question,
> a point in the right direction would help greatly)

Your buttons should tell the LayerHandler to turn a layer on or off.
It will fire events to all other LayerListeners so they can accurately
display whether a layer is visible or not. If you are using toggle
buttons, they should be LayerListeners to the LayerHandler, and set
whether they are activated based on LayerEvents from the LayerHandler
(instead of toggling their states themselves).

> The second question is, how hard (and do you know of an easy way to do
> this) will it be to get my time slider to animate layers on the map?
> It doesn't have to be true animation I just need a way to step thru
> the images.

That is true animation. :)

> For instance I have a radar layer that I wrote to grab raster images
> and display them, so I am planning on keeping track of those images
> and then with the time line just stepping thru the list of the radar
> images and having OpenMap redraw them (now my question is: would I go
> about doing that by adding my layer to the map like normal and then
> via the external widgets control the layer by changing it's data and
> calling it's repaint?)

The com.bbn.openmap.graphicLoader.scenario.ScenarioGraphicLoader does
something like this. But yes, you'd do exactly what you think you
should do.

- Don

Don Dietrick,
BBN Technologies, Cambridge, MA

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Received on Thu Jul 15 2004 - 19:47:56 EDT

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