dynamic image demo: suggestions sought

Haven't had a chance to test your example yet but hopefully

    > I can take a look tomorrow. I haven't done much memory leak
    > testing against the _image module yet so this will be a good
    > opportunity. I very recently rewrote _image.cpp using cxx.
    > I trust you have a fresh CVS checkout?

Hi Andrew - found and fixed the memory leak. Can't really call it a
leak - more like a "memory gusher". This was in the agg (and image)
module "to string" methods. In my tests, the leak went from 600k per
frame to approx 600 bytes per frame, which is on par for what I see in
other agg memory leak tests.

I made a number of comments in your example to point out places where
you probably should be using matplotlib a little differently - most of
these I flagged with my initials so you can search for them. Modified
script is below.

After you get the script in the final form you want and purge the
comments and memory reporting stuff where appropriate, please add it
to CVS.

I liked the example so much I made an analogous one dynamic_image_gtk.
It's faster than wxagg (13FPS vs 4FPS on my system) which is not
surprising since gtkagg has extension code to transfer agg to the GUI
canvas, and doesn't flicker. Very nice! I would really like to get
that wxagg flicker problem figured out, and the extension code
added... Did I hear you volunteering to be the wxagg maintainer :-)?

#!/usr/bin/env python
"""
Copyright (C) 2003-2004 Jeremy O'Donoghue and others

License: This work is licensed under the PSF. A copy should be included
with this source code, and is also available at
http://www.python.org/psf/license.html

"""
import sys, time, os, gc

import matplotlib
matplotlib.use('WXAgg')

# jdh: you need to control Numeric vs numarray with numerix, otherwise
# matplotlib may be using numeric under the hood and while you are
# using numarray and this isn't efficient. Also, if you use
# numerix=numarray, it is important to compile matplotlib for numarray
# by setting NUMERIX = 'numarray' in setup.py before building
from matplotlib import rcParams
rcParams['numerix'] = 'numarray'

# jdh: you can import cm directly, you don't need to go via
# matplotlib.matlab
import matplotlib.cm as cm

from matplotlib.backends.backend_wxagg import Toolbar, FigureCanvasWxAgg

# jdh: you don't need a figure manager in the GUI - this class was
# designed for the matlab interface

from matplotlib.figure import Figure
import matplotlib.numerix as numerix
from wxPython.wx import *

TIMER_ID = wxNewId()

# jdh: use this function, or something similar, when reporting a
# memory leak
def report_memory(i):
    pid = os.getpid()
    a2 = os.popen('ps -p %d -o rss,sz' % pid).readlines()
    print i, ' ', a2[1],
    return int(a2[1].split()[0])

class PlotFigure(wxFrame):

    def __init__(self):
        wxFrame.__init__(self, None, -1, "Test embedded wxFigure")

        self.fig = Figure((5,4), 75)
        self.canvas = FigureCanvasWxAgg(self, -1, self.fig)
        self.toolbar = Toolbar(self.canvas)
        self.toolbar.Realize()

        # On Windows, default frame size behaviour is incorrect
        # you don't need this under Linux
        tw, th = self.toolbar.GetSizeTuple()
        fw, fh = self.canvas.GetSizeTuple()
        self.toolbar.SetSize(wxSize(fw, th))

        # Create a figure manager to manage things

        # Now put all into a sizer
        sizer = wxBoxSizer(wxVERTICAL)
        # This way of adding to sizer allows resizing
        sizer.Add(self.canvas, 1, wxLEFT|wxTOP|wxGROW)
        # Best to allow the toolbar to resize!
        sizer.Add(self.toolbar, 0, wxGROW)
        self.SetSizer(sizer)
        self.Fit()
        EVT_TIMER(self, TIMER_ID, self.onTimer)
        self.cnt = 0

    def init_plot_data(self):
        # jdh you can add a subplot directly from the fig rather than
        # the fig manager
        a = self.fig.add_subplot(111)
        self.x = numerix.arange(120.0)*2*numerix.pi/120.0
        self.x.resize((100,120))
        self.y = numerix.arange(100.0)*2*numerix.pi/100.0
        self.y.resize((120,100))
        self.y = numerix.transpose(self.y)
        z = numerix.sin(self.x) + numerix.cos(self.y)
        self.im = a.imshow( z, cmap=cm.jet)#, interpolation='nearest')

    def GetToolBar(self):
        # You will need to override GetToolBar if you are using an
        # unmanaged toolbar in your frame
        return self.toolbar
    
    def onTimer(self, evt):
        self.x += numerix.pi/15
        self.y += numerix.pi/20
        z = numerix.sin(self.x) + numerix.cos(self.y)
        self.im.set_array(z)
        self.canvas.draw()
        #self.canvas.gui_repaint() # jdh wxagg_draw calls this already

        val = report_memory(self.cnt)
        if self.cnt==1:
            self.start = val # skip cnt=0
            self.tstart = time.time()
        elif self.cnt==50:
            end = val
            print 'Average memory consumed per loop: %1.4f\n' % ((end-self.start)/float(self.cnt))
            print 'FPS', self.cnt/(time.time() - self.tstart)
            sys.exit()
            
        self.cnt += 1
        gc.collect()
        
    def onEraseBackground(self, evt):
        # this is supposed to prevent redraw flicker on some X servers...
        pass
        
if __name__ == '__main__':
    app = wxPySimpleApp()
    frame = PlotFigure()
    frame.init_plot_data()
    
    # Initialise the timer - wxPython requires this to be connected to the
    # receivicng event handler
    t = wxTimer(frame, TIMER_ID)
    t.Start(200)
    
    frame.Show()
    app.MainLoop()

Hi John,

  Today i finally got around to trying a suggestion
that you made on May 22...on how to put a legend on a Figure
(outside of the axis). So i hacked up the example
legendDemo.py to experiment with:

# Haked up legendDemp.py

# Thanks to Charles Twardy for this example
from matplotlib.matlab import *

a = arange(0,3,.02)
b = arange(0,3,.02)
c=exp(a)
d=c.tolist()
d.reverse()
d = array(d)

ax = subplot(111)
lines = plot(a,c,'k--',a,d,'k:',a,c+d,'k')
#legend(('Model length', 'Data length', 'Total message length'), 'upper
left')
fig = gcf()

line1 = lines[0]
line2 = lines[1]
line3 = lines[2]

fig.legend((line1, line2, line3),
           ('Model length', 'Data length', 'Total message length'),
           'upper left')

ax.set_ylim([-1,20])
ax.grid(0)
xlabel('Model complexity --->')
ylabel('Message length --->')
title('Minimum Message Length')
set(gca(), 'yticklabels', [])
set(gca(), 'xticklabels', [])

savefig('legend_demo_small', dpi=60)
savefig('legend_demo_large', dpi=120)

show()

# End of: Haked up legendDemp.py

I then go the following error:

clavius:/home/jbenson/python>python legendDemo.py
Traceback (most recent call last):
  File "legendDemo.py", line 22, in ?
    'upper left')
  File "/usr/local/lib/python2.3/site-packages/matplotlib/figure.py", line
179, in legend
    l = Legend(handles, labels, loc)
TypeError: __init__() takes exactly 5 arguments (4 given)
clavius:/home/jbenson/python>

Should that line 179 in figure.py be:

        l = Legend(self, handles, labels, loc) # -added ->self<- ?

Just for fun, i tried that change and re-ran:

clavius:/home/jbenson/python>python legendDemo.py
Traceback (most recent call last):
  File "legendDemo.py", line 22, in ?
    'upper left')
  File "/usr/local/lib/python2.3/site-packages/matplotlib/figure.py", line
179, in legend
    l = Legend(self, handles, labels, loc)
  File "/usr/local/lib/python2.3/site-packages/matplotlib/legend.py", line
107, in __init__
    self._texts = self._get_texts(labels, textleft, upper)
  File "/usr/local/lib/python2.3/site-packages/matplotlib/legend.py", line
215, in _get_texts
    HEIGHT = self._approx_text_height()
  File "/usr/local/lib/python2.3/site-packages/matplotlib/legend.py", line
126, in _approx_text_height
    return
self.FONTSIZE/72.0*self.figure.dpi.get()/self.parent.bbox.height()
AttributeError: 'NoneType' object has no attribute 'dpi'
clavius:/home/jbenson/python>

...so those errors look worse.

(i'm using matplotlib-0.54.2)

Any more hints?

Thanks,

Jim

John Hunter wrote:

"John" == John Hunter <jdhunter@...4...> writes:
           
   > Haven't had a chance to test your example yet but hopefully
   > I can take a look tomorrow. I haven't done much memory leak
   > testing against the _image module yet so this will be a good
   > opportunity. I very recently rewrote _image.cpp using cxx.
   > I trust you have a fresh CVS checkout?

Hi Andrew - found and fixed the memory leak. Can't really call it a
leak - more like a "memory gusher". This was in the agg (and image)

That makes a HUGE difference -- great!

I made a number of comments in your example to point out places where
you probably should be using matplotlib a little differently.

OK, I see I have a lot of learning to do! It's a lot cleaner now, but I left comments in for "common pitfalls to avoid when embedding in wx" enthusiasts.

Please add it to CVS.

Done.

I liked the example so much I made an analogous one dynamic_image_gtk.

Cool! The GTK demo is nice because of the simplicity allowed by not embedding in a foreign GUI, but mainly using the matplotlib interface.

It's faster than wxagg (13FPS vs 4FPS on my system) which is not
surprising since gtkagg has extension code to transfer agg to the GUI
canvas,

It's even less surprising given that the wxagg app is driven by a timer callback set to run at 5 FPS! :slight_smile:

and doesn't flicker. Very nice! I would really like to get
that wxagg flicker problem figured out, and the extension code
added... Did I hear you volunteering to be the wxagg maintainer :-)?

Well, I'll hopefully have a chance to poke around in wxagg once in a while, but "maintainer" may be a bit grandiose for my time availability in the forseeable futurue...

Cheers!
Andrew