[Matplotlib-users] Autonomous display of image/plot/figure

[James K. G. <jk...@sa...>]

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I'm not sure if this is the right venue for this question.  I've searched the 
archives, but without success so far.  If this is covered there (or elsewhere 
on the web), I'd apprciate a pointer to it so it doesn't duplicate bandwidth 
here.  

Anyway, what I'd like to do is have a python script which reads data from a 
file, displays an image/plot/whatever made from the data, and then exits, 
keeping the image displayed.  

I'm running Fedora 8, python 2.5.1, and matplotlib 0.91.2-1.fc8 from the yum 
repository.   Backend is set to GTKAgg in my matplotlibrc file.  

My initial attempt used the "double fork" method from the python cookbook:

- -------------Code follows----------------------
  if __name__ == "__main__":

  #From Python Cookbook
  try:
    pid = os.fork()
    if pid > 0:
      # Exit first parent
      sys.exit(0)
  except OSError, e:
    print >>sys.stderr, "fork #1 failed: %d (%s)" %(e.errno, e.strerror)
    sys.exit(1)

  # Decouple from parent environment
  #os.chdir("/")
  os.setsid()
  os.umask(0)

  # Do second fork
  try:
    pid = os.fork()
    if pid > 0:
      # Exit from second parent; print eventual PID before exiting
      print "Image PID %d" % pid
      sys.exit(0)
  except OSError, e:
    print >>sys.stderr, "fork #2 failed:  %d (%s)"%(e.errno, e.strerror)
    sys.exit(1)

  # Start the main loop to display image
  main()
  
- --------------END CODE--------------------------------------

The main() function reads the values appropriately into the variable "myarr",
and then calls imshow and show:

- ------------ Code follows -------------------
       :
       :
  pylab.imshow(myarr)
  pylab.show()
- --------------END CODE--------------------------------------

. . . and then exits.  

All works well until I try to kill the figure/image  by clicking on the X in 
the upper-right corner.   It disappears alright, but the process remains 
running, and I have to manually kill it with the kill -SIGTERM <pid> command.

I'd like the process to die when I close the window.  

I'm really an application programmer, not a system programmer, and usually 
don't delve this deeply into process management, so I'm probably doing 
something extremely ignorant.  Help is appreciated.

Thanks!

  James

 
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