Having some issues getting a png to flow out to a web page. I am trying to
use savefig( sys.stdout ), but I am getting an error. Well at least I can
show the error when I run the script from a command prompt.
I took most of the example from the matplotlib pdf file. I added a couple
print statements in order to get more feedback from the web server.
When run from the command prompt in Windows, My output looks like this:
hello world<br>
This is the second line.<br>
Traceback (most recent call last):
File "C:\www\app\webroot\cgi-bin\stdout.py", line 12, in <module>
savefig( sys.stdout )
File
"C:\Python25\lib\site-packages\matplotlib-0.91.2.0001-py2.5-win32.egg\matplo
tlib\pyplot.py", line 269, in savefig
return fig.savefig(*args, **kwargs)
File
"C:\Python25\lib\site-packages\matplotlib-0.91.2.0001-py2.5-win32.egg\matplo
tlib\figure.py", line 782, in savefig
self.canvas.print_figure(*args, **kwargs)
File
"C:\Python25\lib\site-packages\matplotlib-0.91.2.0001-py2.5-win32.egg\matplo
tlib\backend_bases.py", line 1195, in print_figure
**kwargs)
File
"C:\Python25\lib\site-packages\matplotlib-0.91.2.0001-py2.5-win32.egg\matplo
tlib\backends\backend_agg.py", line 397, in print_png
self.get_renderer()._renderer.write_png(str(filename),
self.figure.dpi.get())
RuntimeError: Could not open file <open file '<stdout>', mode 'w' at
0x00A0F068>
···
---
Here is some version info:
Windows XP Pro
Python 2.5.2
matplotlib-0.91.2.0001-py2.5-win32.egg
numpy-1.0.4.0002-py2.5-win32.egg
My entire script is listed below:
#!c:/Python25/python.exe -u
print
print "hello world<br>"
import sys
import matplotlib
# this is not supported across all backends , as of matplotlib -0.63
matplotlib.use('Agg')
from pylab import *
print "This is the second line.<br>"
plot ([1 ,2 ,3])
savefig( sys.stdout )
---
When I put this script in the cgi directory and refer to it in my URL, the
response only shows Hello World. The "This is the second line." never
displays. Seems that as soon as I import matplotlib I am not able to print
to stdout.
Any suggestions would be appreciated.
-Rodney