Unit converters now handle instances of subclasses

Unit converters now also handle instances of subclasses of the class they have

been registered for.

`~pyplot.imsave` gained support for the ``metadata`` and ``pil_kwargs`` parameters

These parameters behave similarly as for the `Figure.savefig()` method.

`cbook.normalize_kwargs` can be used to normalize artist property names

`cbook.normalize_kwargs` now presents a convenient interface to normalize

artist properties (e.g., from "lw" to "linewidth"):

>>> cbook.normalize_kwargs({"lw": 1}, Line2D)

The first argument is the mapping to be normalized, and the second argument can

be an artist class or an artist instance (it can also be a mapping in a

specific format; see the function's docstring for details).

The *fname* argument to `FontProperties` can now be an `os.PathLike`\s

e.g. ``FontProperties(fname=pathlib.Path("/path/to/font.ttf"))``.

Gouraud-shaded mesh alpha channels in the pdf backend

The pdf backend now supports an alpha channel in Gouraud-shaded

triangle meshes.

Kerning adjustments now use correct values

Due to an error in how kerning adjustments were applied, previous versions of

Matplotlib would under-correct kerning. This version will now correctly apply

kerning (for fonts supported by FreeType). To restore the old behavior (e.g.,

for test images), you may set :rc:`text.kerning_factor` to 6 (instead of 0).

Other values have undefined behavior.

.. plot::

import matplotlib.pyplot as plt

# Use old kerning values:

plt.rcParams['text.kerning_factor'] = 6

fig, ax = plt.subplots()

ax.text(0.0, 0.05, 'BRAVO\nAWKWARD\nVAT\nW.Test', fontsize=56)

ax.set_title('Before (text.kerning_factor = 6)')

Note how the spacing between characters is uniform between their bounding boxes

(above). With corrected kerning (below), slanted characters (e.g., AV or VA)

will be spaced closer together, as well as various other character pairs,

depending on font support (e.g., T and e, or the period after the W).

.. plot::

import matplotlib.pyplot as plt

# Use new kerning values:

plt.rcParams['text.kerning_factor'] = 0

fig, ax = plt.subplots()

ax.text(0.0, 0.05, 'BRAVO\nAWKWARD\nVAT\nW.Test', fontsize=56)

ax.set_title('After (text.kerning_factor = 0)')

bar3d gained support for the ``lightsource`` parameter

bar3d now supports lighting from different angles when the *shade* parameter is

True.

Errorbar plots can shift which points have error bars

Previously, `plt.errorbar()` accepted a kwarg `errorevery` such that the

command `plt.errorbar(x, y, yerr, errorevery=6)` would add error bars to

datapoints `x[::6], y[::6]`.

`errorbar()` now also accepts a tuple for `errorevery` such that

`plt.errorbar(x, y, yerr, errorevery=(start, N))` adds error bars to points

`x[start::N], y[start::N]`.

Errorbar plots can shift which points have error bars

Previously, `plt.errorbar()` accepted a kwarg `errorevery` such that the

command `plt.errorbar(x, y, yerr, errorevery=6)` would add error bars to

datapoints `x[::6], y[::6]`.

`errorbar()` now also accepts a tuple for `errorevery` such that

`plt.errorbar(x, y, yerr, errorevery=(start, N))` adds error bars to points

`x[start::N], y[start::N]`.

Improvements in Logit scale ticker and formatter

Introduced in version 1.5, the logit scale didn't have an appropriate ticker and

formatter. Previously, the location of ticks was not zoom dependent, too many labels

were displayed causing overlapping which broke readability, and label formatting

did not adapt to precision.

Starting from this version, the logit locator has nearly the same behavior as the

locator for the log scale or the linear

scale, depending on used zoom. The number of ticks is controlled. Some minor

labels are displayed adaptively as sublabels in log scale. Formatting is adapted

for probabilities and the precision is adapts to the scale.

rcParams for default axes title location and color

Two new rcParams have been added: ``axes.titlelocation`` denotes the default axes title

alignment, and ``axes.titlecolor`` the default axes title color.

Valid values for ``axes.titlelocation`` are: left, center, and right.

Valid values for ``axes.titlecolor`` are: auto or a color. Setting it to auto

will fall back to previous behaviour, which is using the color in ``text.color``.

3-digit and 4-digit hex colors

Colors can now be specified using 3-digit or 4-digit hex colors, shorthand for

the colors obtained by duplicating each character, e.g. ``#123`` is equivalent to

``#112233`` and ``#123a`` is equivalent to ``#112233aa``.

.. include:: prev_whats_new/whats_new_3.2.0.rst