matplotlib-users Mailing List for matplotlib

Some more info. I'm running a 1.8Ghz PIV laptop with windows XP
professional. Not sure if speed of machine has anything todo with it. The
repaints cause flicker on the window, and then after a while the messages
appear.
-----Original Message-----
From: Schalkwyk, Johan 
Sent: Tuesday, June 29, 2004 11:25 AM
To: 'John Hunter'; Schalkwyk, Johan
Cc: mat...@li...
Subject: RE: [Matplotlib-users] Assertion triggered in wxMemory DC
With the attached example code you sent me I get the following messages
after some time. It seems to be caught in some form of endless loop, just
scrolling the messages over and over.
Also thank you for the example. I can simply my app code much more now.
Where can I find the src distribution. I probably did not look properly on
the web site.
Johan
line 570, in new_gc
 self.gc = GraphicsContextWx(self.bitmap, self)
 File
"c:\Tools\Python23\lib\site-packages\matplotlib\backends\backend_wx.py",
line 682, in __init__
 self.SelectObject(bitmap)
 File "C:\Tools\Python23\Lib\site-packages\wx\gdi.py", line 3017, in
SelectObje
ct
 return _gdi.MemoryDC_SelectObject(*args, **kwargs)
wx.core.PyAssertionError: C++ assertion "wxAssertFailure" failed in
..\..\src\ms
w\dcmemory.cpp(133): Couldn't select a bitmap into wxMemoryDC
Traceback (most recent call last):
 File "mattest2.py", line 42, in OnPaint
 self.canvas.draw()
 File
"c:\Tools\Python23\lib\site-packages\matplotlib\backends\backend_wx.py",
line 921, in draw
 self.figure.draw(self.renderer)
 File "c:\Tools\Python23\lib\site-packages\matplotlib\figure.py", line 132,
in
draw
 if self.frameon: self._figurePatch.draw(renderer)
 File "C:\Tools\Python23\Lib\site-packages\matplotlib\patches.py", line 54,
in
draw
 gc = renderer.new_gc()
 File
"c:\Tools\Python23\lib\site-packages\matplotlib\backends\backend_wx.py",
line 570, in new_gc
-----Original Message-----
From: John Hunter [mailto:jdh...@ac...] 
Sent: Tuesday, June 29, 2004 10:47 AM
To: Schalkwyk, Johan
Cc: mat...@li...
Subject: Re: [Matplotlib-users] Assertion triggered in wxMemory DC
>>>>> "Schalkwyk," == Schalkwyk, Johan <Joh...@sc...>
writes:
 Schalkwyk,> Thank you for the help I removed the show() command
 Schalkwyk,> from the loop. Now just calling grid(True) multiple
 Schalkwyk,> times. On my machine I narrowed the loop to 57 and it
 Schalkwyk,> started happening. At 50 it did not.
Perhaps I didn't make myself clear. The way you are using matplotlib
does not make sense. matplotlib has two modes: a "matlab interface"
and an embedded interface. You should not embed the matlab interface
directly into a GUI. The matlab interface does a lot of stuff under
the hood, like creating and managing figures and figure windows,
managing redraws, etc. When you create your own figure window outside
this framework, and then try to use the framework, the result is
undefined. If you are using matplotlib in a GUI, *do not import
matplotlib.matlab*. You need to follow the example of
embedding_in_wx2.py.
Below is your example translated to the GUI interface - on my system,
calling grid until the sun sets presents no problems, and it really
couldn't because all it does is set a boolean. In the matlab
interface, if you have interactive: True in your rc file, calling grid
does a lot more, including repainting the figure. Try running this
example, shaking it, resizing it, etc... and see if you can crash it;
I was unable to cause any problems.
If you have trouble, please let me know, but also consider trying
replacing wx for wxagg, which uses antigrain for drawing and is
probably more stable than wx, which does occasionally show dc related
errors.
By the way, there was an error in your legend code
You had
 legend('line', blahblah)
and you need
 legend( ('line',), blahblah)
That is, legend expects a list or tuple of strings, not a string.
 Schalkwyk,> By the way Kudos for matplotlib. Amazing. I had to dig
 Schalkwyk,> around the code and news groups to figure out how to
 Schalkwyk,> find the user coordinates of a mouse click. Reading
 Schalkwyk,> the code opens your eyes the wonderful design that is
 Schalkwyk,> backend dependent.
Thanks. Do you have the src distribution? There is an example in the
examples directory examples/coords_demo.py (works with Tk, GTK and WX)
that shows you how to get the mouse click coordinates. The examples
dir is your first line of defense when you want to figure out
something new. Unfortunately, I forgot to upload the zip file with
the 0.54.2 release, so look here
 http://matplotlib.sf.net/examples
Here's the example:
#!/usr/bin/env python
"""
An example of how to use wx or wxagg in an application w/o the toolbar
"""
from matplotlib.numerix import arange, sin, pi
import matplotlib
matplotlib.use('WX')
from matplotlib.backends.backend_wx import FigureCanvasWx as FigureCanvas
from matplotlib.figure import Figure
from wxPython.wx import *
class CanvasFrame(wxFrame):
 
 def __init__(self):
 wxFrame.__init__(self,None,-1,
 'CanvasFrame',size=(550,350))
 self.SetBackgroundColour(wxNamedColor("WHITE"))
 self.figure = Figure(figsize=(5,4), dpi=100)
 self.ax = self.figure.add_subplot(111)
 t = arange(0.0, 2.0, 0.01)
 s = sin(2*pi*t)
 l = self.ax.plot(t, s, linewidth=1.0)
 self.ax.set_xlabel('time (s)')
 self.ax.set_ylabel('voltage (mV)')
 self.ax.set_title('About as simple as it gets, folks')
 self.ax.legend(('line',), loc='upper right')
 for i in range(100):
 self.ax.grid(True)
 self.canvas = FigureCanvas(self, -1, self.figure)
 self.sizer = wxBoxSizer(wxVERTICAL)
 self.sizer.Add(self.canvas, 1, wxTOP | wxLEFT | wxEXPAND)
 # Capture the paint message 
 EVT_PAINT(self, self.OnPaint) 
 def OnPaint(self, event):
 self.canvas.draw()
 
class App(wxApp):
 
 def OnInit(self):
 'Create the main window and insert the custom frame'
 frame = CanvasFrame()
 frame.Show(true)
 return true
app = App(0)
app.MainLoop()

With the attached example code you sent me I get the following messages
after some time. It seems to be caught in some form of endless loop, just
scrolling the messages over and over.
Also thank you for the example. I can simply my app code much more now.
Where can I find the src distribution. I probably did not look properly on
the web site.
Johan
line 570, in new_gc
 self.gc = GraphicsContextWx(self.bitmap, self)
 File
"c:\Tools\Python23\lib\site-packages\matplotlib\backends\backend_wx.py",
line 682, in __init__
 self.SelectObject(bitmap)
 File "C:\Tools\Python23\Lib\site-packages\wx\gdi.py", line 3017, in
SelectObje
ct
 return _gdi.MemoryDC_SelectObject(*args, **kwargs)
wx.core.PyAssertionError: C++ assertion "wxAssertFailure" failed in
..\..\src\ms
w\dcmemory.cpp(133): Couldn't select a bitmap into wxMemoryDC
Traceback (most recent call last):
 File "mattest2.py", line 42, in OnPaint
 self.canvas.draw()
 File
"c:\Tools\Python23\lib\site-packages\matplotlib\backends\backend_wx.py",
line 921, in draw
 self.figure.draw(self.renderer)
 File "c:\Tools\Python23\lib\site-packages\matplotlib\figure.py", line 132,
in
draw
 if self.frameon: self._figurePatch.draw(renderer)
 File "C:\Tools\Python23\Lib\site-packages\matplotlib\patches.py", line 54,
in
draw
 gc = renderer.new_gc()
 File
"c:\Tools\Python23\lib\site-packages\matplotlib\backends\backend_wx.py",
line 570, in new_gc
-----Original Message-----
From: John Hunter [mailto:jdh...@ac...] 
Sent: Tuesday, June 29, 2004 10:47 AM
To: Schalkwyk, Johan
Cc: mat...@li...
Subject: Re: [Matplotlib-users] Assertion triggered in wxMemory DC
>>>>> "Schalkwyk," == Schalkwyk, Johan <Joh...@sc...>
writes:
 Schalkwyk,> Thank you for the help I removed the show() command
 Schalkwyk,> from the loop. Now just calling grid(True) multiple
 Schalkwyk,> times. On my machine I narrowed the loop to 57 and it
 Schalkwyk,> started happening. At 50 it did not.
Perhaps I didn't make myself clear. The way you are using matplotlib
does not make sense. matplotlib has two modes: a "matlab interface"
and an embedded interface. You should not embed the matlab interface
directly into a GUI. The matlab interface does a lot of stuff under
the hood, like creating and managing figures and figure windows,
managing redraws, etc. When you create your own figure window outside
this framework, and then try to use the framework, the result is
undefined. If you are using matplotlib in a GUI, *do not import
matplotlib.matlab*. You need to follow the example of
embedding_in_wx2.py.
Below is your example translated to the GUI interface - on my system,
calling grid until the sun sets presents no problems, and it really
couldn't because all it does is set a boolean. In the matlab
interface, if you have interactive: True in your rc file, calling grid
does a lot more, including repainting the figure. Try running this
example, shaking it, resizing it, etc... and see if you can crash it;
I was unable to cause any problems.
If you have trouble, please let me know, but also consider trying
replacing wx for wxagg, which uses antigrain for drawing and is
probably more stable than wx, which does occasionally show dc related
errors.
By the way, there was an error in your legend code
You had
 legend('line', blahblah)
and you need
 legend( ('line',), blahblah)
That is, legend expects a list or tuple of strings, not a string.
 Schalkwyk,> By the way Kudos for matplotlib. Amazing. I had to dig
 Schalkwyk,> around the code and news groups to figure out how to
 Schalkwyk,> find the user coordinates of a mouse click. Reading
 Schalkwyk,> the code opens your eyes the wonderful design that is
 Schalkwyk,> backend dependent.
Thanks. Do you have the src distribution? There is an example in the
examples directory examples/coords_demo.py (works with Tk, GTK and WX)
that shows you how to get the mouse click coordinates. The examples
dir is your first line of defense when you want to figure out
something new. Unfortunately, I forgot to upload the zip file with
the 0.54.2 release, so look here
 http://matplotlib.sf.net/examples
Here's the example:
#!/usr/bin/env python
"""
An example of how to use wx or wxagg in an application w/o the toolbar
"""
from matplotlib.numerix import arange, sin, pi
import matplotlib
matplotlib.use('WX')
from matplotlib.backends.backend_wx import FigureCanvasWx as FigureCanvas
from matplotlib.figure import Figure
from wxPython.wx import *
class CanvasFrame(wxFrame):
 
 def __init__(self):
 wxFrame.__init__(self,None,-1,
 'CanvasFrame',size=(550,350))
 self.SetBackgroundColour(wxNamedColor("WHITE"))
 self.figure = Figure(figsize=(5,4), dpi=100)
 self.ax = self.figure.add_subplot(111)
 t = arange(0.0, 2.0, 0.01)
 s = sin(2*pi*t)
 l = self.ax.plot(t, s, linewidth=1.0)
 self.ax.set_xlabel('time (s)')
 self.ax.set_ylabel('voltage (mV)')
 self.ax.set_title('About as simple as it gets, folks')
 self.ax.legend(('line',), loc='upper right')
 for i in range(100):
 self.ax.grid(True)
 self.canvas = FigureCanvas(self, -1, self.figure)
 self.sizer = wxBoxSizer(wxVERTICAL)
 self.sizer.Add(self.canvas, 1, wxTOP | wxLEFT | wxEXPAND)
 # Capture the paint message 
 EVT_PAINT(self, self.OnPaint) 
 def OnPaint(self, event):
 self.canvas.draw()
 
class App(wxApp):
 
 def OnInit(self):
 'Create the main window and insert the custom frame'
 frame = CanvasFrame()
 frame.Show(true)
 return true
app = App(0)
app.MainLoop()

The example I created was the smallest sample code I could make to reproduce
the problem. 
The code below is more true to my application. It does not use the matlab
interface. It does however mimick the matlab interface. I did not have the
src distribution so I created this from reading the code. Note the main
frame calls the draw command on the canvas (MatlabFigure) 100 times. This
triggers the problem as well.
I'll take a look at the source distribution.
Thank you for the help
Johan
import wx
import matplotlib
import numarray
matplotlib.use('WX')
from matplotlib.figure import Figure
from matplotlib.backends.backend_wx import FigureCanvasWx
from matplotlib.backend_bases import FigureManagerBase, error_msg
from matplotlib.axes import Axes
from matplotlib.cbook import flatten, is_string_like, exception_to_str
import matplotlib.mlab as mlab
#---------------------------------------------------------------------------
class MatlabFigure(FigureCanvasWx):
 def __init__(self, parent):
 self.fig = Figure()
 FigureCanvasWx.__init__(self, parent, -1, self.fig)
 
 self.figmgr = FigureManagerBase(self, 0)
 self.gca = self.figmgr.get_current_axis()
 # end def
 def GetXY(self, event):
 screenPos= numarray.array( event.GetPosition())
 ymin, height = self.fig.bbox.intervaly().get_bounds()
 x, y = screenPos[0], height-screenPos[1]
 if self.gca.in_axes(x, y):
 xy = self.gca.transData.inverse_xy_tup((x, y))
 return xy
 else:
 return None
 # end if
 # end def
 
 def axis(self, *v):
 if len(v)==1 and is_string_like(v[0]):
 s = v[0]
 if s.lower()=='on': self.gca.set_axis_on()
 elif s.lower()=='off': self.gca.set_axis_off()
 else:
 error_msg('Unrecognized string %s to axis; try on or off' %
s)
 return
 # end if
 
 try: v[0]
 except IndexError:
 xlim = self.gca.get_xlim()
 ylim = self.gca.get_ylim()
 return [xlim[0], xlim[1], ylim[0], ylim[1]]
 # end except
 
 v = v[0]
 if len(v) != 4:
 error_msg('v must contain [xmin xmax ymin ymax]')
 return
 # end if
 self.gca.set_xlim([v[0], v[1]])
 self.gca.set_ylim([v[2], v[3]])
 # end def
 def axes(self, *args, **kwargs):
 nargs = len(args)
 if len(args)==0: return subplot(111, **kwargs)
 if nargs>1:
 error_msg('Only one non keyword arg to axes allowed')
 return
 # end if
 
 arg = args[0]
 if isinstance(arg, Axes):
 self.figmgr.set_current_axes(arg)
 ret = arg
 else:
 rect = arg
 ret = self.figmgr.add_axes(rect, **kwargs)
 # end if
 return ret
 # end def
 def bar(self, *args, **kwargs):
 try: patches = self.gca.bar(*args, **kwargs)
 except Exception, msg:
 s = exception_to_str(msg)
 error_msg(s)
 raise RuntimeError(msg)
 # end except
 return patches
 # end def
 def cla(self):
 self.gca.cla()
 # end def
 def clf(self):
 self.figmgr.clf()
 # end def
 def errorbar(self, x, y, yerr=None, xerr=None, fmt='b-', ecolor='k',
capsize=3):
 try: ret = self.gca.errorbar(x, y, yerr, xerr, fmt, ecolor,
capsize)
 except ValueError, msg:
 msg = raise_msg_to_str(msg)
 error_msg(msg)
 else:
 return ret
 # end try
 # end def
 def figlegend(self, handles, labels, loc):
 l = self.legend(handles, labels, loc)
 return l
 # end def
 def fill(self, *args, **kwargs):
 try: patch = self.gca.fill(*args, **kwargs)
 except Exception, msg:
 s = exception_to_str(msg)
 error_msg(s)
 raise RuntimeError('Could not exectute fill')
 # end except
 return patch
 # end def
 def grid(self, b):
 self.gca.grid(b)
 # end def
 def hist(self, x, bins=10, noplot=0, normed=0, bottom=0):
 if noplot: return mlab.hist(x, bins, normed)
 else:
 try:
 ret = self.gca.hist(x, bins, normed, bottom)
 except ValueError, msg:
 msg = raise_msg_to_str(msg)
 error_msg(msg)
 raise RuntimeError, msg
 return ret
 # end if
 # end def
 def legend(self, *args, **kwargs):
 ret = self.gca.legend(*args, **kwargs)
 return ret
 # end def
 
 def plot(self, *args, **kwargs):
 try: lines = self.gca.plot(*args, **kwargs)
 except ValueError, msg:
 msg = raise_msg_to_str(msg)
 error_msg(msg)
 return lines
 # end def
 def savefig(self, *args, **kwargs):
 for key in ('dpi', 'facecolor', 'edgecolor'):
 if not kwargs.has_key(key):
 kwargs[key] = rcParams['savefig.%s'%key]
 self.print_figure(*args, **kwargs)
 # end def
 def scatter(self, *args, **kwargs):
 try: patches = self.gca.scatter(*args, **kwargs)
 except ValueError, msg:
 msg = raise_msg_to_str(msg)
 error_msg(msg)
 raise RuntimeError, msg
 return patches
 # end def
 def scatter_classic(self, *args, **kwargs):
 try: patches = self.gca.scatter_classic(*args, **kwargs)
 except ValueError, msg:
 msg = raise_msg_to_str(msg)
 error_msg(msg)
 raise RuntimeError, msg
 return patches
 # end def
 def stem(self, *args, **kwargs):
 try: ret = self.gca.stem(*args, **kwargs)
 except ValueError, msg:
 msg = raise_msg_to_str(msg)
 error_msg(msg)
 else:
 return ret
 # end def
 def subplot(self, *args, **kwargs):
 try:
 self.figmgr.add_subplot(*args, **kwargs)
 self.gca = self.figmgr.get_current_axis()
 except ValueError, msg:
 msg = raise_msg_to_str(msg)
 error_msg(msg)
 raise RuntimeError, msg
 return self.gca
 # end def
 def text(self, x, y, label, fontdict=None, **kwargs):
 t = self.gca.text(x, y, label, fontdict, **kwargs)
 return t
 # end def
 def title(self, s, *args, **kwargs):
 l = self.gca.set_title(s, *args, **kwargs)
 return l
 # end def
 def vlines(self, *args, **kwargs): 
 try: lines = self.gca.vlines(*args, **kwargs)
 except ValueError, msg:
 msg = raise_msg_to_str(msg)
 error_msg(msg)
 raise RuntimeError, msg
 return lines
 # end def
 def xlabel(self, s, *args, **kwargs):
 l = self.gca.set_xlabel(s, *args, **kwargs)
 return l
 # end def
 def ylabel(self, s, *args, **kwargs):
 l = self.gca.set_ylabel(s, *args, **kwargs)
 return l
 # end def
 
#---------------------------------------------------------------------------
# class MatFrame(wx.MDIChildFrame):
class MatFrame(wx.Frame):
 
 def __init__(self, parent):
 #wx.MDIChildFrame.__init__(self, parent, -1, "Matlab WX interface",
 # size=(600,600))
 wx.Frame.__init__(self, None, -1, "Matlab WX interface",
 size=(600,600))
 self.figure = figure = MatlabFigure(self)
 # histg = figure.hist([1,2,3,4,5,6,7,7,8,9,1,23,4,5,5,6])
 histg = figure.bar([1,2,3,4], [10,15, 7, 3], width=1)
 line1 = figure.plot([1,2,3,4], [2,3,6,7], 'b-')
 line2 = figure.plot([0,10,20], [0,10,20], 'g')
 figure.axis([0,30,0,20])
 
 figure.grid(1)
 figure.xlabel('Confidence', {'fontsize': 'small'})
 figure.ylabel('Count', {'fontsize': 'small'})
 figure.legend((line1, line2, histg),
 ('line1', 'line2', 'histg'),
 'upper right')
 figure.title('Confidence Histogram')
 
 figure.Bind(wx.EVT_LEFT_DOWN, self.OnSelectBucket)
 # end def
 
 def OnSelectBucket(self, event):
 xy = self.figure.GetXY(event)
 print xy
 # end def
#---------------------------------------------------------------------------
class MatlabMDI(wx.MDIParentFrame):
 def __init__(self):
 wx.MDIParentFrame.__init__(self, None, -1, "Matlab
MDI",size=(900,700))
 MatFrame(self)
 self.Show()
 # end def
class App(wx.App):
 """Application class."""
 def OnInit(self):
 #MatlabMDI()
 frame = MatFrame(self)
 frame.Show()
 for i in range(100):
 frame.figure.draw()
 # end for
 
 #self.xframe = MatFrame()
 #self.xframe.Show()
 #self.xframe.grid(0)
 return True
 # end def
#---------------------------------------------------------------------------
if __name__ == '__main__':
 app = App()
 app.MainLoop()
 
-----Original Message-----
From: John Hunter [mailto:jdh...@ac...] 
Sent: Tuesday, June 29, 2004 10:47 AM
To: Schalkwyk, Johan
Cc: mat...@li...
Subject: Re: [Matplotlib-users] Assertion triggered in wxMemory DC
>>>>> "Schalkwyk," == Schalkwyk, Johan <Joh...@sc...>
writes:
 Schalkwyk,> Thank you for the help I removed the show() command
 Schalkwyk,> from the loop. Now just calling grid(True) multiple
 Schalkwyk,> times. On my machine I narrowed the loop to 57 and it
 Schalkwyk,> started happening. At 50 it did not.
Perhaps I didn't make myself clear. The way you are using matplotlib
does not make sense. matplotlib has two modes: a "matlab interface"
and an embedded interface. You should not embed the matlab interface
directly into a GUI. The matlab interface does a lot of stuff under
the hood, like creating and managing figures and figure windows,
managing redraws, etc. When you create your own figure window outside
this framework, and then try to use the framework, the result is
undefined. If you are using matplotlib in a GUI, *do not import
matplotlib.matlab*. You need to follow the example of
embedding_in_wx2.py.
Below is your example translated to the GUI interface - on my system,
calling grid until the sun sets presents no problems, and it really
couldn't because all it does is set a boolean. In the matlab
interface, if you have interactive: True in your rc file, calling grid
does a lot more, including repainting the figure. Try running this
example, shaking it, resizing it, etc... and see if you can crash it;
I was unable to cause any problems.
If you have trouble, please let me know, but also consider trying
replacing wx for wxagg, which uses antigrain for drawing and is
probably more stable than wx, which does occasionally show dc related
errors.
By the way, there was an error in your legend code
You had
 legend('line', blahblah)
and you need
 legend( ('line',), blahblah)
That is, legend expects a list or tuple of strings, not a string.
 Schalkwyk,> By the way Kudos for matplotlib. Amazing. I had to dig
 Schalkwyk,> around the code and news groups to figure out how to
 Schalkwyk,> find the user coordinates of a mouse click. Reading
 Schalkwyk,> the code opens your eyes the wonderful design that is
 Schalkwyk,> backend dependent.
Thanks. Do you have the src distribution? There is an example in the
examples directory examples/coords_demo.py (works with Tk, GTK and WX)
that shows you how to get the mouse click coordinates. The examples
dir is your first line of defense when you want to figure out
something new. Unfortunately, I forgot to upload the zip file with
the 0.54.2 release, so look here
 http://matplotlib.sf.net/examples
Here's the example:
#!/usr/bin/env python
"""
An example of how to use wx or wxagg in an application w/o the toolbar
"""
from matplotlib.numerix import arange, sin, pi
import matplotlib
matplotlib.use('WX')
from matplotlib.backends.backend_wx import FigureCanvasWx as FigureCanvas
from matplotlib.figure import Figure
from wxPython.wx import *
class CanvasFrame(wxFrame):
 
 def __init__(self):
 wxFrame.__init__(self,None,-1,
 'CanvasFrame',size=(550,350))
 self.SetBackgroundColour(wxNamedColor("WHITE"))
 self.figure = Figure(figsize=(5,4), dpi=100)
 self.ax = self.figure.add_subplot(111)
 t = arange(0.0, 2.0, 0.01)
 s = sin(2*pi*t)
 l = self.ax.plot(t, s, linewidth=1.0)
 self.ax.set_xlabel('time (s)')
 self.ax.set_ylabel('voltage (mV)')
 self.ax.set_title('About as simple as it gets, folks')
 self.ax.legend(('line',), loc='upper right')
 for i in range(100):
 self.ax.grid(True)
 self.canvas = FigureCanvas(self, -1, self.figure)
 self.sizer = wxBoxSizer(wxVERTICAL)
 self.sizer.Add(self.canvas, 1, wxTOP | wxLEFT | wxEXPAND)
 # Capture the paint message 
 EVT_PAINT(self, self.OnPaint) 
 def OnPaint(self, event):
 self.canvas.draw()
 
class App(wxApp):
 
 def OnInit(self):
 'Create the main window and insert the custom frame'
 frame = CanvasFrame()
 frame.Show(true)
 return true
app = App(0)
app.MainLoop()

>>>>> "Schalkwyk," == Schalkwyk, Johan <Joh...@sc...> writes:
 Schalkwyk,> Thank you for the help I removed the show() command
 Schalkwyk,> from the loop. Now just calling grid(True) multiple
 Schalkwyk,> times. On my machine I narrowed the loop to 57 and it
 Schalkwyk,> started happening. At 50 it did not.
Perhaps I didn't make myself clear. The way you are using matplotlib
does not make sense. matplotlib has two modes: a "matlab interface"
and an embedded interface. You should not embed the matlab interface
directly into a GUI. The matlab interface does a lot of stuff under
the hood, like creating and managing figures and figure windows,
managing redraws, etc. When you create your own figure window outside
this framework, and then try to use the framework, the result is
undefined. If you are using matplotlib in a GUI, *do not import
matplotlib.matlab*. You need to follow the example of
embedding_in_wx2.py.
Below is your example translated to the GUI interface - on my system,
calling grid until the sun sets presents no problems, and it really
couldn't because all it does is set a boolean. In the matlab
interface, if you have interactive: True in your rc file, calling grid
does a lot more, including repainting the figure. Try running this
example, shaking it, resizing it, etc... and see if you can crash it;
I was unable to cause any problems.
If you have trouble, please let me know, but also consider trying
replacing wx for wxagg, which uses antigrain for drawing and is
probably more stable than wx, which does occasionally show dc related
errors.
By the way, there was an error in your legend code
You had
 legend('line', blahblah)
and you need
 legend( ('line',), blahblah)
That is, legend expects a list or tuple of strings, not a string.
 Schalkwyk,> By the way Kudos for matplotlib. Amazing. I had to dig
 Schalkwyk,> around the code and news groups to figure out how to
 Schalkwyk,> find the user coordinates of a mouse click. Reading
 Schalkwyk,> the code opens your eyes the wonderful design that is
 Schalkwyk,> backend dependent.
Thanks. Do you have the src distribution? There is an example in the
examples directory examples/coords_demo.py (works with Tk, GTK and WX)
that shows you how to get the mouse click coordinates. The examples
dir is your first line of defense when you want to figure out
something new. Unfortunately, I forgot to upload the zip file with
the 0.54.2 release, so look here
 http://matplotlib.sf.net/examples
Here's the example:
#!/usr/bin/env python
"""
An example of how to use wx or wxagg in an application w/o the toolbar
"""
from matplotlib.numerix import arange, sin, pi
import matplotlib
matplotlib.use('WX')
from matplotlib.backends.backend_wx import FigureCanvasWx as FigureCanvas
from matplotlib.figure import Figure
from wxPython.wx import *
class CanvasFrame(wxFrame):
 
 def __init__(self):
 wxFrame.__init__(self,None,-1,
 'CanvasFrame',size=(550,350))
 self.SetBackgroundColour(wxNamedColor("WHITE"))
 self.figure = Figure(figsize=(5,4), dpi=100)
 self.ax = self.figure.add_subplot(111)
 t = arange(0.0, 2.0, 0.01)
 s = sin(2*pi*t)
 l = self.ax.plot(t, s, linewidth=1.0)
 self.ax.set_xlabel('time (s)')
 self.ax.set_ylabel('voltage (mV)')
 self.ax.set_title('About as simple as it gets, folks')
 self.ax.legend(('line',), loc='upper right')
 for i in range(100):
 self.ax.grid(True)
 self.canvas = FigureCanvas(self, -1, self.figure)
 self.sizer = wxBoxSizer(wxVERTICAL)
 self.sizer.Add(self.canvas, 1, wxTOP | wxLEFT | wxEXPAND)
 # Capture the paint message 
 EVT_PAINT(self, self.OnPaint) 
 def OnPaint(self, event):
 self.canvas.draw()
 
class App(wxApp):
 
 def OnInit(self):
 'Create the main window and insert the custom frame'
 frame = CanvasFrame()
 frame.Show(true)
 return true
app = App(0)
app.MainLoop()

Thank you for the help
I removed the show() command from the loop. Now just calling grid(True)
multiple times. On my machine I narrowed the loop to 57 and it started
happening. At 50 it did not. 
Another way I found to trigger this problem is to remove the for loop all
together. Then it just pops up the display. Now grab the window with the
mouse and shake the window continuously around, forcing multiple Paint
events. Eventually it triggers the assert. The application I am developing
using multiple matplotlib windows in an MDI window seems to trigger this
quite easily. Everytime a window is added to the MDIParent all MDIChild
windows gets repainted. Something to do with the paint event.
By the way Kudos for matplotlib. Amazing. I had to dig around the code and
news groups to figure out how to find the user coordinates of a mouse click.
Reading the code opens your eyes the wonderful design that is backend
dependent.
import wx
import matplotlib
import time
matplotlib.use('WX')
from matplotlib.matlab import *
class App(wx.App):
 """Application class."""
 def OnInit(self):
 t = arange(0.0, 2.0, 0.01)
 s = sin(2*pi*t)
 l = plot(t, s, linewidth=1.0)
 xlabel('time (s)')
 ylabel('voltage (mV)')
 title('About as simple as it gets, folks')
 legend('line', loc='upper right')
 
 for i in range(100):
 grid(True)
 return True
#---------------------------------------------------------------------------
# run the app
app = App()
app.MainLoop()
-----Original Message-----
From: John Hunter [mailto:jdh...@ac...] 
Sent: Monday, June 28, 2004 11:17 PM
To: Schalkwyk, Johan
Cc: mat...@li...
Subject: Re: [Matplotlib-users] Assertion triggered in wxMemory DC
>>>>> "Schalkwyk," == Schalkwyk, Johan <Joh...@sc...>
writes:
 Schalkwyk,> The code snippet below reproduces the
 Schalkwyk,> problem. Basically calling "show()" in a loop forces
 Schalkwyk,> repaint of the same window many times. After a while a
 Schalkwyk,> strange stack trace appears with the assertion
 Schalkwyk,> above. Sometimes the stack trace creates garbage all
 Schalkwyk,> over the screen which has to be cleared by repainting
 Schalkwyk,> the whole screen.
You should only call show at most once per matplotlib script - for
more information on show see http://matplotlib.sf.net/faq.html#SHOW.
When embedding matplotlib in an application, typically you won't use
show at all.
When embedding matplotlib in a GUI like WX, you should use
canvas.draw() to repaint the figure. See embedding_in_wx.py in the
examples directory of the matplotlib src distribution of the script
embedding_in_wx2.py attached with this email for an example of how to
use matplotlib in a wx app.
I can't promise you this will fix your problem, but will at least make
your example consistent with how matplotlib is meant to be used in a
wx app. If you still get a problem, please post the revised code and
I'll take a look.
Good luck!
JDH
#!/usr/bin/env python
"""
An example of how to use wx or wxagg in an application w/o the toolbar
"""
from matplotlib.numerix import arange, sin, pi
import matplotlib
# uncomment the following to use wx rather than wxagg
#matplotlib.use('WX')
#from matplotlib.backends.backend_wx import FigureCanvasWx as FigureCanvas
# comment out the following to use wx rather than wxagg
matplotlib.use('WXAgg')
from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg as
FigureCanvas
from matplotlib.figure import Figure
from wxPython.wx import *
class CanvasFrame(wxFrame):
 
 def __init__(self):
 wxFrame.__init__(self,None,-1,
 'CanvasFrame',size=(550,350))
 self.SetBackgroundColour(wxNamedColor("WHITE"))
 self.figure = Figure(figsize=(5,4), dpi=100)
 self.axes = self.figure.add_subplot(111)
 t = arange(0.0,3.0,0.01)
 s = sin(2*pi*t)
 
 self.axes.plot(t,s)
 self.canvas = FigureCanvas(self, -1, self.figure)
 self.sizer = wxBoxSizer(wxVERTICAL)
 self.sizer.Add(self.canvas, 1, wxTOP | wxLEFT | wxEXPAND)
 # Capture the paint message 
 EVT_PAINT(self, self.OnPaint) 
 def OnPaint(self, event):
 self.canvas.draw()
 
class App(wxApp):
 
 def OnInit(self):
 'Create the main window and insert the custom frame'
 frame = CanvasFrame()
 frame.Show(true)
 return true
app = App(0)
app.MainLoop()

>>>>> "Andrew" == Andrew Straw <str...@as...> writes:
 Andrew> Hi plotters, I've shamelessly modified dynamic_demo_wx.py
 Andrew> to create dynamic_image_wxagg.py, attached. This is my
 Andrew> initial attempt to get matplotlib to dynamically update
 Andrew> images. Basically it all works hunky-dory except 1) an
 Andrew> apparent memory leak and 2) flicker when I run this in
 Andrew> linux (haven't tested other OSes). I offer #1 to John or
 Andrew> other memory-leak hunters out there and ask if any WXpert
 Andrew> can address #2. I've googled a bit and it appears the WX
 Andrew> backend (from which WXAgg is derived) does the Right Thing
 Andrew> and calls wxClientDC on a non-OS generated redraw request,
 Andrew> which is supposed to reduce or eliminate flicker. The
 Andrew> other tip is to catch EVT_ERASE_BACKGROUND, which I've
 Andrew> also done to no apparent improvement. Thus, I ask for help
 Andrew> -- any suggestions on how to eliminate this flicker?
Hi Andrew,
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?
As for the flicker problem, I've noticed it too, and would also be
thankful if any wx gurus have some advice.
BTW, wxagg currently uses a string copy in python to render agg to a
wx bitmap via a wx image. It would be nice if some enterprising
soul wrote some extension code ala _tkagg.cpp and _gtkagg.cpp which
transfers the agg canvas to wx directly. Should be a pretty big win
performance wise. We could keep the string method as a fallback in
case the extension wasn't compiled, but it would help for people who
want to use wxagg for dynamic applications (hint hint). 
This should at least be on the goals page.
JDH

>>>>> "Schalkwyk," == Schalkwyk, Johan <Joh...@sc...> writes:
 Schalkwyk,> The code snippet below reproduces the
 Schalkwyk,> problem. Basically calling "show()" in a loop forces
 Schalkwyk,> repaint of the same window many times. After a while a
 Schalkwyk,> strange stack trace appears with the assertion
 Schalkwyk,> above. Sometimes the stack trace creates garbage all
 Schalkwyk,> over the screen which has to be cleared by repainting
 Schalkwyk,> the whole screen.
You should only call show at most once per matplotlib script - for
more information on show see http://matplotlib.sf.net/faq.html#SHOW.
When embedding matplotlib in an application, typically you won't use
show at all.
When embedding matplotlib in a GUI like WX, you should use
canvas.draw() to repaint the figure. See embedding_in_wx.py in the
examples directory of the matplotlib src distribution of the script
embedding_in_wx2.py attached with this email for an example of how to
use matplotlib in a wx app.
I can't promise you this will fix your problem, but will at least make
your example consistent with how matplotlib is meant to be used in a
wx app. If you still get a problem, please post the revised code and
I'll take a look.
Good luck!
JDH
#!/usr/bin/env python
"""
An example of how to use wx or wxagg in an application w/o the toolbar
"""
from matplotlib.numerix import arange, sin, pi
import matplotlib
# uncomment the following to use wx rather than wxagg
#matplotlib.use('WX')
#from matplotlib.backends.backend_wx import FigureCanvasWx as FigureCanvas
# comment out the following to use wx rather than wxagg
matplotlib.use('WXAgg')
from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg as FigureCanvas
from matplotlib.figure import Figure
from wxPython.wx import *
class CanvasFrame(wxFrame):
 
 def __init__(self):
 wxFrame.__init__(self,None,-1,
 'CanvasFrame',size=(550,350))
 self.SetBackgroundColour(wxNamedColor("WHITE"))
 self.figure = Figure(figsize=(5,4), dpi=100)
 self.axes = self.figure.add_subplot(111)
 t = arange(0.0,3.0,0.01)
 s = sin(2*pi*t)
 
 self.axes.plot(t,s)
 self.canvas = FigureCanvas(self, -1, self.figure)
 self.sizer = wxBoxSizer(wxVERTICAL)
 self.sizer.Add(self.canvas, 1, wxTOP | wxLEFT | wxEXPAND)
 # Capture the paint message 
 EVT_PAINT(self, self.OnPaint) 
 def OnPaint(self, event):
 self.canvas.draw()
 
class App(wxApp):
 
 def OnInit(self):
 'Create the main window and insert the custom frame'
 frame = CanvasFrame()
 frame.Show(true)
 return true
app = App(0)
app.MainLoop()

>>>>> "Charles" == Charles R Twardy <cha...@in...> writes:
 Charles> Wow, matplot sure has grown up since I last saw it
 Charles> (0.32?). I was trying to get back in the game and tried
 Charles> the debian packages from mentors.
Hi Charles, glad to see you back.
 Charles> But I can only see the python-matplotlib-doc, not
 Charles> python-matplotlib. I'm guessing it hasn't been built for
 Charles> PowerPC. I'll try apt-get source when mentors.debian is
 Charles> back up (or when I can see it anyway).
I CCd Vittorio, the debian maintainer. I don't know if he's on the
user list. He may have some comments for you.
Cheers,
JDH