Text rendering, derivatives, netCDF enhancements

VisAD will now render Text data.  You need to define a ScalarMap
from a TextType to Display.Text, just as you would map a RealType
to Display.XAxis, etc.  The signature of the ScalarMap constructor
has changed its first argument from RealType to ScalarType in
order to include TextTypes.  There is also a TextControl (that
you get from the ScalarMap by getControl() after the ScalarMap
has been added to a DisplayImpl via addMap).  The TextControl
lets you control the relative size of text, and whether it is
centered or to the right of the location defined by whatever
you map to XAxis, YAxis, etc.  There is a Font in TextControl
but it is currently unused - the font is just VisAD's own vector
font (all alpha characters are rendered in upper case).  Cases
44 and 45 of examples/DisplayTest.java illustrate the use of
Display.Text and TextControl.  Note that Text data cannot be
used in FlatFields, so these test cases construct FieldImpls.
VisAD now implements a general derivative method for Function.
This is the partial derivative with respect to any RealType in
the Function's domain RealTupleType, or in the reference
RealTupleType of the domain CoordinateSystem.  This effort
includes new signatures for the binary and unary methods of Data
that allow applications to control the MathType of results, as
well as fixes to the existing signatures of binary and unary for
cases when the operation changes the Units of results.
It looks like the most common way to get data into VisAD is via
netCDF files.  A considerable increase in the speed of reading
netCDF files is in the works, as well as very useful changes to
the MathTypes produced by the netCDF Plain adapter.
We expect to announce the VisAD Spread Sheet next week, although
it has been available for some time in the visad.ss package.  It
provides a way to use VisAD without any programming.
Bill Hibbard, SSEC, 1225 W. Dayton St., Madison, WI  53706
whibbard@xxxxxxxxxxxxx  608-263-4427  fax: 608-263-6738
"kill cross-platform Java by growing the polluted Java market"
   - from an internal Microsoft planning document