Changes in 1.2.x¶

The classic option of the rc parameter toolbar is deprecated and will be removed in the next release.
The matplotlib.cbook.isvector method has been removed since it is no longer functional.
The rasterization_zorder property on Axes sets a zorder below which artists are rasterized. This has defaulted to -30000.0, but it now defaults to None, meaning no artists will be rasterized. In order to rasterize artists below a given zorder value, set_rasterization_zorder must be explicitly called.
In scatter(), and scatter, when specifying a marker using a tuple, the angle is now specified in degrees, not radians.
Using twinx() or twiny() no longer overrides the current locaters and formatters on the axes.
In contourf(), the handling of the extend kwarg has changed. Formerly, the extended ranges were mapped after to 0, 1 after being normed, so that they always corresponded to the extreme values of the colormap. Now they are mapped outside this range so that they correspond to the special colormap values determined by the set_under() and set_over() methods, which default to the colormap end points.
The new rc parameter savefig.format replaces cairo.format and savefig.extension, and sets the default file format used by matplotlib.figure.Figure.savefig().
In pyplot.pie() and axes.Axes.pie(), one can now set the radius of the pie; setting the radius to 'None' (the default value), will result in a pie with a radius of 1 as before.

Use of matplotlib.projections.projection_factory is now deprecated in favour of axes class identification using matplotlib.projections.process_projection_requirements followed by direct axes class invocation (at the time of writing, functions which do this are: add_axes(), add_subplot() and gca()). Therefore:

key = figure._make_key(*args, **kwargs)
ispolar = kwargs.pop('polar', False)
projection = kwargs.pop('projection', None)
if ispolar:
    if projection is not None and projection != 'polar':
        raise ValueError('polar and projection args are inconsistent')
    projection = 'polar'
ax = projection_factory(projection, self, rect, **kwargs)
key = self._make_key(*args, **kwargs)

# is now

projection_class, kwargs, key = \
                   process_projection_requirements(self, *args, **kwargs)
ax = projection_class(self, rect, **kwargs)

This change means that third party objects can expose themselves as Matplotlib axes by providing a _as_mpl_axes method. See Developer's guide for creating scales and transformations for more detail.

A new keyword extendfrac in colorbar() and ColorbarBase allows one to control the size of the triangular minimum and maximum extensions on colorbars.
A new keyword capthick in errorbar() has been added as an intuitive alias to the markeredgewidth and mew keyword arguments, which indirectly controlled the thickness of the caps on the errorbars. For backwards compatibility, specifying either of the original keyword arguments will override any value provided by capthick.
Transform subclassing behaviour is now subtly changed. If your transform implements a non-affine transformation, then it should override the transform_non_affine method, rather than the generic transform method. Previously transforms would define transform and then copy the method into transform_non_affine:
```
class MyTransform(mtrans.Transform):
    def transform(self, xy):
        ...
    transform_non_affine = transform
```
This approach will no longer function correctly and should be changed to:
```
class MyTransform(mtrans.Transform):
    def transform_non_affine(self, xy):
        ...
```
Artists no longer have x_isdata or y_isdata attributes; instead any artist's transform can be interrogated with artist_instance.get_transform().contains_branch(ax.transData)

Lines added to an axes now take into account their transform when updating the data and view limits. This means transforms can now be used as a pre-transform. For instance:

>>> import matplotlib.pyplot as plt
>>> import matplotlib.transforms as mtrans
>>> ax = plt.axes()
>>> ax.plot(range(10), transform=mtrans.Affine2D().scale(10) + ax.transData)
>>> print(ax.viewLim)
Bbox('array([[  0.,   0.],\n       [ 90.,  90.]])')

One can now easily get a transform which goes from one transform's coordinate system to another, in an optimized way, using the new subtract method on a transform. For instance, to go from data coordinates to axes coordinates:
```
>>> import matplotlib.pyplot as plt
>>> ax = plt.axes()
>>> data2ax = ax.transData - ax.transAxes
>>> print(ax.transData.depth, ax.transAxes.depth)
3, 1
>>> print(data2ax.depth)
2
```
for versions before 1.2 this could only be achieved in a sub-optimal way, using ax.transData + ax.transAxes.inverted() (depth is a new concept, but had it existed it would return 4 for this example).
twinx and twiny now returns an instance of SubplotBase if parent axes is an instance of SubplotBase.
All Qt3-based backends are now deprecated due to the lack of py3k bindings. Qt and QtAgg backends will continue to work in v1.2.x for py2.6 and py2.7. It is anticipated that the Qt3 support will be completely removed for the next release.
matplotlib.colors.ColorConverter, Colormap and Normalize now subclasses object
ContourSet instances no longer have a transform attribute. Instead, access the transform with the get_transform method.