VisADders,
I'm back with another question on using VisADLineArray to make histogram
bars. In previous episodes (about a month back), with help from Bill, Tom
and Ugo, I've created a vertical bar, attached it to a vertical ScaleMap,
so that its length is determined by the variable on that axis. What I don't
understand is how this length is determined: if I have a little line (in
Jython)
# Idea from Ugo
pBarMap = ScalarMap(intensity, DisplayShape)
pBarScaleMap = ScalarMap(intensity, DisplayShapeScale)
pBars = VisADLineArray()
pBars.vertexCount = 2
x = 1.0
pBars.coordinates = [ 0.0, 0.0, 0.0, 0.0, x, 0.0]
pBarScaleMap.setRange(0.0, x/2.0) # Scale as recommended by Bill H.
I would expect that when this line is scaled, the first vertex should
remain unchanged at [0.0, 0.0, 0.0]. Instead, there appears to be some
vertical translation as well as scaling, so that the scaled lines no longer
begin at the horizontal axis, but instead float at a height related to the
intensity value to which they are mapped - they not only get bigger as the
intensity increases, they also "float" higher.
I'd would *really* appreciated any insight you guys can offer.
Thanks.
-Frank
PhD, Computational Biologist,
Harvard Medical School BCMP/SGM-322, 250 Longwood Ave, Boston MA 02115, USA.
Tel: 617-432-3555 Fax:
617-432-3557 http://llama.med.harvard.edu/~fgibbons
