matplotlib / matplotlib

Fix image triage tool with Qt6

ENH: Only do constrained layout at draw...

On Linux, the expected image may be a symlink to the repository file,
which causes a crash if you try to copy it over.

Make test_change_epoch more robust.

PR #20733 added module-level `__getattr__` functions to several
modules. All of the functions with the exception of the one in
`matplotlib.style.core` had a terminal `raise AttributeError` to
handle unmatched attributes.

The omission in `matplotlib.style.core` was probably
unintentional; it results in confusing and buggy behavior
such as:

```pycon
>>> import matplotlib.style.core
>>> if hasattr(matplotlib.style.core, '__warningregistry__'):
...     del matplotlib.style.core.__warningregistry__
...
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
AttributeError: __warningregistry__
```

This causes problems in the unit tests for astropy affiliated
packages. See astropy/astropy#12038.

FIX: tickspacing for subfigures

The epoch is set by explicitly calling `mdates.set_epoch`, or implicitly
set to the default by `mdates.get_epoch` (which is also called when
converting datetimes.)

However, when running tests in parallel, there is no guarantee that any
other call to `[gs]et_epoch` might have been made to lock it in, so we
need to do that explicitly.

circle: Switch to next-gen image.

add doc-link to dufte

[1] https://circleci.com/docs/2.0/circleci-images/#next-gen-language-images

MNT: Rename callbacksSM to callbacks

This makes the code more consistent throughout with objects
having a `callbacks` attribute, rather than associating a name
with them on the end.

Re-remove deprecated Qt globals.

These were removed in 15c39a3, but
resurrected in the Qt6 PR.

FIX: don't fail on first show if animation already exhausted

Deprecate globals using module-level `__getattr__`.

FIX: Check for colorbar creation with multi-dimensional alpha

If we need to get the first frame in `_init_draw()` (because the user did not
pass an initialization function) fails, warn instead of raising.

closes #17770

Consistent with other artists and allows properties controlled by `set_XYZ` to
be set at init time.

Co-authored-by: Elliott Sales de Andrade <quantum.analyst@gmail.com>

Change legend guide to object oriented approach

Fix collection offsets

Point [SOURCE] documents to github

Support for PyQt6/PySide6.

This is left over from an early pass at nose -> pytest conversion

If pyqt4 is imported the code just above will catch the problem and
if pyqt4 is not imported we can rely on `plt.switch_backend` to handle
the fallback between pyqt/pyside versions.