Python GUI from Java

Question

I am working on a program which takes a user input and generates an output as a map projection plot. The easiest map projection library that I have found is matplotlib-basemap, written in python a language I am not much familier with (I work on Java ).I have written the user interface in Java. Currently I am executing the python code and sending command arrays with data using Runtime and exec() command calling the ".py" file. This exectues the command and shows the plot as a separate window.

My Question is this: Is it possible to embed this basemap (Interactive with Zoom features) on a Jpanel? Or on a python GUI which can then be embedded on a JPanel? I know I can save the image generated by matplotlib as a file which can be fixed on a panel, but then it won't be interactive, The Zoom features won't be available then. Or is using a Java based tool rather than basemap is more appropriate?(I haven't found any as good)

----Edit on 22nd May 2013------

Jython is not a solution as matplotlib is incompatible with it. Doing the whole thing in python I agree will be optimum but this is what I have to work with.

JACOB Jar: I wasn't able to find an example code showing how to embed a seperate application(basemap) on a JPanel or JFrame.

Currently I am planning on embedding the basemap into a wxpython GUI and then use sockets to communicate between the two languages.

TCP/IP Socket with Server Java and Client Python.

Answer 1

This is if you're open to new ideas and learning new things.
It's not a solution on your specific problem that you want to join two languages, this is a replacement for that idea to incorporate everything in Python.

#!/usr/bin/python
import pyglet
from time import time, sleep

class Window(pyglet.window.Window):
    def __init__(self):
        super(Window, self).__init__(vsync = False)
        self.alive = 1

        self.click = None
        self.drag = False

        with open('map.png', 'rb') as fh:
            self.geodata_image = pyglet.image.load('map.png', file=fh)
            self.geo_info = self.geodata_image.width, self.geodata_image.height

    def on_draw(self):
        self.render()

    def on_mouse_press(self, x, y, button, modifiers):
        self.click = x,y

    def on_mouse_drag(self, x, y, dx, dy, buttons, modifiers):
        if self.click:
            self.drag = True
            print 'Drag offset:',(dx,dy)

    def on_mouse_release(self, x, y, button, modifiers):
        if not self.drag and self.click:
            print 'You clicked here', self.click, 'Relese point:',(x,y)
            ## Do work on corindate
        else:
            print 'You draged from', self.click, 'to:',(x,y)
            ## Move or link two points, or w/e you want to do.
        self.click = None
        self.drag = False

    def render(self):
        self.clear()
        ## An alternative to only getting a region if you only want to show a specific part of
        ## the image:
        # subimage = self.geodata_image.get_region(0, 0, self.geo_info[0], self.geo_info[1])
        self.geodata_image.blit(0, 0, 0) # x, y, z from the bottom left corner
        self.flip()

    def on_close(self):
        self.alive = 0

    def run(self):
        while self.alive:
            self.render()

            ## self.dispatch_events() must be in the main loop
            ## or any loop that you want to "render" something
            ## Because it is what lets Pyglet continue with the next frame.
            event = self.dispatch_events()
            sleep(1.0/25) # 25FPS limit

win = Window()
win.run()

All you need is:

• Python2 (or 3)
• Pyglet

---

Python mockup of running as a submodule to Javav

import sys
for line in sys.stdin.readline():
    if line == 'plot':
        pass # create image here

For instance.

Answer 2

You can certainly embed your GUI in Jython, a Java implementation of Python. Unfortunately it doesn't support matplotlib, as it relies on native code. You could try and use execnet to invoke Python from Jython.