matplotlib-users Mailing List for matplotlib (Page 8)

Hello,

I am using the class interface to mpl and I was wondering if it is an intended behaviour, that you cannot set the label to 'None'.  Using:

Axes.set_xlabel(None)

will cause errors that result in the plots not being displayed.

Of course I can check for None myself, but I was wondering how I then will be able to turn off the axes labels once they are set.

Regards,

Niklas Volbers.

__________________________________________________________
Mit WEB.DE FreePhone mit hoechster Qualitaet ab 0 Ct./Min.
weltweit telefonieren! http://freephone.web.de/?mc=021201

Hi Reik,

FT_KERNING_DEFAULT is defined in freetype2/freetype/freetype=
.h.
If it's not there, you need to upgrade freetype2.

Nadia Dencheva=


---- Original message ----
>Date: Sun, 5 Dec 2004 16:51:48 +0100
>=
From: "Reik H. B=F6rger" <rei...@gm...>  =

>Subject: [Matplotlib-users] installing matplotlib  =

>To: mat...@li...
>
>Hi,
>
>once again I t=
ry to install matplotlib on a new install of
MacOSX 10.3. =

>I think, I got all the required dependencies and when I start
the =

>installation of matplotlib via
>python setup.py build
>it starts work=
ing, but after some steps it terminates with:
>
>src/ft2font.cpp: In m=
ember function 'void
FT2Font::load_glyphs()':
>src/ft2font.cpp:376: er=
ror: 'FT_KERNING_DEFAULT' undeclared
(first use =

>this function)
>src/ft2font.cpp:376: error: (Each undeclared identifie=
r is
reported =

>only once for each funtion it appears in.)
>error: command 'gcc' faile=
d with exit status 1
>
>What went wrong? Any suggestions? I am lost...=
 :-(
>
>Thanks
>Reik
>
>
>
>-------------------------------------=
------------------
>SF email is sponsored by - The IT Product Guide
>R=
ead honest & candid reviews on hundreds of IT Products from
real users.=

>Discover which products truly live up to the hype. Start
reading now=
. =

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_____________________
>Matplotlib-users mailing list
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@lists.sourceforge.net
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tplotlib-users

Hi,

once again I try to install matplotlib on a new install of MacOSX 10.3. 
I think, I got all the required dependencies and when I start the 
installation of matplotlib via
python setup.py build
it starts working, but after some steps it terminates with:

src/ft2font.cpp: In member function 'void FT2Font::load_glyphs()':
src/ft2font.cpp:376: error: 'FT_KERNING_DEFAULT' undeclared (first use 
this function)
src/ft2font.cpp:376: error: (Each undeclared identifier is reported 
only once for each funtion it appears in.)
error: command 'gcc' failed with exit status 1

What went wrong? Any suggestions? I am lost... :-(

Thanks
Reik

Just found axvline/axhline which serves for my purpose at the moment. The 
tick-marks would not have been more than a special treat anyway...


Am Samstag, 4. Dezember 2004 18:30 schrieb Norbert Nemec:
> Hi there,
>
> checking the documentation, I could not find any information about
> displaying the zero-axis, possibly even moving the tick-marks and lables
> from the edge of the plotting area to the zero-axis (as it is often done in
> mathematics)
>
> Is there any specific support for this that I did not notice? Has anybody
> already spent thought on the subject?
>
> The simplest solution would probably be to (ab-)use the gridline mechanism
> or extend it with a third option ("minor","major" and "zero"). Anyhow,
> sometimes, one would want both displayed: the zeroaxis in black and some
> gridlines in faint gray. Furthermore, this simple solution is not
> extendable to putting the ticks on the zeroaxis.
>
> Any ideas?
>
> Ciao,
> Nobbi

-- 
_________________________________________Norbert Nemec
         Bernhardstr. 2 ... D-93053 Regensburg
     Tel: 0941 - 2009638 ... Mobil: 0179 - 7475199
           eMail: <No...@Ne...>

Hi there,

checking the documentation, I could not find any information about displaying 
the zero-axis, possibly even moving the tick-marks and lables from the edge 
of the plotting area to the zero-axis (as it is often done in mathematics)

Is there any specific support for this that I did not notice? Has anybody 
already spent thought on the subject?

The simplest solution would probably be to (ab-)use the gridline mechanism or 
extend it with a third option ("minor","major" and "zero"). Anyhow, 
sometimes, one would want both displayed: the zeroaxis in black and some 
gridlines in faint gray. Furthermore, this simple solution is not extendable 
to putting the ticks on the zeroaxis.

Any ideas?

Ciao,
Nobbi

-- 
_________________________________________Norbert Nemec
         Bernhardstr. 2 ... D-93053 Regensburg
     Tel: 0941 - 2009638 ... Mobil: 0179 - 7475199
           eMail: <No...@Ne...>

Dear all,

At the moment I'm heavily using the scatter plot (great!). But if I want =
to add
a color bar (with the command colorbar(), directly following the call to
scatter) to explain the meaning of the colors of the patches, matplotlib =
(0.64)
refuses to make a colorbar with the following message:

First define a mappable image (eg imshow, figimage, pcolor, scatter

I checked how colorbar knows that the plot under consideration is a 'mapp=
able
image': it calls gci() . And indeed, if I do that by hand, after a plot w=
ith
scatter, I get the message that there is no mappable image.
According to the doc's and the error message above, the patches plotted b=
y
scatter should count as a mappable image, but apparently, they don't.

Is this a bug or a misunderstanding on my side?

Regards,
Arnold

PS: at the moment I'm using a workaround, by making my own colorbar comma=
nd:
just stealing the code from the original routine, but without getting the
colors and number ranges from the image itself (I have to define those by
hand).

> Date: Thu, 02 Dec 2004 10:04:20 +0100
> From: Nils Wagner <nw...@me...>
> To: SciPy Developers List <sci...@sc...>
> Cc: mat...@li...
> Subject: [Matplotlib-users] Feature request : Comparison of sparse matrices is not implemented.
> 
> Hi all,
>  
> I tried to visualize the structure of large and sparse matrices using
> 
> from matplotlib.colors import LinearSegmentedColormap
> from matplotlib.matlab import *
> from scipy import *
> import IPython
> 
> def spy2(Z):
>     """
>     SPY(Z) plots the sparsity pattern of the matrix S as an image
>     """
> 
>     #binary colormap min white, max black
>     cmapdata = {
>          'red'  :  ((0., 1., 1.), (1., 0., 0.)),
>          'green':  ((0., 1., 1.), (1., 0., 0.)),
>          'blue' :  ((0., 1., 1.), (1., 0., 0.))
>          }
>     binary =  LinearSegmentedColormap('binary',  cmapdata, 2)
> 
>     Z = where(Z>0,1.,0.)
>     imshow(transpose(Z), interpolation='nearest', cmap=binary)
> 
> rows, cols, entries, rep, field, symm = io.mminfo('k0.mtx')
> print 'number of rows, cols and entries', rows, cols, entries
> print 'Start reading matrix - this may take a minute'
> ma = io.mmread('k0.mtx')
> print 'Finished'
> flag = 1
> if flag == 1:
>  spy2(ma)
>  show()
> 
> It failed. Is it somehow possible to visualize sparse matrices ?
> Any suggestion would be appreciated.

To plot sparsity patterns, I read matrices in MatrixMarket format using 
the PySparse package. Once I have arrays with row and column indices, I 
simply use scatter() with arguments to modify the size of the 'bubbles' 
and their color (and alpha) depending on the magnitude on the nonzero 
element. The result is great. Of course when matrices are symmetric, you 
only hold the lower (or upper) triangular part, then tell scatter() to 
plot the other triangle.

Dominique

Hi all,

Can someone help me with imshow() for sparse matrices ?

Nils

 

This was fixed in CVS. See the message to this list from Steve Chaplin 
dated approx Nov 9 2004.

m.

Chris Barker wrote:
> HI all,
> 
> When I do:
> 
> from matplotlib.matlab import *
> 
> I get the following warning message:
> 
> Could not load matplotlib icon: Couldn't recognize the image file format 
> for file '/usr/share/matplotlib/matplotlib.svg'
> 
> This is really just a minor annoyance, but it's been doing this for the 
> last couple of releases. Anyone know why? why is it trying to load an svg?
> 
> Gentoo Linux Python 2.3.3, matplotlib 0.64, pygtk2.0 (I think)
> 
> -Chris
> 
> 
> 
> 

Thank you for your help. The matplotlib is now installed properly on my =
win xp computer.
I think using mingw instead of msvc was the key. That's the way it =
worked on my machine:

1.) Download and install all the required things as descibed in the =
win32_static/README but use the newest versions and for the GTK stuff =
goto =
<http://prdownloads.sourceforge.net/gladewin32/gtk-win32-devel-2.4-rc23.e=
xe?download>.
There is no need to change the "cygwinccompiler.py" but I had to adjust =
the "profile24.bat" and the "importlib24.bat".

2.) Add the following code to line 234 in the setupext.py:

        if major=3D=3D2 and minor1=3D=3D4:
            print '\tBuilding for python24'
            module.include_dirs.extend(['win32_static/include/tcl84'])
            module.library_dirs.extend(['C:/Python24/dlls'])       =20
            module.libraries.extend(['tk84', 'tcl84'])       =20
        el

3.) python setup.py build --compiler=3Dmingw32 bdist_wininst

Regards,
Frederik


-----Urspr=FCngliche Nachricht-----
Von: John Hunter [mailto:jdh...@ni...]=20
Gesendet: Freitag, 26. November 2004 17:59
An: Transier, Frederik
Cc: 'mat...@li...'
Betreff: Re: [Matplotlib-users] Installing matplotlib with python 2.4


>>>>> "Transier," =3D=3D Transier, Frederik <fre...@sa...> =
writes:

    Frederik> Hello, while I was trying to build the matplotlib 0.64
    Frederik> with python 2.4 on my win xp machine

    Frederik> a lot of errors occurred. Has anyone managed to install
    Frederik> it under these conditions?

    Frederik> Or is there any location I can download the binaries
    Frederik> for python 2.4 and win xp?

    Frederik> Any help would be appreciated.

Building on windows is a pain.  I'll try to include a python2.4rc1
installer with the next release, possibly next week.  If you need
something sooner, you'll have to post some more information to the
list.  Have you read the instructions for building win32 in
setupext.py, and downloaded the win32_static file from the matplotlib
web site that is pointed to in setupext?

JDH
=20

True. Just had to check this again to make sure, but even PS3 does not support 
Alpha transparency in any way. The big improvement there was bitmapped 
masking of images, but the whole concept of true transparency really seems to 
be an extremely new idea.


Am Donnerstag, 2. Dezember 2004 13:26 schrieb John Hunter:
> >>>>> "Carol" == Carol Leger <car...@sr...> writes:
>
>     Carol> The that the polar plot overlayed on a rectangular plot is
>     Carol> working in Postscipt, I am having trouble with the
>     Carol> semi-transparent boxes around the text.
>
> postscript doesn't support the alpha channel and there is nothing
> matplotlib can do about it.  It's a postscript limitation.  Right now
> the only vector output that supports alpha is SVG.  Hopefully we'll
> get a PDF backend one day which also supports alpha.
>
> JDH
>
>
> -------------------------------------------------------
> SF email is sponsored by - The IT Product Guide
> Read honest & candid reviews on hundreds of IT Products from real users.
> Discover which products truly live up to the hype. Start reading now.
> http://productguide.itmanagersjournal.com/
> _______________________________________________
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> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

-- 
_________________________________________Norbert Nemec
         Bernhardstr. 2 ... D-93053 Regensburg
     Tel: 0941 - 2009638 ... Mobil: 0179 - 7475199
           eMail: <No...@Ne...>

>>>>> "Carol" == Carol Leger <car...@sr...> writes:

    Carol> The that the polar plot overlayed on a rectangular plot is
    Carol> working in Postscipt, I am having trouble with the
    Carol> semi-transparent boxes around the text.

postscript doesn't support the alpha channel and there is nothing
matplotlib can do about it.  It's a postscript limitation.  Right now
the only vector output that supports alpha is SVG.  Hopefully we'll
get a PDF backend one day which also supports alpha.

JDH

OK, now I understand: my problem was just the ordering of show() and savefig()

Doing savefig first and show lateron solved the problem with no further 
changes...

Thanks!

Am Donnerstag, 2. Dezember 2004 10:26 schrieb Darren Dale:
> On Thursday 02 December 2004 04:12 am, Norbert Nemec wrote:
> > Hi there,
> >
> > probably a trivial question, but somehow, I'm stuck anyway:
> >
> > I have the following script:
> >
> > ----------
> > #!/usr/bin/env python
> > import matplotlib.matlab
> > ... do some data preparation ...
> > plot(something)
> > show()
> > savefig("output.eps")
> > ----------
> >
> > If I call this script with the -dGtkAgg option, it displays the plot on
> > screen and saves an empty eps file. If I call it with -dPS, it displays
> > nothing and outputs the correct eps - so far everything as I would expect
> > it.
> >
> > Up to now, I just used the -dGtkAgg backend (as default) to get an
> > impression about the plots and then ran the script again to create the
> > .eps.
> >
> > Now, I would like the script to do both in one run: display the plot on
> > screen, and save it to disk at the same time.
> >
> > Somehow I have not achieved doing so. My first idea was to place
> >  matplotlib.use('PS')
> > right before the savefig, but that does not change anything and still
> > writes an empty .eps file.
> >
> > What should I do?
>
> Hi Norbert,
>
> Try running this:
>
> ----------
> #!/usr/bin/env python
> matplotlib.use('GTKAgg')
> import matplotlib.matlab
> ... do some data preparation ...
> plot(something)
> savefig("output.eps")
> show()
> ----------
>
> That should save the file as eps and show the plot using the GTK backend.
> matplotlib.use('PS') would have to be called before importing
> matplotlib.matlab, which is why it seemed unresponsive in your script. But
> you dont need to call it for what you want to accomplish.

-- 
_________________________________________Norbert Nemec
         Bernhardstr. 2 ... D-93053 Regensburg
     Tel: 0941 - 2009638 ... Mobil: 0179 - 7475199
           eMail: <No...@Ne...>

On Thu, 2004-12-02 at 04:49, Darren Dale wrote:
> On Wednesday 01 December 2004 07:34 pm, Stephen Walton wrote:
> > On Tue, 2004-11-30 at 17:06 -0500, Perry Greenfield wrote:
> > > Yesterday I brought up some user interface issues with John.
> >
> > A minor point:  it would be nice if in toolbar2 the currently active
> > zoom or pan tool was highlighted in some way.

depending on the backend, it already is...(see fltk for example). I
think it is not too difficult to add this for other backends...but only
the other backends developers can tell :-)
It is also available in the message area (nothing, or "pan/zoom mode",
or "zoom to rect mode" is written before the cursor coordinates). 

> Also a minor point on toolbar2, I have a suggestion for the zoom tool. If one 
> wanted to zoom in on the a region near the corner or edge of a plot, I think 
> it would be helpful if the zoom tool would remember the lower limits of the 
> axis where the pointer exits the axis. The way it works now, you have to be 
> sure to have the pointer on that last pixel inside the axis boundary when you 
> release the mouse button.

Good point, the behavior was intentional (as a way to cancel a zoom when
you started it and though afterward is was not such a good idea), but I
have also found this to be more annoying than useful, and anyway the
back button is already there ready to help you cancel any action...
I will have a look at this to change the behavior (it should check the
coordinates of the zoom rect, and adjust it to clip to current axes
limits)

On Thursday 02 December 2004 04:12 am, Norbert Nemec wrote:
> Hi there,
>
> probably a trivial question, but somehow, I'm stuck anyway:
>
> I have the following script:
>
> ----------
> #!/usr/bin/env python
> import matplotlib.matlab
> ... do some data preparation ...
> plot(something)
> show()
> savefig("output.eps")
> ----------
>
> If I call this script with the -dGtkAgg option, it displays the plot on
> screen and saves an empty eps file. If I call it with -dPS, it displays
> nothing and outputs the correct eps - so far everything as I would expect
> it.
>
> Up to now, I just used the -dGtkAgg backend (as default) to get an
> impression about the plots and then ran the script again to create the
> .eps.
>
> Now, I would like the script to do both in one run: display the plot on
> screen, and save it to disk at the same time.
>
> Somehow I have not achieved doing so. My first idea was to place
>  matplotlib.use('PS')
> right before the savefig, but that does not change anything and still
> writes an empty .eps file.
>
> What should I do?
>

Hi Norbert,

Try running this:

----------
#!/usr/bin/env python
matplotlib.use('GTKAgg')
import matplotlib.matlab
... do some data preparation ...
plot(something)
savefig("output.eps")
show()
----------

That should save the file as eps and show the plot using the GTK backend. 
matplotlib.use('PS') would have to be called before importing 
matplotlib.matlab, which is why it seemed unresponsive in your script. But 
you dont need to call it for what you want to accomplish.


-- 

Darren

Hi there,

probably a trivial question, but somehow, I'm stuck anyway:

I have the following script:

----------
#!/usr/bin/env python
import matplotlib.matlab
... do some data preparation ...
plot(something)
show()
savefig("output.eps")
----------

If I call this script with the -dGtkAgg option, it displays the plot on screen 
and saves an empty eps file. If I call it with -dPS, it displays nothing and 
outputs the correct eps - so far everything as I would expect it.

Up to now, I just used the -dGtkAgg backend (as default) to get an impression 
about the plots and then ran the script again to create the .eps.

Now, I would like the script to do both in one run: display the plot on 
screen, and save it to disk at the same time.

Somehow I have not achieved doing so. My first idea was to place
 matplotlib.use('PS')
right before the savefig, but that does not change anything and still writes 
an empty .eps file.

What should I do?

Thanks,
Norbert

-- 
_________________________________________Norbert Nemec
         Bernhardstr. 2 ... D-93053 Regensburg
     Tel: 0941 - 2009638 ... Mobil: 0179 - 7475199
           eMail: <No...@Ne...>

Hi all,
 
I tried to visualize the structure of large and sparse matrices using

from matplotlib.colors import LinearSegmentedColormap
from matplotlib.matlab import *
from scipy import *
import IPython

def spy2(Z):
    """
    SPY(Z) plots the sparsity pattern of the matrix S as an image
    """

    #binary colormap min white, max black
    cmapdata = {
         'red'  :  ((0., 1., 1.), (1., 0., 0.)),
         'green':  ((0., 1., 1.), (1., 0., 0.)),
         'blue' :  ((0., 1., 1.), (1., 0., 0.))
         }
    binary =  LinearSegmentedColormap('binary',  cmapdata, 2)

    Z = where(Z>0,1.,0.)
    imshow(transpose(Z), interpolation='nearest', cmap=binary)

rows, cols, entries, rep, field, symm = io.mminfo('k0.mtx')
print 'number of rows, cols and entries', rows, cols, entries
print 'Start reading matrix - this may take a minute'
ma = io.mmread('k0.mtx')
print 'Finished'
flag = 1
if flag == 1:
 spy2(ma)
 show()

It failed. Is it somehow possible to visualize sparse matrices ?
Any suggestion would be appreciated.

Thanks in advance

                                     Nils

number of rows, cols and entries 67986 67986 4222171
Start reading matrix - this may take a minute
Finished
Traceback (most recent call last):
  File "spy.py", line 29, in ?
    spy2(ma)
  File "spy.py", line 19, in spy2
    Z = where(Z>0,1.,0.)
  File "/usr/lib/python2.3/site-packages/scipy/sparse/Sparse.py", line 145, in __cmp__
    raise TypeError, "Comparison of sparse matrices is not implemented."
TypeError: Comparison of sparse matrices is not implemented.

On Wednesday 01 December 2004 07:34 pm, Stephen Walton wrote:
> On Tue, 2004-11-30 at 17:06 -0500, Perry Greenfield wrote:
> > Yesterday I brought up some user interface issues with John.
>
> A minor point:  it would be nice if in toolbar2 the currently active
> zoom or pan tool was highlighted in some way.

Also a minor point on toolbar2, I have a suggestion for the zoom tool. If one 
wanted to zoom in on the a region near the corner or edge of a plot, I think 
it would be helpful if the zoom tool would remember the lower limits of the 
axis where the pointer exits the axis. The way it works now, you have to be 
sure to have the pointer on that last pixel inside the axis boundary when you 
release the mouse button.

-- 

Darren

John Hunter wrote:

>Plea to distutils gurus: if you can figure out a way in the current
>matplotlib setup.py setup to get a module named pylab.py into
>site-packages, please advise!  The current module layout is somewhat
>complicated and already stretches my distutils capabilities.
>  
>

I wouldn't call myself a distutils guru, but is this what you mean?

#!/usr/bin/env python
from distutils.core import setup

setup(py_modules=['pylab'],
      package_dir = {'':'path/to/where/pylab.py/source/is/located'})

The that the polar plot overlayed on a rectangular plot is working in 
Postscipt, I am having trouble with the semi-transparent boxes around 
the text.

The png file looks fine, but the postcript file does not show the 
differences in the alpha value.

Since the code is short, I'll supply it here:

#!/usr/bin python
from matplotlib.matlab import *

def OverlayText(xmax):
	x=0
	y = 0.65*xmax
	ystep = 0.2*xmax
	alpha = arange(0.0,1.2,0.2)

	
	for a in alpha:
		stext = 'Alpha = %.1f' % a
		t = text(x,y,stext)
		set(t,bbox={'edgecolor':'w','facecolor':'w','alpha':a})
		y = y - ystep


if __name__ == "__main__":
	# Make some kind of plot

	xmin = -750
	xmax = 750
	ymin = xmin
	ymax = xmax
	x = [xmin,xmax,xmax,xmin]
	y = [ymin,ymin,ymax,ymax]
	fill(x,y,'g',edgecolor='b')
	a = gca()
	a.set_xlim([xmin,xmax])
	a.set_ylim([ymin,ymax])


	OverlayText(xmax)

	savefig('overlay2.png')
	savefig('overlay2.ps')

	show()


-- 
Ms. Carol A. Leger
SRI International			Phone: (650) 859-4114
333 Ravenswood Avenue G-273
Menlo Park, CA 94025                    e-mail: le...@sr...

I don't know where the problem is and I know Fernando is out there
somewhere.  Try the following:

In [2]: import numarray.random_array as ra
=20
In [3]: x=3Dra.random((50,50))
=20
In [4]: x.size()
Out[4]: 2500
=20
In [5]: imshow(x)
Out[5]: <matplotlib.image.AxesImage instance at 0x5658c7cc>
=20
In [6]: axis('square')
=20
After the last step you get an error dialog, but clicking OK causes the
whole session to hang.  IPython and matplotlib both at version 0.64,
running on Fedora Core 2, numerix: numarray, backend: GTKAgg.

I know now that the last command is incorrect :-), but it is something a
naive MATLAB user coming to matplotlib/ipython for the first time is
likely to try.

--=20
Stephen Walton, Professor, Dept. of Physics & Astronomy, Cal State Northrid=
ge
ste...@cs...

On Tue, 2004-11-30 at 17:06 -0500, Perry Greenfield wrote:
> Yesterday I brought up some user interface issues with John.

A minor point:  it would be nice if in toolbar2 the currently active
zoom or pan tool was highlighted in some way.

--=20
Stephen Walton, Professor, Dept. of Physics & Astronomy, Cal State Northrid=
ge
ste...@cs...

Hello, I have a simple script that creates a few plots. Although the
script is in a while loop and creates plots endlessly, what I want is to
have one plot that is updated. How can I tell my script to update a
figure rather than create a new one? Thanks.
 
I'm using the WX backend. Thanks.
 
 

>>>>> "Carol" == Carol Leger <car...@sr...> writes:

    >> Yep, this is a bug.  In backend_ps in the the set_linedashes
    >> function on line 103, replace the line if seq: with if seq is
    >> not None and len(seq): My guess is you are using numarray, and
    >> if memory serves numarray but not Numeric fails on using an
    >> array as a boolean, which is what backend ps is doing here.
    >> 
    Carol> Yes, I am using numarray.  I made the change to line 103
    Carol> and now line 102 is reporting a similar error.

Ignore my last post - the solution I posted was as buggy as before.  I
think I finally nailed this down.  Basically, we are comparing seq1
and seq2, either are possibly None, or general sequences, or arrays.
I wrote a little function

def seq_allequal(seq1, seq2):
    """
    seq1 and seq2 are either None or sequences or numerix arrays
    Return True if both are None or both are seqs with identical
    elements
    """
    if seq1 is None:
        return seq2 is None

    if seq2 is None:
        return False
    #ok, neither are None:, assuming iterable
        
    if len(seq1) != len(seq2): return False
    return alltrue(equal(seq1, seq2))

You should import alltrue and equal from the numerix module at the top
of backend_ps, add this function to backend_ps and then replace
set_linedash with

    def set_linedash(self, offset, seq):        
        if self.linedash is not None:
            oldo, oldseq = self.linedash
            if seq_allequal(seq, oldseq): return
            
        if seq is not None and len(seq):
            s="[%s] %d setdash\n"%(_nums_to_str(*seq), offset)
            self._pswriter.write(s)
        else:
            self._pswriter.write("[] 0 setdash\n")
        self.linedash = (offset,seq)


I think this is finally coherent.  At least it passes my tests now...

JDH

>>>>> "Gregory" == Gregory Lielens <gre...@ff...> writes:

    Gregory> I though that calling draw() would update the active
    Gregory> figure without starting the mainloop already, or am I
    Gregory> confused? Alternatively, in the fltk backend, I have
    Gregory> allowed calling show() multiple times, it just check
    Gregory> before running the mainloop that it is not already
    Gregory> running...Maybe this is also feasible in a more general
    Gregory> way?

The matlab interface draw function does not need the renderer passed
as an arg (the FigureCanvas.draw method does) and it is intended for
interactive use when you want to force a redraw

  >>> o = title('blah')
  >>> o.set_fontsize(12)         # no draw
  >>> o.set_fontstyle('italic')  # no draw
  >>> draw()                     # draw

Perry and I discussed trying to come up with some python magic such
that calls to setattr on an artist would trigger a call to
the matlab interface draw_if_interactive.  This would have to be done
carefully, because some users will explicitly not want to force a
redraw on any call to a setter since drawing is potentially an
expensive operation.  True, they could temporarily turn interaction
off, but I think any solution here would need to be optional.

JDH