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Thanks Mike.
> I'm not quite sure what the above lines are meant to do.
> matplotlib.transforms doesn't have a Polar member --
> matplotlib.projections.polar.Polar does not have a PolarTransform member
> (on master or your polar_fun branch). Even given that, I think the user
> should be specifying a projection, not a transformation, to create a new
> axes. There is potential for confusion that some transformations will
> allow getting a projection out and some won't (for some it doesn't even
> really make sense).
That was meant to be
matplotlib.projections.polar.PolarAxes.PolarTransform but your right,
defining the "projection" in the transform could lead to confusion,
yet initialising an Axes as a projection seems like unnecessary
complexity. This suggests that defining a "projection" class which is
neither Transform nor Axes might make the most sense (note, what
follows is pseudo code and does not exist in the branch):
>>> polar_proj = Polar(theta0=np.pi/2)
>>> ax = plt.axes(projection=polar_proj)
>>> print ax.projection
Polar(theta0=1.57)
The PolarAxes would be initialised with the Projection instance, and
the PolarAxes can initialise the PolarTransform with a reference to
that projection. Thus changing the theta0 of the projection in the
Axes would also change the projection which is used in the Transform
instance, i.e.:
ax.projection.theta0 = 3*np.pi/2
Would change the way that the overall axes looked.
Interestingly, the work that I have been doing which requires the
aforementioned pull request is doing precisely this - I have
projection classes, one for each type of projection, but where each
type of projection is parameterised, which, when passed through
plt.axes(projection=<my projection class>) instantiate a generic
"GenericProjectionAxes", which itself instantiates a generic
"GenericProjectionTransform" (names for illustration purposes only)
all the while the original projection is mutable via the
MultiProjectionAxes.projection attribute.
Did you have any feelings on the pull request?
Thanks again for your time,
Phil