Version 3.1.1
matplotlib
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Table of Contents

API Changes

If updating Matplotlib breaks your scripts, this list may help you figure out what caused the breakage and how to fix it by updating your code.

For API changes in older versions see

Changes for the latest version are listed below. For new features that were added to Matplotlib, see Whats New.

API Changes for 3.1.1

Behavior changes

Locator.nonsingular return order

Locator.nonsingular (introduced in mpl 3.1) now returns a range v0, v1 with v0 <= v1. This behavior is consistent with the implementation of nonsingular by the LogLocator and LogitLocator subclasses.

API Changes for 3.1.0

Behavior changes

Matplotlib.use

Switching backends via matplotlib.use is now allowed by default, regardless of whether matplotlib.pyplot has been imported. If the user tries to switch from an already-started interactive backend to a different interactive backend, an ImportError will be raised.

mplot3d auto-registration

mpl_toolkits.mplot3d is always registered by default now. It is no longer necessary to import mplot3d to create 3d axes with

ax = fig.add_subplot(111, projection="3d")

Invalid points in PathCollections

PathCollections created with scatter now keep track of invalid points. Previously, points with nonfinite (infinite or nan) coordinates would not be included in the offsets (as returned by PathCollection.get_offsets) of a PathCollection created by scatter, and points with nonfinite values (as specified by the c kwarg) would not be included in the array (as returned by PathCollection.get_array)

Such points are now included, but masked out by returning a masked array.

If the plotnonfinite kwarg to scatter is set, then points with nonfinite values are plotted using the bad color of the collections.PathCollection's colormap (as set by colors.Colormap.set_bad()).

Alpha blending in imshow of RBGA input

The alpha-channel of RBGA images is now re-sampled independently of RGB channels. While this is a bug fix, it does change the output and may result in some down-stream image comparison tests to fail.

Autoscaling

On log-axes where a single value is plotted at a "full" decade (1, 10, 100, etc.), the autoscaling now expands the axis symmetrically around that point, instead of adding a decade only to the right.

Log-scaled axes

When the default LogLocator would generate no ticks for an axis (e.g., an axis with limits from 0.31 to 0.39) or only a single tick, it now instead falls back on the linear AutoLocator to pick reasonable tick positions.

Figure.add_subplot with no arguments

Calling Figure.add_subplot() with no positional arguments used to do nothing; this now is equivalent to calling add_subplot(111) instead.

bxp and rcparams

bxp now respects rcParams["boxplot.boxprops.linewidth"] even when patch_artist is set. Previously, when the patch_artist parameter was set, bxp would ignore rcParams["boxplot.boxprops.linewidth"]. This was an oversight -- in particular, boxplot did not ignore it.

Major/minor tick collisions

Minor ticks that collide with major ticks are now hidden by default. Previously, certain locator classes (LogLocator, AutoMinorLocator) contained custom logic to avoid emitting tick locations that collided with major ticks when they were used as minor locators. This logic has now moved to the Axis class, and is used regardless of the locator class. You can control this behavior via the remove_overlaping_locs attribute on Axis.

If you were relying on both the major and minor tick labels to appear on the same tick, you may need to update your code. For example, the following snippet

import numpy as np
import matplotlib.dates as mdates
import matplotlib.pyplot as plt

t = np.arange("2018-11-03", "2018-11-06", dtype="datetime64")
x = np.random.rand(len(t))

fig, ax = plt.subplots()
ax.plot(t, x)
ax.xaxis.set(
    major_locator=mdates.DayLocator(),
    major_formatter=mdates.DateFormatter("\n%a"),
    minor_locator=mdates.HourLocator((0, 6, 12, 18)),
    minor_formatter=mdates.DateFormatter("%H:%M"),
)
# disable removing overlapping locations
ax.xaxis.remove_overlapping_locs = False
plt.show()

labeled days using major ticks, and hours and minutes using minor ticks and added a newline to the major ticks labels to avoid them crashing into the minor tick labels. Setting the remove_overlapping_locs property (also accessible via set_remove_overlapping_locs / get_remove_overlapping_locs and setp) disables removing overlapping tick locations.

The major tick labels could also be adjusted include hours and minutes, as the minor ticks are gone, so the major_formatter would be:

mdates.DateFormatter("%H:%M\n%a")

usetex support

Previously, if rcParams["text.usetex"] was True, then constructing a TextPath on a non-mathtext string with usetex=False would rely on the mathtext parser (but not on usetex support!) to parse the string. The mathtext parser is not invoked anymore, which may cause slight changes in glyph positioning.

get_window_extents

matplotlib.axes.Axes.get_window_extent used to return a bounding box that was slightly larger than the axes, presumably to take into account the ticks that may be on a spine. However, it was not scaling the tick sizes according to the dpi of the canvas, and it did not check if the ticks were visible, or on the spine.

Now matplotlib.axes.Axes.get_window_extent just returns the axes extent with no padding for ticks.

This affects matplotlib.axes.Axes.get_tightbbox in cases where there are outward ticks with no tick labels, and it also removes the (small) pad around axes in that case.

spines.Spine.get_window_extent now takes into account ticks that are on the spine.

Sankey

Previously, Sankey.add would only accept a single string as the labels argument if its length is equal to the number of flows, in which case it would use one character of the string for each flow.

The behavior has been changed to match the documented one: when a single string is passed, it is used to label all the flows.

FontManager scores

font_manager.FontManager.score_weight is now more strict with its inputs. Previously, when a weight string was passed to font_manager.FontManager.score_weight,

  • if the weight was the string representation of an integer, it would be converted to that integer,
  • otherwise, if the weight was not a standard weight name, it would be silently replaced by a value of 500 ("normal" weight).

font_manager.FontManager.score_weight now raises an exception on such inputs.

Text alignment

Text alignment was previously incorrect, in particular for multiline text objects with large descenders (i.e. subscripts) and rotated text. These have been fixed and made more consistent, but could make old code that has compensated for this no longer have the correct alignment.

Upper case color strings

Support for passing single-letter colors (one of "rgbcmykw") as UPPERCASE characters is deprecated; these colors will become case-sensitive (lowercase) after the deprecation period has passed.

The goal is to decrease the number of ambiguous cases when using the data keyword to plotting methods; e.g. plot("X", "Y", data={"X": ..., "Y": ...}) will not warn about "Y" possibly being a color anymore after the deprecation period has passed.

Degenerate limits

When bounds passed to set_xlim are degenerate (i.e. the lower and upper value are equal), the method used to "expand" the bounds now matches the expansion behavior of autoscaling when the plot contains a single x-value, and should in particular produce nicer limits for non-linear scales.

plot format string parsing

In certain cases, plot would previously accept format strings specifying more than one linestyle (e.g. "---." which specifies both "--" and "-."); only use one of them would be used. This now raises a ValueError instead.

HTMLWriter

The HTMLWriter constructor is more strict: it no longer normalizes unknown values of default_mode to 'loop', but errors out instead.

AFM parsing

In accordance with the AFM spec, the AFM parser no longer truncates the UnderlinePosition and UnderlineThickness fields to integers.

The Notice field (which can only be publicly accessed by the deprecated afm.parse_afm API) is no longer decoded to a str, but instead kept as bytes, to support non-conformant AFM files that use non-ASCII characters in that field.

Artist.set keyword normalisation

Artist.set now normalizes keywords before sorting them. Previously it sorted its keyword arguments in reverse alphabetical order (with a special-case to put color at the end) before applying them.

It now normalizes aliases (and, as above, emits a warning on duplicate properties) before doing the sorting (so c goes to the end too).

Axes.tick_params argument checking

Previously Axes.tick_params silently did nothing when an invalid axis parameter was supplied. This behavior has been changed to raise a ValueError instead.

Axes.hist output

Input that consists of multiple empty lists will now return a list of histogram values for each one of the lists. For example, an input of [[],[]] will return 2 lists of histogram values. Previously, a single list was returned.

backend_bases.Timer.remove_callback future signature change

Currently, backend_bases.Timer.remove_callback(func, *args, **kwargs) removes a callback previously added by backend_bases.Timer.add_callback(func, *args, **kwargs), but if *args, **kwargs is not passed in (ex, Timer.remove_callback(func)), then the first callback with a matching func is removed, regardless of whether it was added with or without *args, **kwargs.

In a future version, Timer.remove_callback will always use the latter behavior (not consider *args, **kwargs); to specifically consider them, add the callback as a functools.partial object

cb = timer.add_callback(functools.partial(func, *args, **kwargs))
# ...
# later
timer.remove_callback(cb)

backend_bases.Timer.add_callback was modified to return func to simplify the above usage (previously it returned None); this also allows using it as a decorator.

The new API is modelled after atexit.register / atexit.unregister.

StemContainer performance increase

StemContainer objects can now store a LineCollection object instead of a list of Line2D objects for stem lines plotted using stem. This gives a very large performance boost to displaying and moving stem plots.

This will become the default behaviour in Matplotlib 3.3. To use it now, the use_line_collection keyword argument to stem can be set to True

ax.stem(..., use_line_collection=True)

Individual line segments can be extracted from the LineCollection using get_segements(). See the LineCollection documentation for other methods to retrieve the collection properties.

ColorbarBase inheritance

matplotlib.colorbar.ColorbarBase is no longer a subclass of cm.ScalarMappable. This inheritance lead to a confusing situation where the cm.ScalarMappable passed to matplotlib.colorbar.Colorbar (colorbar) had a set_norm method, as did the colorbar. The colorbar is now purely a follower to the ScalarMappable norm and colormap, and the old inherited methods set_norm, set_cmap, set_clim are deprecated, as are the getter versions of those calls. To set the norm associated with a colorbar do colorbar.mappable.set_norm() etc.

FreeType and libpng search paths

The MPLBASEDIRLIST environment variables and basedirlist entry in setup.cfg have no effect anymore. Instead, if building in situations where FreeType or libpng are not in the compiler or linker's default path, set the standard environment variables CFLAGS/LDFLAGS on Linux or OSX, or CL/LINK on Windows, to indicate the relevant paths.

See details in Installing.

Setting artist properties twice or more in the same call

Setting the same artist property multiple time via aliases is deprecated. Previously, code such as

plt.plot([0, 1], c="red", color="blue")

would emit a warning indicating that c and color are aliases of one another, and only keep the color kwarg. This behavior has been deprecated; in a future version, this will raise a TypeError, similar to Python's behavior when a keyword argument is passed twice

plt.plot([0, 1], c="red", c="blue")

This warning is raised by normalize_kwargs.

Path code types

Path code types like Path.MOVETO are now np.uint8 instead of int Path.STOP, Path.MOVETO, Path.LINETO, Path.CURVE3, Path.CURVE4 and Path.CLOSEPOLY are now of the type Path.code_type (np.uint8 by default) instead of plain int. This makes their type match the array value type of the Path.codes array.

LaTeX code in matplotlibrc file

Previously, the rc file keys pgf.preamble and text.latex.preamble were parsed using commmas as separators. This would break valid LaTeX code, such as:

\usepackage[protrusion=true, expansion=false]{microtype}

The parsing has been modified to pass the complete line to the LaTeX system, keeping all commas. Passing a list of strings from within a Python script still works as it used to. Passing a list containing non-strings now fails, instead of coercing the results to strings.

Axes.spy

The method Axes.spy now raises a TypeError for the keyword arguments interpolation and linestyle instead of silently ignoring them.

Furthermore, Axes.spy spy does now allow for an extent argument (was silently ignored so far).

A bug with Axes.spy(..., origin='lower') is fixed. Previously this flipped the data but not the y-axis resulting in a mismatch between axes labels and actual data indices. Now, origin='lower' flips both the data and the y-axis labels.

Boxplot tick methods

The manage_xticks parameter of boxplot and bxp has been renamed (with a deprecation period) to manage_ticks, to take into account the fact that it manages either x or y ticks depending on the vert parameter.

When manage_ticks=True (the default), these methods now attempt to take previously drawn boxplots into account when setting the axis limits, ticks, and tick labels.

MouseEvents

MouseEvents now include the event name in their str(). Previously they contained the prefix "MPL MouseEvent".

RGBA buffer return type

FigureCanvasAgg.buffer_rgba and RendererAgg.buffer_rgba now return a memoryview The buffer_rgba method now allows direct access to the renderer's underlying buffer (as a (m, n, 4)-shape memoryview) rather than copying the data to a new bytestring. This is consistent with the behavior on Py2, where a buffer object was returned.

matplotlib.font_manager.win32InstalledFonts return type

matplotlib.font_manager.win32InstalledFonts returns an empty list instead of None if no fonts are found.

Axes.fmt_xdata and Axes.fmt_ydata error handling

Previously, if the user provided a Axes.fmt_xdata or Axes.fmt_ydata function that raised a TypeError (or set them to a non-callable), the exception would be silently ignored and the default formatter be used instead. This is no longer the case; the exception is now propagated out.

Deprecation of redundant Tick attributes

The gridOn, tick1On, tick2On, label1On, and label2On Tick attributes have been deprecated. Directly get and set the visibility on the underlying artists, available as the gridline, tick1line, tick2line, label1, and label2 attributes.

The label attribute, which was an alias for label1, has been deprecated.

Subclasses that relied on setting the above visibility attributes needs to be updated; see e.g. examples/api/skewt.py.

Passing a Line2D's drawstyle together with the linestyle is deprecated

Instead of plt.plot(..., linestyle="steps--"), use plt.plot(..., linestyle="--", drawstyle="steps"). ds is now an alias for drawstyle.

pgi support dropped

Support for pgi in the GTK3 backends has been dropped. pgi is an alternative implementation to PyGObject. PyGObject should be used instead.

rcParam changes

Removed

The following deprecated rcParams have been removed:

  • text.dvipnghack
  • nbagg.transparent (use rcParams["figure.facecolor"] instead)
  • plugins.directory
  • axes.hold
  • backend.qt4 and backend.qt5 (set the QT_API environment variable instead)

Deprecated

The associated validator functions rcsetup.validate_qt4 and validate_qt5 are deprecated.

The verbose.fileo and verbose.level rcParams have been deprecated. These have had no effect since the switch from Matplotlib's old custom Verbose logging to the stdlib's logging module. In addition the rcsetup.validate_verbose function is deprecated.

The text.latex.unicode rcParam now defaults to True and is deprecated (i.e., in future versions of Matplotlib, unicode input will always be supported). Moreover, the underlying implementation now uses \usepackage[utf8]{inputenc} instead of \usepackage{ucs}\usepackage[utf8x]{inputenc}.

Exception changes

  • mpl_toolkits.axes_grid1.axes_size.GetExtentHelper now raises ValueError for invalid directions instead of KeyError.
  • Previously, subprocess failures in the animation framework would raise either in a RuntimeError or a ValueError depending on when the error occurred. They now raise a subprocess.CalledProcessError with attributes set as documented by the exception class.
  • In certain cases, Axes methods (and pyplot functions) used to raise a RuntimeError if they were called with a data kwarg and otherwise mismatched arguments. They now raise a TypeError instead.
  • Axes.streamplot does not support irregularly gridded x and y values. So far, it used to silently plot an incorrect result. This has been changed to raise a ValueError instead.
  • The streamplot.Grid class, which is internally used by streamplot code, also throws a ValueError when irregularly gridded values are passed in.

Removals

The following deprecated APIs have been removed:

Classes and methods

  • Verbose (replaced by python logging library)
  • artist.Artist.hitlist (no replacement)
  • artist.Artist.is_figure_set (use artist.figure is not None instead)
  • axis.Axis.unit_data (use axis.Axis.units instead)
  • backend_bases.FigureCanvasBase.onRemove (no replacement) backend_bases.FigureManagerBase.show_popup (this never did anything)
  • backend_wx.SubplotToolWx (no replacement)
  • backend_wx.Toolbar (use backend_wx.NavigationToolbar2Wx instead)
  • cbook.align_iterators (no replacment)
  • contour.ContourLabeler.get_real_label_width (no replacement)
  • legend.Legend.draggable (use legend.Legend.set_draggable() instead)
  • texmanager.TexManager.postscriptd, texmanager.TexManager.pscnt, texmanager.TexManager.make_ps, texmanager.TexManager.get_ps_bbox (no replacements)

Arguments

Other

The following miscellaneous API elements have been removed

  • svgfont support (in rcParams["svg.fonttype"])

  • Logging is now done with the standard python logging library. matplotlib.verbose and the command line switches --verbose-LEVEL have been removed.

    To control the logging output use:

    import logging
    logger = logging.getLogger('matplotlib')
    logger.set_level(logging.INFO)
    
  • __version__numpy__

  • collections.CIRCLE_AREA_FACTOR

  • font_manager.USE_FONTCONFIG

  • font_manager.cachedir

matplotlib.mlab removals

Lots of code inside the matplotlib.mlab module which was deprecated in Matplotlib 2.2 has been removed. See below for a list:

  • mlab.exp_safe (use numpy.exp instead)
  • mlab.amap
  • mlab.logspace (use numpy.logspace instead)
  • mlab.rms_flat
  • mlab.l1norm (use numpy.linalg.norm(a, ord=1) instead)
  • mlab.l2norm (use numpy.linalg.norm(a, ord=2) instead)
  • mlab.norm_flat (use numpy.linalg.norm(a.flat, ord=2) instead)
  • mlab.frange (use numpy.arange instead)
  • mlab.identity (use numpy.identity instead)
  • mlab.base_repr
  • mlab.binary_repr
  • mlab.ispower2
  • mlab.log2 (use numpy.log2 instead)
  • mlab.isvector
  • mlab.movavg
  • mlab.safe_isinf (use numpy.isinf instead)
  • mlab.safe_isnan (use numpy.isnan instead)
  • mlab.cohere_pairs (use scipy.signal.coherence instead)
  • mlab.entropy (use scipy.stats.entropy instead)
  • mlab.normpdf (use scipy.stats.norm.pdf instead)
  • mlab.find (use np.nonzero(np.ravel(condition)) instead)
  • mlab.longest_contiguous_ones
  • mlab.longest_ones
  • mlab.PCA
  • mlab.prctile (use numpy.percentile instead)
  • mlab.prctile_rank
  • mlab.center_matrix
  • mlab.rk4 (use scipy.integrate.ode instead)
  • mlab.bivariate_normal
  • mlab.get_xyz_where
  • mlab.get_sparse_matrix
  • mlab.dist (use numpy.hypot instead)
  • mlab.dist_point_to_segment
  • mlab.griddata (use scipy.interpolate.griddata)
  • mlab.less_simple_linear_interpolation (use numpy.interp)
  • mlab.slopes
  • mlab.stineman_interp
  • mlab.segments_intersect
  • mlab.fftsurr
  • mlab.offset_line
  • mlab.quad2cubic
  • mlab.vector_lengths
  • mlab.distances_along_curve
  • mlab.path_length
  • mlab.cross_from_above
  • mlab.cross_from_below
  • mlab.contiguous_regions (use cbook.contiguous_regions instead)
  • mlab.is_closed_polygon
  • mlab.poly_between
  • mlab.poly_below
  • mlab.inside_poly
  • mlab.csv2rec
  • mlab.rec2csv (use numpy.recarray.tofile instead)
  • mlab.rec2text (use numpy.recarray.tofile instead)
  • mlab.rec_summarize
  • mlab.rec_join
  • mlab.recs_join
  • mlab.rec_groupby
  • mlab.rec_keep_fields
  • mlab.rec_drop_fields
  • mlab.rec_append_fields
  • mlab.csvformat_factory
  • mlab.get_formatd
  • mlab.FormatDatetime (use datetime.datetime.strftime instead)
  • mlab.FormatDate (use datetime.date.strftime instead)
  • mlab.FormatMillions, mlab.FormatThousands, mlab.FormatPercent, mlab.FormatBool, mlab.FormatInt, mlab.FormatFloat, mlab.FormatFormatStr, mlab.FormatString, mlab.FormatObj
  • mlab.donothing_callback

matplotlib.pylab removals

Lots of code inside the matplotlib.mlab module which was deprecated in Matplotlib 2.2 has been removed. This means the following functions are no longer available in the matplotlib.pylab module:

  • amap
  • base_repr
  • binary_repr
  • bivariate_normal
  • center_matrix
  • csv2rec (use numpy.recarray.tofile instead)
  • dist (use numpy.hypot instead)
  • dist_point_to_segment
  • distances_along_curve
  • entropy (use scipy.stats.entropy instead)
  • exp_safe (use numpy.exp instead)
  • fftsurr
  • find (use np.nonzero(np.ravel(condition)) instead)
  • frange (use numpy.arange instead)
  • get_sparse_matrix
  • get_xyz_where
  • griddata (use scipy.interpolate.griddata instead)
  • identity (use numpy.identity instead)
  • inside_poly
  • is_closed_polygon
  • ispower2
  • isvector
  • l1norm (use numpy.linalg.norm(a, ord=1) instead)
  • l2norm (use numpy.linalg.norm(a, ord=2) instead)
  • log2 (use numpy.log2 instead)
  • longest_contiguous_ones
  • longest_ones
  • movavg
  • norm_flat (use numpy.linalg.norm(a.flat, ord=2) instead)
  • normpdf (use scipy.stats.norm.pdf instead)
  • path_length
  • poly_below
  • poly_between
  • prctile (use numpy.percentile instead)
  • prctile_rank
  • rec2csv (use numpy.recarray.tofile instead)
  • rec_append_fields
  • rec_drop_fields
  • rec_join
  • rk4 (use scipy.integrate.ode instead)
  • rms_flat
  • segments_intersect
  • slopes
  • stineman_interp
  • vector_lengths

mplot3d changes

Voxel shading

Axes3D.voxels now shades the resulting voxels; for more details see What's new. The previous behavior can be achieved by passing

ax.voxels(.., shade=False)

Equal aspect axes disabled

Setting the aspect on 3D axes previously returned non-sensical results (e.g. see #1077). Calling ax.set_aspect('equal') or ax.set_aspect(num) on a 3D axes now raises a NotImplementedError.

Poly3DCollection.set_zsort

Poly3DCollection.set_zsort no longer silently ignores invalid inputs, or False (which was always broken). Passing True to mean "average" is deprecated.

Testing

The --no-network flag to tests.py has been removed (no test requires internet access anymore). If it is desired to disable internet access both for old and new versions of Matplotlib, use tests.py -m 'not network' (which is now a no-op).

The image comparison test decorators now skip (rather than xfail) the test for uncomparable formats. The affected decorators are image_comparison and check_figures_equal. The deprecated ImageComparisonTest class is likewise changed.

Dependency changes

numpy

Matplotlib 3.1 now requires numpy>=1.11.

ghostscript

Support for ghostscript 8.60 (released in 2007) has been removed. The oldest supported version of ghostscript is now 9.0 (released in 2010).

Mathtext changes

  • In constructs such as "$1~2$", mathtext now interprets the tilde as a space, consistently with TeX (this was previously a parse error).

Deprecations

  • The \stackrel mathtext command hsa been deprecated (it behaved differently from LaTeX's \stackrel. To stack two mathtext expressions, use \genfrac{left-delim}{right-delim}{fraction-bar-thickness}{}{top}{bottom}.
  • The mathcircled mathtext command (which is not a real TeX command) is deprecated. Directly use unicode characters (e.g. "\N{CIRCLED LATIN CAPITAL LETTER A}" or "\u24b6") instead.
  • Support for setting rcParams["mathtext.default"] to circled is deprecated.

Signature deprecations

The following signature related behaviours are deprecated:

  • The withdash keyword argument to Axes.text(). Consider using Axes.annotate() instead.
  • Passing (n, 1)-shaped error arrays to Axes.errorbar(), which was not documented and did not work for n = 2. Pass a 1D array instead.
  • The frameon kwarg to savefig and the rcParams["savefig.frameon"] rcParam. To emulate frameon = False, set facecolor to fully transparent ("none", or (0, 0, 0, 0)).
  • Passing a non-1D (typically, (n, 1)-shaped) input to Axes.pie. Pass a 1D array instead.
  • The TextPath constructor used to silently drop ignored arguments; this behavior is deprecated.
  • The usetex parameter of TextToPath.get_text_path is deprecated and folded into the ismath parameter, which can now take the values False, True, and "TeX", consistently with other low-level text processing functions.
  • Passing 'normal' to axes.Axes.axis() is deprecated, use ax.axis('auto') instead.
  • Passing the block argument of pyplot.show positionally is deprecated; it should be passed by keyword.
  • When using the nbagg backend, pyplot.show used to silently accept and ignore all combinations of positional and keyword arguments. This behavior is deprecated.
  • The unused shape and imlim parameters to Axes.imshow are deprecated. To avoid triggering the deprecation warning, the filternorm, filterrad, resample, and url arguments should be passed by keyword.
  • The interp_at_native parameter to BboxImage, which has had no effect since Matplotlib 2.0, is deprecated.
  • All arguments to the cbook.deprecated decorator and cbook.warn_deprecated function, except the first one (the version where the deprecation occurred), are now keyword-only. The goal is to avoid accidentally setting the "message" argument when the "name" (or "alternative") argument was intended, as this has repeatedly occurred in the past.
  • The arguments of matplotlib.testing.compare.calculate_rms have been renamed from expectedImage, actualImage, to expected_image, actual_image.
  • Passing positional arguments to Axis.set_ticklabels beyond ticklabels itself has no effect, and support for them is deprecated.
  • Passing shade=None to plot_surface is deprecated. This was an unintended implementation detail with the same semantics as shade=False. Please use the latter code instead.
  • matplotlib.ticker.MaxNLocator and its set_params method will issue a warning on unknown keyword arguments instead of silently ignoring them. Future versions will raise an error.

Changes in parameter names

  • The arg parameter to matplotlib.use has been renamed to backend.

    This will only affect cases where that parameter has been set as a keyword argument. The common usage pattern as a positional argument matplotlib.use('Qt5Agg') is not affected.

  • The normed parameter to Axes.hist2d has been renamed to density.

  • The s parameter to Annotation (and indirectly Axes.annotation) has been renamed to text.

  • The tolerence parameter to bezier.find_bezier_t_intersecting_with_closedpath, bezier.split_bezier_intersecting_with_closedpath, bezier.find_r_to_boundary_of_closedpath, bezier.split_path_inout and bezier.check_if_parallel has been renamed to tolerance.

In each case, the old parameter name remains supported (it cannot be used simultaneously with the new name), but support for it will be dropped in Matplotlib 3.3.

Class/method/attribute deprecations

Support for custom backends that do not provide a GraphicsContextBase.set_hatch_color method is deprecated. We suggest that custom backends let their GraphicsContext class inherit from GraphicsContextBase, to at least provide stubs for all required methods.

  • spine.Spine.is_frame_like

This has not been used in the codebase since its addition in 2009.

Internal Helper Functions

  • checkdep_dvipng
  • checkdep_ghostscript
  • checkdep_pdftops
  • checkdep_inkscape
  • ticker.decade_up
  • ticker.decade_down
  • cbook.dedent
  • docstring.Appender
  • docstring.dedent
  • docstring.copy_dedent

Use the standard library's docstring manipulation tools instead, such as inspect.cleandoc and inspect.getdoc.

These are considered internal and will be removed from the public API in a future version.

Multiple internal functions that were exposed as part of the public API of mpl_toolkits.mplot3d are deprecated,

mpl_toolkits.mplot3d.art3d

mpl_toolkits.mplot3d.proj3d

If your project relies on these functions, consider vendoring them.

Font Handling

Axes3D

  • axes3d.Axes3D.w_xaxis
  • axes3d.Axes3D.w_yaxis
  • axes3d.Axes3D.w_zaxis

Use axes3d.Axes3D.xaxis, axes3d.Axes3D.and `.axes3d.Axes3D.zaxis instead.

Testing

Test functions should use pytest.mark.backend(...), and the mark will be picked up by the matplotlib.testing.conftest.mpl_test_settings fixture.

Quiver

  • .color attribute of Quiver objects

Instead, use (as for any Collection) the get_facecolor method. Note that setting to the .color attribute did not update the quiver artist, whereas calling set_facecolor does.

GUI / backend details

  • get_py2exe_datafiles`
  • tk_window_focus`
  • backend_gtk3.FileChooserDialog
  • backend_gtk3.NavigationToolbar2GTK3.get_filechooser
  • backend_gtk3.SaveFigureGTK3.get_filechooser
  • NavigationToolbar2QT.adj_window attribute. This is unused and always None.
  • backend_wx.IDLE_DELAY global variable This is unused and only relevant to the now removed wx "idling" code (note that as it is a module-level global, no deprecation warning is emitted when accessing it).
  • mlab.demean
  • backend_gtk3cairo.FigureCanvasGTK3Cairo,
  • backend_wx.debug_on_error, backend_wx.fake_stderr, backend_wx.raise_msg_to_str, backend_wx.MenuButtonWx, backend_wx.PrintoutWx,
  • matplotlib.backends.qt_editor.formlayout module

This module is a vendored, modified version of the official formlayout module available on PyPI. Install that module separately if you need it.

Transforms / scales

  • LogTransformBase
  • Log10Transform
  • Log2Transform,
  • NaturalLogTransformLog
  • InvertedLogTransformBase
  • InvertedLog10Transform
  • InvertedLog2Transform
  • InvertedNaturalLogTransform

These classes defined in matplotlib.scales are deprecated. As a replacement, use the general LogTransform and InvertedLogTransform classes, whose constructors take a base argument.

Locators / Formatters

  • OldScalarFormatter.pprint_val
  • ScalarFormatter.pprint_val
  • LogFormatter.pprint_val

These are helper methods that do not have a consistent signature across formatter classes.

Path tools

Use get_path_collection_extents instead.

Use not np.isfinite(path.vertices).all() instead.

  • bezier.find_r_to_boundary_of_closedpath function is deprecated

This has always returned None instead of the requested radius.

Text

Unused attributes

These are unused and never updated.

Sphinx extensions

  • matplotlib.sphinxext.mathmpl.math_directive
  • matplotlib.sphinxext.plot_directive.plot_directive

This is because the matplotlib.sphinxext.mathmpl and matplotlib.sphinxext.plot_directive interfaces have changed from the (Sphinx-)deprecated function-based interface to a class-based interface; this should not affect end users.

  • mpl_toolkits.axisartist.axis_artist.UnimplementedException

Environmental Variables

  • The MATPLOTLIBDATA environment variable

Axis

  • Axis.iter_ticks

This only served as a helper to the private Axis._update_ticks

Undeprecations

The following API elements have bee un-deprecated:

New features

Text now has a c alias for the color property

For consistency with Line2D, the Text class has gained the c alias for the color property. For example, one can now write

ax.text(.5, .5, "foo", c="red")

Cn colors now support n>=10

It is now possible to go beyond the tenth color in the property cycle using Cn syntax, e.g.

plt.plot([1, 2], color="C11")

now uses the 12th color in the cycle.

Note that previously, a construct such as:

plt.plot([1, 2], "C11")

would be interpreted as a request to use color C1 and marker 1 (an "inverted Y"). To obtain such a plot, one should now use

plt.plot([1, 2], "1C1")

(so that the first "1" gets correctly interpreted as a marker specification), or, more explicitly:

plt.plot([1, 2], marker="1", color="C1")

New Formatter.format_ticks method

The Formatter class gained a new format_ticks method, which takes the list of all tick locations as a single argument and returns the list of all formatted values. It is called by the axis tick handling code and, by default, first calls set_locs with all locations, then repeatedly calls __call__ for each location.

Tick-handling code in the codebase that previously performed this sequence (set_locs followed by repeated __call__) have been updated to use format_ticks.

format_ticks is intended to be overridden by Formatter subclasses for which the formatting of a tick value depends on other tick values, such as ConciseDateFormatter.

Added support for RGB(A) images in pcolorfast

pcolorfast now accepts 3D images (RGB or RGBA) arrays if the X and Y specifications allow image or pcolorimage rendering; they remain unsupported by the more general quadmesh rendering

Invalid inputs

Passing invalid locations to legend and table used to fallback on a default location. This behavior is deprecated and will throw an exception in a future version.

offsetbox.AnchoredText is unable to handle the horizontalalignment or verticalalignment kwargs, and used to ignore them with a warning. This behavior is deprecated and will throw an exception in a future version.

Passing steps less than 1 or greater than 10 to MaxNLocator used to result in undefined behavior. It now throws a ValueError.

The signature of the (private) Axis._update_ticks has been changed to not take the renderer as argument anymore (that argument is unused).