Behaviour Changes

plot() shorthand format interprets "Cn" (n>9) as a color-cycle color ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Previously, plot(..., "-C11") would be interpreted as requesting a plot using linestyle "-", color "C1" (color #1 of the color cycle), and marker "1" ("tri-down"). It is now interpreted as requesting linestyle "-" and color "C11" (color #11 of the color cycle).

It is recommended to pass ambiguous markers (such as "1") explicitly using the marker keyword argument. If the shorthand form is desired, such markers can also be unambiguously set by putting them before the color string.

Legend labels for plot ^^^^^^^^^^^^^^^^^^^^^^^^^^

Previously if a sequence was passed to the label parameter of ~.Axes.plot when plotting a single dataset, the sequence was automatically cast to string for the legend label. Now, if the sequence has only one element, that element will be the legend label. To keep the old behavior, cast the sequence to string before passing.

Boxplots now ignore masked data points ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

~matplotlib.axes.Axes.boxplot and ~matplotlib.cbook.boxplot_stats now ignore any masked points in the input data.

axhspan and axvspan now return Rectangle\s, not Polygon\s ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

This change allows using ~.Axes.axhspan to draw an annulus on polar axes.

This change also affects other elements built via ~.Axes.axhspan and ~.Axes.axvspan, such as Slider.poly.

Improved handling of pan/zoom events of overlapping Axes ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The forwarding of pan/zoom events is now determined by the visibility of the background-patch (e.g. ax.patch.get_visible()) and by the zorder of the axes.

Axes with a visible patch capture the event and do not pass it on to axes below. Only the Axes with the highest zorder that contains the event is triggered (if there are multiple Axes with the same zorder, the last added Axes counts)
Axes with an invisible patch are also invisible to events and they are passed on to the axes below.

To override the default behavior and explicitly set whether an Axes should forward navigation events, use .Axes.set_forward_navigation_events.

loc='best' for legend now considers Text and PolyCollections ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The location selection legend now considers the existence of Text and PolyCollections in the badness calculation.

Note: The best option can already be quite slow for plots with large amounts of data. For PolyCollections, it only considers the Path of PolyCollections and not the enclosed area when checking for overlap to reduce additional latency. However, it can still be quite slow when there are large amounts of PolyCollections in the plot to check for.

Exception when not passing a Bbox to BboxTransform*-classes ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The exception when not passing a Bbox to BboxTransform*-classes that expect one, e.g., ~matplotlib.transforms.BboxTransform has changed from ValueError to TypeError.

loc parameter of Cell no longer accepts None ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The default value of the loc parameter has been changed from None to right, which already was the default location. The behavior of .Cell didn't change when called without an explicit loc parameter.

ContourLabeler.add_label now respects use_clabeltext ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

... and sets .Text.set_transform_rotates_text accordingly.

Line2D ^^^^^^^^^^

When creating a Line2D or using .Line2D.set_xdata and .Line2D.set_ydata, passing x/y data as non sequence is now an error.

ScalarMappable\s auto-scale their norm when an array is set ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Collections previously deferred auto-scaling of the norm until draw time. This has been changed to scale the norm whenever the first array is set to align with the docstring and reduce unexpected behavior when accessing the norm before drawing.

SubplotParams moved from matplotlib.figure to matplotlib.gridspec ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

It is still importable from matplotlib.figure, so does not require any changes to existing code.

PowerNorm no longer clips values below vmin ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

When clip=False is set (the default) on ~matplotlib.colors.PowerNorm, values below vmin are now linearly normalised. Previously they were clipped to zero. This fixes issues with the display of colorbars associated with a power norm.

Image path semantics of toolmanager-based tools ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Previously, MEP22 ("toolmanager-based") Tools would try to load their icon (tool.image) relative to the current working directory, or, as a fallback, from Matplotlib's own image directory. Because both approaches are problematic for third-party tools (the end-user may change the current working directory at any time, and third-parties cannot add new icons in Matplotlib's image directory), this behavior is deprecated; instead, tool.image is now interpreted relative to the directory containing the source file where the Tool.image class attribute is defined. (Defining tool.image as an absolute path also works and is compatible with both the old and the new semantics.)