Source code for matplotlib._enums

Enums representing sets of strings that Matplotlib uses as input parameters.

Matplotlib often uses simple data types like strings or tuples to define a
concept; e.g. the line capstyle can be specified as one of 'butt', 'round',
or 'projecting'. The classes in this module are used internally and serve to
document these concepts formally.

As an end-user you will not use these classes directly, but only the values
they define.

from enum import Enum, auto
from matplotlib import cbook, docstring

class _AutoStringNameEnum(Enum):
    """Automate the ``name = 'name'`` part of making a (str, Enum)."""

    def _generate_next_value_(name, start, count, last_values):
        return name

    def __hash__(self):
        return str(self).__hash__()

def _deprecate_case_insensitive_join_cap(s):
    s_low = s.lower()
    if s != s_low:
        if s_low in ['miter', 'round', 'bevel']:
                "3.3", message="Case-insensitive capstyles are deprecated "
                "since %(since)s and support for them will be removed "
                "%(removal)s; please pass them in lowercase.")
        elif s_low in ['butt', 'round', 'projecting']:
                "3.3", message="Case-insensitive joinstyles are deprecated "
                "since %(since)s and support for them will be removed "
                "%(removal)s; please pass them in lowercase.")
        # Else, error out at the check_in_list stage.
    return s_low

[docs]class JoinStyle(str, _AutoStringNameEnum): """ Define how the connection between two line segments is drawn. For a visual impression of each *JoinStyle*, `view these docs online <JoinStyle>`, or run `JoinStyle.demo`. Lines in Matplotlib are typically defined by a 1D `~.path.Path` and a finite ``linewidth``, where the underlying 1D `~.path.Path` represents the center of the stroked line. By default, `~.backend_bases.GraphicsContextBase` defines the boundaries of a stroked line to simply be every point within some radius, ``linewidth/2``, away from any point of the center line. However, this results in corners appearing "rounded", which may not be the desired behavior if you are drawing, for example, a polygon or pointed star. **Supported values:** .. rst-class:: value-list 'miter' the "arrow-tip" style. Each boundary of the filled-in area will extend in a straight line parallel to the tangent vector of the centerline at the point it meets the corner, until they meet in a sharp point. 'round' stokes every point within a radius of ``linewidth/2`` of the center lines. 'bevel' the "squared-off" style. It can be thought of as a rounded corner where the "circular" part of the corner has been cut off. .. note:: Very long miter tips are cut off (to form a *bevel*) after a backend-dependent limit called the "miter limit", which specifies the maximum allowed ratio of miter length to line width. For example, the PDF backend uses the default value of 10 specified by the PDF standard, while the SVG backend does not even specify the miter limit, resulting in a default value of 4 per the SVG specification. Matplotlib does not currently allow the user to adjust this parameter. A more detailed description of the effect of a miter limit can be found in the `Mozilla Developer Docs <>`_ .. plot:: :alt: Demo of possible JoinStyle's from matplotlib._enums import JoinStyle JoinStyle.demo() """ miter = auto() round = auto() bevel = auto() def __init__(self, s): s = _deprecate_case_insensitive_join_cap(s) Enum.__init__(self)
[docs] @staticmethod def demo(): """Demonstrate how each JoinStyle looks for various join angles.""" import numpy as np import matplotlib.pyplot as plt def plot_angle(ax, x, y, angle, style): phi = np.radians(angle) xx = [x + .5, x, x + .5*np.cos(phi)] yy = [y, y, y + .5*np.sin(phi)] ax.plot(xx, yy, lw=12, color='tab:blue', solid_joinstyle=style) ax.plot(xx, yy, lw=1, color='black') ax.plot(xx[1], yy[1], 'o', color='tab:red', markersize=3) fig, ax = plt.subplots(figsize=(5, 4), constrained_layout=True) ax.set_title('Join style') for x, style in enumerate(['miter', 'round', 'bevel']): ax.text(x, 5, style) for y, angle in enumerate([20, 45, 60, 90, 120]): plot_angle(ax, x, y, angle, style) if x == 0: ax.text(-1.3, y, f'{angle} degrees') ax.set_xlim(-1.5, 2.75) ax.set_ylim(-.5, 5.5) ax.set_axis_off()
JoinStyle.input_description = "{" \ + ", ".join([f"'{}'" for js in JoinStyle]) \ + "}"
[docs]class CapStyle(str, _AutoStringNameEnum): r""" Define how the two endpoints (caps) of an unclosed line are drawn. How to draw the start and end points of lines that represent a closed curve (i.e. that end in a `~.path.Path.CLOSEPOLY`) is controlled by the line's `JoinStyle`. For all other lines, how the start and end points are drawn is controlled by the *CapStyle*. For a visual impression of each *CapStyle*, `view these docs online <CapStyle>` or run `CapStyle.demo`. **Supported values:** .. rst-class:: value-list 'butt' the line is squared off at its endpoint. 'projecting' the line is squared off as in *butt*, but the filled in area extends beyond the endpoint a distance of ``linewidth/2``. 'round' like *butt*, but a semicircular cap is added to the end of the line, of radius ``linewidth/2``. .. plot:: :alt: Demo of possible CapStyle's from matplotlib._enums import CapStyle CapStyle.demo() """ butt = 'butt' projecting = 'projecting' round = 'round' def __init__(self, s): s = _deprecate_case_insensitive_join_cap(s) Enum.__init__(self)
[docs] @staticmethod def demo(): """Demonstrate how each CapStyle looks for a thick line segment.""" import matplotlib.pyplot as plt fig = plt.figure(figsize=(4, 1.2)) ax = fig.add_axes([0, 0, 1, 0.8]) ax.set_title('Cap style') for x, style in enumerate(['butt', 'round', 'projecting']): ax.text(x+0.25, 0.85, style, ha='center') xx = [x, x+0.5] yy = [0, 0] ax.plot(xx, yy, lw=12, color='tab:blue', solid_capstyle=style) ax.plot(xx, yy, lw=1, color='black') ax.plot(xx, yy, 'o', color='tab:red', markersize=3) ax.text(2.25, 0.55, '(default)', ha='center') ax.set_ylim(-.5, 1.5) ax.set_axis_off()
CapStyle.input_description = "{" \ + ", ".join([f"'{}'" for cs in CapStyle]) \ + "}" docstring.interpd.update({'JoinStyle': JoinStyle.input_description, 'CapStyle': CapStyle.input_description})