Pzy3d - 3d charts for Python

Build Jzy3d charts for Python.

Jzy3d is a java library that can be invoked multiple ways :

• Py4j binding : python initialize a Java Virtual Machine acting like a server. Python scripts then exchange informations with this server. See src/main/python/py4j-*.py
• Jython : your python program is interpreted inside a JVM. It can use Java objects. See src/main/jython/jython-*.py

Using Py4j

Py4j allows calling a Java Virtual Machine from Python. Py4j can call java methods and access java instance references.

Install using Pip

pip install pyzy3d

Run

from pyzy3d.pyzy3d import Pyzy3d
from pyzy3d.generator import Generator

pz = Pyzy3d()

# Generate data
n = 10000
coords = pz.new_coords(n)
Generator().scatter(coords, n)


# Drawable scatter
scatter = pz.new_scatter(coords)
scatter.setWidth(5.0)


# Chart
chart = pz.chart(0)
chart.getQuality().setSmoothPoint(True);
chart.add(scatter)
chart.open("Pyzy3d - Scatter", 800, 600)

pz.shutdown()

Will prompt

<img src="doc/example_scatter.png">

Console should show it started Py4j Gateway and connected successfully as follow:

Will start Pyzy3d Gateway : /Users/martin/Dev/jzy3d/public/pyzy3d/src/main/python/pyzy3d/bin/pyzy3d-1.0.1-SNAPSHOT.jar
Pyzy3d gateway invoked : /Users/martin/Dev/jzy3d/public/pyzy3d/src/main/python/pyzy3d/bin/pyzy3d-1.0.1-SNAPSHOT.jar
Joining Pyzy3d gateway ...
Pyzy3d gateway joined

and then show a scatter plot:

• Start a JVM using Pzy3d Jar file located in bin/
• Initialize a java Coord3ds to provide a java point cloud Reference
• Set coordinates and colors from python
• Open a Jzy3d chart

Run example plots

cd src/main/python # go to source folder if you are developing pyzy3d

python examples/example_scatter.py
python examples/example_surface.py

Surface example is interesting since it shows a way to define a <i>function</i> to render by the JVM gateway.

It will produce the below chart:

<img src="doc/example_surface.png"/>

Surface example is based on pyzy3d default Func3d

from numpy import *

class Func3d(object):
    def __init__(self, monitor=False):
        self.k = 0
        self.doMonitor = monitor

    def f(self, x, y):
        self.monitor()
        return cos(x) + sin(y)

    def monitor(self):
        ...

    class Java:
        implements = ['org.pyzy3d.PyFunc3d']

Last line states that Func3d implements the <a href="https://github.com/jzy3d/pyzy3d/blob/master/src/main/java/org/pyzy3d/PyFunc3d.java">PyFunc3d java interface</a>. Overriding Func3d.f(x,y) let the JVM ask to python which Z value should be generated for a given {X,Y} pair.

TODO

• shutdown callback server when caller as finished processing
• detect if gateway is up or no to guess if it should be started
• flag to state if it should remain up + how to reconnect to callback server

Help

• Kill a running instance of Py4j JavaGateway

lsof -n -i4TCP:25334 | grep LISTEN

Will show callback server process that <i>might</i> remain awake if Pyzy3d.shutdown() did not execute. Read process id and

kill [pid]

Packaging the Python library

Help

• https://python-packaging.readthedocs.io/en/latest/
• https://github.com/urbanairship/mvn-python-packaging/blob/master/pom.xml
• https://docs.python.org/3/distutils/setupscript.html#installing-additional-files
• https://blog.jetbrains.com/pycharm/2017/05/how-to-publish-your-package-on-pypi/

Build java gateway

mvn clean package
cp target/pyzy3d-1.0.1-SNAPSHOT.jar src/main/python/pyzy3d/bin/

The java gateway sources are <a href="https://github.com/jzy3d/pyzy3d/blob/master/src/main/java/org/pyzy3d/Pyzy3d.java">here</a>

Verify you can run the python tests

cd src/main/python
pytest -svv

Build python package

cd src/main/python
python setup.py sdist

Install pyzy3d with an alias so that updated source do not need re-install

pip install -e .

otherwise

pip install .

Deploy python package

Now register for test deployement

twine register dist/pyzy3d-1.0.1.tar.gz -r testpypi

https://testpypi.python.org/pypi/pyzy3d

Now deploy to test

twine upload dist/* -r testpypi

Using Jython

Install Jython

• Mac OS brew install jython
• Other google install jython

Run example plots

./run-jython-scatter.sh
./run-jython-surface.sh

Building Pyzy3d Jar Jython

Compile as follow

mvn clean package
cp target/pzy3d-api-1.0.1-SNAPSHOT.jar bin/

Using Pyzy3d with Jython

Jython requires path to be defined as follow jython -Dpython.path=bin/pzy3d-api-1.0.1-SNAPSHOT.jar src/main/jython/jython-surface.py

Using Pyzy3d with Py4j

Py4j requires gateway to be started with java -jar bin/pzy3d-api-1.0.1-SNAPSHOT.jar. Then run a script like python src/main/python/py4j-scatter.py