Hi Dave,
Here's a test program I wrote up just to display a particle doing a random
walk. Jar files for the example are available at
http://dods.shore.mbari.org/brian/pub/. The classes are in test.jar; the source
is in test_src.jar. Run it from the command line as: java -cp
test.jar;visad.jar org.mbari.test.PointVis3
The PointVis3 example is fairly simple. I've taken a slightly different
approach when I need to add or remove DataReferences on the fly. To do that, I
subclass JPanel and add code to initialize the DisplayImpl, RealTypes and the
associated ScalarMaps and add the display to the Panel. Then I pass references
of the display and RealTypes to a DataHandler class that creates the gravy that
visad needs (tuples, functions, fields, etc), sets the data values, creates a
DataReferenceImpl, and adds the DataReference to the display. The DataHandler
class implements a listener interface, which would look something like:
public interface ISomeDataListener {
public void update(Point point);
}
The DataHandler's update method then looks something like:
public void update(Point point) throws RemoteException {
// Pop the new point in the top of the queue and drop the lastpoint
for (int i = points.length - 1; i > 0; i--) {
points[i] = points[i - 1];
}
points[0] = (Point) point.clone();
// Update the data on the display
try {
// the getXY method is illustrated below
pointsFf.setSamples(getXY()); // a FlatField
} catch (VisADException e) {
e.printStackTrace();
}
}
private float[][] getXY() {
float[][] tmp = new float[2][points.length];
for (int i = 0; i < points.length; i++) {
if (points[i] != null) {
tmp[0][i] = (float) points[i].getX();
tmp[1][i] = (float) points[i].getY();
} else {
tmp[0][i] = 0F;
tmp[1][i] = 0F;
}
}
return tmp;
}
The nice thing about this approach is that you can add and remove
DataReferences as needed and whenever you update the data in a FlatField (with
setSamples()) the display is updated.
Anyway, hope that helps.
Cheers
B
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Brian Schlining
Software Application Developer
Monterey Bay Aquarium Research Institute
brian@xxxxxxxxx
(831) 775-1855
http://www.mbari.org/~brian
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> -----Original Message-----
> From: David Homiak [mailto:dhomiak@xxxxxxxxxxxx]
> Sent: Wednesday, November 07, 2001 12:36 PM
> To: 'Schlining, Brian'
> Subject: RE: Setting Aspect Ratio while using autoscale
>
> Brian,
> I've been interested in visualizing real-time data (time --> value)
> in VisAD as well, but am unsure of the best approach to incrementally and
> efficiently add data to the Gridded1DdoubleSet (time) and FlatField
> (value)
> so that the DisplayImpl updates properly with each addition. Would you
> mind
> sharing the approach you've taken to handle this? Thanks much!
>
> Dave Homiak
> dhomiak@xxxxxxxxxxxx
>
> > -----Original Message-----
> > From: Schlining, Brian [SMTP:brian@xxxxxxxxx]
> > Sent: Wednesday, November 07, 2001 1:15 PM
> > To: 'visad-list@xxxxxxxxxxxxx'
> > Subject: Setting Aspect Ratio while using autoscale
> >
> > I've a display that's tracking the position of several objects
> continually
> > in real time. The display is set to autoscale (i.e
> > display.setAlwaysAutoScale(true)). My question is...Is there some way to
> > fix the Aspect Ratio of the display, so that 1 unit along the x-axis is
> > the same length as 1 unit along the y-axis, while using auto scaling?
> >
> > Cheers
> > B
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > Brian Schlining
> > Software Application Developer
> > Monterey Bay Aquarium Research Institute
> > brian@xxxxxxxxx
> > (831) 775-1855
> > http://www.mbari.org/~brian
> >
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
