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José Gómez-Dans wrote:
> Hi,
> I have written a quick'n'dirty image segmentation algorithm. It seems to work 
> fine. However, I am interested in getting contours of the segments 
> (essentially, (x,y) pairs of the edges of each segment). I can plot the 
> contours with MPL (pylab.contour()), but I'd like to have the locations of 
> the edges, so that I can actually do something with them. 
> 
> Does anyone have any hints on how to go on about this?

cs = contour(Z)
for lev, col in zip(cs.levels, cs.collections):
     s = col._segments


s will be a list of numpy arrays, each containing the (x,y) vertices 
defining a contour line at level lev.

This illustrates a shortcoming of the contour and/or LineCollection 
code; to get what I think you want, you have to use a private attribute, 
_segments. It should be part of the public API. After some other changes 
and reorganizations in mpl have settled down, I will fix this.  Feel 
free to send me a reminder in a month.

Eric

Peter I. Hansen wrote:
> On Nov 30, 2007 4:58 PM, Michael Droettboom <md...@st...> wrote:
>> Peter I. Hansen wrote:
>>> Hi
>>>
>>> I'm typestting some graphs including a few axvspan's with eg. a
>>> facecolor='0.6' . This looks very nice if I output a PNG, but when I
>>> inculde this in my TeX document the axis labels dosn't scale. Then I
>>> try to go the postscript way, and the the labels scale nicely but the
>>> colored fields of axvspan prints as a coarse raster color.
>> I assume you mean that the axvspan prints as a solid color, rather than
>> semi-transparent (alpha-blended).  That is an unfortunate limitation of
>> the Postscript format -- it can not handle transparency.
> 
> Yes, I'm using a solid color.
> 
>>> Is there a best way of optimizing print quality?
>> Each of the output formats has a number of different limitations -- it
>> depends a lot on what you're rendering and where you need it to go.
>>
>> You could try saving as a PDF, and then using pdftex to generate your
>> document, if that's an option for you.
> 
> Unfortunately, saving directly as PDF does not work on my (Debian)
> system. It gives a "NotImplementedError". I'm using version 0.90.1,
> and maybe this will change for 0.91 .

Can you please send the full traceback that accompanies this error?  PDF 
should be working is general, but perhaps you are running into a 
specific feature of the PDF backend that is not working, and there may 
be a workaround (or 0.91 may work)...

Cheers,
Mike

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

On Nov 30, 2007 4:58 PM, Michael Droettboom <md...@st...> wrote:
> Peter I. Hansen wrote:
> > Hi
> >
> > I'm typestting some graphs including a few axvspan's with eg. a
> > facecolor='0.6' . This looks very nice if I output a PNG, but when I
> > inculde this in my TeX document the axis labels dosn't scale. Then I
> > try to go the postscript way, and the the labels scale nicely but the
> > colored fields of axvspan prints as a coarse raster color.
>
> I assume you mean that the axvspan prints as a solid color, rather than
> semi-transparent (alpha-blended).  That is an unfortunate limitation of
> the Postscript format -- it can not handle transparency.

Yes, I'm using a solid color.

> > Is there a best way of optimizing print quality?
>
> Each of the output formats has a number of different limitations -- it
> depends a lot on what you're rendering and where you need it to go.
>
> You could try saving as a PDF, and then using pdftex to generate your
> document, if that's an option for you.

Unfortunately, saving directly as PDF does not work on my (Debian)
system. It gives a "NotImplementedError". I'm using version 0.90.1,
and maybe this will change for 0.91 .

Peter I. Hansen wrote:
> Hi
> 
> I'm typestting some graphs including a few axvspan's with eg. a
> facecolor='0.6' . This looks very nice if I output a PNG, but when I
> inculde this in my TeX document the axis labels dosn't scale. Then I
> try to go the postscript way, and the the labels scale nicely but the
> colored fields of axvspan prints as a coarse raster color.

I assume you mean that the axvspan prints as a solid color, rather than 
semi-transparent (alpha-blended).  That is an unfortunate limitation of 
the Postscript format -- it can not handle transparency.

> Is there a best way of optimizing print quality?

Each of the output formats has a number of different limitations -- it 
depends a lot on what you're rendering and where you need it to go.

You could try saving as a PDF, and then using pdftex to generate your 
document, if that's an option for you.

Cheers,
Mike

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

Hi

I'm typestting some graphs including a few axvspan's with eg. a
facecolor='0.6' . This looks very nice if I output a PNG, but when I
inculde this in my TeX document the axis labels dosn't scale. Then I
try to go the postscript way, and the the labels scale nicely but the
colored fields of axvspan prints as a coarse raster color.
Is there a best way of optimizing print quality?

-Peter

Hi,
I have written a quick'n'dirty image segmentation algorithm. It seems to work 
fine. However, I am interested in getting contours of the segments 
(essentially, (x,y) pairs of the edges of each segment). I can plot the 
contours with MPL (pylab.contour()), but I'd like to have the locations of 
the edges, so that I can actually do something with them. 

Does anyone have any hints on how to go on about this?

Thanks!
Jose

I don't know if I dreamed it or was real, but I recall seeing somewhere 
that it was possible to add a control to the navigation bar, but now 
cannot seem to find any reference to this.

Is is possible to add a control to the navigation bar? (I want to add a 
drop down box)
I am using pyGtk, can add to somewhere else in my form, .. but it makes 
logical sense if it is on the navigation bar.

Any suggestions?
Thanks
Steve