matplotlib-users Mailing List for matplotlib

Hi,

unfortunately  32-bit ;-) I tried digging around, but I don't know  
much about tcl/tk. Seeing a  char string argv atol'ed into a pointer  
address left me with an uncomfortable feeling...
Anyway her is the argv value

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xb7c516c0 (LWP 5638)]
0xb6f4500e in PyAggImagePhoto (clientdata=0x0, interp=0x87396f0, argc=5,
     argv=0xbfc8874c) at src/_transforms.h:362
362       Point* ll_api() {return _ll;}
Current language:  auto; currently c++
(gdb) p argv[4]
$1 = 0x895d0f0 "3085736160"
(gdb) p bboxo
$2 = (PyObject *) 0x7fffffff

The cast doesn't seem to work.

Cheers,
Malte

On 14/05/2008, at 10:47 PM, Michael Droettboom wrote:

> Ouch!  The way that pointer is obtained is really weird (though I  
> believe it is a common idiom in Tcl extensions):
>
> PyAggImagePhoto(ClientData clientdata, Tcl_Interp* interp,
>               int argc, char **argv) {
>    ...
>      bboxo = (PyObject*)atol(argv[4]);
>    if (bboxo != Py_None) {
>      bbox = (Bbox*)bboxo;
>
> That means the pointer comes to us encoded as a string of digits,  
> which gets converted to an integer, cast to a (PyObject*), and then  
> cast to a (Bbox*) (which is a subclass of PyObject, in the C-object- 
> oriented sense).  That's just one of those things you'd rather not  
> be doing ;)
>
> Are you running the 64-bit version of OpenSUSE by any chance?  That  
> might explain this if the atol call is overflowing.  That's only  
> theoretical, as I think it *should* work.  atol is supposed to  
> return a "long", which is supposed to be 64-bit on a 64-bit Linux  
> machine.  Could you try replacing "atol" with "atoll", recompile  
> and see what happens?  Do you get any warnings during compilation  
> of _tkagg.cpp?
>
> Failing that, it would be useful, I suppose, to print out "argv[4]"  
> from the debugger.
>
> Thanks for helping with this.  Hopefully we're honing in on something.
>
> Mike
>
> Malte Marquarding wrote:
>> Hi,
>>
>> The segv also occurs in matplotlib-0.90.1. A clean build doesn't  
>> help.
>>
>> Here is the gdb output, looks like something is pointing into  
>> nirvana..
>>
>> (gdb) p bboxo
>> $1 = <value optimized out>
>> (gdb) p bbox
>> $2 = (Bbox *) 0x7ffffffb
>> (gdb) p bbox->_ll
>> Cannot access memory at address 0x7ffffffb
>>
>> Cheers,
>> Malte
>>
>> On 13/05/2008, at 10:19 PM, Michael Droettboom wrote:
>>
>>> p bboxo
>>> p bbox
>>> p bbox->_ll
>>
>>
>>
>>
>>
>
> -- 
> Michael Droettboom
> Science Software Branch
> Operations and Engineering Division
> Space Telescope Science Institute
> Operated by AURA for NASA
>

Malte Marquarding
Mal...@cs...

Hi,

I'm trying to insert a slider into my figure like the on in the example
slider_demo.py.

from the slider_demo i have:

axcolor = 'lightgoldenrodyellow'
axfreq = axes([0.25, 0.1, 0.65, 0.03])
sfreq = Slider(axfreq, 'Freq', 0.1, 30.0, valinit = f0)

i have a figure with an axes where i displayed an image using imshow. Like:

a = self.fig.gca()
a.imshow(img)

I've tried different stuff, but i get an assertion error when I try:

self.fig.add_axes(axfreq)

Has anyone here tried doing the slider_demo under wxpython?

Soren

On Wed, May 14, 2008 at 11:41 AM, Michael Droettboom <md...@st...> wrote:

> I haven't done anything with the record array stuff, so I'll leave this
> to another developer to look at.

Fixed in r5139.  This was a consequence of moving the excel and gtk
imports out of mlab to improve load time.  The location is now
mpl_toolkits.exceltools.rec2xls

JDH

Thanks.  These have been applied on the SVN trunk r5138.  The problem 
with legend_scatter.py was a type error created when edgecolors changed 
to a Numpy array (which is optionally zero-length).

Matthias Michler wrote:
> - the function mlab.rec2excel does not exist anymore
> -> in matplotlib/mlab.py:  
>     line 73:  rec2excel(r, 'test.xls', formatd=formatd) 
>     needs to be removed
> -> examples/loadrec.py needs to be changed accordingly (I don't 
> know what is properly in that case )
>   
I haven't done anything with the record array stuff, so I'll leave this 
to another developer to look at.

Cheers,
Mike

-- 
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA

Hello list,

It may not be very important, but I collected some small bugs while exploring 
the examples and for some of them I got little patches. 

- for me their occur two "typos" in matplotlib/text.py (see the attached 
text.patch, please)

- some examples don't work for me (see attached some_examples.patch, please)
  e.g. changes in legend_scatter.py due to a DeprecationWarning
  (matplotlib/axes.py:4288) although that doesn't fix the problem of the 
legend_scatter.py (see attached output_of_legend_scatter.out, please)
I recognized, that the 'handle._edgecolors' is an empty list at this point, 
but unfortunately I couldn't figure out why.

- the function mlab.rec2excel does not exist anymore
-> in matplotlib/mlab.py:  
    line 73:  rec2excel(r, 'test.xls', formatd=formatd) 
    needs to be removed
-> examples/loadrec.py needs to be changed accordingly (I don't 
know what is properly in that case )

best regards
Matthias

Ouch!  The way that pointer is obtained is really weird (though I 
believe it is a common idiom in Tcl extensions):

PyAggImagePhoto(ClientData clientdata, Tcl_Interp* interp,
               int argc, char **argv) {
    ...
   
    bboxo = (PyObject*)atol(argv[4]);
    if (bboxo != Py_None) {
      bbox = (Bbox*)bboxo;

That means the pointer comes to us encoded as a string of digits, which 
gets converted to an integer, cast to a (PyObject*), and then cast to a 
(Bbox*) (which is a subclass of PyObject, in the C-object-oriented 
sense).  That's just one of those things you'd rather not be doing ;)

Are you running the 64-bit version of OpenSUSE by any chance?  That 
might explain this if the atol call is overflowing.  That's only 
theoretical, as I think it *should* work.  atol is supposed to return a 
"long", which is supposed to be 64-bit on a 64-bit Linux machine.  Could 
you try replacing "atol" with "atoll", recompile and see what happens?  
Do you get any warnings during compilation of _tkagg.cpp?

Failing that, it would be useful, I suppose, to print out "argv[4]" from 
the debugger.

Thanks for helping with this.  Hopefully we're honing in on something.

Mike

Malte Marquarding wrote:
> Hi,
>
> The segv also occurs in matplotlib-0.90.1. A clean build doesn't help.
>
> Here is the gdb output, looks like something is pointing into nirvana..
>
> (gdb) p bboxo
> $1 = <value optimized out>
> (gdb) p bbox
> $2 = (Bbox *) 0x7ffffffb
> (gdb) p bbox->_ll
> Cannot access memory at address 0x7ffffffb
>
> Cheers,
> Malte
>
> On 13/05/2008, at 10:19 PM, Michael Droettboom wrote:
>
>> p bboxo
>> p bbox
>> p bbox->_ll
>
>
>
>
>

-- 
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA

Sorry -- I don't know where slider_demo.py lives and am not too familiar 
with how the website is updated.  Anyone?

Cheers,
Mike

Matthias Michler wrote:
> Hello list,
>
> On Wednesday 07 May 2008 19:08:23 Michael Droettboom wrote:
>   
>> Matthias Michler wrote:
>>     
>>> The second problem arises only with latest svn.
>>> At the end of the mail there's the Traceback, which arises after clicking
>>> the radiobutton during running examples/widgets/radio_buttons.py.
>>>       
>> This is now fixed in SVN.  It hadn't been updated to use the new
>> transforms framework.
>>     
>
> First of all: Thank you Mike for the fast implementation.
>
> Secondly I ask again for changing the online-version of the nice Slider-demo 
> at http://matplotlib.sourceforge.net/screenshots/slider_demo.py , where the 
> replacement 
> hovercolor=0.975
> to hovercolor="0.975"
> is needed to fulfill standards of mpl colors, please.
> We refered our students to the nice collection of screenshots on mpl-homepage 
> and therefore it would be great, if someone could change that, so that we 
> don't run into much bug reports on our side.
>
> Thanks in advance. 
> Matthias
>
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-- 
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA

Hello list,

On Wednesday 07 May 2008 19:08:23 Michael Droettboom wrote:
> Matthias Michler wrote:
> > The second problem arises only with latest svn.
> > At the end of the mail there's the Traceback, which arises after clicking
> > the radiobutton during running examples/widgets/radio_buttons.py.
>
> This is now fixed in SVN.  It hadn't been updated to use the new
> transforms framework.

First of all: Thank you Mike for the fast implementation.

Secondly I ask again for changing the online-version of the nice Slider-demo 
at http://matplotlib.sourceforge.net/screenshots/slider_demo.py , where the 
replacement 
hovercolor=0.975
to hovercolor="0.975"
is needed to fulfill standards of mpl colors, please.
We refered our students to the nice collection of screenshots on mpl-homepage 
and therefore it would be great, if someone could change that, so that we 
don't run into much bug reports on our side.

Thanks in advance. 
Matthias

Hello Markus,

On Saturday 10 May 2008 22:01:22 Markus Kuhn wrote:
> How can I extract from a figure or axes the data that it currently
> displays?
>
> I had hoped that something like
>
> from pylab import *
> plot([1,3,2])
> data = getp(gca(), 'data')
> xdata = getp(gca(), 'xdata')
> ydata = getp(gca(), 'ydata')

An axes instance does not provide data-properties. They belong to the lines, 
that were already plotted in that axes. But the axes instance provides a list 
of all plotted lines (gca().lines).

xdata = getp(gca().lines[0], 'xdata')
# or the OOP-way
# last line instance of the list of lines: 
line = gca().lines[-1]                                   
ydata = line.get_ydata()

regards Matthias

> P.S.: It seems that the link
>
>   http://matplotlib.sourceforge.net/matplotlib.pyplot.html#-getp
>
> on
>
>   http://matplotlib.sourceforge.net/
>
> is broken.

(+1)