matplotlib-users Mailing List for matplotlib

Chris Fonnesbeck wrote:
> On Mon, 07 Feb 2005 10:47:51 -0800, Chris Barker <Chr...@no...> wrote:
>>John Hunter wrote
>>>    Chris> I am wondering if it would be worthwhile making TkAgg the
>>>    Chris> default backend in an OSX binary, since the current default
>>>    Chris> kills the python process:
>>>Yes, that is what I do for win32.
>>Except that Tk is not installed by default in OS-X either. It is
>>probably more common than GTK, however.
> Right, maybe PS would be a more sensible default, although I'm willing
> to bet most users end up using Tk.

I'd vote for Agg. Postscript is not the native format on OS-X that it is 
on other unices.

Is there a way to make the default back-end system dependent on install?

-Chris


-- 
Christopher Barker, Ph.D.
Oceanographer
                                     		
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Chr...@no...

kristen kaasbjerg wrote:

>Hola
>
>When i try to fit a polynomial of order 4 to 5 data
>points, I get an answer far from what I would expect.
>  
>
If I run your script and print out the polynomial coefficients, they are 
very large and alternate in sign:

In [166]: p
Out[166]:
array([ -1779.1645838 ,   7613.24170642, -12137.79572888,
         8529.6429996 ,  -2239.34146635])

This means that the problem is ill posed.  In general, high order 
polynomial fitting is a bad idea;  if you just want an interpolant and 
don't care about coefficients, use a cubic spline.

Hi,

I recently got matplotlib working on OSX (only agg so far) and am now 
trying to create a picture with two overlayed images so that only a certain 
range of values of the top-most figure are blended with the bottom one.

The first image would be plotted with the gray palette:
im_bottom=figimage(bottom_data,xo=0, yo=0,cmap=cm.gray)

The second image would be in colors:
im_top=figimage(top_data,xo=0, yo=0,cmap=cm.hot)

I would like to 'threshold' the top figure so that only values, say, 
greater than 30 are plotted with 'hot' colors and elsewhere the gray 
im_bottom is shown (without blending it with the colors of im_top).

I was hoping that I could do something easy like this:
im_top=figimage(where(less(data_top,30),do_not_plot_this_value,data_top),xo=0,yo=0,cmap=cm.hot,alpha=0.5)

How to do this?
Do I have to combine the RGB values of the two images 'manually'?


Cheers,


--
Teemu Rinne

John Hunter wrote:
>     Chris> I am wondering if it would be worthwhile making TkAgg the
>     Chris> default backend in an OSX binary, since the current default
>     Chris> kills the python process:
> 
> Yes, that is what I do for win32.

Except that Tk is not installed by default in OS-X either. It is 
probably more common than GTK, however.

-Chris



-- 
Christopher Barker, Ph.D.
Oceanographer
                                     		
NOAA/OR&R/HAZMAT         (206) 526-6959   voice
7600 Sand Point Way NE   (206) 526-6329   fax
Seattle, WA  98115       (206) 526-6317   main reception

Chr...@no...

>>>>> "Chris" == Chris Fonnesbeck <fon...@gm...> writes:

    Chris> I am wondering if it would be worthwhile making TkAgg the
    Chris> default backend in an OSX binary, since the current default
    Chris> kills the python process:

Yes, that is what I do for win32.

JDH

I am wondering if it would be worthwhile making TkAgg the default
backend in an OSX binary, since the current default kills the python
process:

Python 2.3 (#1, Sep 13 2003, 00:49:11) 
[GCC 3.3 20030304 (Apple Computer, Inc. build 1495)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import pylab
No module named pygtk
PyGTK version 1.99.16 or greater is required to run the GTK Matplotlib backends

Hi folks-

I have had matplotlib working on OS X (Panther) for a while.  However,
I haven't used it heavily yet, so I don't know if there are problems
hiding under the covers.  I do know that I ran many of the demos
without any problems, both with TkAgg and wx; of course, those that
require GTK would not run.  

By the way, don't try to get it and scipy to work under Jaguar.
I spent several days attempting this, with lots of back and forth
with the scipy and macpython list folks, with no luck.  The $100
upgrading to Panther was a small price compared to the time lost
trying to get it all working on Jaguar.

Unfortunately I'm swamped and can't offer any significant assitance
with the OS-X binary issue at the moment.  But I thought one
observation might be useful.  Though I have some Fink stuff on
my Mac, it is only a few things (xfig and gv are the only Fink
things I use).  In particular, I believe the version of Freetype
that my matplotlib is using is not from Fink, but rather one
I installed with the TeX/LaTeX OS X "i-Installer" which can
install a number of useful binary packages besides TeX in a
pretty painless way (freetype2, jpeg/png/tiff libraries,
ghostscript...).  There is more about it here:

http://www.rna.nl/ii.html

I don't think its usefulness beyond TeX is appreciated as
well as it should be, though it certainly is confusing to
have all these different installation mechanims (OS X package
installers, i-Installer packages, setup.py, configure/make...).

-Tom

>>>>> "Andrew" == Andrew Straw <str...@as...> writes:

    Andrew> Again, a no brainer:

Glad you found the answer :-)

See also Fernando's matshow command in CVS.  The data scaling with
aspect='preserve' in imshow is currently broken -- the axes
coordinates on the shorter dimension are wrong and because of this
zoom to rect doesn't do what it should.  Fernando's command works
around this problem by creating a figure and axes with the proper
aspect ratio .  Currently, it only works with arrays, but you could
easily patch it to work with pil images as you did for imshow.

Cheers,
JDH

Andrew Straw wrote:

>
> Now, on to determine how to plot an image with origin='upper' with the 
> extent going the other way...

Again, a no brainer:

(modifications to image_demo3.py)

w,h = lena.size
extent = 0,w,h,0
figure(figsize=figsize)

im = imshow(lena, origin='upper', aspect='preserve', extent=extent)

Andrew Straw wrote:

> Simple question:  how can I plot something such that the y axis is 
> "inverted"?  (Increasing downwards?)

Simple answer:

ymin,ymax= get(gca(),'ylim')
set(gca(),'ylim',[ymax,ymin])

Now, on to determine how to plot an image with origin='upper' with the 
extent going the other way...

Cheers!
Andrew

Simple question:  how can I plot something such that the y axis is 
"inverted"?  (Increasing downwards?)

(I thought I'd better ask before fubaring my copy of mpl's transAxes, 
transData, bbox code and going insane in the process.)

Cheers!
Andrew