Another Alpha Question


Greetings,

I'm still struggling with the use of Alpha in a 2D display (TwoDDisplayRendererJ3D to be specific). I have a FlatField (lat,lon)->Alt in a 2D display. I then create a "wedge" shape using DelaunayCustom.fill and add the shape to the display while setting its alpha value to 0.5.

     ConstantMap[] pointMap = { new ConstantMap (0.0f, Display.Red),
                               new ConstantMap (0.0f, Display.Green),
                               new ConstantMap (0.0f, Display.Blue),
                               new ConstantMap (0.5f, Display.Alpha),
                               new ConstantMap (4.0f, Display.PointSize) };


    DataReferenceImpl widthRef = new DataReferenceImpl("widthRef");
    display.addReference(widthRef, pointMap);
    widthRef.setData(widthSet);

The wedge is not transparent to the displayed data "below" it.  Please see:

http://www.cimms.ou.edu/~kmanross/VCPRPE/VisADSamples/VisADAlphaIssue.gif


The only thing that changing the value for Display.Alpha does it change the color of the wedge from black (0.0) to white (1.0).

I am hoping for the wedge to behave like the transparent radar echoes do in Don Murray's 1st two examples:

http://www.unidata.ucar.edu/staff/donm/radar_pics.html

where you can see the state boundaries below the radar echo.

Also, If I translate the displayed image (left click drag) to the upper left corner, it covers up the cursor readout when the middle button is clicked. Is there a way that I can ensure that readout remains visible when data is displayed in that region of the window?

Many thanks!!

-kevin.



--
+------------------------------------------------------------+
Kevin L. Manross        [KD5MYD] <><          (405)-366-0557
CIMMS Research Associate               kevin.manross@xxxxxxxx
[NSSL-WRDD/SWATN]           http://www.cimms.ou.edu/~kmanross

"My opinions are my own and not representative of CIMMS, NSSL,
 NOAA or any affiliates"
+------------------------------------------------------------+