RE: [OpenMap Users] AreaShapeLayer and gradients

From: Graham, John <>
Date: Thu, 17 May 2007 13:26:03 -0400

 Thanks Don - this does help. I'll probably end up extending OMPoly as
you mentioned.
- John

-----Original Message-----
From: Don Dietrick []
Sent: Thursday, May 17, 2007 11:57 AM
To: Graham, John
Subject: Re: [OpenMap Users] AreaShapeLayer and gradients

Hi John,

The OMGraphics fill color is actually a fill Paint object, which you can
substitute a java.awt.GradientPaint object that should do what you want.
You'll have to write the code that sets the GradientPaint on the
OMGraphics with the blending you want - choosing the colors and the
point locations of where the the colors are located.

You'll have to set the fill paint after the OMGraphic has been generated
with the projection, so you know where the screen points are to give to
the GradientPaint. That leads me to think you might want to extend
OMPoly to do this for you - so that you can give it a set of colors and
lat/lon locations of neighbors and then override the
generate(Projection) method to figure those points out before setting
the GradiantPaint parameters.

Hope this helps,


On May 17, 2007, at 11:45 AM, Graham, John wrote:

> Hi,
> I am working on an application that uses AreaShapeLayer to display
> provinces in Afghanistan. I use the fillcolor property to fill each
> province with a specific color.
> No problem there. Now reference
> national/political_divisions/political_divisions_34.pdf
> Suppose the "Nimroz" province has a fillcolor of CC99FF and the
> "Hilmand" province has a fillcolor of CCFF33. Now suppose "Farah"
> province has a fillcolor of FFFF33.
> What I would like to do is be able to do a gradient color blend
> from one province to the other along the border. In other words,
> there is a blending of colors between adjacent provinces. For
> example, the fillcolor of Nimroz blends into Farah (the two colors mix

> in a gradual gradient blending along the border), and Nimroz blends
> into Hilmand and Farah, and so on. Each province would retain its
> primary fillcolor, but that color would gradually mix and blend into
> the adjacent province as you approach the province border. Note that
> PowerPoint allows you to do this manually this when you fill a polygon

> using a two-color "gradient".
> Any advice on how to approach this in OpenMap?
> Thanks,
> John

Don Dietrick,
BBN Technologies, Cambridge, MA

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Received on Thu May 17 2007 - 13:27:08 EDT

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