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# API Changes

Log of changes to Matplotlib that affect the outward-facing API. 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 new features that were added to Matplotlib, please see What’s new in matplotlib.

## API Changes in 2.0.1

### Extensions to `matplotlib.backend_bases.GraphicsContextBase`

To better support controlling the color of hatches, the method `matplotlib.backend_bases.GraphicsContextBase.set_hatch_color` was added to the expected API of `GraphicsContext` classes. Calls to this method are currently wrapped with a `try:...except Attribute:` block to preserve back-compatibility with any third-party backends which do not extend `GraphicsContextBase`.

This value can be accessed in the backends via `matplotlib.backend_bases.GraphicsContextBase.get_hatch_color` (which was added in 2.0 see Extension to matplotlib.backend_bases.GraphicsContextBase) and should be used to color the hatches.

In the future there may also be `hatch_linewidth` and `hatch_density` related methods added. It is encouraged, but not required that third-party backends extend `GraphicsContextBase` to make adapting to these changes easier.

### `afm.get_fontconfig_fonts` returns a list of paths and does not check for existence

`afm.get_fontconfig_fonts` used to return a set of paths encoded as a `{key: 1, ...}` dict, and checked for the existence of the paths. It now returns a list and dropped the existence check, as the same check is performed by the caller (`afm.findSystemFonts`) as well.

### `bar` now returns rectangles of negative height or width if the corresponding input is negative

`plt.bar` used to normalize the coordinates of the rectangles that it created, to keep their height and width positives, even if the corresponding input was negative. This normalization has been removed to permit a simpler computation of the correct `sticky_edges` to use.

### Do not clip line width when scaling dashes

The algorithm to scale dashes was changed to no longer clip the scaling factor: the dash patterns now continue to shrink at thin line widths. If the line width is smaller than the effective pixel size, this may result in dashed lines turning into solid gray-ish lines. This also required slightly tweaking the default patterns for ‘–’, ‘:’, and ‘.-‘ so that with the default line width the final patterns would not change.

There is no way to restore the old behavior.

### Deprecate ‘Vega’ color maps

The “Vega” colormaps are deprecated in Matplotlib 2.0.1 and will be removed in Matplotlib 2.2. Use the “tab” colormaps instead: “tab10”, “tab20”, “tab20b”, “tab20c”.

## API Changes in 2.0.0

### Deprecation and removal

#### Color of Axes

The `axisbg` and `axis_bgcolor` properties on `Axes` have been deprecated in favor of `facecolor`.

#### GTK and GDK backends deprecated

The GDK and GTK backends have been deprecated. These obsolete backends allow figures to be rendered via the GDK API to files and GTK2 figures. They are untested and known to be broken, and their use has been discouraged for some time. Instead, use the `GTKAgg` and `GTKCairo` backends for rendering to GTK2 windows.

#### WX backend deprecated

The WX backend has been deprecated. It is untested, and its use has been discouraged for some time. Instead, use the `WXAgg` backend for rendering figures to WX windows.

#### CocoaAgg backend removed

The deprecated and not fully functional CocoaAgg backend has been removed.

#### `round` removed from TkAgg Backend

The TkAgg backend had its own implementation of the `round` function. This was unused internally and has been removed. Instead, use either the `round` builtin function or `numpy.round`.

#### ‘hold’ functionality deprecated

The ‘hold’ keyword argument and all functions and methods related to it are deprecated, along with the ‘axes.hold’ `rcParams` entry. The behavior will remain consistent with the default `hold=True` state that has long been in place. Instead of using a function or keyword argument (`hold=False`) to change that behavior, explicitly clear the axes or figure as needed prior to subsequent plotting commands.

### `Artist.update` has return value

The methods `matplotlib.artist.Artist.set`, `matplotlib.Artist.update`, and the function `matplotlib.artist.setp` now use a common codepath to look up how to update the given artist properties (either using the setter methods or an attribute/property).

The behavior of `matplotlib.Artist.update` is slightly changed to return a list of the values returned from the setter methods to avoid changing the API of `matplotlib.Artist.set` and `matplotlib.artist.setp`.

The keys passed into `matplotlib.Artist.update` are now converted to lower case before being processed, to match the behavior of `matplotlib.Artist.set` and `matplotlib.artist.setp`. This should not break any user code because there are no set methods with capitals in their names, but this puts a constraint on naming properties in the future.

### `Legend` initializers gain edgecolor and facecolor kwargs

The `Legend` background patch (or ‘frame’) can have its `edgecolor` and `facecolor` determined by the corresponding keyword arguments to the `matplotlib.legend.Legend` initializer, or to any of the methods or functions that call that initializer. If left to their default values of `None`, their values will be taken from `matplotlib.rcParams`. The previously-existing `framealpha` kwarg still controls the alpha transparency of the patch.

### Qualitative colormaps

Colorbrewer’s qualitative/discrete colormaps (“Accent”, “Dark2”, “Paired”, “Pastel1”, “Pastel2”, “Set1”, “Set2”, “Set3”) are now implemented as `ListedColormap` instead of `LinearSegmentedColormap`.

To use these for images where categories are specified as integers, for instance, use:

    plt.imshow(x, cmap='Dark2', norm=colors.NoNorm())

### Change in the `draw_image` backend API

The `draw_image` method implemented by backends has changed its interface.

This change is only relevant if the backend declares that it is able to transform images by returning `True` from `option_scale_image`. See the `draw_image` docstring for more information.

### `matplotlib.ticker.LinearLocator` algorithm update

The `matplotlib.ticker.LinearLocator` is used to define the range and location of axis ticks when the user wants an exact number of ticks. `LinearLocator` thus differs from the default locator `MaxNLocator`, for which the user specifies a maximum number of intervals rather than a precise number of ticks.

The view range algorithm in `matplotlib.ticker.LinearLocator` has been changed so that more convenient tick locations are chosen. The new algorithm returns a plot view range that is a multiple of the user-requested number of ticks. This ensures tick marks will be located at whole integers more consistently. For example, when both y-axes of a“twinx“ plot use `matplotlib.ticker.LinearLocator` with the same number of ticks, their y-tick locations and grid lines will coincide.

### `matplotlib.ticker.LogLocator` gains numticks kwarg

The maximum number of ticks generated by the `LogLocator` can now be controlled explicitly via setting the new ‘numticks’ kwarg to an integer. By default the kwarg is None which internally sets it to the ‘auto’ string, triggering a new algorithm for adjusting the maximum according to the axis length relative to the ticklabel font size.

### `matplotlib.ticker.LogFormatter`: two new kwargs

Previously, minor ticks on log-scaled axes were not labeled by default. An algorithm has been added to the `LogFormatter` to control the labeling of ticks between integer powers of the base. The algorithm uses two parameters supplied in a kwarg tuple named ‘minor_thresholds’. See the docstring for further explanation.

To improve support for axes using `SymmetricLogLocator`, a ‘linthresh’ kwarg was added.

### New defaults for 3D quiver function in mpl_toolkits.mplot3d.axes3d.py

Matplotlib has both a 2D and a 3D `quiver` function. These changes affect only the 3D function and make the default behavior of the 3D function match the 2D version. There are two changes:

1. The 3D quiver function previously normalized the arrows to be the same length, which makes it unusable for situations where the arrows should be different lengths and does not match the behavior of the 2D function. This normalization behavior is now controlled with the `normalize` keyword, which defaults to False.
2. The `pivot` keyword now defaults to `tail` instead of `tip`. This was done in order to match the default behavior of the 2D quiver function.

To obtain the previous behavior with the 3D quiver function, one can call the function with

    ax.quiver(x, y, z, u, v, w, normalize=True, pivot='tip')

where “ax” is an `Axes3d` object created with something like

    import mpl_toolkits.mplot3d.axes3d
    ax = plt.sublot(111, projection='3d')

### Stale figure behavior

Attempting to draw the figure will now mark it as not stale (independent if the draw succeeds). This change is to prevent repeatedly trying to re-draw a figure which is raising an error on draw. The previous behavior would only mark a figure as not stale after a full re-draw succeeded.

### The spectral colormap is now nipy_spectral

The colormaps formerly known as `spectral` and `spectral_r` have been replaced by `nipy_spectral` and `nipy_spectral_r` since Matplotlib 1.3.0. Even though the colormap was deprecated in Matplotlib 1.3.0, it never raised a warning. As of Matplotlib 2.0.0, using the old names raises a deprecation warning. In the future, using the old names will raise an error.

### Default install no longer includes test images

To reduce the size of wheels and source installs, the tests and baseline images are no longer included by default.

To restore installing the tests and images, use a `setup.cfg` with

    [packages]
    tests = True
    toolkits_tests = True

in the source directory at build/install time.

## Changes in 1.5.3

### `ax.plot(..., marker=None)` gives default marker

Prior to 1.5.3 kwargs passed to `plot` were handled in two parts – default kwargs generated internal to `plot` (such as the cycled styles) and user supplied kwargs. The internally generated kwargs were passed to the `matplotlib.lines.Line2D.__init__` and the user kwargs were passed to `ln.set(**kwargs)` to update the artist after it was created. Now both sets of kwargs are merged and passed to `__init__`. This change was made to allow `None` to be passed in via the user kwargs to mean ‘do the default thing’ as is the convention through out mpl rather than raising an exception.

Unlike most `Line2D` setter methods `set_marker` did accept `None` as a valid input which was mapped to ‘no marker’. Thus, by routing this `marker=None` through `__init__` rather than `set(...)` the meaning of `ax.plot(..., marker=None)` changed from ‘no markers’ to ‘default markers from rcparams’.

This is change is only evident if `mpl.rcParams['lines.marker']` has a value other than `'None'` (which is string `'None'` which means ‘no marker’).

## Changes in 1.5.2

### Default Behavior Changes

#### Changed default `autorange` behavior in boxplots

Prior to v1.5.2, the whiskers of boxplots would extend to the mininum and maximum values if the quartiles were all equal (i.e., Q1 = median = Q3). This behavior has been disabled by default to restore consistency with other plotting packages.

To restore the old behavior, simply set `autorange=True` when calling `plt.boxplot`.

## Changes in 1.5.0

### Code Changes

#### Reversed `matplotlib.cbook.ls_mapper`, added `ls_mapper_r`

Formerly, `matplotlib.cbook.ls_mapper` was a dictionary with the long-form line-style names (`"solid"`) as keys and the short forms (`"-"`) as values. This long-to-short mapping is now done by `ls_mapper_r`, and the short-to-long mapping is done by the `ls_mapper`.

#### Prevent moving artists between Axes, Property-ify Artist.axes, deprecate Artist.{get,set}_axes

This was done to prevent an Artist that is already associated with an Axes from being moved/added to a different Axes. This was never supported as it causes havoc with the transform stack. The apparent support for this (as it did not raise an exception) was the source of multiple bug reports and questions on SO.

For almost all use-cases, the assignment of the axes to an artist should be taken care of by the axes as part of the `Axes.add_*` method, hence the deprecation of {get,set}_axes.

Removing the `set_axes` method will also remove the ‘axes’ line from the ACCEPTS kwarg tables (assuming that the removal date gets here before that gets overhauled).

#### Tightened input validation on ‘pivot’ kwarg to quiver

Tightened validation so that only {‘tip’, ‘tail’, ‘mid’, and ‘middle’} (but any capitalization) are valid values for the ‘pivot’ kwarg in the `Quiver.__init__` (and hence `Axes.quiver` and `plt.quiver` which both fully delegate to `Quiver`). Previously any input matching ‘mid.*’ would be interpreted as ‘middle’, ‘tip.*’ as ‘tip’ and any string not matching one of those patterns as ‘tail’.

The value of `Quiver.pivot` is normalized to be in the set {‘tip’, ‘tail’, ‘middle’} in `Quiver.__init__`.

#### Reordered `Axes.get_children`

The artist order returned by `Axes.get_children` did not match the one used by `Axes.draw`. They now use the same order, as `Axes.draw` now calls `Axes.get_children`.

#### Changed behaviour of contour plots

The default behaviour of `contour()` and `contourf()` when using a masked array is now determined by the new keyword argument `corner_mask`, or if this is not specified then the new rcParam `contour.corner_mask` instead. The new default behaviour is equivalent to using `corner_mask=True`; the previous behaviour can be obtained using `corner_mask=False` or by changing the rcParam. The example http://matplotlib.org/examples/pylab_examples/contour_corner_mask.html demonstrates the difference. Use of the old contouring algorithm, which is obtained with `corner_mask='legacy'`, is now deprecated.

Contour labels may now appear in different places than in earlier versions of Matplotlib.

In addition, the keyword argument `nchunk` now applies to `contour()` as well as `contourf()`, and it subdivides the domain into subdomains of exactly `nchunk` by `nchunk` quads, whereas previously it was only roughly `nchunk` by `nchunk` quads.

The C/C++ object that performs contour calculations used to be stored in the public attribute QuadContourSet.Cntr, but is now stored in a private attribute and should not be accessed by end users.

#### Added set_params function to all Locator types

This was a bug fix targeted at making the api for Locators more consistent.

In the old behavior, only locators of type MaxNLocator have set_params() defined, causing its use on any other Locator to raise an AttributeError ( aside: set_params(args) is a function that sets the parameters of a Locator instance to be as specified within args). The fix involves moving set_params() to the Locator class such that all subtypes will have this function defined.

Since each of the Locator subtypes have their own modifiable parameters, a universal set_params() in Locator isn’t ideal. Instead, a default no-operation function that raises a warning is implemented in Locator. Subtypes extending Locator will then override with their own implementations. Subtypes that do not have a need for set_params() will fall back onto their parent’s implementation, which raises a warning as intended.

In the new behavior, Locator instances will not raise an AttributeError when set_params() is called. For Locators that do not implement set_params(), the default implementation in Locator is used.

#### Disallow `None` as x or y value in ax.plot

Do not allow `None` as a valid input for the `x` or `y` args in `ax.plot`. This may break some user code, but this was never officially supported (ex documented) and allowing `None` objects through can lead to confusing exceptions downstream.

To create an empty line use

    ln1, = ax.plot([], [], ...)
    ln2, = ax.plot([], ...)

In either case to update the data in the `Line2D` object you must update both the `x` and `y` data.

#### Removed `args` and `kwargs` from `MicrosecondLocator.__call__`

The call signature of `__call__()` has changed from `__call__(self, *args, **kwargs)` to `__call__(self)`. This is consistent with the superclass `Locator` and also all the other Locators derived from this superclass.

#### No `ValueError` for the MicrosecondLocator and YearLocator

The `MicrosecondLocator` and `YearLocator` objects when called will return an empty list if the axes have no data or the view has no interval. Previously, they raised a `ValueError`. This is consistent with all the Date Locators.

#### ‘OffsetBox.DrawingArea’ respects the ‘clip’ keyword argument

The call signature was `OffsetBox.DrawingArea(..., clip=True)` but nothing was done with the `clip` argument. The object did not do any clipping regardless of that parameter. Now the object can and does clip the child `Artists` if they are set to be clipped.

You can turn off the clipping on a per-child basis using `child.set_clip_on(False)`.

#### Add salt to clipPath id

Add salt to the hash used to determine the id of the `clipPath` nodes. This is to avoid conflicts when two svg documents with the same clip path are included in the same document (see https://github.com/ipython/ipython/issues/8133 and https://github.com/matplotlib/matplotlib/issues/4349 ), however this means that the svg output is no longer deterministic if the same figure is saved twice. It is not expected that this will affect any users as the current ids are generated from an md5 hash of properties of the clip path and any user would have a very difficult time anticipating the value of the id.

#### Changed snap threshold for circle markers to inf

When drawing circle markers above some marker size (previously 6.0) the path used to generate the marker was snapped to pixel centers. However, this ends up distorting the marker away from a circle. By setting the snap threshold to inf snapping is never done on circles.

This change broke several tests, but is an improvement.

#### Preserve units with Text position

Previously the ‘get_position’ method on Text would strip away unit information even though the units were still present. There was no inherent need to do this, so it has been changed so that unit data (if present) will be preserved. Essentially a call to ‘get_position’ will return the exact value from a call to ‘set_position’.

If you wish to get the old behaviour, then you can use the new method called ‘get_unitless_position’.

#### New API for custom Axes view changes

Interactive pan and zoom were previously implemented using a Cartesian-specific algorithm that was not necessarily applicable to custom Axes. Three new private methods, `_get_view()`, `_set_view()`, and `_set_view_from_bbox()`, allow for custom `Axes` classes to override the pan and zoom algorithms. Implementors of custom `Axes` who override these methods may provide suitable behaviour for both pan and zoom as well as the view navigation buttons on the interactive toolbars.

### MathTex visual changes

The spacing commands in mathtext have been changed to more closely match vanilla TeX.

#### Improved spacing in mathtext

The extra space that appeared after subscripts and superscripts has been removed.

#### No annotation coordinates wrap

In #2351 for 1.4.0 the behavior of [‘axes points’, ‘axes pixel’, ‘figure points’, ‘figure pixel’] as coordinates was change to no longer wrap for negative values. In 1.4.3 this change was reverted for ‘axes points’ and ‘axes pixel’ and in addition caused ‘axes fraction’ to wrap. For 1.5 the behavior has been reverted to as it was in 1.4.0-1.4.2, no wrapping for any type of coordinate.

### Deprecation

#### Deprecated `GraphicsContextBase.set_graylevel`

The `GraphicsContextBase.set_graylevel` function has been deprecated in 1.5 and will be removed in 1.6. It has been unused. The `GraphicsContextBase.set_foreground` could be used instead.

#### deprecated idle_event

The `idle_event` was broken or missing in most backends and causes spurious warnings in some cases, and its use in creating animations is now obsolete due to the animations module. Therefore code involving it has been removed from all but the wx backend (where it partially works), and its use is deprecated. The animations module may be used instead to create animations.

#### `color_cycle` deprecated

In light of the new property cycling feature, the Axes method set_color_cycle is now deprecated. Calling this method will replace the current property cycle with one that cycles just the given colors.

Similarly, the rc parameter axes.color_cycle is also deprecated in lieu of the new axes.prop_cycle parameter. Having both parameters in the same rc file is not recommended as the result cannot be predicted. For compatibility, setting axes.color_cycle will replace the cycler in axes.prop_cycle with a color cycle. Accessing axes.color_cycle will return just the color portion of the property cycle, if it exists.

Timeline for removal has not been set.

### Bundled jquery

The version of jquery bundled with the webagg backend has been upgraded from 1.7.1 to 1.11.3. If you are using the version of jquery bundled with webagg you will need to update your html files as such

    -    <script src="_static/jquery/js/jquery-1.7.1.min.js"></script>
    +    <script src="_static/jquery/js/jquery-1.11.3.min.js"></script>

### Code Removed

#### Removed `Image` from main namespace

`Image` was imported from PIL/pillow to test if PIL is available, but there is no reason to keep `Image` in the namespace once the availability has been determined.

#### Removed `lod` from Artist

Removed the method set_lod and all references to the attribute _lod as the are not used anywhere else in the code base. It appears to be a feature stub that was never built out.

#### Removed threading related classes from cbook

The classes `Scheduler`, `Timeout`, and `Idle` were in cbook, but are not used internally. They appear to be a prototype for the idle event system which was not working and has recently been pulled out.

#### Removed `Lena` images from sample_data

The `lena.png` and `lena.jpg` images have been removed from Matplotlib’s sample_data directory. The images are also no longer available from `matplotlib.cbook.get_sample_data`. We suggest using `matplotlib.cbook.get_sample_data('grace_hopper.png')` or `matplotlib.cbook.get_sample_data('grace_hopper.jpg')` instead.

#### Legend

Removed handling of `loc` as a positional argument to `Legend`

#### Legend handlers

Remove code to allow legend handlers to be callable. They must now implement a method `legend_artist`.

#### Axis

Removed method `set_scale`. This is now handled via a private method which should not be used directly by users. It is called via `Axes.set_{x,y}scale` which takes care of ensuring the related changes are also made to the Axes object.

#### finance.py

Removed functions with ambiguous argument order from finance.py

#### Annotation

Removed `textcoords` and `xytext` proprieties from Annotation objects.

#### spinxext.ipython_*.py

Both `ipython_console_highlighting` and `ipython_directive` have been moved to `IPython`.

Change your import from ‘matplotlib.sphinxext.ipython_directive’ to ‘IPython.sphinxext.ipython_directive’ and from ‘matplotlib.sphinxext.ipython_directive’ to ‘IPython.sphinxext.ipython_directive’

#### LineCollection.color

Deprecated in 2005, use `set_color`

#### remove `'faceted'` as a valid value for `shading` in `tri.tripcolor`

Use `edgecolor` instead. Added validation on `shading` to only be valid values.

#### Remove `faceted` kwarg from scatter

Remove support for the `faceted` kwarg. This was deprecated in d48b34288e9651ff95c3b8a071ef5ac5cf50bae7 (2008-04-18!) and replaced by `edgecolor`.

#### Remove `set_colorbar` method from `ScalarMappable`

Remove `set_colorbar` method, use `colorbar` attribute directly.

#### patheffects.svg

> - remove `get_proxy_renderer` method from `AbstarctPathEffect` class
> - remove `patch_alpha` and `offset_xy` from `SimplePatchShadow`

#### Remove `testing.image_util.py`

Contained only a no-longer used port of functionality from PIL

#### Remove `mlab.FIFOBuffer`

Not used internally and not part of core mission of mpl.

#### Remove `mlab.prepca`

Deprecated in 2009.

#### Remove `NavigationToolbar2QTAgg`

Added no functionality over the base `NavigationToolbar2Qt`

#### mpl.py

Remove the module `matplotlib.mpl`. Deprecated in 1.3 by PR #1670 and commit 78ce67d161625833cacff23cfe5d74920248c5b2

## Changes in 1.4.x

### Code changes

- A major refactoring of the axes module was made. The axes module has been split into smaller modules:

  > - the `_base` module, which contains a new private _AxesBase class. This class contains all methods except plotting and labelling methods.
  > - the `axes` module, which contains the Axes class. This class inherits from _AxesBase, and contains all plotting and labelling methods.
  > - the `_subplot` module, with all the classes concerning subplotting.

There are a couple of things that do not exists in the `axes` module’s namespace anymore. If you use them, you need to import them from their original location:

> - math -> `import math`
> - ma -> `from numpy import ma`
> - cbook -> `from matplotlib import cbook`
> - docstring -> `from matplotlib import docstring`
> - is_sequence_of_strings -> `from matplotlib.cbook import is_sequence_of_strings`
> - is_string_like -> `from matplotlib.cbook import is_string_like`
> - iterable -> `from matplotlib.cbook import iterable`
> - itertools -> `import itertools`
> - martist -> `from matplotlib import artist as martist`
> - matplotlib -> `import matplotlib`
> - mcoll -> `from matplotlib import collections as mcoll`
> - mcolors -> `from matplotlib import colors as mcolors`
> - mcontour -> `from matplotlib import contour as mcontour`
> - mpatches -> `from matplotlib import patches as mpatches`
> - mpath -> `from matplotlib import path as mpath`
> - mquiver -> `from matplotlib import quiver as mquiver`
> - mstack -> `from matplotlib import stack as mstack`
> - mstream -> `from matplotlib import stream as mstream`
> - mtable -> `from matplotlib import table as mtable`

- As part of the refactoring to enable Qt5 support, the module `matplotlib.backends.qt4_compat` was renamed to `matplotlib.qt_compat`. `qt4_compat` is deprecated in 1.4 and will be removed in 1.5.

- The `errorbar()` method has been changed such that the upper and lower limits (lolims, uplims, xlolims, xuplims) now point in the correct direction.

- The fmt kwarg for `plot()` defaults.

- A bug has been fixed in the path effects rendering of fonts, which now means that the font size is consistent with non-path effect fonts. See https://github.com/matplotlib/matplotlib/issues/2889 for more detail.

- The Sphinx extensions `ipython_directive` and `ipython_console_highlighting` have been moved to the IPython project itself. While they remain in Matplotlib for this release, they have been deprecated. Update your extensions in `conf.py` to point to `IPython.sphinxext.ipython_directive` instead of `matplotlib.sphinxext.ipython_directive`.

- In `finance`, almost all functions have been deprecated and replaced with a pair of functions name `*_ochl` and `*_ohlc`. The former is the ‘open-close-high-low’ order of quotes used previously in this module, and the latter is the ‘open-high-low-close’ order that is standard in finance.

- For consistency the `face_alpha` keyword to `matplotlib.patheffects.SimplePatchShadow` has been deprecated in favour of the `alpha` keyword. Similarly, the keyword `offset_xy` is now named `offset` across all `_Base`` has been renamed to `matplotlib.patheffects.AbstractPathEffect`. `matplotlib.patheffect.ProxyRenderer` has been renamed to `matplotlib.patheffects.PathEffectRenderer` and is now a full RendererBase subclass.

- The artist used to draw the outline of a `colorbar` has been changed from a `matplotlib.lines.Line2D` to `matplotlib.patches.Polygon`, thus `colorbar.ColorbarBase.outline` is now a `matplotlib.patches.Polygon` object.

- The legend handler interface has changed from a callable, to any object which implements the `legend_artists` method (a deprecation phase will see this interface be maintained for v1.4). See Legend guide for further details. Further legend changes include:

  > - `matplotlib.axes.Axes._get_legend_handles()` now returns a generator of handles, rather than a list.
  > - The `legend()` function’s “loc” positional argument has been deprecated. Use the “loc” keyword instead.

- The rcParams `savefig.transparent` has been added to control default transparency when saving figures.

- Slightly refactored the `Annotation` family. The text location in `Annotation` is now handled entirely handled by the underlying `Text` object so `set_position` works as expected. The attributes `xytext` and `textcoords` have been deprecated in favor of `xyann` and `anncoords` so that `Annotation` and `AnnotaionBbox` can share a common sensibly named api for getting/setting the location of the text or box.

  > - `xyann` -> set the location of the annotation
  > - `xy` -> set where the arrow points to
  > - `anncoords` -> set the units of the annotation location
  > - `xycoords` -> set the units of the point location
  > - `set_position()` -> `Annotation` only set location of annotation

- `matplotlib.mlab.specgram`, `matplotlib.mlab.psd`, `matplotlib.mlab.csd`, `matplotlib.mlab.cohere`, `matplotlib.mlab.cohere_pairs`, `matplotlib.pyplot.specgram`, `matplotlib.pyplot.psd`, `matplotlib.pyplot.csd`, and `matplotlib.pyplot.cohere` now raise ValueError where they previously raised AssertionError.

- For `matplotlib.mlab.psd`, `matplotlib.mlab.csd`, `matplotlib.mlab.cohere`, `matplotlib.mlab.cohere_pairs`, `matplotlib.pyplot.specgram`, `matplotlib.pyplot.psd`, `matplotlib.pyplot.csd`, and `matplotlib.pyplot.cohere`, in cases where a shape (n, 1) array is returned, this is now converted to a (n, ) array. Previously, (n, m) arrays were averaged to an (n, ) array, but (n, 1) arrays were returend unchanged. This change makes the dimensions consistent in both cases.

- Added the rcParam `axes.fromatter.useoffset` to control the default value of `useOffset` in `ticker.ScalarFormatter`

- Added `Formatter` sub-class `StrMethodFormatter` which does the exact same thing as `FormatStrFormatter`, but for new-style formatting strings.

- Deprecated `matplotlib.testing.image_util` and the only function within, `matplotlib.testing.image_util.autocontrast`. These will be removed completely in v1.5.0.

- The `fmt` argument of `plot_date()` has been changed from `bo` to just `o`, so color cycling can happen by default.

- Removed the class `FigureManagerQTAgg` and deprecated `NavigationToolbar2QTAgg` which will be removed in 1.5.

- Removed formerly public (non-prefixed) attributes `rect` and `drawRect` from `FigureCanvasQTAgg`; they were always an implementation detail of the (preserved) `drawRectangle()` function.

- The function signatures of `tight_bbox.adjust_bbox` and `tight_bbox.process_figure_for_rasterizing` have been changed. A new `fixed_dpi` parameter allows for overriding the `figure.dpi` setting instead of trying to deduce the intended behaviour from the file format.

- Added support for horizontal/vertical axes padding to `mpl_toolkits.axes_grid1.ImageGrid` — argument `axes_pad` can now be tuple-like if separate axis padding is required. The original behavior is preserved.

- Added support for skewed transforms to `matplotlib.transforms.Affine2D`, which can be created using the `skew` and `skew_deg` methods.

- Added clockwise parameter to control sectors direction in `axes.pie`

- In `matplotlib.lines.Line2D` the `markevery` functionality has been extended. Previously an integer start-index and stride-length could be specified using either a two-element-list or a two-element-tuple. Now this can only be done using a two-element-tuple. If a two-element-list is used then it will be treated as numpy fancy indexing and only the two markers corresponding to the given indexes will be shown.

- removed prop kwarg from `mpl_toolkits.axes_grid1.anchored_artists.AnchoredSizeBar` call. It was passed through to the base-class `__init__` and is only used for setting padding. Now `fontproperties` (which is what is really used to set the font properties of `AnchoredSizeBar`) is passed through in place of `prop`. If `fontpropreties` is not passed in, but `prop` is, then `prop` is used inplace of `fontpropreties`. If both are passed in, `prop` is silently ignored.

- The use of the index 0 in `plt.subplot` and related commands is deprecated. Due to a lack of validation calling `plt.subplots(2, 2, 0)` does not raise an exception, but puts an axes in the _last_ position. This is due to the indexing in subplot being 1-based (to mirror MATLAB) so before indexing into the `GridSpec` object used to determine where the axes should go, 1 is subtracted off. Passing in 0 results in passing -1 to `GridSpec` which results in getting the last position back. Even though this behavior is clearly wrong and not intended, we are going through a deprecation cycle in an abundance of caution that any users are exploiting this ‘feature’. The use of 0 as an index will raise a warning in 1.4 and an exception in 1.5.

- Clipping is now off by default on offset boxes.

- Matplotlib now uses a less-aggressive call to `gc.collect(1)` when closing figures to avoid major delays with large numbers of user objects in memory.

- The default clip value of all pie artists now defaults to `False`.

### Code removal

- Removed `mlab.levypdf`. The code raised a numpy error (and has for a long time) and was not the standard form of the Levy distribution. `scipy.stats.levy` should be used instead

## Changes in 1.3.x

### Changes in 1.3.1

It is rare that we make an API change in a bugfix release, however, for 1.3.1 since 1.3.0 the following change was made:

- `text.Text.cached` (used to cache font objects) has been made into a private variable. Among the obvious encapsulation benefit, this removes this confusing-looking member from the documentation.
- The method `hist()` now always returns bin occupancies as an array of type `float`. Previously, it was sometimes an array of type `int`, depending on the call.

### Code removal

- The following items that were deprecated in version 1.2 or earlier have now been removed completely.

  > - The Qt 3.x backends (`qt` and `qtagg`) have been removed in favor of the Qt 4.x backends (`qt4` and `qt4agg`).

  > - The FltkAgg and Emf backends have been removed.

  > - The `matplotlib.nxutils` module has been removed. Use the functionality on `matplotlib.path.Path.contains_point` and friends instead.

  > - Instead of `axes.Axes.get_frame`, use `axes.Axes.patch`.

  > - The following `kwargs` to the `legend` function have been renamed:

  >   - `pad` -> `borderpad`
  >   - `labelsep` -> `labelspacing`
  >   - `handlelen` -> `handlelength`
  >   - `handletextsep` -> `handletextpad`
  >   - `axespad` -> `borderaxespad`

  >   Related to this, the following rcParams have been removed:

  >   - `legend.pad`, `legend.labelsep`, `legend.handlelen`, `legend.handletextsep` and `legend.axespad`

  > - For the `hist` function, instead of `width`, use `rwidth` (relative width).

  > - On `patches.Circle`, the `resolution` kwarg has been removed. For a circle made up of line segments, use `patches.CirclePolygon`.

  > - The printing functions in the Wx backend have been removed due to the burden of keeping them up-to-date.

  > - `mlab.liaupunov` has been removed.

  > - `mlab.save`, `mlab.load`, `pylab.save` and `pylab.load` have been removed. We recommend using `numpy.savetxt` and `numpy.loadtxt` instead.

  > - `widgets.HorizontalSpanSelector` has been removed. Use `widgets.SpanSelector` instead.

### Code deprecation

- The CocoaAgg backend has been deprecated, with the possibility for deletion or resurrection in a future release.

- The top-level functions in `matplotlib.path` that are implemented in C++ were never meant to be public. Instead, users should use the Pythonic wrappers for them in the `path.Path` and `collections.Collection` classes. Use the following mapping to update your code:

  > - `point_in_path` -> `path.Path.contains_point`
  > - `get_path_extents` -> `path.Path.get_extents`
  > - `point_in_path_collection` -> `collection.Collection.contains`
  > - `path_in_path` -> `path.Path.contains_path`
  > - `path_intersects_path` -> `path.Path.intersects_path`
  > - `convert_path_to_polygons` -> `path.Path.to_polygons`
  > - `cleanup_path` -> `path.Path.cleaned`
  > - `points_in_path` -> `path.Path.contains_points`
  > - `clip_path_to_rect` -> `path.Path.clip_to_bbox`

- `matplotlib.colors.normalize` and `matplotlib.colors.no_norm` have been deprecated in favour of `matplotlib.colors.Normalize` and `matplotlib.colors.NoNorm` respectively.

- The `ScalarMappable` class’ `set_colorbar` is now deprecated. Instead, the `matplotlib.cm.ScalarMappable.colorbar` attribute should be used. In previous Matplotlib versions this attribute was an undocumented tuple of `(colorbar_instance, colorbar_axes)` but is now just `colorbar_instance`. To get the colorbar axes it is possible to just use the `ax` attribute on a colorbar instance.

- The `mpl` module is now deprecated. Those who relied on this module should transition to simply using `import matplotlib as mpl`.

### Code changes

- `Patch` now fully supports using RGBA values for its `facecolor` and `edgecolor` attributes, which enables faces and edges to have different alpha values. If the `Patch` object’s `alpha` attribute is set to anything other than `None`, that value will override any alpha-channel value in both the face and edge colors. Previously, if `Patch` had `alpha=None`, the alpha component of `edgecolor` would be applied to both the edge and face.

- The optional `isRGB` argument to `set_foreground()` (and the other GraphicsContext classes that descend from it) has been renamed to `isRGBA`, and should now only be set to `True` if the `fg` color argument is known to be an RGBA tuple.

- For `Patch`, the `capstyle` used is now `butt`, to be consistent with the default for most other objects, and to avoid problems with non-solid `linestyle` appearing solid when using a large `linewidth`. Previously, `Patch` used `capstyle='projecting'`.

- `Path` objects can now be marked as `readonly` by passing `readonly=True` to its constructor. The built-in path singletons, obtained through `Path.unit*` class methods return readonly paths. If you have code that modified these, you will need to make a deepcopy first, using either:

      import copy
      path = copy.deepcopy(Path.unit_circle())

      # or

      path = Path.unit_circle().deepcopy()

  Deep copying a `Path` always creates an editable (i.e. non-readonly) `Path`.

- The list at `Path.NUM_VERTICES` was replaced by a dictionary mapping Path codes to the number of expected vertices at `NUM_VERTICES_FOR_CODE`.

- To support XKCD style plots, the `matplotlib.path.cleanup_path()` method’s signature was updated to require a sketch argument. Users of `matplotlib.path.cleanup_path()` are encouraged to use the new `cleaned()` Path method.

- Data limits on a plot now start from a state of having “null” limits, rather than limits in the range (0, 1). This has an effect on artists that only control limits in one direction, such as `axvline` and `axhline`, since their limits will not longer also include the range (0, 1). This fixes some problems where the computed limits would be dependent on the order in which artists were added to the axes.

- Fixed a bug in setting the position for the right/top spine with data position type. Previously, it would draw the right or top spine at +1 data offset.

- In `FancyArrow`, the default arrow head width, `head_width`, has been made larger to produce a visible arrow head. The new value of this kwarg is `head_width = 20 * width`.

- It is now possible to provide `number of levels + 1` colors in the case of `extend='both'` for contourf (or just `number of levels` colors for an extend value `min` or `max`) such that the resulting colormap’s `set_under` and `set_over` are defined appropriately. Any other number of colors will continue to behave as before (if more colors are provided than levels, the colors will be unused). A similar change has been applied to contour, where `extend='both'` would expect `number of levels + 2` colors.

- A new keyword extendrect in `colorbar()` and `ColorbarBase` allows one to control the shape of colorbar extensions.

- The extension of `MultiCursor` to both vertical (default) and/or horizontal cursor implied that `self.line` is replaced by `self.vline` for vertical cursors lines and `self.hline` is added for the horizontal cursors lines.

- On POSIX platforms, the `report_memory()` function raises `NotImplementedError` instead of `OSError` if the ps command cannot be run.

- The `matplotlib.cbook.check_output()` function has been moved to `matplotlib.compat.subprocess()`.

### Configuration and rcParams

- On Linux, the user-specific `matplotlibrc` configuration file is now located in `config/matplotlib/matplotlibrc` to conform to the XDG Base Directory Specification.
- The `font.*` rcParams now affect only text objects created after the rcParam has been set, and will not retroactively affect already existing text objects. This brings their behavior in line with most other rcParams.
- Removed call of `grid()` in `plotfile()`. To draw the axes grid, set the `axes.grid` rcParam to True, or explicitly call `grid()`.

## Changes in 1.2.x

- The `classic` option of the rc parameter `toolbar` is deprecated and will be removed in the next release.

- The `isvector()` method has been removed since it is no longer functional.

- The `rasterization_zorder` property on `Axes` 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 `pie()` and `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 `projection_factory()` is now deprecated in favour of axes class identification using `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.

- `ColorConverter`, `Colormap` and `Normalize` now subclasses `object`

- ContourSet instances no longer have a `transform` attribute. Instead, access the transform with the `get_transform` method.

## Changes in 1.1.x

- Added new `matplotlib.sankey.Sankey` for generating Sankey diagrams.
- In `imshow()`, setting interpolation to ‘nearest’ will now always mean that the nearest-neighbor interpolation is performed. If you want the no-op interpolation to be performed, choose ‘none’.
- There were errors in how the tri-functions were handling input parameters that had to be fixed. If your tri-plots are not working correctly anymore, or you were working around apparent mistakes, please see issue #203 in the github tracker. When in doubt, use kwargs.
- The ‘symlog’ scale had some bad behavior in previous versions. This has now been fixed and users should now be able to use it without frustrations. The fixes did result in some minor changes in appearance for some users who may have been depending on the bad behavior.
- There is now a common set of markers for all plotting functions. Previously, some markers existed only for `scatter()` or just for `plot()`. This is now no longer the case. This merge did result in a conflict. The string ‘d’ now means “thin diamond” while ‘D’ will mean “regular diamond”.

## Changes beyond 0.99.x

- The default behavior of `matplotlib.axes.Axes.set_xlim()`, `matplotlib.axes.Axes.set_ylim()`, and `matplotlib.axes.Axes.axis()`, and their corresponding pyplot functions, has been changed: when view limits are set explicitly with one of these methods, autoscaling is turned off for the matching axis. A new auto kwarg is available to control this behavior. The limit kwargs have been renamed to left and right instead of xmin and xmax, and bottom and top instead of ymin and ymax. The old names may still be used, however.
- There are five new Axes methods with corresponding pyplot functions to facilitate autoscaling, tick location, and tick label formatting, and the general appearance of ticks and tick labels:
  - `matplotlib.axes.Axes.autoscale()` turns autoscaling on or off, and applies it.
  - `matplotlib.axes.Axes.margins()` sets margins used to autoscale the `matplotlib.axes.Axes.viewLim` based on the `matplotlib.axes.Axes.dataLim`.
  - `matplotlib.axes.Axes.locator_params()` allows one to adjust axes locator parameters such as nbins.
  - `matplotlib.axes.Axes.ticklabel_format()` is a convenience method for controlling the `matplotlib.ticker.ScalarFormatter` that is used by default with linear axes.
  - `matplotlib.axes.Axes.tick_params()` controls direction, size, visibility, and color of ticks and their labels.
- The `matplotlib.axes.Axes.bar()` method accepts a error_kw kwarg; it is a dictionary of kwargs to be passed to the errorbar function.
- The `matplotlib.axes.Axes.hist()` color kwarg now accepts a sequence of color specs to match a sequence of datasets.
- The `EllipseCollection` has been changed in two ways:
  - There is a new units option, ‘xy’, that scales the ellipse with the data units. This matches the :class:’~matplotlib.patches.Ellipse` scaling.
  - The height and width kwargs have been changed to specify the height and width, again for consistency with `Ellipse`, and to better match their names; previously they specified the half-height and half-width.
- There is a new rc parameter `axes.color_cycle`, and the color cycle is now independent of the rc parameter `lines.color`. `matplotlib.Axes.set_default_color_cycle()` is deprecated.
- You can now print several figures to one pdf file and modify the document information dictionary of a pdf file. See the docstrings of the class `matplotlib.backends.backend_pdf.PdfPages` for more information.
- Removed configobj and enthought.traits packages, which are only required by the experimental traited config and are somewhat out of date. If needed, install them independently.

- The new rc parameter `savefig.extension` sets the filename extension that is used by `matplotlib.figure.Figure.savefig()` if its fname argument lacks an extension.

- In an effort to simplify the backend API, all clipping rectangles and paths are now passed in using GraphicsContext objects, even on collections and images. Therefore:

      draw_path_collection(self, master_transform, cliprect, clippath,
                           clippath_trans, paths, all_transforms, offsets,
                           offsetTrans, facecolors, edgecolors, linewidths,
                           linestyles, antialiaseds, urls)

      # is now

      draw_path_collection(self, gc, master_transform, paths, all_transforms,
                           offsets, offsetTrans, facecolors, edgecolors,
                           linewidths, linestyles, antialiaseds, urls)

      draw_quad_mesh(self, master_transform, cliprect, clippath,
                     clippath_trans, meshWidth, meshHeight, coordinates,
                     offsets, offsetTrans, facecolors, antialiased,
                     showedges)

      # is now

      draw_quad_mesh(self, gc, master_transform, meshWidth, meshHeight,
                     coordinates, offsets, offsetTrans, facecolors,
                     antialiased, showedges)

      draw_image(self, x, y, im, bbox, clippath=None, clippath_trans=None)

      # is now

      draw_image(self, gc, x, y, im)

- There are four new Axes methods with corresponding pyplot functions that deal with unstructured triangular grids:

  - `matplotlib.axes.Axes.tricontour()` draws contour lines on a triangular grid.
  - `matplotlib.axes.Axes.tricontourf()` draws filled contours on a triangular grid.
  - `matplotlib.axes.Axes.tripcolor()` draws a pseudocolor plot on a triangular grid.
  - `matplotlib.axes.Axes.triplot()` draws a triangular grid as lines and/or markers.

## Changes in 0.99

- pylab no longer provides a load and save function. These are available in matplotlib.mlab, or you can use numpy.loadtxt and numpy.savetxt for text files, or np.save and np.load for binary numpy arrays.
- User-generated colormaps can now be added to the set recognized by `matplotlib.cm.get_cmap()`. Colormaps can be made the default and applied to the current image using `matplotlib.pyplot.set_cmap()`.
- changed use_mrecords default to False in mlab.csv2rec since this is partially broken
- Axes instances no longer have a “frame” attribute. Instead, use the new “spines” attribute. Spines is a dictionary where the keys are the names of the spines (e.g., ‘left’,’right’ and so on) and the values are the artists that draw the spines. For normal (rectilinear) axes, these artists are Line2D instances. For other axes (such as polar axes), these artists may be Patch instances.
- Polar plots no longer accept a resolution kwarg. Instead, each Path must specify its own number of interpolation steps. This is unlikely to be a user-visible change – if interpolation of data is required, that should be done before passing it to Matplotlib.

## Changes for 0.98.x

- psd(), csd(), and cohere() will now automatically wrap negative frequency components to the beginning of the returned arrays. This is much more sensible behavior and makes them consistent with specgram(). The previous behavior was more of an oversight than a design decision.

- Added new keyword parameters nonposx, nonposy to `matplotlib.axes.Axes` methods that set log scale parameters. The default is still to mask out non-positive values, but the kwargs accept ‘clip’, which causes non-positive values to be replaced with a very small positive value.

- Added new `matplotlib.pyplot.fignum_exists()` and `matplotlib.pyplot.get_fignums()`; they merely expose information that had been hidden in `matplotlib._pylab_helpers`.

- Deprecated numerix package.

- Added new `matplotlib.image.imsave()` and exposed it to the `matplotlib.pyplot` interface.

- Remove support for pyExcelerator in exceltools – use xlwt instead

- Changed the defaults of acorr and xcorr to use usevlines=True, maxlags=10 and normed=True since these are the best defaults

- Following keyword parameters for `matplotlib.label.Label` are now deprecated and new set of parameters are introduced. The new parameters are given as a fraction of the font-size. Also, scatteryoffsets, fancybox and columnspacing are added as keyword parameters.

  > Deprecated | New
  > --- | ---
  > pad | borderpad
  > labelsep | labelspacing
  > handlelen | handlelength
  > handlestextsep | handletextpad
  > axespad | borderaxespad

- Removed the configobj and experimental traits rc support

- Modified `matplotlib.mlab.psd()`, `matplotlib.mlab.csd()`, `matplotlib.mlab.cohere()`, and `matplotlib.mlab.specgram()` to scale one-sided densities by a factor of 2. Also, optionally scale the densities by the sampling frequency, which gives true values of densities that can be integrated by the returned frequency values. This also gives better MATLAB compatibility. The corresponding `matplotlib.axes.Axes` methods and `matplotlib.pyplot` functions were updated as well.

- Font lookup now uses a nearest-neighbor approach rather than an exact match. Some fonts may be different in plots, but should be closer to what was requested.

- `matplotlib.axes.Axes.set_xlim()`, `matplotlib.axes.Axes.set_ylim()` now return a copy of the `viewlim` array to avoid modify-in-place surprises.

- `matplotlib.afm.AFM.get_fullname()` and `matplotlib.afm.AFM.get_familyname()` no longer raise an exception if the AFM file does not specify these optional attributes, but returns a guess based on the required FontName attribute.

- Changed precision kwarg in `matplotlib.pyplot.spy()`; default is 0, and the string value ‘present’ is used for sparse arrays only to show filled locations.

- `matplotlib.collections.EllipseCollection` added.

- Added `angles` kwarg to `matplotlib.pyplot.quiver()` for more flexible specification of the arrow angles.

- Deprecated (raise NotImplementedError) all the mlab2 functions from `matplotlib.mlab` out of concern that some of them were not clean room implementations.

- Methods `matplotlib.collections.Collection.get_offsets()` and `matplotlib.collections.Collection.set_offsets()` added to `Collection` base class.

- `matplotlib.figure.Figure.figurePatch` renamed `matplotlib.figure.Figure.patch`; `matplotlib.axes.Axes.axesPatch` renamed `matplotlib.axes.Axes.patch`; `matplotlib.axes.Axes.axesFrame` renamed `matplotlib.axes.Axes.frame`. `matplotlib.axes.Axes.get_frame()`, which returns `matplotlib.axes.Axes.patch`, is deprecated.

- Changes in the `matplotlib.contour.ContourLabeler` attributes (`matplotlib.pyplot.clabel()` function) so that they all have a form like `.labelAttribute`. The three attributes that are most likely to be used by end users, `.cl`, `.cl_xy` and `.cl_cvalues` have been maintained for the moment (in addition to their renamed versions), but they are deprecated and will eventually be removed.

- Moved several functions in `matplotlib.mlab` and `matplotlib.cbook` into a separate module `matplotlib.numerical_methods` because they were unrelated to the initial purpose of mlab or cbook and appeared more coherent elsewhere.

## Changes for 0.98.1

- Removed broken `matplotlib.axes3d` support and replaced it with a non-implemented error pointing to 0.91.x

## Changes for 0.98.0

- `matplotlib.image.imread()` now no longer always returns RGBA data—if the image is luminance or RGB, it will return a MxN or MxNx3 array if possible. Also uint8 is no longer always forced to float.
- Rewrote the `matplotlib.cm.ScalarMappable` callback infrastructure to use `matplotlib.cbook.CallbackRegistry` rather than custom callback handling. Any users of `matplotlib.cm.ScalarMappable.add_observer()` of the `ScalarMappable` should use the `matplotlib.cm.ScalarMappable.callbacks` `CallbackRegistry` instead.
- New axes function and Axes method provide control over the plot color cycle: `matplotlib.axes.set_default_color_cycle()` and `matplotlib.axes.Axes.set_color_cycle()`.
- Matplotlib now requires Python 2.4, so `matplotlib.cbook` will no longer provide `set`, `enumerate()`, `reversed()` or `izip()` compatibility functions.
- In Numpy 1.0, bins are specified by the left edges only. The axes method `matplotlib.axes.Axes.hist()` now uses future Numpy 1.3 semantics for histograms. Providing `binedges`, the last value gives the upper-right edge now, which was implicitly set to +infinity in Numpy 1.0. This also means that the last bin doesn’t contain upper outliers any more by default.
- New axes method and pyplot function, `hexbin()`, is an alternative to `scatter()` for large datasets. It makes something like a `pcolor()` of a 2-D histogram, but uses hexagonal bins.
- New kwarg, `symmetric`, in `matplotlib.ticker.MaxNLocator` allows one require an axis to be centered around zero.
- Toolkits must now be imported from `mpl_toolkits` (not `matplotlib.toolkits`)

### Notes about the transforms refactoring

A major new feature of the 0.98 series is a more flexible and extensible transformation infrastructure, written in Python/Numpy rather than a custom C extension.

The primary goal of this refactoring was to make it easier to extend matplotlib to support new kinds of projections. This is mostly an internal improvement, and the possible user-visible changes it allows are yet to come.

See `matplotlib.transforms` for a description of the design of the new transformation framework.

For efficiency, many of these functions return views into Numpy arrays. This means that if you hold on to a reference to them, their contents may change. If you want to store a snapshot of their current values, use the Numpy array method copy().

The view intervals are now stored only in one place – in the `matplotlib.axes.Axes` instance, not in the locator instances as well. This means locators must get their limits from their `matplotlib.axis.Axis`, which in turn looks up its limits from the `Axes`. If a locator is used temporarily and not assigned to an Axis or Axes, (e.g., in `matplotlib.contour`), a dummy axis must be created to store its bounds. Call `matplotlib.ticker.Locator.create_dummy_axis()` to do so.

The functionality of `Pbox` has been merged with `Bbox`. Its methods now all return copies rather than modifying in place.

The following lists many of the simple changes necessary to update code from the old transformation framework to the new one. In particular, methods that return a copy are named with a verb in the past tense, whereas methods that alter an object in place are named with a verb in the present tense.

#### `matplotlib.transforms`

Old method | New method
--- | ---
`Bbox.get_bounds()` | `transforms.Bbox.bounds`
`Bbox.width()` | `transforms.Bbox.width`
`Bbox.height()` | `transforms.Bbox.height`
`Bbox.intervalx().get_bounds()` | `transforms.Bbox.intervalx`
`Bbox.intervalx().set_bounds()` | [`Bbox.intervalx` is now a property.]
`Bbox.intervaly().get_bounds()` | `transforms.Bbox.intervaly`
`Bbox.intervaly().set_bounds()` | [`Bbox.intervaly` is now a property.]
`Bbox.xmin()` | `transforms.Bbox.x0` or `transforms.Bbox.xmin` [1]
`Bbox.ymin()` | `transforms.Bbox.y0` or `transforms.Bbox.ymin` [1]
`Bbox.xmax()` | `transforms.Bbox.x1` or `transforms.Bbox.xmax` [1]
`Bbox.ymax()` | `transforms.Bbox.y1` or `transforms.Bbox.ymax` [1]
`Bbox.overlaps(bboxes)` | `Bbox.count_overlaps(bboxes)`
`bbox_all(bboxes)` | `Bbox.union(bboxes)` [`transforms.Bbox.union()` is a staticmethod.]
`lbwh_to_bbox(l, b, w, h)` | `Bbox.from_bounds(x0, y0, w, h)` [`transforms.Bbox.from_bounds()` is a staticmethod.]
`inverse_transform_bbox(trans, bbox)` | `Bbox.inverse_transformed(trans)`
`Interval.contains_open(v)` | `interval_contains_open(tuple, v)`
`Interval.contains(v)` | `interval_contains(tuple, v)`
`identity_transform()` | `matplotlib.transforms.IdentityTransform`
`blend_xy_sep_transform(xtrans, ytrans)` | `blended_transform_factory(xtrans, ytrans)`
`scale_transform(xs, ys)` | `Affine2D().scale(xs[, ys])`
`get_bbox_transform(boxin, boxout)` | `BboxTransform(boxin, boxout)` or `BboxTransformFrom(boxin)` or `BboxTransformTo(boxout)`
`Transform.seq_xy_tup(points)` | `Transform.transform(points)`
`Transform.inverse_xy_tup(points)` | `Transform.inverted().transform(points)`

[1] | (1, 2, 3, 4) The `Bbox` is bound by the points (x0, y0) to (x1, y1) and there is no defined order to these points, that is, x0 is not necessarily the left edge of the box. To get the left edge of the `Bbox`, use the read-only property `xmin`.

#### `matplotlib.axes`

Old method | New method
--- | ---
`Axes.get_position()` | `matplotlib.axes.Axes.get_position()` [2]
`Axes.set_position()` | `matplotlib.axes.Axes.set_position()` [3]
`Axes.toggle_log_lineary()` | `matplotlib.axes.Axes.set_yscale()` [4]
`Subplot` class | removed.

The `Polar` class has moved to `matplotlib.projections.polar`.

[2] | `matplotlib.axes.Axes.get_position()` used to return a list of points, now it returns a `matplotlib.transforms.Bbox` instance.

[3] | `matplotlib.axes.Axes.set_position()` now accepts either four scalars or a `matplotlib.transforms.Bbox` instance.

[4] | Since the recfactoring allows for more than two scale types (‘log’ or ‘linear’), it no longer makes sense to have a toggle. `Axes.toggle_log_lineary()` has been removed.

#### `matplotlib.artist`

Old method | New method
--- | ---
`Artist.set_clip_path(path)` | `Artist.set_clip_path(path, transform)` [5]

[5] | `matplotlib.artist.Artist.set_clip_path()` now accepts a `matplotlib.path.Path` instance and a `matplotlib.transforms.Transform` that will be applied to the path immediately before clipping.

#### `matplotlib.collections`

Old method | New method
--- | ---
`linestyle` | `linestyles` [6]

[6] | Linestyles are now treated like all other collection attributes, i.e. a single value or multiple values may be provided.

#### `matplotlib.colors`

Old method | New method
--- | ---
`ColorConvertor.to_rgba_list(c)` | `ColorConvertor.to_rgba_array(c)` [`matplotlib.colors.ColorConvertor.to_rgba_array()` returns an Nx4 Numpy array of RGBA color quadruples.]

#### `matplotlib.contour`

Old method | New method
--- | ---
`Contour._segments` | `matplotlib.contour.Contour.get_paths`()` [Returns a list of `matplotlib.path.Path` instances.]

#### `matplotlib.figure`

Old method | New method
--- | ---
`Figure.dpi.get()` / `Figure.dpi.set()` | `matplotlib.figure.Figure.dpi` (a property)

#### `matplotlib.patches`

Old method | New method
--- | ---
`Patch.get_verts()` | `matplotlib.patches.Patch.get_path()` [Returns a `matplotlib.path.Path` instance]

#### `matplotlib.backend_bases`

Old method | New method
--- | ---
`GraphicsContext.set_clip_rectangle(tuple)` | `GraphicsContext.set_clip_rectangle(bbox)`
`GraphicsContext.get_clip_path()` | `GraphicsContext.get_clip_path()` [7]
`GraphicsContext.set_clip_path()` | `GraphicsContext.set_clip_path()` [8]

#### `RendererBase`

New methods:

> - `draw_path(self, gc, path, transform, rgbFace)`
> - `draw_markers(self, gc, marker_path, marker_trans, path, trans, rgbFace)`
> - `draw_path_collection(self, master_transform, cliprect, clippath, clippath_trans, paths, all_transforms, offsets, offsetTrans, facecolors, edgecolors, linewidths, linestyles, antialiaseds)` [optional]

Changed methods:

> - `draw_image(self, x, y, im, bbox)` is now `draw_image(self, x, y, im, bbox, clippath, clippath_trans)`

Removed methods:

> - `draw_arc`
> - `draw_line_collection`
> - `draw_line`
> - `draw_lines`
> - `draw_point`
> - `draw_quad_mesh`
> - `draw_poly_collection`
> - `draw_polygon`
> - `draw_rectangle`
> - `draw_regpoly_collection`

[7] | `matplotlib.backend_bases.GraphicsContext.get_clip_path()` returns a tuple of the form (path, affine_transform), where path is a `matplotlib.path.Path` instance and affine_transform is a `matplotlib.transforms.Affine2D` instance.

[8] | `matplotlib.backend_bases.GraphicsContext.set_clip_path()` now only accepts a `matplotlib.transforms.TransformedPath` instance.

## Changes for 0.91.2

- For `csv2rec()`, checkrows=0 is the new default indicating all rows will be checked for type inference
- A warning is issued when an image is drawn on log-scaled axes, since it will not log-scale the image data.
- Moved `rec2gtk()` to `matplotlib.toolkits.gtktools`
- Moved `rec2excel()` to `matplotlib.toolkits.exceltools`
- Removed, dead/experimental ExampleInfo, Namespace and Importer code from `matplotlib.__init__`

## Changes for 0.91.1

## Changes for 0.91.0

- Changed `cbook.is_file_like()` to `cbook.is_writable_file_like()` and corrected behavior.
- Added ax kwarg to `pyplot.colorbar()` and `Figure.colorbar()` so that one can specify the axes object from which space for the colorbar is to be taken, if one does not want to make the colorbar axes manually.
- Changed `cbook.reversed()` so it yields a tuple rather than a (index, tuple). This agrees with the python reversed builtin, and cbook only defines reversed if python doesn’t provide the builtin.
- Made skiprows=1 the default on `csv2rec()`
- The gd and paint backends have been deleted.
- The errorbar method and function now accept additional kwargs so that upper and lower limits can be indicated by capping the bar with a caret instead of a straight line segment.
- The `matplotlib.dviread` file now has a parser for files like psfonts.map and pdftex.map, to map TeX font names to external files.
- The file `matplotlib.type1font` contains a new class for Type 1 fonts. Currently it simply reads pfa and pfb format files and stores the data in a way that is suitable for embedding in pdf files. In the future the class might actually parse the font to allow e.g., subsetting.
- `matplotlib.FT2Font` now supports `FT_Attach_File()`. In practice this can be used to read an afm file in addition to a pfa/pfb file, to get metrics and kerning information for a Type 1 font.
- The `AFM` class now supports querying CapHeight and stem widths. The get_name_char method now has an isord kwarg like get_width_char.
- Changed `pcolor()` default to shading=’flat’; but as noted now in the docstring, it is preferable to simply use the edgecolor kwarg.
- The mathtext font commands (`\cal`, `\rm`, `\it`, `\tt`) now behave as TeX does: they are in effect until the next font change command or the end of the grouping. Therefore uses of `$\cal{R}$` should be changed to `${\cal R}$`. Alternatively, you may use the new LaTeX-style font commands (`\mathcal`, `\mathrm`, `\mathit`, `\mathtt`) which do affect the following group, e.g., `$\mathcal{R}$`.
- Text creation commands have a new default linespacing and a new `linespacing` kwarg, which is a multiple of the maximum vertical extent of a line of ordinary text. The default is 1.2; `linespacing=2` would be like ordinary double spacing, for example.
- Changed default kwarg in `matplotlib.colors.Normalize.__init__`()` to `clip=False`; clipping silently defeats the purpose of the special over, under, and bad values in the colormap, thereby leading to unexpected behavior. The new default should reduce such surprises.
- Made the emit property of `set_xlim()` and `set_ylim()` `True` by default; removed the Axes custom callback handling into a ‘callbacks’ attribute which is a `CallbackRegistry` instance. This now supports the ‘xlim_changed’ and ‘ylim_changed’ Axes events.

## Changes for 0.90.1

    The file dviread.py has a (very limited and fragile) dvi reader
    for usetex support. The API might change in the future so don't
    depend on it yet.

    Removed deprecated support for a float value as a gray-scale;
    now it must be a string, like '0.5'.  Added alpha kwarg to
    ColorConverter.to_rgba_list.

    New method set_bounds(vmin, vmax) for formatters, locators sets
    the viewInterval and dataInterval from floats.

    Removed deprecated colorbar_classic.

    Line2D.get_xdata and get_ydata valid_only=False kwarg is replaced
    by orig=True.  When True, it returns the original data, otherwise
    the processed data (masked, converted)

    Some modifications to the units interface.
    units.ConversionInterface.tickers renamed to
    units.ConversionInterface.axisinfo and it now returns a
    units.AxisInfo object rather than a tuple.  This will make it
    easier to add axis info functionality (e.g., I added a default label
    on this iteration) w/o having to change the tuple length and hence
    the API of the client code every time new functionality is added.
    Also, units.ConversionInterface.convert_to_value is now simply
    named units.ConversionInterface.convert.

    Axes.errorbar uses Axes.vlines and Axes.hlines to draw its error
    limits int he vertical and horizontal direction.  As you'll see
    in the changes below, these functions now return a LineCollection
    rather than a list of lines.  The new return signature for
    errorbar is  ylins, caplines, errorcollections where
    errorcollections is a xerrcollection, yerrcollection

    Axes.vlines and Axes.hlines now create and returns a LineCollection, not a list
    of lines.  This is much faster.  The kwarg signature has changed,
    so consult the docs

    MaxNLocator accepts a new Boolean kwarg ('integer') to force
    ticks to integer locations.

    Commands that pass an argument to the Text constructor or to
    Text.set_text() now accept any object that can be converted
    with '%s'.  This affects xlabel(), title(), etc.

    Barh now takes a **kwargs dict instead of most of the old
    arguments. This helps ensure that bar and barh are kept in sync,
    but as a side effect you can no longer pass e.g., color as a
    positional argument.

    ft2font.get_charmap() now returns a dict that maps character codes
    to glyph indices (until now it was reversed)

    Moved data files into lib/matplotlib so that setuptools' develop
    mode works. Re-organized the mpl-data layout so that this source
    structure is maintained in the installation. (i.e., the 'fonts' and
    'images' sub-directories are maintained in site-packages.).
    Suggest removing site-packages/matplotlib/mpl-data and
    ~/.matplotlib/ttffont.cache before installing

## Changes for 0.90.0

    All artists now implement a "pick" method which users should not
    call.  Rather, set the "picker" property of any artist you want to
    pick on (the epsilon distance in points for a hit test) and
    register with the "pick_event" callback.  See
    examples/pick_event_demo.py for details

    Bar, barh, and hist have "log" binary kwarg: log=True
    sets the ordinate to a log scale.

    Boxplot can handle a list of vectors instead of just
    an array, so vectors can have different lengths.

    Plot can handle 2-D x and/or y; it plots the columns.

    Added linewidth kwarg to bar and barh.

    Made the default Artist._transform None (rather than invoking
    identity_transform for each artist only to have it overridden
    later).  Use artist.get_transform() rather than artist._transform,
    even in derived classes, so that the default transform will be
    created lazily as needed

    New LogNorm subclass of Normalize added to colors.py.
    All Normalize subclasses have new inverse() method, and
    the __call__() method has a new clip kwarg.

    Changed class names in colors.py to match convention:
    normalize -> Normalize, no_norm -> NoNorm.  Old names
    are still available for now.

    Removed obsolete pcolor_classic command and method.

    Removed lineprops and markerprops from the Annotation code and
    replaced them with an arrow configurable with kwarg arrowprops.
    See examples/annotation_demo.py - JDH

## Changes for 0.87.7

    Completely reworked the annotations API because I found the old
    API cumbersome.  The new design is much more legible and easy to
    read.  See matplotlib.text.Annotation and
    examples/annotation_demo.py

    markeredgecolor and markerfacecolor cannot be configured in
    matplotlibrc any more. Instead, markers are generally colored
    automatically based on the color of the line, unless marker colors
    are explicitly set as kwargs - NN

    Changed default comment character for load to '#' - JDH

    math_parse_s_ft2font_svg from mathtext.py & mathtext2.py now returns
    width, height, svg_elements. svg_elements is an instance of Bunch (
    cmbook.py) and has the attributes svg_glyphs and svg_lines, which are both
    lists.

    Renderer.draw_arc now takes an additional parameter, rotation.
    It specifies to draw the artist rotated in degrees anti-
    clockwise.  It was added for rotated ellipses.

    Renamed Figure.set_figsize_inches to Figure.set_size_inches to
    better match the get method, Figure.get_size_inches.

    Removed the copy_bbox_transform from transforms.py; added
    shallowcopy methods to all transforms.  All transforms already
    had deepcopy methods.

    FigureManager.resize(width, height): resize the window
    specified in pixels

    barh: x and y args have been renamed to width and bottom
    respectively, and their order has been swapped to maintain
    a (position, value) order.

    bar and barh: now accept kwarg 'edgecolor'.

    bar and barh: The left, height, width and bottom args can
    now all be scalars or sequences; see docstring.

    barh: now defaults to edge aligned instead of center
    aligned bars

    bar, barh and hist: Added a keyword arg 'align' that
    controls between edge or center bar alignment.

    Collections: PolyCollection and LineCollection now accept
    vertices or segments either in the original form [(x,y),
    (x,y), ...] or as a 2D numerix array, with X as the first column
    and Y as the second. Contour and quiver output the numerix
    form.  The transforms methods Bbox.update() and
    Transformation.seq_xy_tups() now accept either form.

    Collections: LineCollection is now a ScalarMappable like
    PolyCollection, etc.

    Specifying a grayscale color as a float is deprecated; use
    a string instead, e.g., 0.75 -> '0.75'.

    Collections: initializers now accept any mpl color arg, or
    sequence of such args; previously only a sequence of rgba
    tuples was accepted.

    Colorbar: completely new version and api; see docstring.  The
    original version is still accessible as colorbar_classic, but
    is deprecated.

    Contourf: "extend" kwarg replaces "clip_ends"; see docstring.
    Masked array support added to pcolormesh.

    Modified aspect-ratio handling:
        Removed aspect kwarg from imshow
        Axes methods:
            set_aspect(self, aspect, adjustable=None, anchor=None)
            set_adjustable(self, adjustable)
            set_anchor(self, anchor)
        Pylab interface:
            axis('image')

     Backend developers: ft2font's load_char now takes a flags
     argument, which you can OR together from the LOAD_XXX
     constants.

## Changes for 0.86

    Matplotlib data is installed into the matplotlib module.
    This is similar to package_data.  This should get rid of
    having to check for many possibilities in _get_data_path().
    The MATPLOTLIBDATA env key is still checked first to allow
    for flexibility.

    1) Separated the color table data from cm.py out into
    a new file, _cm.py, to make it easier to find the actual
    code in cm.py and to add new colormaps. Everything
    from _cm.py is imported by cm.py, so the split should be
    transparent.
    2) Enabled automatic generation of a colormap from
    a list of colors in contour; see modified
    examples/contour_demo.py.
    3) Support for imshow of a masked array, with the
    ability to specify colors (or no color at all) for
    masked regions, and for regions that are above or
    below the normally mapped region.  See
    examples/image_masked.py.
    4) In support of the above, added two new classes,
    ListedColormap, and no_norm, to colors.py, and modified
    the Colormap class to include common functionality. Added
    a clip kwarg to the normalize class.

## Changes for 0.85

    Made xtick and ytick separate props in rc

    made pos=None the default for tick formatters rather than 0 to
    indicate "not supplied"

    Removed "feature" of minor ticks which prevents them from
    overlapping major ticks.  Often you want major and minor ticks at
    the same place, and can offset the major ticks with the pad.  This
    could be made configurable

    Changed the internal structure of contour.py to a more OO style.
    Calls to contour or contourf in axes.py or pylab.py now return
    a ContourSet object which contains references to the
    LineCollections or PolyCollections created by the call,
    as well as the configuration variables that were used.
    The ContourSet object is a "mappable" if a colormap was used.

    Added a clip_ends kwarg to contourf. From the docstring:
             * clip_ends = True
               If False, the limits for color scaling are set to the
               minimum and maximum contour levels.
               True (default) clips the scaling limits.  Example:
               if the contour boundaries are V = [-100, 2, 1, 0, 1, 2, 100],
               then the scaling limits will be [-100, 100] if clip_ends
               is False, and [-3, 3] if clip_ends is True.
    Added kwargs linewidths, antialiased, and nchunk to contourf.  These
    are experimental; see the docstring.

    Changed Figure.colorbar():
        kw argument order changed;
        if mappable arg is a non-filled ContourSet, colorbar() shows
                lines instead hof polygons.
        if mappable arg is a filled ContourSet with clip_ends=True,
                the endpoints are not labelled, so as to give the
                correct impression of open-endedness.

    Changed LineCollection.get_linewidths to get_linewidth, for
    consistency.

## Changes for 0.84

    Unified argument handling between hlines and vlines.  Both now
    take optionally a fmt argument (as in plot) and a keyword args
    that can be passed onto Line2D.

    Removed all references to "data clipping" in rc and lines.py since
    these were not used and not optimized.  I'm sure they'll be
    resurrected later with a better implementation when needed.

    'set' removed - no more deprecation warnings.  Use 'setp' instead.

    Backend developers: Added flipud method to image and removed it
    from to_str.  Removed origin kwarg from backend.draw_image.
    origin is handled entirely by the frontend now.

## Changes for 0.83

    - Made HOME/.matplotlib the new config dir where the matplotlibrc
      file, the ttf.cache, and the tex.cache live.  The new default
      filenames in .matplotlib have no leading dot and are not hidden.
      e.g., the new names are matplotlibrc, tex.cache, and ttffont.cache.
      This is how ipython does it so it must be right.

      If old files are found, a warning is issued and they are moved to
      the new location.

    - backends/__init__.py no longer imports new_figure_manager,
      draw_if_interactive and show from the default backend, but puts
      these imports into a call to pylab_setup.  Also, the Toolbar is no
      longer imported from WX/WXAgg.  New usage:

        from backends import pylab_setup
        new_figure_manager, draw_if_interactive, show = pylab_setup()

    - Moved Figure.get_width_height() to FigureCanvasBase. It now
      returns int instead of float.

## Changes for 0.82

    - toolbar import change in GTKAgg, GTKCairo and WXAgg

    - Added subplot config tool to GTK* backends -- note you must now
      import the NavigationToolbar2 from your backend of choice rather
      than from backend_gtk because it needs to know about the backend
      specific canvas -- see examples/embedding_in_gtk2.py.  Ditto for
      wx backend -- see examples/embedding_in_wxagg.py

    - hist bin change

        Sean Richards notes there was a problem in the way we created
        the binning for histogram, which made the last bin
        underrepresented.  From his post:

          I see that hist uses the linspace function to create the bins
          and then uses searchsorted to put the values in their correct
          bin. That's all good but I am confused over the use of linspace
          for the bin creation. I wouldn't have thought that it does
          what is needed, to quote the docstring it creates a "Linear
          spaced array from min to max". For it to work correctly
          shouldn't the values in the bins array be the same bound for
          each bin? (i.e. each value should be the lower bound of a
          bin). To provide the correct bins for hist would it not be
          something like

          def bins(xmin, xmax, N):
            if N==1: return xmax
            dx = (xmax-xmin)/N # instead of N-1
            return xmin + dx*arange(N)

         This suggestion is implemented in 0.81.  My test script with these
         changes does not reveal any bias in the binning

          from matplotlib.numerix.mlab import randn, rand, zeros, Float
          from matplotlib.mlab import hist, mean

          Nbins = 50
          Ntests = 200
          results = zeros((Ntests,Nbins), typecode=Float)
          for i in range(Ntests):
              print 'computing', i
              x = rand(10000)
              n, bins = hist(x, Nbins)
              results[i] = n
          print mean(results)

## Changes for 0.81

    - pylab and artist "set" functions renamed to setp to avoid clash
      with python2.4 built-in set.  Current version will issue a
      deprecation warning which will be removed in future versions

    - imshow interpolation arguments changes for advanced interpolation
      schemes.  See help imshow, particularly the interpolation,
      filternorm and filterrad kwargs

    - Support for masked arrays has been added to the plot command and
      to the Line2D object.  Only the valid points are plotted.  A
      "valid_only" kwarg was added to the get_xdata() and get_ydata()
      methods of Line2D; by default it is False, so that the original
      data arrays are returned. Setting it to True returns the plottable
      points.

    - contour changes:

      Masked arrays: contour and contourf now accept masked arrays as
        the variable to be contoured.  Masking works correctly for
        contour, but a bug remains to be fixed before it will work for
        contourf.  The "badmask" kwarg has been removed from both
        functions.

       Level argument changes:

         Old version: a list of levels as one of the positional
         arguments specified the lower bound of each filled region; the
         upper bound of the last region was taken as a very large
         number.  Hence, it was not possible to specify that z values
         between 0 and 1, for example, be filled, and that values
         outside that range remain unfilled.

         New version: a list of N levels is taken as specifying the
         boundaries of N-1 z ranges.  Now the user has more control over
         what is colored and what is not.  Repeated calls to contourf
         (with different colormaps or color specifications, for example)
         can be used to color different ranges of z.  Values of z
         outside an expected range are left uncolored.

         Example:
           Old: contourf(z, [0, 1, 2]) would yield 3 regions: 0-1, 1-2, and >2.
           New: it would yield 2 regions: 0-1, 1-2.  If the same 3 regions were
           desired, the equivalent list of levels would be [0, 1, 2,
           1e38].

## Changes for 0.80

    - xlim/ylim/axis always return the new limits regardless of
      arguments.  They now take kwargs which allow you to selectively
      change the upper or lower limits while leaving unnamed limits
      unchanged.  See help(xlim) for example

## Changes for 0.73

    - Removed deprecated ColormapJet and friends

    - Removed all error handling from the verbose object

    - figure num of zero is now allowed

## Changes for 0.72

    - Line2D, Text, and Patch copy_properties renamed update_from and
      moved into artist base class

    - LineCollecitons.color renamed to LineCollections.set_color for
      consistency with set/get introspection mechanism,

    - pylab figure now defaults to num=None, which creates a new figure
      with a guaranteed unique number

    - contour method syntax changed - now it is MATLAB compatible

        unchanged: contour(Z)
        old: contour(Z, x=Y, y=Y)
        new: contour(X, Y, Z)

      see http://matplotlib.sf.net/matplotlib.pylab.html#-contour

     - Increased the default resolution for save command.

     - Renamed the base attribute of the ticker classes to _base to avoid conflict
       with the base method.  Sitt for subs

     - subs=none now does autosubbing in the tick locator.

     - New subplots that overlap old will delete the old axes.  If you
       do not want this behavior, use fig.add_subplot or the axes
       command

## Changes for 0.71

    Significant numerix namespace changes, introduced to resolve
    namespace clashes between python built-ins and mlab names.
    Refactored numerix to maintain separate modules, rather than
    folding all these names into a single namespace.  See the following
    mailing list threads for more information and background

      http://sourceforge.net/mailarchive/forum.php?thread_id=6398890&forum_id=36187
      http://sourceforge.net/mailarchive/forum.php?thread_id=6323208&forum_id=36187

    OLD usage

      from matplotlib.numerix import array, mean, fft

    NEW usage

      from matplotlib.numerix import array
      from matplotlib.numerix.mlab import mean
      from matplotlib.numerix.fft import fft

    numerix dir structure mirrors numarray (though it is an incomplete
    implementation)

      numerix
      numerix/mlab
      numerix/linear_algebra
      numerix/fft
      numerix/random_array

    but of course you can use 'numerix : Numeric' and still get the
    symbols.

    pylab still imports most of the symbols from Numerix, MLab, fft,
    etc, but is more cautious.  For names that clash with python names
    (min, max, sum), pylab keeps the builtins and provides the numeric
    versions with an a* prefix, e.g., (amin, amax, asum)

## Changes for 0.70

    MplEvent factored into a base class Event and derived classes
    MouseEvent and KeyEvent

    Removed definct set_measurement in wx toolbar

## Changes for 0.65.1

    removed add_axes and add_subplot from backend_bases.  Use
    figure.add_axes and add_subplot instead.  The figure now manages the
    current axes with gca and sca for get and set current axes.  If you
    have code you are porting which called, e.g., figmanager.add_axes, you
    can now simply do figmanager.canvas.figure.add_axes.

## Changes for 0.65

    mpl_connect and mpl_disconnect in the MATLAB interface renamed to
    connect and disconnect

    Did away with the text methods for angle since they were ambiguous.
    fontangle could mean fontstyle (obligue, etc) or the rotation of the
    text.  Use style and rotation instead.

## Changes for 0.63

    Dates are now represented internally as float days since 0001-01-01,
    UTC.

    All date tickers and formatters are now in matplotlib.dates, rather
    than matplotlib.tickers

    converters have been abolished from all functions and classes.
    num2date and date2num are now the converter functions for all date
    plots

    Most of the date tick locators have a different meaning in their
    constructors.  In the prior implementation, the first argument was a
    base and multiples of the base were ticked.  e.g.,

      HourLocator(5)  # old: tick every 5 minutes

    In the new implementation, the explicit points you want to tick are
    provided as a number or sequence

       HourLocator(range(0,5,61))  # new: tick every 5 minutes

    This gives much greater flexibility.  I have tried to make the
    default constructors (no args) behave similarly, where possible.

    Note that YearLocator still works under the base/multiple scheme.
    The difference between the YearLocator and the other locators is
    that years are not recurrent.

    Financial functions:

      matplotlib.finance.quotes_historical_yahoo(ticker, date1, date2)

       date1, date2 are now datetime instances.  Return value is a list
       of quotes where the quote time is a float - days since gregorian
       start, as returned by date2num

       See examples/finance_demo.py for example usage of new API

## Changes for 0.61

    canvas.connect is now deprecated for event handling.  use
    mpl_connect and mpl_disconnect instead.  The callback signature is
    func(event) rather than func(widget, event)

## Changes for 0.60

    ColormapJet and Grayscale are deprecated.  For backwards
    compatibility, they can be obtained either by doing

      from matplotlib.cm import ColormapJet

    or

      from matplotlib.matlab import *

    They are replaced by cm.jet and cm.grey

## Changes for 0.54.3

    removed the set_default_font / get_default_font scheme from the
    font_manager to unify customization of font defaults with the rest of
    the rc scheme.  See examples/font_properties_demo.py and help(rc) in
    matplotlib.matlab.

## Changes for 0.54

### MATLAB interface

#### dpi

Several of the backends used a PIXELS_PER_INCH hack that I added to try and make images render consistently across backends. This just complicated matters. So you may find that some font sizes and line widths appear different than before. Apologies for the inconvenience. You should set the dpi to an accurate value for your screen to get true sizes.

#### pcolor and scatter

There are two changes to the MATLAB interface API, both involving the patch drawing commands. For efficiency, pcolor and scatter have been rewritten to use polygon collections, which are a new set of objects from matplotlib.collections designed to enable efficient handling of large collections of objects. These new collections make it possible to build large scatter plots or pcolor plots with no loops at the python level, and are significantly faster than their predecessors. The original pcolor and scatter functions are retained as pcolor_classic and scatter_classic.

The return value from pcolor is a PolyCollection. Most of the propertes that are available on rectangles or other patches are also available on PolyCollections, e.g., you can say:

    c = scatter(blah, blah)
    c.set_linewidth(1.0)
    c.set_facecolor('r')
    c.set_alpha(0.5)

or:

    c = scatter(blah, blah)
    set(c, 'linewidth', 1.0, 'facecolor', 'r', 'alpha', 0.5)

Because the collection is a single object, you no longer need to loop over the return value of scatter or pcolor to set properties for the entire list.

If you want the different elements of a collection to vary on a property, e.g., to have different line widths, see matplotlib.collections for a discussion on how to set the properties as a sequence.

For scatter, the size argument is now in points^2 (the area of the symbol in points) as in MATLAB and is not in data coords as before. Using sizes in data coords caused several problems. So you will need to adjust your size arguments accordingly or use scatter_classic.

#### mathtext spacing

For reasons not clear to me (and which I’ll eventually fix) spacing no longer works in font groups. However, I added three new spacing commands which compensate for this ” (regular space), ‘/’ (small space) and ‘hspace{frac}’ where frac is a fraction of fontsize in points. You will need to quote spaces in font strings, is:

    title(r'$\rm{Histogram\ of\ IQ:}\ \mu=100,\ \sigma=15$')

### Object interface - Application programmers

#### Autoscaling

> The x and y axis instances no longer have autoscale view. These are handled by axes.autoscale_view

#### Axes creation

> You should not instantiate your own Axes any more using the OO API. Rather, create a Figure as before and in place of:

>     f = Figure(figsize=(5,4), dpi=100)
>     a = Subplot(f, 111)
>     f.add_axis(a)

> use:

>     f = Figure(figsize=(5,4), dpi=100)
>     a = f.add_subplot(111)

> That is, add_axis no longer exists and is replaced by:

>     add_axes(rect, axisbg=defaultcolor, frameon=True)
>     add_subplot(num, axisbg=defaultcolor, frameon=True)

#### Artist methods

> If you define your own Artists, you need to rename the _draw method to draw

#### Bounding boxes

> matplotlib.transforms.Bound2D is replaced by matplotlib.transforms.Bbox. If you want to construct a bbox from left, bottom, width, height (the signature for Bound2D), use matplotlib.transforms.lbwh_to_bbox, as in

> > bbox = clickBBox = lbwh_to_bbox(left, bottom, width, height)

> The Bbox has a different API than the Bound2D. e.g., if you want to get the width and height of the bbox

> > OLD::
> >   width = fig.bbox.x.interval() height = fig.bbox.y.interval()
> > New::
> >   width = fig.bbox.width() height = fig.bbox.height()

#### Object constructors

> You no longer pass the bbox, dpi, or transforms to the various Artist constructors. The old way or creating lines and rectangles was cumbersome because you had to pass so many attributes to the Line2D and Rectangle classes not related directly to the geometry and properties of the object. Now default values are added to the object when you call axes.add_line or axes.add_patch, so they are hidden from the user.

> If you want to define a custom transformation on these objects, call o.set_transform(trans) where trans is a Transformation instance.

> In prior versions of you wanted to add a custom line in data coords, you would have to do

> > l = Line2D(dpi, bbox, x, y,
> >   color = color, transx = transx, transy = transy, )

> now all you need is

> > l = Line2D(x, y, color=color)

> and the axes will set the transformation for you (unless you have set your own already, in which case it will eave it unchanged)

#### Transformations

> The entire transformation architecture has been rewritten. Previously the x and y transformations where stored in the xaxis and yaxis instances. The problem with this approach is it only allows for separable transforms (where the x and y transformations don’t depend on one another). But for cases like polar, they do. Now transformations operate on x,y together. There is a new base class matplotlib.transforms.Transformation and two concrete implementations, matplotlib.transforms.SeparableTransformation and matplotlib.transforms.Affine. The SeparableTransformation is constructed with the bounding box of the input (this determines the rectangular coordinate system of the input, i.e., the x and y view limits), the bounding box of the display, and possibly nonlinear transformations of x and y. The 2 most frequently used transformations, data coordinates -> display and axes coordinates -> display are available as ax.transData and ax.transAxes. See alignment_demo.py which uses axes coords.

> Also, the transformations should be much faster now, for two reasons

> > - they are written entirely in extension code

> > - because they operate on x and y together, they can do the entire transformation in one loop. Earlier I did something along the lines of:

> >       xt = sx*func(x) + tx
> >       yt = sy*func(y) + ty

> >   Although this was done in numerix, it still involves 6 length(x) for-loops (the multiply, add, and function evaluation each for x and y). Now all of that is done in a single pass.

> If you are using transformations and bounding boxes to get the cursor position in data coordinates, the method calls are a little different now. See the updated examples/coords_demo.py which shows you how to do this.

> Likewise, if you are using the artist bounding boxes to pick items on the canvas with the GUI, the bbox methods are somewhat different. You will need to see the updated examples/object_picker.py.

> See unit/transforms_unit.py for many examples using the new transformations.

## Changes for 0.50

    * refactored Figure class so it is no longer backend dependent.
      FigureCanvasBackend takes over the backend specific duties of the
      Figure.  matplotlib.backend_bases.FigureBase moved to
      matplotlib.figure.Figure.

    * backends must implement FigureCanvasBackend (the thing that
      controls the figure and handles the events if any) and
      FigureManagerBackend (wraps the canvas and the window for MATLAB
      interface).  FigureCanvasBase implements a backend switching
      mechanism

    * Figure is now an Artist (like everything else in the figure) and
      is totally backend independent

    * GDFONTPATH renamed to TTFPATH

    * backend faceColor argument changed to rgbFace

    * colormap stuff moved to colors.py

    * arg_to_rgb in backend_bases moved to class ColorConverter in
      colors.py

    * GD users must upgrade to gd-2.0.22 and gdmodule-0.52 since new gd
      features (clipping, antialiased lines) are now used.

    * Renderer must implement points_to_pixels

    Migrating code:

    MATLAB interface:

      The only API change for those using the MATLAB interface is in how
      you call figure redraws for dynamically updating figures.  In the
      old API, you did

        fig.draw()

      In the new API, you do

        manager = get_current_fig_manager()
        manager.canvas.draw()

      See the examples system_monitor.py, dynamic_demo.py, and anim.py

    API

      There is one important API change for application developers.
      Figure instances used subclass GUI widgets that enabled them to be
      placed directly into figures.  e.g., FigureGTK subclassed
      gtk.DrawingArea.  Now the Figure class is independent of the
      backend, and FigureCanvas takes over the functionality formerly
      handled by Figure.  In order to include figures into your apps,
      you now need to do, for example

        # gtk example
        fig = Figure(figsize=(5,4), dpi=100)
        canvas = FigureCanvasGTK(fig)  # a gtk.DrawingArea
        canvas.show()
        vbox.pack_start(canvas)

      If you use the NavigationToolbar, this in now initialized with a
      FigureCanvas, not a Figure.  The examples embedding_in_gtk.py,
      embedding_in_gtk2.py, and mpl_with_glade.py all reflect the new
      API so use these as a guide.

      All prior calls to

       figure.draw()  and
       figure.print_figure(args)

      should now be

       canvas.draw()  and
       canvas.print_figure(args)

      Apologies for the inconvenience.  This refactorization brings
      significant more freedom in developing matplotlib and should bring
      better plotting capabilities, so I hope the inconvenience is worth
      it.

## Changes for 0.42

    * Refactoring AxisText to be backend independent.  Text drawing and
      get_window_extent functionality will be moved to the Renderer.

    * backend_bases.AxisTextBase is now text.Text module

    * All the erase and reset functionality removed from AxisText - not
      needed with double buffered drawing.  Ditto with state change.
      Text instances have a get_prop_tup method that returns a hashable
      tuple of text properties which you can use to see if text props
      have changed, e.g., by caching a font or layout instance in a dict
      with the prop tup as a key -- see RendererGTK.get_pango_layout in
      backend_gtk for an example.

    * Text._get_xy_display renamed Text.get_xy_display

    * Artist set_renderer and wash_brushes methods removed

    * Moved Legend class from matplotlib.axes into matplotlib.legend

    * Moved Tick, XTick, YTick, Axis, XAxis, YAxis from matplotlib.axes
      to matplotlib.axis

    * moved process_text_args to matplotlib.text

    * After getting Text handled in a backend independent fashion, the
      import process is much cleaner since there are no longer cyclic
      dependencies

    * matplotlib.matlab._get_current_fig_manager renamed to
      matplotlib.matlab.get_current_fig_manager to allow user access to
      the GUI window attribute, e.g., figManager.window for GTK and
      figManager.frame for wx

## Changes for 0.40

    - Artist
        * __init__ takes a DPI instance and a Bound2D instance which is
          the bounding box of the artist in display coords
        * get_window_extent returns a Bound2D instance
        * set_size is removed; replaced by bbox and dpi
        * the clip_gc method is removed.  Artists now clip themselves with
          their box
        * added _clipOn boolean attribute.  If True, gc clip to bbox.

    - AxisTextBase
        * Initialized with a transx, transy which are Transform instances
        * set_drawing_area removed
        * get_left_right and get_top_bottom are replaced by get_window_extent

    - Line2D Patches now take transx, transy
        * Initialized with a transx, transy which are Transform instances

    - Patches
       * Initialized with a transx, transy which are Transform instances

    - FigureBase attributes dpi is a DPI intance rather than scalar and
      new attribute bbox is a Bound2D in display coords, and I got rid
      of the left, width, height, etc... attributes.  These are now
      accessible as, for example, bbox.x.min is left, bbox.x.interval()
      is width, bbox.y.max is top, etc...

    - GcfBase attribute pagesize renamed to figsize

    - Axes
        * removed figbg attribute
        * added fig instance to __init__
        * resizing is handled by figure call to resize.

    - Subplot
        * added fig instance to __init__

    - Renderer methods for patches now take gcEdge and gcFace instances.
      gcFace=None takes the place of filled=False

    - True and False symbols provided by cbook in a python2.3 compatible
      way

    - new module transforms supplies Bound1D, Bound2D and Transform
      instances and more

    - Changes to the MATLAB helpers API

      * _matlab_helpers.GcfBase is renamed by Gcf.  Backends no longer
        need to derive from this class.  Instead, they provide a factory
        function new_figure_manager(num, figsize, dpi).  The destroy
        method of the GcfDerived from the backends is moved to the derived
        FigureManager.

      * FigureManagerBase moved to backend_bases

      * Gcf.get_all_figwins renamed to Gcf.get_all_fig_managers

    Jeremy:

      Make sure to self._reset = False in AxisTextWX._set_font.  This was
      something missing in my backend code.