matplotlib-devel Mailing List for matplotlib

On Thu, Dec 31, 2009 at 4:54 AM, Darren Dale <dsd...@gm...> wrote:
> I have been resistant to committing this patch because (in my opinion)
> mpl should not have to provide workarounds for bugs in package X on OS
> Y, distribution Z. I think this particular issue was fixed when
> PyQt4-4.6.2 was released. But its time to get practical, I suppose.
> The patch looks fine, I just checked it into the trunk.

Thanks!  As the zen goes, practicality beats purity :)  I understand
your reluctance though, it's annoying to pepper mpl's code with this
kind of junk.

Happy New Year!

f

On Wed, Dec 30, 2009 at 11:11 PM, Fernando Perez <fpe...@gm...> wrote:
> Howdy,
>
> On Sat, Nov 7, 2009 at 12:30 PM, Darren Dale <dsd...@gm...> wrote:
>> Me too. And thank you for posting the report and a workaround.
>
> Quick question: would it be worth adding this monkeypatch to mpl
> proper?  Right now, the qt4 backend is effectively unusable out of the
> box in distros like Karmic.

I have been resistant to committing this patch because (in my opinion)
mpl should not have to provide workarounds for bugs in package X on OS
Y, distribution Z. I think this particular issue was fixed when
PyQt4-4.6.2 was released. But its time to get practical, I suppose.
The patch looks fine, I just checked it into the trunk.

Darren

Howdy,

are there fundamental reasons to keep this code around in
backends/__init__.py:use() ?

    if 'matplotlib.backends' in sys.modules:
        if warn: warnings.warn(_use_error_msg)
        return

I am now testing the new IPython gui stuff, and if I comment that out
and call pyplot.switch_backend() when I load mpl (along with the qt
patch I sent earlier), I can hop around backends, at least with Qt4
and Wx:

In [10]: %pylab qt

Welcome to pylab, a matplotlib-based Python environment.
Backend in use: Qt4Agg
For more information, type 'help(pylab)'.

In [11]: run simpleplot.py

In [13]: %pylab wx

Welcome to pylab, a matplotlib-based Python environment.
Backend in use: WXAgg
For more information, type 'help(pylab)'.

In [16]: run simpleplot.py

In [17]: figure()
Out[17]: <matplotlib.figure.Figure object at 0xa311b0c>

In [18]: plot(sin(linspace(0,2*pi,200)**2))
Out[18]: [<matplotlib.lines.Line2D object at 0xa49862c>]

In [19]: %pylab qt

Welcome to pylab, a matplotlib-based Python environment.
Backend in use: Qt4Agg
For more information, type 'help(pylab)'.

In [20]: run simpleplot.py

In [21]: figure()
Out[21]: <matplotlib.figure.Figure object at 0xa64fb2c>

In [22]: plot(sin(linspace(0,2*pi,200)))
Out[22]: [<matplotlib.lines.Line2D object at 0xa67d26c>]

etc...


I see lockups trying to throw Tk or Gtk in the mix, but being able to
switch from Wx to Qt and back would be nice, especially since it would
allow using Mayavi and other enthought apps together with Qt-based
tools.  mpl closes open windows on backend switch, but at least you
can go back and forth, which is better than nothing and can be useful
for debugging.

This is still very early/experimental ipython code, I just want to
start getting a feel for the mpl-side of the equation...

Cheers,

f

Howdy,

On Sat, Nov 7, 2009 at 12:30 PM, Darren Dale <dsd...@gm...> wrote:
> Me too. And thank you for posting the report and a workaround.

Quick question: would it be worth adding this monkeypatch to mpl
proper?  Right now, the qt4 backend is effectively unusable out of the
box in distros like Karmic.  Which is a bummer, because with the
ipython sitting on my laptop, one can now load 'pylab' at any time
during a session:

maqroll[scratch]> ip
Python 2.6.4 (r264:75706, Dec  7 2009, 18:45:15)
Type "copyright", "credits" or "license" for more information.

IPython 0.11.bzr.r1219 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object'. ?object also works, ?? prints more.

In [1]: import sys

In [2]: 'matplotlib' in sys.modules
Out[2]: False

In [3]: %pylab wx
Activating matplotlib with backend: WXAgg

  Welcome to pylab, a matplotlib-based Python environment.
  For more information, type 'help(pylab)'.

Switching IPython gui support to: wx True

In [4]: 'matplotlib' in sys.modules
Out[4]: True

In [5]: plot(sin(linspace(0,2*pi,200)))
Out[5]: [<matplotlib.lines.Line2D object at 0xae0dccc>]


This is starting to look very promising, but unfortunately:

- right now we don't have gui switching support for Qt3 at all in
ipython.  Help is welcome, but I have no clue if it's easy/hard or
even needed much anymore...

- qt4 is unusable with the system's qt/pyqt...

So perhaps a local patch would be worth it, no?  I can confirm that
with the attached patch, the new ipython support works:

In [1]: %pylab qt
Activating matplotlib with backend: Qt4Agg

  Welcome to pylab, a matplotlib-based Python environment.
  For more information, type 'help(pylab)'.


In [2]: run simpleplot.py

In [3]: close('all')

In [4]: run simpleplot.py


whereas before, I'd get the same nasty error mentioned above.

The patch now has no run-time impact (I modified Pierre's code a bit
so the check is done only once), but I'm not about to commit something
in the Qt backend without someone else's eyes, especially Darren's :)

Cheers,

f