[OpenMap Users] How to use the BufferedMapBean

From: Tim Schreiner <tjs_at_ll.mit.edu>
Date: Wed, 26 Sep 2007 15:54:24 -0400


I've got a .shp file layer in my OpenMap application and have replaced the
default PanMouseMode class with one that basically allows the map to be
dragged around in real time. (my mousedragged implementation calculates a
new map center based on the new mouse position and calls

When I use the standard MapBean and do the dragging, the .shp layer is
simple enough that it can be drawn quickly and everything looks good.
Except! There is this annoying flashing.

Traditional graphics systems, ala OpenGL, support the notion of double
buffering to address this very problem.

I noticed a BufferedMapBean and the documentation seem to advertise this
does the buffering I want.

I tried it, and unfortunately, it behaves rather badly, leaving behind
copies of the last position of the shape file all over the screen.

Has anyone successfully use the BufferedMapBean in a mouseDrag operation as
I have described? Isn't this the situation you would normally use this

Does this BufferedMapBean actually support 2 Images, rendering the "current"
image in the back buffer and then flipping the back for the front as I would
expect such a buffering scheme to do?


-----Original Message-----
From: Tim Schreiner [mailto:tjs_at_ll.mit.edu]
Sent: Wednesday, September 26, 2007 10:09 AM
To: 'Don Dietrick'
Cc: 'openmap-users_at_bbn.com'
Subject: RE: [OpenMap Users] How to see RpfCoverage


I assume this is the RPF "coverage" property.
I don't see the coverage(s) when I zoom way out. How come?


-----Original Message-----
From: owner-openmap-users_at_bbn.com [mailto:owner-openmap-users_at_bbn.com] On
Behalf Of Don Dietrick
Sent: Thursday, September 20, 2007 12:51 PM
To: Tim Schreiner
Cc: openmap-users_at_bbn.com
Subject: Re: [OpenMap Users] How to see RpfCoverage

Hi Tim,

The RpfCoverage object is built into the layer. You turn it with a
checkbox on via the layer's palette.

- Don

On Sep 20, 2007, at 12:28 PM, Tim Schreiner wrote:

> I have some rpf data that I can view quite nicely when I'm zoomed
> in on the data. It's a CIB data file. When I zoom way out on the
> entire globe, I'd like to draw some form of outline of the coverage
> on my map. I tried using RpfCoverage to do this, feeding it my rpf
> layer, but I don't see anything on the map. What do I need to do to
> see the RpfCoverage data?
> Currently I am doing this, in my drawing code:
> . /// if s_Layers[i] is a RpfLayer
> RpfCoverage r = new RpfCoverage(s_Layers[i]);
> r.allCoveragesOn();
> r.generate(this.getProjection());
> r.paint(this.getGraphics());
> Tim

Don Dietrick, dietrick_at_bbn.com
BBN Technologies, Cambridge MA

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Received on Wed Sep 26 2007 - 15:55:25 EDT

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