API Reference
matplotlib.font_manager

`matplotlib.font_manager`#

A module for finding, managing, and using fonts across platforms.

This module provides a single FontManager instance, fontManager, that can be shared across backends and platforms. The findfont function returns the best TrueType (TTF) font file in the local or system font path that matches the specified FontProperties instance. The FontManager also handles Adobe Font Metrics (AFM) font files for use by the PostScript backend. The FontManager.addfont function adds a custom font from a file without installing it into your operating system.

The design is based on the W3C Cascading Style Sheet, Level 1 (CSS1) font specification. Future versions may implement the Level 2 or 2.1 specifications.

class matplotlib.font_manager.FontManager(size=None, weight='normal')[source]#

Bases: object

On import, the FontManager singleton instance creates a list of ttf and afm fonts and caches their FontProperties. The FontManager.findfont method does a nearest neighbor search to find the font that most closely matches the specification. If no good enough match is found, the default font is returned.

Fonts added with the FontManager.addfont method will not persist in the cache; therefore, addfont will need to be called every time Matplotlib is imported. This method should only be used if and when a font cannot be installed on your operating system by other means.

Notes

The FontManager.addfont method must be called on the global FontManager instance.

Example usage:

import matplotlib.pyplot as plt
from matplotlib import font_manager

font_dirs = ["/resources/fonts"]  # The path to the custom font file.
font_files = font_manager.findSystemFonts(fontpaths=font_dirs)

for font_file in font_files:
    font_manager.fontManager.addfont(font_file)

addfont(path)[source]#

Cache the properties of the font at path to make it available to the FontManager. The type of font is inferred from the path suffix.

Parameters:

pathstr or path-like

Notes

This method is useful for adding a custom font without installing it in your operating system. See the FontManager singleton instance for usage and caveats about this function.

property defaultFont#

findfont(prop, fontext='ttf', directory=None, fallback_to_default=True, rebuild_if_missing=True)[source]#

Find the path to the font file most closely matching the given font properties.

Parameters:

propstr or FontProperties

The font properties to search for. This can be either a FontProperties object or a string defining a fontconfig patterns.

fontext{'ttf', 'afm'}, default: 'ttf'

The extension of the font file:

'ttf': TrueType and OpenType fonts (.ttf, .ttc, .otf)
'afm': Adobe Font Metrics (.afm)

directorystr, optional

If given, only search this directory and its subdirectories. If MPL_IGNORE_SYSTEM_FONTS is set, then this defaults to Matplotlib's internal font directory.

fallback_to_defaultbool

If True, will fall back to the default font family (usually "DejaVu Sans" or "Helvetica") if the first lookup hard-fails.

rebuild_if_missingbool

Whether to rebuild the font cache and search again if the first match appears to point to a nonexisting font (i.e., the font cache contains outdated entries).

Returns:

FontPath: The filename of the best matching font.

Notes

This performs a nearest neighbor search. Each font is given a similarity score to the target font properties. The first font with the highest score is returned. If no matches below a certain threshold are found, the default font (usually DejaVu Sans) is returned.

The result is cached, so subsequent lookups don't have to perform the O(n) nearest neighbor search.

See the W3C Cascading Style Sheet, Level 1 documentation for a description of the font finding algorithm.

static get_default_size()[source]#: Return the default font size.

get_default_weight()[source]#: Return the default font weight.

get_font_names()[source]#: Return the list of available fonts.

score_family(families, family2)[source]#

Return a match score between the list of font families in families and the font family name family2.

An exact match at the head of the list returns 0.0.

A match further down the list will return between 0 and 1.

No match will return 1.0.

score_size(size1, size2)[source]#

Return a match score between size1 and size2.

If size2 (the size specified in the font file) is 'scalable', this function always returns 0.0, since any font size can be generated.

Otherwise, the result is the absolute distance between size1 and size2, normalized so that the usual range of font sizes (6pt - 72pt) will lie between 0.0 and 1.0.

score_stretch(stretch1, stretch2)[source]#

Return a match score between stretch1 and stretch2.

The result is the absolute value of the difference between the CSS numeric values of stretch1 and stretch2, normalized between 0.0 and 1.0.

score_style(style1, style2)[source]#

Return a match score between style1 and style2.

An exact match returns 0.0.

A match between 'italic' and 'oblique' returns 0.1.

No match returns 1.0.

score_variant(variant1, variant2)[source]#

Return a match score between variant1 and variant2.

An exact match returns 0.0, otherwise 1.0.

score_weight(weight1, weight2)[source]#

Return a match score between weight1 and weight2.

The result is 0.0 if both weight1 and weight 2 are given as strings and have the same value.

Otherwise, the result is the absolute value of the difference between the CSS numeric values of weight1 and weight2, normalized between 0.05 and 1.0.

set_default_weight(weight)[source]#: Set the default font weight. The initial value is 'normal'.

class matplotlib.font_manager.FontPath(path, face_index)[source]#

Bases: str

A class to describe a path to a font with a face index.

Parameters:

pathstr: The path to a font.
face_indexint: The face index in the font.

property face_index#: The face index in a font.

property path#: The path to a font.

class matplotlib.font_manager.FontProperties(family=None, style=None, variant=None, weight=None, stretch=None, size=None, fname=None, math_fontfamily=None)[source]#

Bases: object

A class for storing and manipulating font properties.

The font properties are the six properties described in the W3C Cascading Style Sheet, Level 1 font specification and math_fontfamily for math fonts:

family: A list of font names in decreasing order of priority. The items may include a generic font family name, either 'sans-serif', 'serif', 'cursive', 'fantasy', or 'monospace'. In that case, the actual font to be used will be looked up from the associated rcParam during the search process in findfont. Default: rcParams["font.family"] (default: ['sans-serif'])
style: Either 'normal', 'italic' or 'oblique'. Default: rcParams["font.style"] (default: 'normal')
variant: Either 'normal' or 'small-caps'. Default: rcParams["font.variant"] (default: 'normal')
stretch: A numeric value in the range 0-1000 or one of 'ultra-condensed', 'extra-condensed', 'condensed', 'semi-condensed', 'normal', 'semi-expanded', 'expanded', 'extra-expanded' or 'ultra-expanded'. Default: rcParams["font.stretch"] (default: 'normal')
weight: A numeric value in the range 0-1000 or one of 'ultralight', 'light', 'normal', 'regular', 'book', 'medium', 'roman', 'semibold', 'demibold', 'demi', 'bold', 'heavy', 'extra bold', 'black'. Default: rcParams["font.weight"] (default: 'normal')
size: Either a relative value of 'xx-small', 'x-small', 'small', 'medium', 'large', 'x-large', 'xx-large' or an absolute font size, e.g., 10. Default: rcParams["font.size"] (default: 10.0)
math_fontfamily: The family of fonts used to render math text. Supported values are: 'dejavusans', 'dejavuserif', 'cm', 'stix', 'stixsans' and 'custom'. Default: rcParams["mathtext.fontset"] (default: 'dejavusans')

Alternatively, a font may be specified using the absolute path to a font file, by using the fname kwarg. However, in this case, it is typically simpler to just pass the path (as a pathlib.Path, not a str) to the font kwarg of the Text object.

The preferred usage of font sizes is to use the relative values, e.g., 'large', instead of absolute font sizes, e.g., 12. This approach allows all text sizes to be made larger or smaller based on the font manager's default font size.

This class accepts a single positional string as fontconfig pattern, or alternatively individual properties as keyword arguments:

FontProperties(pattern)
FontProperties(*, family=None, style=None, variant=None, ...)

This support does not depend on fontconfig; we are merely borrowing its pattern syntax for use here.

Note that Matplotlib's internal font manager and fontconfig use a different algorithm to lookup fonts, so the results of the same pattern may be different in Matplotlib than in other applications that use fontconfig.

copy()[source]#: Return a copy of self.

get_family()[source]#

Return a list of individual font family names or generic family names.

The font families or generic font families (which will be resolved from their respective rcParams when searching for a matching font) in the order of preference.

get_file()[source]#: Return the filename of the associated font.

get_fontconfig_pattern()[source]#

Get a fontconfig pattern suitable for looking up the font as specified with fontconfig's fc-match utility.

This support does not depend on fontconfig; we are merely borrowing its pattern syntax for use here.

get_math_fontfamily()[source]#

Return the name of the font family used for math text.

The default font is rcParams["mathtext.fontset"] (default: 'dejavusans').

get_name()[source]#: Return the name of the font that best matches the font properties.

get_size()[source]#: Return the font size.

get_size_in_points()[source]#: Return the font size.

get_slant()[source]#: Return the font style. Values are: 'normal', 'italic' or 'oblique'.

get_stretch()[source]#: Return the font stretch or width. Options are: 'ultra-condensed', 'extra-condensed', 'condensed', 'semi-condensed', 'normal', 'semi-expanded', 'expanded', 'extra-expanded', 'ultra-expanded'.

get_style()[source]#: Return the font style. Values are: 'normal', 'italic' or 'oblique'.

get_variant()[source]#: Return the font variant. Values are: 'normal' or 'small-caps'.

get_weight()[source]#: Get the font weight. Options are: A numeric value in the range 0-1000 or one of 'light', 'normal', 'regular', 'book', 'medium', 'roman', 'semibold', 'demibold', 'demi', 'bold', 'heavy', 'extra bold', 'black'

set_family(family)[source]#: Change the font family. Can be either an alias (generic name is CSS parlance), such as: 'serif', 'sans-serif', 'cursive', 'fantasy', or 'monospace', a real font name or a list of real font names. Real font names are not supported when rcParams["text.usetex"] (default: False) is True. Default: rcParams["font.family"] (default: ['sans-serif'])

set_file(file)[source]#: Set the filename of the fontfile to use. In this case, all other properties will be ignored.

set_fontconfig_pattern(pattern)[source]#

Set the properties by parsing a fontconfig pattern.

This support does not depend on fontconfig; we are merely borrowing its pattern syntax for use here.

set_math_fontfamily(fontfamily)[source]#

Set the font family for text in math mode.

If not set explicitly, rcParams["mathtext.fontset"] (default: 'dejavusans') will be used.

Parameters:

fontfamilystr

The name of the font family.

Available font families are defined in the default matplotlibrc file.

matplotlib.font_manager#

`matplotlib.font_manager`#