2D X-Y style plotter update

I have put in some update to my 2D X-Y style plotter at

http://www.geocities.com/qomo/visad/

major changes are 

1) now one can run the demo without recompiling.
With VisAD installed, just

java -cp "xy.jar;%CLASSPATH%" herschel.spire.qla.plot.Example

will do (in Windows). The source and compiled class files are
all in one jar file.

2) Functionality-wise I add in support so that one can modify
the primitive data array passed to the plotter and let the
plotter update the display accordingly. This is still a prototype
but quite useable now.

======= 00Readme.txt ========

This package is a quick and dirty prototype. It is an attempt to make
it easy for java programmers and end users to make X-Y style line
plot,
and to control the rendation of the plot, using VisAD.

To put it in plain terms, the plotter accepts multiple "plottable"
objects,
each of which can have multiple Y values and one set of X values. If
you
only have one set of X values, the plotter can directly accept the X
and
Y arrays without requiring you to make the plottable object first (it
makes an internal one for you).

1) To install:
You need to down load VisAD jar at
ftp://ftp.ssec.wisc.edu/pub/visad-2.0/visad.jar
Put the jar file on your local system if you don't have one
already, and put the file name with its full path in your CLASSPATH
environment variable.

See VisAD home page at  http://www.ssec.wisc.edu/~billh/visad.html
for more details on installation.

2)

If you don't want to compile the source files, see 3)

To compile, extract the source files from xy.jar by jar xvf xy.jar
then compile.

3)

a) Run the Example. It's a mini demo. 

If you compiled the source files, get the CLASSPATH setup then type

java herschel.spire.qla.plot.Example

If you don't compile the source files and only want to use the jar
file:
put the xy.jar with full path in your CLASSPATH, or type something
like

java -cp "xy.jar;%CLASSPATH%" herschel.spire.qla.plot.Example
in Windows or

java -cp "xy.jar:$CLASSPATH" herschel.spire.qla.plot.Example
in unix

Look at the screen after the window pops out and press <enter>
when it asks.

The source code of Example.java should give you some good ideas
how to use this package.

b) to play with plotting in Jython (or VisAD's Jython editor):

Put xy.jar in your CLASSPATH and type these in Jython
command line (I use ">>>" for the Jython prompt):

>>>from java.awt import Color
>>>from visad import *

first, if you don't have anything to plot, this plotter will make
some junk data
to plot for you, just for testing.

>>> p=PlotVisAD2D()

you can play with it: (see javeDoc of PlotVisAD2D for more options)
for example:

>>> p.setBackgroundColor(Color.yellow)

There are many more things (about 18 so far) you can set. you need to
look at the javaDocs for PlotControlVisAD2D.java .

You can plot some data with a one-liner

>>> p=PlotVisAD2D([0,1,3,4,6],[[4,2,2,3.5,0]],"foo",["bar"])

or a more relaxed

>>> x = [0,1,3,4,6]
>>> d0 = [4,2,2,3.5,0]
>>> d1 = [1,0,1,0,2]
>>> p=PlotVisAD2D(x,[d1, d2],"foo",["bar"],boxColor=Color.orange)

Note that after "bar" the name of the data set d1 is not given. "Y1"
is used.

If you see setXXX()/getXXX() method pairs in PlotControlVisAD2D.java,
you can use
xXX (lower case for the first letter) like how the above "boxColor"
is used when
the plot is constructed.

Of course you can also do like

>>> p.setBoxColor(Color.red)

after the plot is constructed.

To control the scale rendation, you need first to get the
ScaleControl for that
axis. 

At this point it's better to look at the source code of Example.java
to figure out. It's all quite simple, for example in Example.java
there are
these lines:

        ScaleControlVisAD2D sc1 = p2.getYScaleControl(0,0);
        ...
        sc1.setSnapToBox(false);

so in Jython you can, after making a plot called "p" above,

>>> sc1 = p.getYScaleControl(0,0)
>>> sc1.setSnapToBox(0);

the "0,0" in getYScaleControl() is for the "plottable" id, and the Y
id in that
plottable. They all count from 0. So "0,0" means get Y scaleControl
for the 
scale in the 0th plottable of the 0th Y data.

To control an individual data line (a pair of X and Y data set), you
get
the control of it e.g.

>>> lc = p.getLineControl(0,0)

then do something like

>>> lc.setLineWidth(2.0f)

Almost anything can be changed programtically (like in Example.java)
can be changed
in Jython.

4)  Note some part (e.g. the direct manipulation and plotting points
and lines at
the same time) haven't been implemented.

Maohai Huang
Dec 15, 2002



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