Re: [Matplotlib-users] converting data between axis [0, 1] and data coordinates [min data, max data]

[Tony S Yu <to...@MI...>]

On Jun 30, 2008, at 11:13 AM, Michael Droettboom wrote:
> transScale is where all of the (optionally) logarithmic  
> transformation takes place.  I'm surprised
>
> >>> transDesired = self.transScale + self.transLimits
>
> didn't work for going from data to a (0, 0) - (1, 1) bounding box.   
> Can you provide a small, yet complete, example that illustrates the  
> bug so I can look at it further?

I tried to put together a simple example showing my problem, but the  
example worked properly! Doh!

It turns out that my problem was specific to using a bounding box as  
an input to transform:

=========
from numpy.random import rand
import matplotlib.pyplot as plt

ax = plt.subplot(111)
xy = rand(5,2)
ax.loglog(xy[:, 0], xy[:, 1], 'ro')

trans = ax.transScale + ax.transLimits
result = trans.transform(ax.dataLim)
=========

The above command gives me:
     TypeError: 'Bbox' object is unsubscriptable
(Note, if I call `plot` instead of `loglog` I don't have problems).  
The quick solution is to replace the last line with

 >>> result = trans.transform(ax.dataLim._points)

I guess I was confused because the transform worked fine with `plot`.  
Is the TypeError above expected behavior?

Thanks for your help.
-Tony