matplotlib-users

[Matplotlib-users] Circle Collection

[sidimok <si...@gm...>]

Hi everyone, 

The code below was working for me as a charm, but since the new matlplotlib
flavor 0.98, I'm getting this error message: 

>> AttributeError: 'CirclePolygon' object has no attribute 'get_verts' << 

Any idea?

- - - - - - - - - - - - - - - - - - -
 
import matplotlib 
from matplotlib.patches import CirclePolygon 
from matplotlib.collections import PolyCollection 
import pylab 

fig=pylab.figure() 
ax=fig.add_subplot(111) 

resolution = 50 # the number of vertices 
N = 20 
x       = pylab.rand(N) 
y       = pylab.rand(N) 
radii   = 0.1*pylab.rand(N) 
colors  = 100*pylab.rand(N) 
verts   = [] 
for x1,y1,r in zip(x, y, radii): 
    circle = CirclePolygon((x1,y1), r, resolution) 
    verts.append(circle.get_verts()) 
    
p = PolyCollection(verts, cmap=matplotlib.cm.jet) 
p.set_array(pylab.array(colors)) 
ax.add_patch(p) 
pylab.colorbar(p) 

ax.axis('equal') 
pylab.show() 

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Re: [Matplotlib-users] Circle Collection

[Michael D. <md...@st...>]

You've hit one of the changed APIs in 0.98.  You can see the list of 
changed APIs here:

http://matplotlib.svn.sourceforge.net/viewvc/*checkout*/matplotlib/trunk/matplotlib/API_CHANGES

Patches no longer store lists of vertices, they store Path objects + 
Affine transforms.  So rather than "get_verts()", you can use the 
admittedly obtuse "circle.get_transform().transform(get_path().vertices)".

Note also another change is required in your script for something that 
probably only worked by accident before.  The "ax.add_patch(p)" should 
be "ax.add_collection(p)", since p is a PolyCollection.

Now -- for the other developers on this list:  We may want to add a 
.get_verts() function back to patches that does exactly what I recommend 
above.  It won't behave identically to 0.91 since it will return a 
transformed copy of the vertices, but that won't matter in all cases 
(such as this one).

We may want to add a PatchCollection class that takes a list of patches, 
so users don't have to manually take patches apart like this.  This is 
now possible because all patches are basically the same thing.  This 
would also make it easier to use an bezier-approximated Ellipse rather 
than a polygonal approximated one.

Cheers,
Mike

sidimok wrote:
> Hi everyone, 
>
> The code below was working for me as a charm, but since the new matlplotlib
> flavor 0.98, I'm getting this error message: 
>
>   
>>> AttributeError: 'CirclePolygon' object has no attribute 'get_verts' << 
>>>       
>
> Any idea?
>
> - - - - - - - - - - - - - - - - - - -
>  
> import matplotlib 
> from matplotlib.patches import CirclePolygon 
> from matplotlib.collections import PolyCollection 
> import pylab 
>
> fig=pylab.figure() 
> ax=fig.add_subplot(111) 
>
> resolution = 50 # the number of vertices 
> N = 20 
> x       = pylab.rand(N) 
> y       = pylab.rand(N) 
> radii   = 0.1*pylab.rand(N) 
> colors  = 100*pylab.rand(N) 
> verts   = [] 
> for x1,y1,r in zip(x, y, radii): 
>     circle = CirclePolygon((x1,y1), r, resolution) 
>     verts.append(circle.get_verts()) 
>     
> p = PolyCollection(verts, cmap=matplotlib.cm.jet) 
> p.set_array(pylab.array(colors)) 
> ax.add_patch(p) 
> pylab.colorbar(p) 
>
> ax.axis('equal') 
> pylab.show() 
>
>   

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

Re: [Matplotlib-users] Circle Collection

[John H. <jd...@gm...>]

On Tue, Jun 17, 2008 at 7:34 AM, Michael Droettboom <md...@st...> wrote:

> Now -- for the other developers on this list:  We may want to add a
> .get_verts() function back to patches that does exactly what I recommend
> above.  It won't behave identically to 0.91 since it will return a
> transformed copy of the vertices, but that won't matter in all cases
> (such as this one).

Hmm, we are asking each other the same question in different threads :-)

  http://sourceforge.net/mailarchive/forum.php?thread_name=88e473830806161822u418bad86hada6ed655dee77bc%40mail.gmail.com&forum_name=matplotlib-users

I committed this method.

JDH

Re: [Matplotlib-users] Circle Collection

[Michael D. <md...@st...>]

My e-mail has been kind of sporadic this morning... but we seem to be in 
agreement.

Just realised get_verts could actually be slightly better --

If we use Path.to_polygons() then any curves in the patch will get 
converted to line segments.  Then even patches like Ellipse and Arc will 
work and do the expected thing.  I've committed this (along with a small 
bugfix to to_polygons).

Cheers,
Mike

John Hunter wrote:
> On Tue, Jun 17, 2008 at 7:34 AM, Michael Droettboom <md...@st...> wrote:
>
>   
>> Now -- for the other developers on this list:  We may want to add a
>> .get_verts() function back to patches that does exactly what I recommend
>> above.  It won't behave identically to 0.91 since it will return a
>> transformed copy of the vertices, but that won't matter in all cases
>> (such as this one).
>>     
>
> Hmm, we are asking each other the same question in different threads :-)
>
>   http://sourceforge.net/mailarchive/forum.php?thread_name=88e473830806161822u418bad86hada6ed655dee77bc%40mail.gmail.com&forum_name=matplotlib-users
>
> I committed this method.
>
> JDH
>   

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

Re: [Matplotlib-users] Circle Collection

[sidimok <si...@gm...>]

Thank you very much indeed guys, you made my day. =)
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