r"""
Patches are `.Artist`\s with a face color and an edge color.
"""
import functools
import inspect
import math
from numbers import Number
import textwrap
from types import SimpleNamespace
from collections import namedtuple
from matplotlib.transforms import Affine2D
import numpy as np
import matplotlib as mpl
from . import (_api, artist, cbook, colors, _docstring, hatch as mhatch,
lines as mlines, transforms)
from .bezier import (
NonIntersectingPathException, get_cos_sin, get_intersection,
get_parallels, inside_circle, make_wedged_bezier2,
split_bezier_intersecting_with_closedpath, split_path_inout)
from .path import Path
from ._enums import JoinStyle, CapStyle
@_docstring.interpd
@_api.define_aliases({
"antialiased": ["aa"],
"edgecolor": ["ec"],
"facecolor": ["fc"],
"linestyle": ["ls"],
"linewidth": ["lw"],
})
class Patch(artist.Artist):
"""
A patch is a 2D artist with a face color and an edge color.
If any of *edgecolor*, *facecolor*, *linewidth*, or *antialiased*
are *None*, they default to their rc params setting.
"""
zorder = 1
# Whether to draw an edge by default. Set on a
# subclass-by-subclass basis.
_edge_default = False
@_api.make_keyword_only("3.6", name="edgecolor")
def __init__(self,
edgecolor=None,
facecolor=None,
color=None,
linewidth=None,
linestyle=None,
antialiased=None,
hatch=None,
fill=True,
capstyle=None,
joinstyle=None,
**kwargs):
"""
The following kwarg properties are supported
%(Patch:kwdoc)s
"""
super().__init__()
if linestyle is None:
linestyle = "solid"
if capstyle is None:
capstyle = CapStyle.butt
if joinstyle is None:
joinstyle = JoinStyle.miter
self._hatch_color = colors.to_rgba(mpl.rcParams['hatch.color'])
self._fill = True # needed for set_facecolor call
if color is not None:
if edgecolor is not None or facecolor is not None:
_api.warn_external(
"Setting the 'color' property will override "
"the edgecolor or facecolor properties.")
self.set_color(color)
else:
self.set_edgecolor(edgecolor)
self.set_facecolor(facecolor)
self._linewidth = 0
self._unscaled_dash_pattern = (0, None) # offset, dash
self._dash_pattern = (0, None) # offset, dash (scaled by linewidth)
self.set_fill(fill)
self.set_linestyle(linestyle)
self.set_linewidth(linewidth)
self.set_antialiased(antialiased)
self.set_hatch(hatch)
self.set_capstyle(capstyle)
self.set_joinstyle(joinstyle)
if len(kwargs):
self._internal_update(kwargs)
def get_verts(self):
"""
Return a copy of the vertices used in this patch.
If the patch contains Bézier curves, the curves will be interpolated by
line segments. To access the curves as curves, use `get_path`.
"""
trans = self.get_transform()
path = self.get_path()
polygons = path.to_polygons(trans)
if len(polygons):
return polygons[0]
return []
def _process_radius(self, radius):
if radius is not None:
return radius
if isinstance(self._picker, Number):
_radius = self._picker
else:
if self.get_edgecolor()[3] == 0:
_radius = 0
else:
_radius = self.get_linewidth()
return _radius
def contains(self, mouseevent, radius=None):
"""
Test whether the mouse event occurred in the patch.
Returns
-------
(bool, empty dict)
"""
inside, info = self._default_contains(mouseevent)
if inside is not None:
return inside, info
radius = self._process_radius(radius)
codes = self.get_path().codes
if codes is not None:
vertices = self.get_path().vertices
# if the current path is concatenated by multiple sub paths.
# get the indexes of the starting code(MOVETO) of all sub paths
idxs, = np.where(codes == Path.MOVETO)
# Don't split before the first MOVETO.
idxs = idxs[1:]
subpaths = map(
Path, np.split(vertices, idxs), np.split(codes, idxs))
else:
subpaths = [self.get_path()]
inside = any(
subpath.contains_point(
(mouseevent.x, mouseevent.y), self.get_transform(), radius)
for subpath in subpaths)
return inside, {}
def contains_point(self, point, radius=None):
"""
Return whether the given point is inside the patch.
Parameters
----------
point : (float, float)
The point (x, y) to check, in target coordinates of
``self.get_transform()``. These are display coordinates for patches
that are added to a figure or axes.
radius : float, optional
Additional margin on the patch in target coordinates of
``self.get_transform()``. See `.Path.contains_point` for further
details.
Returns
-------
bool
Notes
-----
The proper use of this method depends on the transform of the patch.
Isolated patches do not have a transform. In this case, the patch
creation coordinates and the point coordinates match. The following
example checks that the center of a circle is within the circle
>>> center = 0, 0
>>> c = Circle(center, radius=1)
>>> c.contains_point(center)
True
The convention of checking against the transformed patch stems from
the fact that this method is predominantly used to check if display
coordinates (e.g. from mouse events) are within the patch. If you want
to do the above check with data coordinates, you have to properly
transform them first:
>>> center = 0, 0
>>> c = Circle(center, radius=1)
>>> plt.gca().add_patch(c)
>>> transformed_center = c.get_transform().transform(center)
>>> c.contains_point(transformed_center)
True
"""
radius = self._process_radius(radius)
return self.get_path().contains_point(point,
self.get_transform(),
radius)
def contains_points(self, points, radius=None):
"""
Return whether the given points are inside the patch.
Parameters
----------
points : (N, 2) array
The points to check, in target coordinates of
``self.get_transform()``. These are display coordinates for patches
that are added to a figure or axes. Columns contain x and y values.
radius : float, optional
Additional margin on the patch in target coordinates of
``self.get_transform()``. See `.Path.contains_point` for further
details.
Returns
-------
length-N bool array
Notes
-----
The proper use of this method depends on the transform of the patch.
See the notes on `.Patch.contains_point`.
"""
radius = self._process_radius(radius)
return self.get_path().contains_points(points,
self.get_transform(),
radius)
def update_from(self, other):
# docstring inherited.
super().update_from(other)
# For some properties we don't need or don't want to go through the
# getters/setters, so we just copy them directly.
self._edgecolor = other._edgecolor
self._facecolor = other._facecolor
self._original_edgecolor = other._original_edgecolor
self._original_facecolor = other._original_facecolor
self._fill = other._fill
self._hatch = other._hatch
self._hatch_color = other._hatch_color
self._unscaled_dash_pattern = other._unscaled_dash_pattern
self.set_linewidth(other._linewidth) # also sets scaled dashes
self.set_transform(other.get_data_transform())
# If the transform of other needs further initialization, then it will
# be the case for this artist too.
self._transformSet = other.is_transform_set()
def get_extents(self):
"""
Return the `Patch`'s axis-aligned extents as a `~.transforms.Bbox`.
"""
return self.get_path().get_extents(self.get_transform())
def get_transform(self):
"""Return the `~.transforms.Transform` applied to the `Patch`."""
return self.get_patch_transform() + artist.Artist.get_transform(self)
def get_data_transform(self):
"""
Return the `~.transforms.Transform` mapping data coordinates to
physical coordinates.
"""
return artist.Artist.get_transform(self)
def get_patch_transform(self):
"""
Return the `~.transforms.Transform` instance mapping patch coordinates
to data coordinates.
For example, one may define a patch of a circle which represents a
radius of 5 by providing coordinates for a unit circle, and a
transform which scales the coordinates (the patch coordinate) by 5.
"""
return transforms.IdentityTransform()
def get_antialiased(self):
"""Return whether antialiasing is used for drawing."""
return self._antialiased
def get_edgecolor(self):
"""Return the edge color."""
return self._edgecolor
def get_facecolor(self):
"""Return the face color."""
return self._facecolor
def get_linewidth(self):
"""Return the line width in points."""
return self._linewidth
def get_linestyle(self):
"""Return the linestyle."""
return self._linestyle
def set_antialiased(self, aa):
"""
Set whether to use antialiased rendering.
Parameters
----------
aa : bool or None
"""
if aa is None:
aa = mpl.rcParams['patch.antialiased']
self._antialiased = aa
self.stale = True
def _set_edgecolor(self, color):
set_hatch_color = True
if color is None:
if (mpl.rcParams['patch.force_edgecolor'] or
not self._fill or self._edge_default):
color = mpl.rcParams['patch.edgecolor']
else:
color = 'none'
set_hatch_color = False
self._edgecolor = colors.to_rgba(color, self._alpha)
if set_hatch_color:
self._hatch_color = self._edgecolor
self.stale = True
def set_edgecolor(self, color):
"""
Set the patch edge color.
Parameters
----------
color : color or None
"""
self._original_edgecolor = color
self._set_edgecolor(color)
def _set_facecolor(self, color):
if color is None:
color = mpl.rcParams['patch.facecolor']
alpha = self._alpha if self._fill else 0
self._facecolor = colors.to_rgba(color, alpha)
self.stale = True
def set_facecolor(self, color):
"""
Set the patch face color.
Parameters
----------
color : color or None
"""
self._original_facecolor = color
self._set_facecolor(color)
def set_color(self, c):
"""
Set both the edgecolor and the facecolor.
Parameters
----------
c : color
See Also
--------
Patch.set_facecolor, Patch.set_edgecolor
For setting the edge or face color individually.
"""
self.set_facecolor(c)
self.set_edgecolor(c)
def set_alpha(self, alpha):
# docstring inherited
super().set_alpha(alpha)
self._set_facecolor(self._original_facecolor)
self._set_edgecolor(self._original_edgecolor)
# stale is already True
def set_linewidth(self, w):
"""
Set the patch linewidth in points.
Parameters
----------
w : float or None
"""
if w is None:
w = mpl.rcParams['patch.linewidth']
self._linewidth = float(w)
self._dash_pattern = mlines._scale_dashes(
*self._unscaled_dash_pattern, w)
self.stale = True
def set_linestyle(self, ls):
"""
Set the patch linestyle.
========================================== =================
linestyle description
========================================== =================
``'-'`` or ``'solid'`` solid line
``'--'`` or ``'dashed'`` dashed line
``'-.'`` or ``'dashdot'`` dash-dotted line
``':'`` or ``'dotted'`` dotted line
``'none'``, ``'None'``, ``' '``, or ``''`` draw nothing
========================================== =================
Alternatively a dash tuple of the following form can be provided::
(offset, onoffseq)
where ``onoffseq`` is an even length tuple of on and off ink in points.
Parameters
----------
ls : {'-', '--', '-.', ':', '', (offset, on-off-seq), ...}
The line style.
"""
if ls is None:
ls = "solid"
if ls in [' ', '', 'none']:
ls = 'None'
self._linestyle = ls
self._unscaled_dash_pattern = mlines._get_dash_pattern(ls)
self._dash_pattern = mlines._scale_dashes(
*self._unscaled_dash_pattern, self._linewidth)
self.stale = True
def set_fill(self, b):
"""
Set whether to fill the patch.
Parameters
----------
b : bool
"""
self._fill = bool(b)
self._set_facecolor(self._original_facecolor)
self._set_edgecolor(self._original_edgecolor)
self.stale = True
def get_fill(self):
"""Return whether the patch is filled."""
return self._fill
# Make fill a property so as to preserve the long-standing
# but somewhat inconsistent behavior in which fill was an
# attribute.
fill = property(get_fill, set_fill)
@_docstring.interpd
def set_capstyle(self, s):
"""
Set the `.CapStyle`.
The default capstyle is 'round' for `.FancyArrowPatch` and 'butt' for
all other patches.
Parameters
----------
s : `.CapStyle` or %(CapStyle)s
"""
cs = CapStyle(s)
self._capstyle = cs
self.stale = True
def get_capstyle(self):
"""Return the capstyle."""
return self._capstyle.name
@_docstring.interpd
def set_joinstyle(self, s):
"""
Set the `.JoinStyle`.
The default joinstyle is 'round' for `.FancyArrowPatch` and 'miter' for
all other patches.
Parameters
----------
s : `.JoinStyle` or %(JoinStyle)s
"""
js = JoinStyle(s)
self._joinstyle = js
self.stale = True
def get_joinstyle(self):
"""Return the joinstyle."""
return self._joinstyle.name
def set_hatch(self, hatch):
r"""
Set the hatching pattern.
*hatch* can be one of::
/ - diagonal hatching
\ - back diagonal
| - vertical
- - horizontal
+ - crossed
x - crossed diagonal
o - small circle
O - large circle
. - dots
* - stars
Letters can be combined, in which case all the specified
hatchings are done. If same letter repeats, it increases the
density of hatching of that pattern.
Hatching is supported in the PostScript, PDF, SVG and Agg
backends only.
Parameters
----------
hatch : {'/', '\\', '|', '-', '+', 'x', 'o', 'O', '.', '*'}
"""
# Use validate_hatch(list) after deprecation.
mhatch._validate_hatch_pattern(hatch)
self._hatch = hatch
self.stale = True
def get_hatch(self):
"""Return the hatching pattern."""
return self._hatch
def _draw_paths_with_artist_properties(
self, renderer, draw_path_args_list):
"""
``draw()`` helper factored out for sharing with `FancyArrowPatch`.
Configure *renderer* and the associated graphics context *gc*
from the artist properties, then repeatedly call
``renderer.draw_path(gc, *draw_path_args)`` for each tuple
*draw_path_args* in *draw_path_args_list*.
"""
renderer.open_group('patch', self.get_gid())
gc = renderer.new_gc()
gc.set_foreground(self._edgecolor, isRGBA=True)
lw = self._linewidth
if self._edgecolor[3] == 0 or self._linestyle == 'None':
lw = 0
gc.set_linewidth(lw)
gc.set_dashes(*self._dash_pattern)
gc.set_capstyle(self._capstyle)
gc.set_joinstyle(self._joinstyle)
gc.set_antialiased(self._antialiased)
self._set_gc_clip(gc)
gc.set_url(self._url)
gc.set_snap(self.get_snap())
gc.set_alpha(self._alpha)
if self._hatch:
gc.set_hatch(self._hatch)
gc.set_hatch_color(self._hatch_color)
if self.get_sketch_params() is not None:
gc.set_sketch_params(*self.get_sketch_params())
if self.get_path_effects():
from matplotlib.patheffects import PathEffectRenderer
renderer = PathEffectRenderer(self.get_path_effects(), renderer)
for draw_path_args in draw_path_args_list:
renderer.draw_path(gc, *draw_path_args)
gc.restore()
renderer.close_group('patch')
self.stale = False
@artist.allow_rasterization
def draw(self, renderer):
# docstring inherited
if not self.get_visible():
return
path = self.get_path()
transform = self.get_transform()
tpath = transform.transform_path_non_affine(path)
affine = transform.get_affine()
self._draw_paths_with_artist_properties(
renderer,
[(tpath, affine,
# Work around a bug in the PDF and SVG renderers, which
# do not draw the hatches if the facecolor is fully
# transparent, but do if it is None.
self._facecolor if self._facecolor[3] else None)])
def get_path(self):
"""Return the path of this patch."""
raise NotImplementedError('Derived must override')
def get_window_extent(self, renderer=None):
return self.get_path().get_extents(self.get_transform())
def _convert_xy_units(self, xy):
"""Convert x and y units for a tuple (x, y)."""
x = self.convert_xunits(xy[0])
y = self.convert_yunits(xy[1])
return x, y
class Shadow(Patch):
def __str__(self):
return f"Shadow({self.patch})"
@_docstring.dedent_interpd
def __init__(self, patch, ox, oy, **kwargs):
"""
Create a shadow of the given *patch*.
By default, the shadow will have the same face color as the *patch*,
but darkened.
Parameters
----------
patch : `~matplotlib.patches.Patch`
The patch to create the shadow for.
ox, oy : float
The shift of the shadow in data coordinates, scaled by a factor
of dpi/72.
**kwargs
Properties of the shadow patch. Supported keys are:
%(Patch:kwdoc)s
"""
super().__init__()
self.patch = patch
self._ox, self._oy = ox, oy
self._shadow_transform = transforms.Affine2D()
self.update_from(self.patch)
color = .3 * np.asarray(colors.to_rgb(self.patch.get_facecolor()))
self.update({'facecolor': color, 'edgecolor': color, 'alpha': 0.5,
# Place shadow patch directly behind the inherited patch.
'zorder': np.nextafter(self.patch.zorder, -np.inf),
**kwargs})
def _update_transform(self, renderer):
ox = renderer.points_to_pixels(self._ox)
oy = renderer.points_to_pixels(self._oy)
self._shadow_transform.clear().translate(ox, oy)
def get_path(self):
return self.patch.get_path()
def get_patch_transform(self):
return self.patch.get_patch_transform() + self._shadow_transform
def draw(self, renderer):
self._update_transform(renderer)
super().draw(renderer)
class Rectangle(Patch):
"""
A rectangle defined via an anchor point *xy* and its *width* and *height*.
The rectangle extends from ``xy[0]`` to ``xy[0] + width`` in x-direction
and from ``xy[1]`` to ``xy[1] + height`` in y-direction. ::
: +------------------+
: | |
: height |
: | |
: (xy)---- width -----+
One may picture *xy* as the bottom left corner, but which corner *xy* is
actually depends on the direction of the axis and the sign of *width*
and *height*; e.g. *xy* would be the bottom right corner if the x-axis
was inverted or if *width* was negative.
"""
def __str__(self):
pars = self._x0, self._y0, self._width, self._height, self.angle
fmt = "Rectangle(xy=(%g, %g), width=%g, height=%g, angle=%g)"
return fmt % pars
@_docstring.dedent_interpd
@_api.make_keyword_only("3.6", name="angle")
def __init__(self, xy, width, height, angle=0.0, *,
rotation_point='xy', **kwargs):
"""
Parameters
----------
xy : (float, float)
The anchor point.
width : float
Rectangle width.
height : float
Rectangle height.
angle : float, default: 0
Rotation in degrees anti-clockwise about the rotation point.
rotation_point : {'xy', 'center', (number, number)}, default: 'xy'
If ``'xy'``, rotate around the anchor point. If ``'center'`` rotate
around the center. If 2-tuple of number, rotate around this
coordinate.
Other Parameters
----------------
**kwargs : `~matplotlib.patches.Patch` properties
%(Patch:kwdoc)s
"""
super().__init__(**kwargs)
self._x0 = xy[0]
self._y0 = xy[1]
self._width = width
self._height = height
self.angle = float(angle)
self.rotation_point = rotation_point
# Required for RectangleSelector with axes aspect ratio != 1
# The patch is defined in data coordinates and when changing the
# selector with square modifier and not in data coordinates, we need
# to correct for the aspect ratio difference between the data and
# display coordinate systems. Its value is typically provide by
# Axes._get_aspect_ratio()
self._aspect_ratio_correction = 1.0
self._convert_units() # Validate the inputs.
def get_path(self):
"""Return the vertices of the rectangle."""
return Path.unit_rectangle()
def _convert_units(self):
"""Convert bounds of the rectangle."""
x0 = self.convert_xunits(self._x0)
y0 = self.convert_yunits(self._y0)
x1 = self.convert_xunits(self._x0 + self._width)
y1 = self.convert_yunits(self._y0 + self._height)
return x0, y0, x1, y1
def get_patch_transform(self):
# Note: This cannot be called until after this has been added to
# an Axes, otherwise unit conversion will fail. This makes it very
# important to call the accessor method and not directly access the
# transformation member variable.
bbox = self.get_bbox()
if self.rotation_point == 'center':
width, height = bbox.x1 - bbox.x0, bbox.y1 - bbox.y0
rotation_point = bbox.x0 + width / 2., bbox.y0 + height / 2.
elif self.rotation_point == 'xy':
rotation_point = bbox.x0, bbox.y0
else:
rotation_point = self.rotation_point
return transforms.BboxTransformTo(bbox) \
+ transforms.Affine2D() \
.translate(-rotation_point[0], -rotation_point[1]) \
.scale(1, self._aspect_ratio_correction) \
.rotate_deg(self.angle) \
.scale(1, 1 / self._aspect_ratio_correction) \
.translate(*rotation_point)
@property
def rotation_point(self):
"""The rotation point of the patch."""
return self._rotation_point
@rotation_point.setter
def rotation_point(self, value):
if value in ['center', 'xy'] or (
isinstance(value, tuple) and len(value) == 2 and
isinstance(value[0], Number) and isinstance(value[1], Number)
):
self._rotation_point = value
else:
raise ValueError("`rotation_point` must be one of "
"{'xy', 'center', (number, number)}.")
def get_x(self):
"""Return the left coordinate of the rectangle."""
return self._x0
def get_y(self):
"""Return the bottom coordinate of the rectangle."""
return self._y0
def get_xy(self):
"""Return the left and bottom coords of the rectangle as a tuple."""
return self._x0, self._y0
def get_corners(self):
"""
Return the corners of the rectangle, moving anti-clockwise from
(x0, y0).
"""
return self.get_patch_transform().transform(
[(0, 0), (1, 0), (1, 1), (0, 1)])
def get_center(self):
"""Return the centre of the rectangle."""
return self.get_patch_transform().transform((0.5, 0.5))
def get_width(self):
"""Return the width of the rectangle."""
return self._width
def get_height(self):
"""Return the height of the rectangle."""
return self._height
def get_angle(self):
"""Get the rotation angle in degrees."""
return self.angle
def set_x(self, x):
"""Set the left coordinate of the rectangle."""
self._x0 = x
self.stale = True
def set_y(self, y):
"""Set the bottom coordinate of the rectangle."""
self._y0 = y
self.stale = True
def set_angle(self, angle):
"""
Set the rotation angle in degrees.
The rotation is performed anti-clockwise around *xy*.
"""
self.angle = angle
self.stale = True
def set_xy(self, xy):
"""
Set the left and bottom coordinates of the rectangle.
Parameters
----------
xy : (float, float)
"""
self._x0, self._y0 = xy
self.stale = True
def set_width(self, w):
"""Set the width of the rectangle."""
self._width = w
self.stale = True
def set_height(self, h):
"""Set the height of the rectangle."""
self._height = h
self.stale = True
def set_bounds(self, *args):
"""
Set the bounds of the rectangle as *left*, *bottom*, *width*, *height*.
The values may be passed as separate parameters or as a tuple::
set_bounds(left, bottom, width, height)
set_bounds((left, bottom, width, height))
.. ACCEPTS: (left, bottom, width, height)
"""
if len(args) == 1:
l, b, w, h = args[0]
else:
l, b, w, h = args
self._x0 = l
self._y0 = b
self._width = w
self._height = h
self.stale = True
def get_bbox(self):
"""Return the `.Bbox`."""
x0, y0, x1, y1 = self._convert_units()
return transforms.Bbox.from_extents(x0, y0, x1, y1)
xy = property(get_xy, set_xy)
class RegularPolygon(Patch):
"""A regular polygon patch."""
def __str__(self):
s = "RegularPolygon((%g, %g), %d, radius=%g, orientation=%g)"
return s % (self.xy[0], self.xy[1], self.numvertices, self.radius,
self.orientation)
@_docstring.dedent_interpd
@_api.make_keyword_only("3.6", name="radius")
def __init__(self, xy, numVertices, radius=5, orientation=0,
**kwargs):
"""
Parameters
----------
xy : (float, float)
The center position.
numVertices : int
The number of vertices.
radius : float
The distance from the center to each of the vertices.
orientation : float
The polygon rotation angle (in radians).
**kwargs
`Patch` properties:
%(Patch:kwdoc)s
"""
self.xy = xy
self.numvertices = numVertices
self.orientation = orientation
self.radius = radius
self._path = Path.unit_regular_polygon(numVertices)
self._patch_transform = transforms.Affine2D()
super().__init__(**kwargs)
def get_path(self):
return self._path
def get_patch_transform(self):
return self._patch_transform.clear() \
.scale(self.radius) \
.rotate(self.orientation) \
.translate(*self.xy)
class PathPatch(Patch):
"""A general polycurve path patch."""
_edge_default = True
def __str__(self):
s = "PathPatch%d((%g, %g) ...)"
return s % (len(self._path.vertices), *tuple(self._path.vertices[0]))
@_docstring.dedent_interpd
def __init__(self, path, **kwargs):
"""
*path* is a `.Path` object.
Valid keyword arguments are:
%(Patch:kwdoc)s
"""
super().__init__(**kwargs)
self._path = path
def get_path(self):
return self._path
def set_path(self, path):
self._path = path
class StepPatch(PathPatch):
"""
A path patch describing a stepwise constant function.
By default, the path is not closed and starts and stops at
baseline value.
"""
_edge_default = False
@_docstring.dedent_interpd
def __init__(self, values, edges, *,
orientation='vertical', baseline=0, **kwargs):
"""
Parameters
----------
values : array-like
The step heights.
edges : array-like
The edge positions, with ``len(edges) == len(vals) + 1``,
between which the curve takes on vals values.
orientation : {'vertical', 'horizontal'}, default: 'vertical'
The direction of the steps. Vertical means that *values* are
along the y-axis, and edges are along the x-axis.
baseline : float, array-like or None, default: 0
The bottom value of the bounding edges or when
``fill=True``, position of lower edge. If *fill* is
True or an array is passed to *baseline*, a closed
path is drawn.
Other valid keyword arguments are:
%(Patch:kwdoc)s
"""
self.orientation = orientation
self._edges = np.asarray(edges)
self._values = np.asarray(values)
self._baseline = np.asarray(baseline) if baseline is not None else None
self._update_path()
super().__init__(self._path, **kwargs)
def _update_path(self):
if np.isnan(np.sum(self._edges)):
raise ValueError('Nan values in "edges" are disallowed')
if self._edges.size - 1 != self._values.size:
raise ValueError('Size mismatch between "values" and "edges". '
"Expected `len(values) + 1 == len(edges)`, but "
f"`len(values) = {self._values.size}` and "
f"`len(edges) = {self._edges.size}`.")
# Initializing with empty arrays allows supporting empty stairs.
verts, codes = [np.empty((0, 2))], [np.empty(0, dtype=Path.code_type)]
_nan_mask = np.isnan(self._values)
if self._baseline is not None:
_nan_mask |= np.isnan(self._baseline)
for idx0, idx1 in cbook.contiguous_regions(~_nan_mask):
x = np.repeat(self._edges[idx0:idx1+1], 2)
y = np.repeat(self._values[idx0:idx1], 2)
if self._baseline is None:
y = np.concatenate([y[:1], y, y[-1:]])
elif self._baseline.ndim == 0: # single baseline value
y = np.concatenate([[self._baseline], y, [self._baseline]])
elif self._baseline.ndim == 1: # baseline array
base = np.repeat(self._baseline[idx0:idx1], 2)[::-1]
x = np.concatenate([x, x[::-1]])
y = np.concatenate([base[-1:], y, base[:1],
base[:1], base, base[-1:]])
else: # no baseline
raise ValueError('Invalid `baseline` specified')
if self.orientation == 'vertical':
xy = np.column_stack([x, y])
else:
xy = np.column_stack([y, x])
verts.append(xy)
codes.append([Path.MOVETO] + [Path.LINETO]*(len(xy)-1))
self._path = Path(np.concatenate(verts), np.concatenate(codes))
def get_data(self):
"""Get `.StepPatch` values, edges and baseline as namedtuple."""
StairData = namedtuple('StairData', 'values edges baseline')
return StairData(self._values, self._edges, self._baseline)
def set_data(self, values=None, edges=None, baseline=None):
"""
Set `.StepPatch` values, edges and baseline.
Parameters
----------
values : 1D array-like or None
Will not update values, if passing None
edges : 1D array-like, optional
baseline : float, 1D array-like or None
"""
if values is None and edges is None and baseline is None:
raise ValueError("Must set *values*, *edges* or *baseline*.")
if values is not None:
self._values = np.asarray(values)
if edges is not None:
self._edges = np.asarray(edges)
if baseline is not None:
self._baseline = np.asarray(baseline)
self._update_path()
self.stale = True
class Polygon(Patch):
"""A general polygon patch."""
def __str__(self):
if len(self._path.vertices):
s = "Polygon%d((%g, %g) ...)"
return s % (len(self._path.vertices), *self._path.vertices[0])
else:
return "Polygon0()"
@_docstring.dedent_interpd
@_api.make_keyword_only("3.6", name="closed")
def __init__(self, xy, closed=True, **kwargs):
"""
*xy* is a numpy array with shape Nx2.
If *closed* is *True*, the polygon will be closed so the
starting and ending points are the same.
Valid keyword arguments are:
%(Patch:kwdoc)s
"""
super().__init__(**kwargs)
self._closed = closed
self.set_xy(xy)
def get_path(self):
"""Get the `.Path` of the polygon."""
return self._path
def get_closed(self):
"""Return whether the polygon is closed."""
return self._closed
def set_closed(self, closed):
"""
Set whether the polygon is closed.
Parameters
----------
closed : bool
True if the polygon is closed
"""
if self._closed == bool(closed):
return
self._closed = bool(closed)
self.set_xy(self.get_xy())
self.stale = True
def get_xy(self):
"""
Get the vertices of the path.
Returns
-------
(N, 2) numpy array
The coordinates of the vertices.
"""
return self._path.vertices
def set_xy(self, xy):
"""
Set the vertices of the polygon.
Parameters
----------
xy : (N, 2) array-like
The coordinates of the vertices.
Notes
-----
Unlike `.Path`, we do not ignore the last input vertex. If the
polygon is meant to be closed, and the last point of the polygon is not
equal to the first, we assume that the user has not explicitly passed a
``CLOSEPOLY`` vertex, and add it ourselves.
"""
xy = np.asarray(xy)
nverts, _ = xy.shape
if self._closed:
# if the first and last vertex are the "same", then we assume that
# the user explicitly passed the CLOSEPOLY vertex. Otherwise, we
# have to append one since the last vertex will be "ignored" by
# Path
if nverts == 1 or nverts > 1 and (xy[0] != xy[-1]).any():
xy = np.concatenate([xy, [xy[0]]])
else:
# if we aren't closed, and the last vertex matches the first, then
# we assume we have an unnecessary CLOSEPOLY vertex and remove it
if nverts > 2 and (xy[0] == xy[-1]).all():
xy = xy[:-1]
self._path = Path(xy, closed=self._closed)
self.stale = True
xy = property(get_xy, set_xy,
doc='The vertices of the path as (N, 2) numpy array.')
class Wedge(Patch):
"""Wedge shaped patch."""
def __str__(self):
pars = (self.center[0], self.center[1], self.r,
self.theta1, self.theta2, self.width)
fmt = "Wedge(center=(%g, %g), r=%g, theta1=%g, theta2=%g, width=%s)"
return fmt % pars
@_docstring.dedent_interpd
@_api.make_keyword_only("3.6", name="width")
def __init__(self, center, r, theta1, theta2, width=None, **kwargs):
"""
A wedge centered at *x*, *y* center with radius *r* that
sweeps *theta1* to *theta2* (in degrees). If *width* is given,
then a partial wedge is drawn from inner radius *r* - *width*
to outer radius *r*.
Valid keyword arguments are:
%(Patch:kwdoc)s
"""
super().__init__(**kwargs)
self.center = center
self.r, self.width = r, width
self.theta1, self.theta2 = theta1, theta2
self._patch_transform = transforms.IdentityTransform()
self._recompute_path()
def _recompute_path(self):
# Inner and outer rings are connected unless the annulus is complete
if abs((self.theta2 - self.theta1) - 360) <= 1e-12:
theta1, theta2 = 0, 360
connector = Path.MOVETO
else:
theta1, theta2 = self.theta1, self.theta2
connector = Path.LINETO
# Form the outer ring
arc = Path.arc(theta1, theta2)
if self.width is not None:
# Partial annulus needs to draw the outer ring
# followed by a reversed and scaled inner ring
v1 = arc.vertices
v2 = arc.vertices[::-1] * (self.r - self.width) / self.r
v = np.concatenate([v1, v2, [(0, 0)]])
c = [*arc.codes, connector, *arc.codes[1:], Path.CLOSEPOLY]
else:
# Wedge doesn't need an inner ring
v = np.concatenate([arc.vertices, [(0, 0), (0, 0)]])
c = [*arc.codes, connector, Path.CLOSEPOLY]
# Shift and scale the wedge to the final location.
self._path = Path(v * self.r + self.center, c)
def set_center(self, center):
self._path = None
self.center = center
self.stale = True
def set_radius(self, radius):
self._path = None
self.r = radius
self.stale = True
def set_theta1(self, theta1):
self._path = None
self.theta1 = theta1
self.stale = True
def set_theta2(self, theta2):
self._path = None
self.theta2 = theta2
self.stale = True
def set_width(self, width):
self._path = None
self.width = width
self.stale = True
def get_path(self):
if self._path is None:
self._recompute_path()
return self._path
# COVERAGE NOTE: Not used internally or from examples
class Arrow(Patch):
"""An arrow patch."""
def __str__(self):
return "Arrow()"
_path = Path._create_closed([
[0.0, 0.1], [0.0, -0.1], [0.8, -0.1], [0.8, -0.3], [1.0, 0.0],
[0.8, 0.3], [0.8, 0.1]])
@_docstring.dedent_interpd
@_api.make_keyword_only("3.6", name="width")
def __init__(self, x, y, dx, dy, width=1.0, **kwargs):
"""
Draws an arrow from (*x*, *y*) to (*x* + *dx*, *y* + *dy*).
The width of the arrow is scaled by *width*.
Parameters
----------
x : float
x coordinate of the arrow tail.
y : float
y coordinate of the arrow tail.
dx : float
Arrow length in the x direction.
dy : float
Arrow length in the y direction.
width : float, default: 1
Scale factor for the width of the arrow. With a default value of 1,
the tail width is 0.2 and head width is 0.6.
**kwargs
Keyword arguments control the `Patch` properties:
%(Patch:kwdoc)s
See Also
--------
FancyArrow
Patch that allows independent control of the head and tail
properties.
"""
super().__init__(**kwargs)
self._patch_transform = (
transforms.Affine2D()
.scale(np.hypot(dx, dy), width)
.rotate(np.arctan2(dy, dx))
.translate(x, y)
.frozen())
def get_path(self):
return self._path
def get_patch_transform(self):
return self._patch_transform
class FancyArrow(Polygon):
"""
Like Arrow, but lets you set head width and head height independently.
"""
_edge_default = True
def __str__(self):
return "FancyArrow()"
@_docstring.dedent_interpd
@_api.make_keyword_only("3.6", name="width")
def __init__(self, x, y, dx, dy, width=0.001, length_includes_head=False,
head_width=None, head_length=None, shape='full', overhang=0,
head_starts_at_zero=False, **kwargs):
"""
Parameters
----------
x, y : float
The x and y coordinates of the arrow base.
dx, dy : float
The length of the arrow along x and y direction.
width : float, default: 0.001
Width of full arrow tail.
length_includes_head : bool, default: False
True if head is to be counted in calculating the length.
head_width : float or None, default: 3*width
Total width of the full arrow head.
head_length : float or None, default: 1.5*head_width
Length of arrow head.
shape : {'full', 'left', 'right'}, default: 'full'
Draw the left-half, right-half, or full arrow.
overhang : float, default: 0
Fraction that the arrow is swept back (0 overhang means
triangular shape). Can be negative or greater than one.
head_starts_at_zero : bool, default: False
If True, the head starts being drawn at coordinate 0
instead of ending at coordinate 0.
**kwargs
`.Patch` properties:
%(Patch:kwdoc)s
"""
self._x = x
self._y = y
self._dx = dx
self._dy = dy
self._width = width
self._length_includes_head = length_includes_head
self._head_width = head_width
self._head_length = head_length
self._shape = shape
self._overhang = overhang
self._head_starts_at_zero = head_starts_at_zero
self._make_verts()
super().__init__(self.verts, closed=True, **kwargs)
def set_data(self, *, x=None, y=None, dx=None, dy=None, width=None,
head_width=None, head_length=None):
"""
Set `.FancyArrow` x, y, dx, dy, width, head_with, and head_length.
Values left as None will not be updated.
Parameters
----------
x, y : float or None, default: None
The x and y coordinates of the arrow base.
dx, dy : float or None, default: None
The length of the arrow along x and y direction.
width : float or None, default: None
Width of full arrow tail.
head_width : float or None, default: None
Total width of the full arrow head.
head_length : float or None, default: None
Length of arrow head.
"""
if x is not None:
self._x = x
if y is not None:
self._y = y
if dx is not None:
self._dx = dx
if dy is not None:
self._dy = dy
if width is not None:
self._width = width
if head_width is not None:
self._head_width = head_width
if head_length is not None:
self._head_length = head_length
self._make_verts()
self.set_xy(self.verts)
def _make_verts(self):
if self._head_width is None:
head_width = 3 * self._width
else:
head_width = self._head_width
if self._head_length is None:
head_length = 1.5 * head_width
else:
head_length = self._head_length
distance = np.hypot(self._dx, self._dy)
if self._length_includes_head:
length = distance
else:
length = distance + head_length
if not length:
self.verts = np.empty([0, 2]) # display nothing if empty
else:
# start by drawing horizontal arrow, point at (0, 0)
hw, hl = head_width, head_length
hs, lw = self._overhang, self._width
left_half_arrow = np.array([
[0.0, 0.0], # tip
[-hl, -hw / 2], # leftmost
[-hl * (1 - hs), -lw / 2], # meets stem
[-length, -lw / 2], # bottom left
[-length, 0],
])
# if we're not including the head, shift up by head length
if not self._length_includes_head:
left_half_arrow += [head_length, 0]
# if the head starts at 0, shift up by another head length
if self._head_starts_at_zero:
left_half_arrow += [head_length / 2, 0]
# figure out the shape, and complete accordingly
if self._shape == 'left':
coords = left_half_arrow
else:
right_half_arrow = left_half_arrow * [1, -1]
if self._shape == 'right':
coords = right_half_arrow
elif self._shape == 'full':
# The half-arrows contain the midpoint of the stem,
# which we can omit from the full arrow. Including it
# twice caused a problem with xpdf.
coords = np.concatenate([left_half_arrow[:-1],
right_half_arrow[-2::-1]])
else:
raise ValueError(f"Got unknown shape: {self._shape!r}")
if distance != 0:
cx = self._dx / distance
sx = self._dy / distance
else:
# Account for division by zero
cx, sx = 0, 1
M = [[cx, sx], [-sx, cx]]
self.verts = np.dot(coords, M) + [
self._x + self._dx,
self._y + self._dy,
]
_docstring.interpd.update(
FancyArrow="\n".join(
(inspect.getdoc(FancyArrow.__init__) or "").splitlines()[2:]))
class CirclePolygon(RegularPolygon):
"""A polygon-approximation of a circle patch."""
def __str__(self):
s = "CirclePolygon((%g, %g), radius=%g, resolution=%d)"
return s % (self.xy[0], self.xy[1], self.radius, self.numvertices)
@_docstring.dedent_interpd
@_api.make_keyword_only("3.6", name="resolution")
def __init__(self, xy, radius=5,
resolution=20, # the number of vertices
** kwargs):
"""
Create a circle at *xy* = (*x*, *y*) with given *radius*.
This circle is approximated by a regular polygon with *resolution*
sides. For a smoother circle drawn with splines, see `Circle`.
Valid keyword arguments are:
%(Patch:kwdoc)s
"""
super().__init__(
xy, resolution, radius=radius, orientation=0, **kwargs)
class Ellipse(Patch):
"""A scale-free ellipse."""
def __str__(self):
pars = (self._center[0], self._center[1],
self.width, self.height, self.angle)
fmt = "Ellipse(xy=(%s, %s), width=%s, height=%s, angle=%s)"
return fmt % pars
@_docstring.dedent_interpd
@_api.make_keyword_only("3.6", name="angle")
def __init__(self, xy, width, height, angle=0, **kwargs):
"""
Parameters
----------
xy : (float, float)
xy coordinates of ellipse centre.
width : float
Total length (diameter) of horizontal axis.
height : float
Total length (diameter) of vertical axis.
angle : float, default: 0
Rotation in degrees anti-clockwise.
Notes
-----
Valid keyword arguments are:
%(Patch:kwdoc)s
"""
super().__init__(**kwargs)
self._center = xy
self._width, self._height = width, height
self._angle = angle
self._path = Path.unit_circle()
# Required for EllipseSelector with axes aspect ratio != 1
# The patch is defined in data coordinates and when changing the
# selector with square modifier and not in data coordinates, we need
# to correct for the aspect ratio difference between the data and
# display coordinate systems.
self._aspect_ratio_correction = 1.0
# Note: This cannot be calculated until this is added to an Axes
self._patch_transform = transforms.IdentityTransform()
def _recompute_transform(self):
"""
Notes
-----
This cannot be called until after this has been added to an Axes,
otherwise unit conversion will fail. This makes it very important to
call the accessor method and not directly access the transformation
member variable.
"""
center = (self.convert_xunits(self._center[0]),
self.convert_yunits(self._center[1]))
width = self.convert_xunits(self._width)
height = self.convert_yunits(self._height)
self._patch_transform = transforms.Affine2D() \
.scale(width * 0.5, height * 0.5 * self._aspect_ratio_correction) \
.rotate_deg(self.angle) \
.scale(1, 1 / self._aspect_ratio_correction) \
.translate(*center)
def get_path(self):
"""Return the path of the ellipse."""
return self._path
def get_patch_transform(self):
self._recompute_transform()
return self._patch_transform
def set_center(self, xy):
"""
Set the center of the ellipse.
Parameters
----------
xy : (float, float)
"""
self._center = xy
self.stale = True
def get_center(self):
"""Return the center of the ellipse."""
return self._center
center = property(get_center, set_center)
def set_width(self, width):
"""
Set the width of the ellipse.
Parameters
----------
width : float
"""
self._width = width
self.stale = True
def get_width(self):
"""
Return the width of the ellipse.
"""
return self._width
width = property(get_width, set_width)
def set_height(self, height):
"""
Set the height of the ellipse.
Parameters
----------
height : float
"""
self._height = height
self.stale = True
def get_height(self):
"""Return the height of the ellipse."""
return self._height
height = property(get_height, set_height)
def set_angle(self, angle):
"""
Set the angle of the ellipse.
Parameters
----------
angle : float
"""
self._angle = angle
self.stale = True
def get_angle(self):
"""Return the angle of the ellipse."""
return self._angle
angle = property(get_angle, set_angle)
def get_corners(self):
"""
Return the corners of the ellipse bounding box.
The bounding box orientation is moving anti-clockwise from the
lower left corner defined before rotation.
"""
return self.get_patch_transform().transform(
[(-1, -1), (1, -1), (1, 1), (-1, 1)])
class Annulus(Patch):
"""
An elliptical annulus.
"""
@_docstring.dedent_interpd
def __init__(self, xy, r, width, angle=0.0, **kwargs):
"""
Parameters
----------
xy : (float, float)
xy coordinates of annulus centre.
r : float or (float, float)
The radius, or semi-axes:
- If float: radius of the outer circle.
- If two floats: semi-major and -minor axes of outer ellipse.
width : float
Width (thickness) of the annular ring. The width is measured inward
from the outer ellipse so that for the inner ellipse the semi-axes
are given by ``r - width``. *width* must be less than or equal to
the semi-minor axis.
angle : float, default: 0
Rotation angle in degrees (anti-clockwise from the positive
x-axis). Ignored for circular annuli (i.e., if *r* is a scalar).
**kwargs
Keyword arguments control the `Patch` properties:
%(Patch:kwdoc)s
"""
super().__init__(**kwargs)
self.set_radii(r)
self.center = xy
self.width = width
self.angle = angle
self._path = None
def __str__(self):
if self.a == self.b:
r = self.a
else:
r = (self.a, self.b)
return "Annulus(xy=(%s, %s), r=%s, width=%s, angle=%s)" % \
(*self.center, r, self.width, self.angle)
def set_center(self, xy):
"""
Set the center of the annulus.
Parameters
----------
xy : (float, float)
"""
self._center = xy
self._path = None
self.stale = True
def get_center(self):
"""Return the center of the annulus."""
return self._center
center = property(get_center, set_center)
def set_width(self, width):
"""
Set the width (thickness) of the annulus ring.
The width is measured inwards from the outer ellipse.
Parameters
----------
width : float
"""
if min(self.a, self.b) <= width:
raise ValueError(
'Width of annulus must be less than or equal semi-minor axis')
self._width = width
self._path = None
self.stale = True
def get_width(self):
"""Return the width (thickness) of the annulus ring."""
return self._width
width = property(get_width, set_width)
def set_angle(self, angle):
"""
Set the tilt angle of the annulus.
Parameters
----------
angle : float
"""
self._angle = angle
self._path = None
self.stale = True
def get_angle(self):
"""Return the angle of the annulus."""
return self._angle
angle = property(get_angle, set_angle)
def set_semimajor(self, a):
"""
Set the semi-major axis *a* of the annulus.
Parameters
----------
a : float
"""
self.a = float(a)
self._path = None
self.stale = True
def set_semiminor(self, b):
"""
Set the semi-minor axis *b* of the annulus.
Parameters
----------
b : float
"""
self.b = float(b)
self._path = None
self.stale = True
def set_radii(self, r):
"""
Set the semi-major (*a*) and semi-minor radii (*b*) of the annulus.
Parameters
----------
r : float or (float, float)
The radius, or semi-axes:
- If float: radius of the outer circle.
- If two floats: semi-major and -minor axes of outer ellipse.
"""
if np.shape(r) == (2,):
self.a, self.b = r
elif np.shape(r) == ():
self.a = self.b = float(r)
else:
raise ValueError("Parameter 'r' must be one or two floats.")
self._path = None
self.stale = True
def get_radii(self):
"""Return the semi-major and semi-minor radii of the annulus."""
return self.a, self.b
radii = property(get_radii, set_radii)
def _transform_verts(self, verts, a, b):
return transforms.Affine2D() \
.scale(*self._convert_xy_units((a, b))) \
.rotate_deg(self.angle) \
.translate(*self._convert_xy_units(self.center)) \
.transform(verts)
def _recompute_path(self):
# circular arc
arc = Path.arc(0, 360)
# annulus needs to draw an outer ring
# followed by a reversed and scaled inner ring
a, b, w = self.a, self.b, self.width
v1 = self._transform_verts(arc.vertices, a, b)
v2 = self._transform_verts(arc.vertices[::-1], a - w, b - w)
v = np.vstack([v1, v2, v1[0, :], (0, 0)])
c = np.hstack([arc.codes, Path.MOVETO,
arc.codes[1:], Path.MOVETO,
Path.CLOSEPOLY])
self._path = Path(v, c)
def get_path(self):
if self._path is None:
self._recompute_path()
return self._path
class Circle(Ellipse):
"""
A circle patch.
"""
def __str__(self):
pars = self.center[0], self.center[1], self.radius
fmt = "Circle(xy=(%g, %g), radius=%g)"
return fmt % pars
@_docstring.dedent_interpd
def __init__(self, xy, radius=5, **kwargs):
"""
Create a true circle at center *xy* = (*x*, *y*) with given *radius*.
Unlike `CirclePolygon` which is a polygonal approximation, this uses
Bezier splines and is much closer to a scale-free circle.
Valid keyword arguments are:
%(Patch:kwdoc)s
"""
super().__init__(xy, radius * 2, radius * 2, **kwargs)
self.radius = radius
def set_radius(self, radius):
"""
Set the radius of the circle.
Parameters
----------
radius : float
"""
self.width = self.height = 2 * radius
self.stale = True
def get_radius(self):
"""Return the radius of the circle."""
return self.width / 2.
radius = property(get_radius, set_radius)
class Arc(Ellipse):
"""
An elliptical arc, i.e. a segment of an ellipse.
Due to internal optimizations, the arc cannot be filled.
"""
def __str__(self):
pars = (self.center[0], self.center[1], self.width,
self.height, self.angle, self.theta1, self.theta2)
fmt = ("Arc(xy=(%g, %g), width=%g, "
"height=%g, angle=%g, theta1=%g, theta2=%g)")
return fmt % pars
@_docstring.dedent_interpd
@_api.make_keyword_only("3.6", name="angle")
def __init__(self, xy, width, height, angle=0.0,
theta1=0.0, theta2=360.0, **kwargs):
"""
Parameters
----------
xy : (float, float)
The center of the ellipse.
width : float
The length of the horizontal axis.
height : float
The length of the vertical axis.
angle : float
Rotation of the ellipse in degrees (counterclockwise).
theta1, theta2 : float, default: 0, 360
Starting and ending angles of the arc in degrees. These values
are relative to *angle*, e.g. if *angle* = 45 and *theta1* = 90
the absolute starting angle is 135.
Default *theta1* = 0, *theta2* = 360, i.e. a complete ellipse.
The arc is drawn in the counterclockwise direction.
Angles greater than or equal to 360, or smaller than 0, are
represented by an equivalent angle in the range [0, 360), by
taking the input value mod 360.
Other Parameters
----------------
**kwargs : `~matplotlib.patches.Patch` properties
Most `.Patch` properties are supported as keyword arguments,
except *fill* and *facecolor* because filling is not supported.
%(Patch:kwdoc)s
"""
fill = kwargs.setdefault('fill', False)
if fill:
raise ValueError("Arc objects can not be filled")
super().__init__(xy, width, height, angle=angle, **kwargs)
self.theta1 = theta1
self.theta2 = theta2
(self._theta1, self._theta2, self._stretched_width,
self._stretched_height) = self._theta_stretch()
self._path = Path.arc(self._theta1, self._theta2)
@artist.allow_rasterization
def draw(self, renderer):
"""
Draw the arc to the given *renderer*.
Notes
-----
Ellipses are normally drawn using an approximation that uses
eight cubic Bezier splines. The error of this approximation
is 1.89818e-6, according to this unverified source:
Lancaster, Don. *Approximating a Circle or an Ellipse Using
Four Bezier Cubic Splines.*
https://www.tinaja.com/glib/ellipse4.pdf
There is a use case where very large ellipses must be drawn
with very high accuracy, and it is too expensive to render the
entire ellipse with enough segments (either splines or line
segments). Therefore, in the case where either radius of the
ellipse is large enough that the error of the spline
approximation will be visible (greater than one pixel offset
from the ideal), a different technique is used.
In that case, only the visible parts of the ellipse are drawn,
with each visible arc using a fixed number of spline segments
(8). The algorithm proceeds as follows:
1. The points where the ellipse intersects the axes (or figure)
bounding box are located. (This is done by performing an inverse
transformation on the bbox such that it is relative to the unit
circle -- this makes the intersection calculation much easier than
doing rotated ellipse intersection directly.)
This uses the "line intersecting a circle" algorithm from:
Vince, John. *Geometry for Computer Graphics: Formulae,
Examples & Proofs.* London: Springer-Verlag, 2005.
2. The angles of each of the intersection points are calculated.
3. Proceeding counterclockwise starting in the positive
x-direction, each of the visible arc-segments between the
pairs of vertices are drawn using the Bezier arc
approximation technique implemented in `.Path.arc`.
"""
if not self.get_visible():
return
self._recompute_transform()
self._update_path()
# Get width and height in pixels we need to use
# `self.get_data_transform` rather than `self.get_transform`
# because we want the transform from dataspace to the
# screen space to estimate how big the arc will be in physical
# units when rendered (the transform that we get via
# `self.get_transform()` goes from an idealized unit-radius
# space to screen space).
data_to_screen_trans = self.get_data_transform()
pwidth, pheight = (
data_to_screen_trans.transform((self._stretched_width,
self._stretched_height)) -
data_to_screen_trans.transform((0, 0)))
inv_error = (1.0 / 1.89818e-6) * 0.5
if pwidth < inv_error and pheight < inv_error:
return Patch.draw(self, renderer)
def line_circle_intersect(x0, y0, x1, y1):
dx = x1 - x0
dy = y1 - y0
dr2 = dx * dx + dy * dy
D = x0 * y1 - x1 * y0
D2 = D * D
discrim = dr2 - D2
if discrim >= 0.0:
sign_dy = np.copysign(1, dy) # +/-1, never 0.
sqrt_discrim = np.sqrt(discrim)
return np.array(
[[(D * dy + sign_dy * dx * sqrt_discrim) / dr2,
(-D * dx + abs(dy) * sqrt_discrim) / dr2],
[(D * dy - sign_dy * dx * sqrt_discrim) / dr2,
(-D * dx - abs(dy) * sqrt_discrim) / dr2]])
else:
return np.empty((0, 2))
def segment_circle_intersect(x0, y0, x1, y1):
epsilon = 1e-9
if x1 < x0:
x0e, x1e = x1, x0
else:
x0e, x1e = x0, x1
if y1 < y0:
y0e, y1e = y1, y0
else:
y0e, y1e = y0, y1
xys = line_circle_intersect(x0, y0, x1, y1)
xs, ys = xys.T
return xys[
(x0e - epsilon < xs) & (xs < x1e + epsilon)
& (y0e - epsilon < ys) & (ys < y1e + epsilon)
]
# Transform the axes (or figure) box_path so that it is relative to
# the unit circle in the same way that it is relative to the desired
# ellipse.
box_path_transform = (
transforms.BboxTransformTo((self.axes or self.figure).bbox)
- self.get_transform())
box_path = Path.unit_rectangle().transformed(box_path_transform)
thetas = set()
# For each of the point pairs, there is a line segment
for p0, p1 in zip(box_path.vertices[:-1], box_path.vertices[1:]):
xy = segment_circle_intersect(*p0, *p1)
x, y = xy.T
# arctan2 return [-pi, pi), the rest of our angles are in
# [0, 360], adjust as needed.
theta = (np.rad2deg(np.arctan2(y, x)) + 360) % 360
thetas.update(
theta[(self._theta1 < theta) & (theta < self._theta2)])
thetas = sorted(thetas) + [self._theta2]
last_theta = self._theta1
theta1_rad = np.deg2rad(self._theta1)
inside = box_path.contains_point(
(np.cos(theta1_rad), np.sin(theta1_rad))
)
# save original path
path_original = self._path
for theta in thetas:
if inside:
self._path = Path.arc(last_theta, theta, 8)
Patch.draw(self, renderer)
inside = False
else:
inside = True
last_theta = theta
# restore original path
self._path = path_original
def _update_path(self):
# Compute new values and update and set new _path if any value changed
stretched = self._theta_stretch()
if any(a != b for a, b in zip(
stretched, (self._theta1, self._theta2, self._stretched_width,
self._stretched_height))):
(self._theta1, self._theta2, self._stretched_width,
self._stretched_height) = stretched
self._path = Path.arc(self._theta1, self._theta2)
def _theta_stretch(self):
# If the width and height of ellipse are not equal, take into account
# stretching when calculating angles to draw between
def theta_stretch(theta, scale):
theta = np.deg2rad(theta)
x = np.cos(theta)
y = np.sin(theta)
stheta = np.rad2deg(np.arctan2(scale * y, x))
# arctan2 has the range [-pi, pi], we expect [0, 2*pi]
return (stheta + 360) % 360
width = self.convert_xunits(self.width)
height = self.convert_yunits(self.height)
if (
# if we need to stretch the angles because we are distorted
width != height
# and we are not doing a full circle.
#
# 0 and 360 do not exactly round-trip through the angle
# stretching (due to both float precision limitations and
# the difference between the range of arctan2 [-pi, pi] and
# this method [0, 360]) so avoid doing it if we don't have to.
and not (self.theta1 != self.theta2 and
self.theta1 % 360 == self.theta2 % 360)
):
theta1 = theta_stretch(self.theta1, width / height)
theta2 = theta_stretch(self.theta2, width / height)
return theta1, theta2, width, height
return self.theta1, self.theta2, width, height
def bbox_artist(artist, renderer, props=None, fill=True):
"""
A debug function to draw a rectangle around the bounding
box returned by an artist's `.Artist.get_window_extent`
to test whether the artist is returning the correct bbox.
*props* is a dict of rectangle props with the additional property
'pad' that sets the padding around the bbox in points.
"""
if props is None:
props = {}
props = props.copy() # don't want to alter the pad externally
pad = props.pop('pad', 4)
pad = renderer.points_to_pixels(pad)
bbox = artist.get_window_extent(renderer)
r = Rectangle(
xy=(bbox.x0 - pad / 2, bbox.y0 - pad / 2),
width=bbox.width + pad, height=bbox.height + pad,
fill=fill, transform=transforms.IdentityTransform(), clip_on=False)
r.update(props)
r.draw(renderer)
def draw_bbox(bbox, renderer, color='k', trans=None):
"""
A debug function to draw a rectangle around the bounding
box returned by an artist's `.Artist.get_window_extent`
to test whether the artist is returning the correct bbox.
"""
r = Rectangle(xy=bbox.p0, width=bbox.width, height=bbox.height,
edgecolor=color, fill=False, clip_on=False)
if trans is not None:
r.set_transform(trans)
r.draw(renderer)
class _Style:
"""
A base class for the Styles. It is meant to be a container class,
where actual styles are declared as subclass of it, and it
provides some helper functions.
"""
def __init_subclass__(cls):
# Automatically perform docstring interpolation on the subclasses:
# This allows listing the supported styles via
# - %(BoxStyle:table)s
# - %(ConnectionStyle:table)s
# - %(ArrowStyle:table)s
# and additionally adding .. ACCEPTS: blocks via
# - %(BoxStyle:table_and_accepts)s
# - %(ConnectionStyle:table_and_accepts)s
# - %(ArrowStyle:table_and_accepts)s
_docstring.interpd.update({
f"{cls.__name__}:table": cls.pprint_styles(),
f"{cls.__name__}:table_and_accepts": (
cls.pprint_styles()
+ "\n\n .. ACCEPTS: ["
+ "|".join(map(" '{}' ".format, cls._style_list))
+ "]")
})
def __new__(cls, stylename, **kwargs):
"""Return the instance of the subclass with the given style name."""
# The "class" should have the _style_list attribute, which is a mapping
# of style names to style classes.
_list = stylename.replace(" ", "").split(",")
_name = _list[0].lower()
try:
_cls = cls._style_list[_name]
except KeyError as err:
raise ValueError(f"Unknown style: {stylename!r}") from err
try:
_args_pair = [cs.split("=") for cs in _list[1:]]
_args = {k: float(v) for k, v in _args_pair}
except ValueError as err:
raise ValueError(
f"Incorrect style argument: {stylename!r}") from err
return _cls(**{**_args, **kwargs})
@classmethod
def get_styles(cls):
"""Return a dictionary of available styles."""
return cls._style_list
@classmethod
def pprint_styles(cls):
"""Return the available styles as pretty-printed string."""
table = [('Class', 'Name', 'Attrs'),
*[(cls.__name__,
# Add backquotes, as - and | have special meaning in reST.
f'``{name}``',
# [1:-1] drops the surrounding parentheses.
str(inspect.signature(cls))[1:-1] or 'None')
for name, cls in cls._style_list.items()]]
# Convert to rst table.
col_len = [max(len(cell) for cell in column) for column in zip(*table)]
table_formatstr = ' '.join('=' * cl for cl in col_len)
rst_table = '\n'.join([
'',
table_formatstr,
' '.join(cell.ljust(cl) for cell, cl in zip(table[0], col_len)),
table_formatstr,
*[' '.join(cell.ljust(cl) for cell, cl in zip(row, col_len))
for row in table[1:]],
table_formatstr,
])
return textwrap.indent(rst_table, prefix=' ' * 4)
@classmethod
def register(cls, name, style):
"""Register a new style."""
if not issubclass(style, cls._Base):
raise ValueError("%s must be a subclass of %s" % (style,
cls._Base))
cls._style_list[name] = style
def _register_style(style_list, cls=None, *, name=None):
"""Class decorator that stashes a class in a (style) dictionary."""
if cls is None:
return functools.partial(_register_style, style_list, name=name)
style_list[name or cls.__name__.lower()] = cls
return cls
@_docstring.dedent_interpd
class BoxStyle(_Style):
"""
`BoxStyle` is a container class which defines several
boxstyle classes, which are used for `FancyBboxPatch`.
A style object can be created as::
BoxStyle.Round(pad=0.2)
or::
BoxStyle("Round", pad=0.2)
or::
BoxStyle("Round, pad=0.2")
The following boxstyle classes are defined.
%(BoxStyle:table)s
An instance of a boxstyle class is a callable object, with the signature ::
__call__(self, x0, y0, width, height, mutation_size) -> Path
*x0*, *y0*, *width* and *height* specify the location and size of the box
to be drawn; *mutation_size* scales the outline properties such as padding.
"""
_style_list = {}
@_register_style(_style_list)
class Square:
"""A square box."""
def __init__(self, pad=0.3):
"""
Parameters
----------
pad : float, default: 0.3
The amount of padding around the original box.
"""
self.pad = pad
def __call__(self, x0, y0, width, height, mutation_size):
pad = mutation_size * self.pad
# width and height with padding added.
width, height = width + 2 * pad, height + 2 * pad
# boundary of the padded box
x0, y0 = x0 - pad, y0 - pad
x1, y1 = x0 + width, y0 + height
return Path._create_closed(
[(x0, y0), (x1, y0), (x1, y1), (x0, y1)])
@_register_style(_style_list)
class Circle:
"""A circular box."""
def __init__(self, pad=0.3):
"""
Parameters
----------
pad : float, default: 0.3
The amount of padding around the original box.
"""
self.pad = pad
def __call__(self, x0, y0, width, height, mutation_size):
pad = mutation_size * self.pad
width, height = width + 2 * pad, height + 2 * pad
# boundary of the padded box
x0, y0 = x0 - pad, y0 - pad
return Path.circle((x0 + width / 2, y0 + height / 2),
max(width, height) / 2)
@_register_style(_style_list)
class Ellipse:
"""
An elliptical box.
.. versionadded:: 3.7
"""
def __init__(self, pad=0.3):
"""
Parameters
----------
pad : float, default: 0.3
The amount of padding around the original box.
"""
self.pad = pad
def __call__(self, x0, y0, width, height, mutation_size):
pad = mutation_size * self.pad
width, height = width + 2 * pad, height + 2 * pad
# boundary of the padded box
x0, y0 = x0 - pad, y0 - pad
a = width / math.sqrt(2)
b = height / math.sqrt(2)
trans = Affine2D().scale(a, b).translate(x0 + width / 2,
y0 + height / 2)
return trans.transform_path(Path.unit_circle())
@_register_style(_style_list)
class LArrow:
"""A box in the shape of a left-pointing arrow."""
def __init__(self, pad=0.3):
"""
Parameters
----------
pad : float, default: 0.3
The amount of padding around the original box.
"""
self.pad = pad
def __call__(self, x0, y0, width, height, mutation_size):
# padding
pad = mutation_size * self.pad
# width and height with padding added.
width, height = width + 2 * pad, height + 2 * pad
# boundary of the padded box
x0, y0 = x0 - pad, y0 - pad,
x1, y1 = x0 + width, y0 + height
dx = (y1 - y0) / 2
dxx = dx / 2
x0 = x0 + pad / 1.4 # adjust by ~sqrt(2)
return Path._create_closed(
[(x0 + dxx, y0), (x1, y0), (x1, y1), (x0 + dxx, y1),
(x0 + dxx, y1 + dxx), (x0 - dx, y0 + dx),
(x0 + dxx, y0 - dxx), # arrow
(x0 + dxx, y0)])
@_register_style(_style_list)
class RArrow(LArrow):
"""A box in the shape of a right-pointing arrow."""
def __call__(self, x0, y0, width, height, mutation_size):
p = BoxStyle.LArrow.__call__(
self, x0, y0, width, height, mutation_size)
p.vertices[:, 0] = 2 * x0 + width - p.vertices[:, 0]
return p
@_register_style(_style_list)
class DArrow:
"""A box in the shape of a two-way arrow."""
# Modified from LArrow to add a right arrow to the bbox.
def __init__(self, pad=0.3):
"""
Parameters
----------
pad : float, default: 0.3
The amount of padding around the original box.
"""
self.pad = pad
def __call__(self, x0, y0, width, height, mutation_size):
# padding
pad = mutation_size * self.pad
# width and height with padding added.
# The width is padded by the arrows, so we don't need to pad it.
height = height + 2 * pad
# boundary of the padded box
x0, y0 = x0 - pad, y0 - pad
x1, y1 = x0 + width, y0 + height
dx = (y1 - y0) / 2
dxx = dx / 2
x0 = x0 + pad / 1.4 # adjust by ~sqrt(2)
return Path._create_closed([
(x0 + dxx, y0), (x1, y0), # bot-segment
(x1, y0 - dxx), (x1 + dx + dxx, y0 + dx),
(x1, y1 + dxx), # right-arrow
(x1, y1), (x0 + dxx, y1), # top-segment
(x0 + dxx, y1 + dxx), (x0 - dx, y0 + dx),
(x0 + dxx, y0 - dxx), # left-arrow
(x0 + dxx, y0)])
@_register_style(_style_list)
class Round:
"""A box with round corners."""
def __init__(self, pad=0.3, rounding_size=None):
"""
Parameters
----------
pad : float, default: 0.3
The amount of padding around the original box.
rounding_size : float, default: *pad*
Radius of the corners.
"""
self.pad = pad
self.rounding_size = rounding_size
def __call__(self, x0, y0, width, height, mutation_size):
# padding
pad = mutation_size * self.pad
# size of the rounding corner
if self.rounding_size:
dr = mutation_size * self.rounding_size
else:
dr = pad
width, height = width + 2 * pad, height + 2 * pad
x0, y0 = x0 - pad, y0 - pad,
x1, y1 = x0 + width, y0 + height
# Round corners are implemented as quadratic Bezier, e.g.,
# [(x0, y0-dr), (x0, y0), (x0+dr, y0)] for lower left corner.
cp = [(x0 + dr, y0),
(x1 - dr, y0),
(x1, y0), (x1, y0 + dr),
(x1, y1 - dr),
(x1, y1), (x1 - dr, y1),
(x0 + dr, y1),
(x0, y1), (x0, y1 - dr),
(x0, y0 + dr),
(x0, y0), (x0 + dr, y0),
(x0 + dr, y0)]
com = [Path.MOVETO,
Path.LINETO,
Path.CURVE3, Path.CURVE3,
Path.LINETO,
Path.CURVE3, Path.CURVE3,
Path.LINETO,
Path.CURVE3, Path.CURVE3,
Path.LINETO,
Path.CURVE3, Path.CURVE3,
Path.CLOSEPOLY]
return Path(cp, com)
@_register_style(_style_list)
class Round4:
"""A box with rounded edges."""
def __init__(self, pad=0.3, rounding_size=None):
"""
Parameters
----------
pad : float, default: 0.3
The amount of padding around the original box.
rounding_size : float, default: *pad*/2
Rounding of edges.
"""
self.pad = pad
self.rounding_size = rounding_size
def __call__(self, x0, y0, width, height, mutation_size):
# padding
pad = mutation_size * self.pad
# Rounding size; defaults to half of the padding.
if self.rounding_size:
dr = mutation_size * self.rounding_size
else:
dr = pad / 2.
width = width + 2 * pad - 2 * dr
height = height + 2 * pad - 2 * dr
x0, y0 = x0 - pad + dr, y0 - pad + dr,
x1, y1 = x0 + width, y0 + height
cp = [(x0, y0),
(x0 + dr, y0 - dr), (x1 - dr, y0 - dr), (x1, y0),
(x1 + dr, y0 + dr), (x1 + dr, y1 - dr), (x1, y1),
(x1 - dr, y1 + dr), (x0 + dr, y1 + dr), (x0, y1),
(x0 - dr, y1 - dr), (x0 - dr, y0 + dr), (x0, y0),
(x0, y0)]
com = [Path.MOVETO,
Path.CURVE4, Path.CURVE4, Path.CURVE4,
Path.CURVE4, Path.CURVE4, Path.CURVE4,
Path.CURVE4, Path.CURVE4, Path.CURVE4,
Path.CURVE4, Path.CURVE4, Path.CURVE4,
Path.CLOSEPOLY]
return Path(cp, com)
@_register_style(_style_list)
class Sawtooth:
"""A box with a sawtooth outline."""
def __init__(self, pad=0.3, tooth_size=None):
"""
Parameters
----------
pad : float, default: 0.3
The amount of padding around the original box.
tooth_size : float, default: *pad*/2
Size of the sawtooth.
"""
self.pad = pad
self.tooth_size = tooth_size
def _get_sawtooth_vertices(self, x0, y0, width, height, mutation_size):
# padding
pad = mutation_size * self.pad
# size of sawtooth
if self.tooth_size is None:
tooth_size = self.pad * .5 * mutation_size
else:
tooth_size = self.tooth_size * mutation_size
hsz = tooth_size / 2
width = width + 2 * pad - tooth_size
height = height + 2 * pad - tooth_size
# the sizes of the vertical and horizontal sawtooth are
# separately adjusted to fit the given box size.
dsx_n = round((width - tooth_size) / (tooth_size * 2)) * 2
dsx = (width - tooth_size) / dsx_n
dsy_n = round((height - tooth_size) / (tooth_size * 2)) * 2
dsy = (height - tooth_size) / dsy_n
x0, y0 = x0 - pad + hsz, y0 - pad + hsz
x1, y1 = x0 + width, y0 + height
xs = [
x0, *np.linspace(x0 + hsz, x1 - hsz, 2 * dsx_n + 1), # bottom
*([x1, x1 + hsz, x1, x1 - hsz] * dsy_n)[:2*dsy_n+2], # right
x1, *np.linspace(x1 - hsz, x0 + hsz, 2 * dsx_n + 1), # top
*([x0, x0 - hsz, x0, x0 + hsz] * dsy_n)[:2*dsy_n+2], # left
]
ys = [
*([y0, y0 - hsz, y0, y0 + hsz] * dsx_n)[:2*dsx_n+2], # bottom
y0, *np.linspace(y0 + hsz, y1 - hsz, 2 * dsy_n + 1), # right
*([y1, y1 + hsz, y1, y1 - hsz] * dsx_n)[:2*dsx_n+2], # top
y1, *np.linspace(y1 - hsz, y0 + hsz, 2 * dsy_n + 1), # left
]
return [*zip(xs, ys), (xs[0], ys[0])]
def __call__(self, x0, y0, width, height, mutation_size):
saw_vertices = self._get_sawtooth_vertices(x0, y0, width,
height, mutation_size)
return Path(saw_vertices, closed=True)
@_register_style(_style_list)
class Roundtooth(Sawtooth):
"""A box with a rounded sawtooth outline."""
def __call__(self, x0, y0, width, height, mutation_size):
saw_vertices = self._get_sawtooth_vertices(x0, y0,
width, height,
mutation_size)
# Add a trailing vertex to allow us to close the polygon correctly
saw_vertices = np.concatenate([saw_vertices, [saw_vertices[0]]])
codes = ([Path.MOVETO] +
[Path.CURVE3, Path.CURVE3] * ((len(saw_vertices)-1)//2) +
[Path.CLOSEPOLY])
return Path(saw_vertices, codes)
@_docstring.dedent_interpd
class ConnectionStyle(_Style):
"""
`ConnectionStyle` is a container class which defines
several connectionstyle classes, which is used to create a path
between two points. These are mainly used with `FancyArrowPatch`.
A connectionstyle object can be either created as::
ConnectionStyle.Arc3(rad=0.2)
or::
ConnectionStyle("Arc3", rad=0.2)
or::
ConnectionStyle("Arc3, rad=0.2")
The following classes are defined
%(ConnectionStyle:table)s
An instance of any connection style class is a callable object,
whose call signature is::
__call__(self, posA, posB,
patchA=None, patchB=None,
shrinkA=2., shrinkB=2.)
and it returns a `.Path` instance. *posA* and *posB* are
tuples of (x, y) coordinates of the two points to be
connected. *patchA* (or *patchB*) is given, the returned path is
clipped so that it start (or end) from the boundary of the
patch. The path is further shrunk by *shrinkA* (or *shrinkB*)
which is given in points.
"""
_style_list = {}
class _Base:
"""
A base class for connectionstyle classes. The subclass needs
to implement a *connect* method whose call signature is::
connect(posA, posB)
where posA and posB are tuples of x, y coordinates to be
connected. The method needs to return a path connecting two
points. This base class defines a __call__ method, and a few
helper methods.
"""
@_api.deprecated("3.7")
class SimpleEvent:
def __init__(self, xy):
self.x, self.y = xy
def _in_patch(self, patch):
"""
Return a predicate function testing whether a point *xy* is
contained in *patch*.
"""
return lambda xy: patch.contains(
SimpleNamespace(x=xy[0], y=xy[1]))[0]
def _clip(self, path, in_start, in_stop):
"""
Clip *path* at its start by the region where *in_start* returns
True, and at its stop by the region where *in_stop* returns True.
The original path is assumed to start in the *in_start* region and
to stop in the *in_stop* region.
"""
if in_start:
try:
_, path = split_path_inout(path, in_start)
except ValueError:
pass
if in_stop:
try:
path, _ = split_path_inout(path, in_stop)
except ValueError:
pass
return path
def __call__(self, posA, posB,
shrinkA=2., shrinkB=2., patchA=None, patchB=None):
"""
Call the *connect* method to create a path between *posA* and
*posB*; then clip and shrink the path.
"""
path = self.connect(posA, posB)
path = self._clip(
path,
self._in_patch(patchA) if patchA else None,
self._in_patch(patchB) if patchB else None,
)
path = self._clip(
path,
inside_circle(*path.vertices[0], shrinkA) if shrinkA else None,
inside_circle(*path.vertices[-1], shrinkB) if shrinkB else None
)
return path
@_register_style(_style_list)
class Arc3(_Base):
"""
Creates a simple quadratic Bézier curve between two
points. The curve is created so that the middle control point
(C1) is located at the same distance from the start (C0) and
end points(C2) and the distance of the C1 to the line
connecting C0-C2 is *rad* times the distance of C0-C2.
"""
def __init__(self, rad=0.):
"""
Parameters
----------
rad : float
Curvature of the curve.
"""
self.rad = rad
def connect(self, posA, posB):
x1, y1 = posA
x2, y2 = posB
x12, y12 = (x1 + x2) / 2., (y1 + y2) / 2.
dx, dy = x2 - x1, y2 - y1
f = self.rad
cx, cy = x12 + f * dy, y12 - f * dx
vertices = [(x1, y1),
(cx, cy),
(x2, y2)]
codes = [Path.MOVETO,
Path.CURVE3,
Path.CURVE3]
return Path(vertices, codes)
@_register_style(_style_list)
class Angle3(_Base):
"""
Creates a simple quadratic Bézier curve between two points. The middle
control point is placed at the intersecting point of two lines which
cross the start and end point, and have a slope of *angleA* and
*angleB*, respectively.
"""
def __init__(self, angleA=90, angleB=0):
"""
Parameters
----------
angleA : float
Starting angle of the path.
angleB : float
Ending angle of the path.
"""
self.angleA = angleA
self.angleB = angleB
def connect(self, posA, posB):
x1, y1 = posA
x2, y2 = posB
cosA = math.cos(math.radians(self.angleA))
sinA = math.sin(math.radians(self.angleA))
cosB = math.cos(math.radians(self.angleB))
sinB = math.sin(math.radians(self.angleB))
cx, cy = get_intersection(x1, y1, cosA, sinA,
x2, y2, cosB, sinB)
vertices = [(x1, y1), (cx, cy), (x2, y2)]
codes = [Path.MOVETO, Path.CURVE3, Path.CURVE3]
return Path(vertices, codes)
@_register_style(_style_list)
class Angle(_Base):
"""
Creates a piecewise continuous quadratic Bézier path between two
points. The path has a one passing-through point placed at the
intersecting point of two lines which cross the start and end point,
and have a slope of *angleA* and *angleB*, respectively.
The connecting edges are rounded with *rad*.
"""
def __init__(self, angleA=90, angleB=0, rad=0.):
"""
Parameters
----------
angleA : float
Starting angle of the path.
angleB : float
Ending angle of the path.
rad : float
Rounding radius of the edge.
"""
self.angleA = angleA
self.angleB = angleB
self.rad = rad
def connect(self, posA, posB):
x1, y1 = posA
x2, y2 = posB
cosA = math.cos(math.radians(self.angleA))
sinA = math.sin(math.radians(self.angleA))
cosB = math.cos(math.radians(self.angleB))
sinB = math.sin(math.radians(self.angleB))
cx, cy = get_intersection(x1, y1, cosA, sinA,
x2, y2, cosB, sinB)
vertices = [(x1, y1)]
codes = [Path.MOVETO]
if self.rad == 0.:
vertices.append((cx, cy))
codes.append(Path.LINETO)
else:
dx1, dy1 = x1 - cx, y1 - cy
d1 = np.hypot(dx1, dy1)
f1 = self.rad / d1
dx2, dy2 = x2 - cx, y2 - cy
d2 = np.hypot(dx2, dy2)
f2 = self.rad / d2
vertices.extend([(cx + dx1 * f1, cy + dy1 * f1),
(cx, cy),
(cx + dx2 * f2, cy + dy2 * f2)])
codes.extend([Path.LINETO, Path.CURVE3, Path.CURVE3])
vertices.append((x2, y2))
codes.append(Path.LINETO)
return Path(vertices, codes)
@_register_style(_style_list)
class Arc(_Base):
"""
Creates a piecewise continuous quadratic Bézier path between two
points. The path can have two passing-through points, a
point placed at the distance of *armA* and angle of *angleA* from
point A, another point with respect to point B. The edges are
rounded with *rad*.
"""
def __init__(self, angleA=0, angleB=0, armA=None, armB=None, rad=0.):
"""
Parameters
----------
angleA : float
Starting angle of the path.
angleB : float
Ending angle of the path.
armA : float or None
Length of the starting arm.
armB : float or None
Length of the ending arm.
rad : float
Rounding radius of the edges.
"""
self.angleA = angleA
self.angleB = angleB
self.armA = armA
self.armB = armB
self.rad = rad
def connect(self, posA, posB):
x1, y1 = posA
x2, y2 = posB
vertices = [(x1, y1)]
rounded = []
codes = [Path.MOVETO]
if self.armA:
cosA = math.cos(math.radians(self.angleA))
sinA = math.sin(math.radians(self.angleA))
# x_armA, y_armB
d = self.armA - self.rad
rounded.append((x1 + d * cosA, y1 + d * sinA))
d = self.armA
rounded.append((x1 + d * cosA, y1 + d * sinA))
if self.armB:
cosB = math.cos(math.radians(self.angleB))
sinB = math.sin(math.radians(self.angleB))
x_armB, y_armB = x2 + self.armB * cosB, y2 + self.armB * sinB
if rounded:
xp, yp = rounded[-1]
dx, dy = x_armB - xp, y_armB - yp
dd = (dx * dx + dy * dy) ** .5
rounded.append((xp + self.rad * dx / dd,
yp + self.rad * dy / dd))
vertices.extend(rounded)
codes.extend([Path.LINETO,
Path.CURVE3,
Path.CURVE3])
else:
xp, yp = vertices[-1]
dx, dy = x_armB - xp, y_armB - yp
dd = (dx * dx + dy * dy) ** .5
d = dd - self.rad
rounded = [(xp + d * dx / dd, yp + d * dy / dd),
(x_armB, y_armB)]
if rounded:
xp, yp = rounded[-1]
dx, dy = x2 - xp, y2 - yp
dd = (dx * dx + dy * dy) ** .5
rounded.append((xp + self.rad * dx / dd,
yp + self.rad * dy / dd))
vertices.extend(rounded)
codes.extend([Path.LINETO,
Path.CURVE3,
Path.CURVE3])
vertices.append((x2, y2))
codes.append(Path.LINETO)
return Path(vertices, codes)
@_register_style(_style_list)
class Bar(_Base):
"""
A line with *angle* between A and B with *armA* and *armB*. One of the
arms is extended so that they are connected in a right angle. The
length of *armA* is determined by (*armA* + *fraction* x AB distance).
Same for *armB*.
"""
def __init__(self, armA=0., armB=0., fraction=0.3, angle=None):
"""
Parameters
----------
armA : float
Minimum length of armA.
armB : float
Minimum length of armB.
fraction : float
A fraction of the distance between two points that will be
added to armA and armB.
angle : float or None
Angle of the connecting line (if None, parallel to A and B).
"""
self.armA = armA
self.armB = armB
self.fraction = fraction
self.angle = angle
def connect(self, posA, posB):
x1, y1 = posA
x20, y20 = x2, y2 = posB
theta1 = math.atan2(y2 - y1, x2 - x1)
dx, dy = x2 - x1, y2 - y1
dd = (dx * dx + dy * dy) ** .5
ddx, ddy = dx / dd, dy / dd
armA, armB = self.armA, self.armB
if self.angle is not None:
theta0 = np.deg2rad(self.angle)
dtheta = theta1 - theta0
dl = dd * math.sin(dtheta)
dL = dd * math.cos(dtheta)
x2, y2 = x1 + dL * math.cos(theta0), y1 + dL * math.sin(theta0)
armB = armB - dl
# update
dx, dy = x2 - x1, y2 - y1
dd2 = (dx * dx + dy * dy) ** .5
ddx, ddy = dx / dd2, dy / dd2
arm = max(armA, armB)
f = self.fraction * dd + arm
cx1, cy1 = x1 + f * ddy, y1 - f * ddx
cx2, cy2 = x2 + f * ddy, y2 - f * ddx
vertices = [(x1, y1),
(cx1, cy1),
(cx2, cy2),
(x20, y20)]
codes = [Path.MOVETO,
Path.LINETO,
Path.LINETO,
Path.LINETO]
return Path(vertices, codes)
def _point_along_a_line(x0, y0, x1, y1, d):
"""
Return the point on the line connecting (*x0*, *y0*) -- (*x1*, *y1*) whose
distance from (*x0*, *y0*) is *d*.
"""
dx, dy = x0 - x1, y0 - y1
ff = d / (dx * dx + dy * dy) ** .5
x2, y2 = x0 - ff * dx, y0 - ff * dy
return x2, y2
@_docstring.dedent_interpd
class ArrowStyle(_Style):
"""
`ArrowStyle` is a container class which defines several
arrowstyle classes, which is used to create an arrow path along a
given path. These are mainly used with `FancyArrowPatch`.
An arrowstyle object can be either created as::
ArrowStyle.Fancy(head_length=.4, head_width=.4, tail_width=.4)
or::
ArrowStyle("Fancy", head_length=.4, head_width=.4, tail_width=.4)
or::
ArrowStyle("Fancy, head_length=.4, head_width=.4, tail_width=.4")
The following classes are defined
%(ArrowStyle:table)s
For an overview of the visual appearance, see
:doc:`/gallery/text_labels_and_annotations/fancyarrow_demo`.
An instance of any arrow style class is a callable object,
whose call signature is::
__call__(self, path, mutation_size, linewidth, aspect_ratio=1.)
and it returns a tuple of a `.Path` instance and a boolean
value. *path* is a `.Path` instance along which the arrow
will be drawn. *mutation_size* and *aspect_ratio* have the same
meaning as in `BoxStyle`. *linewidth* is a line width to be
stroked. This is meant to be used to correct the location of the
head so that it does not overshoot the destination point, but not all
classes support it.
Notes
-----
*angleA* and *angleB* specify the orientation of the bracket, as either a
clockwise or counterclockwise angle depending on the arrow type. 0 degrees
means perpendicular to the line connecting the arrow's head and tail.
.. plot:: gallery/text_labels_and_annotations/angles_on_bracket_arrows.py
"""
_style_list = {}
class _Base:
"""
Arrow Transmuter Base class
ArrowTransmuterBase and its derivatives are used to make a fancy
arrow around a given path. The __call__ method returns a path
(which will be used to create a PathPatch instance) and a boolean
value indicating the path is open therefore is not fillable. This
class is not an artist and actual drawing of the fancy arrow is
done by the FancyArrowPatch class.
"""
# The derived classes are required to be able to be initialized
# w/o arguments, i.e., all its argument (except self) must have
# the default values.
@staticmethod
def ensure_quadratic_bezier(path):
"""
Some ArrowStyle classes only works with a simple quadratic
Bézier curve (created with `.ConnectionStyle.Arc3` or
`.ConnectionStyle.Angle3`). This static method checks if the
provided path is a simple quadratic Bézier curve and returns its
control points if true.
"""
segments = list(path.iter_segments())
if (len(segments) != 2 or segments[0][1] != Path.MOVETO or
segments[1][1] != Path.CURVE3):
raise ValueError(
"'path' is not a valid quadratic Bezier curve")
return [*segments[0][0], *segments[1][0]]
def transmute(self, path, mutation_size, linewidth):
"""
The transmute method is the very core of the ArrowStyle class and
must be overridden in the subclasses. It receives the *path*
object along which the arrow will be drawn, and the
*mutation_size*, with which the arrow head etc. will be scaled.
The *linewidth* may be used to adjust the path so that it does not
pass beyond the given points. It returns a tuple of a `.Path`
instance and a boolean. The boolean value indicate whether the
path can be filled or not. The return value can also be a list of
paths and list of booleans of the same length.
"""
raise NotImplementedError('Derived must override')
def __call__(self, path, mutation_size, linewidth,
aspect_ratio=1.):
"""
The __call__ method is a thin wrapper around the transmute method
and takes care of the aspect ratio.
"""
if aspect_ratio is not None:
# Squeeze the given height by the aspect_ratio
vertices = path.vertices / [1, aspect_ratio]
path_shrunk = Path(vertices, path.codes)
# call transmute method with squeezed height.
path_mutated, fillable = self.transmute(path_shrunk,
mutation_size,
linewidth)
if np.iterable(fillable):
# Restore the height
path_list = [Path(p.vertices * [1, aspect_ratio], p.codes)
for p in path_mutated]
return path_list, fillable
else:
return path_mutated, fillable
else:
return self.transmute(path, mutation_size, linewidth)
class _Curve(_Base):
"""
A simple arrow which will work with any path instance. The
returned path is the concatenation of the original path, and at
most two paths representing the arrow head or bracket at the start
point and at the end point. The arrow heads can be either open
or closed.
"""
arrow = "-"
fillbegin = fillend = False # Whether arrows are filled.
def __init__(self, head_length=.4, head_width=.2, widthA=1., widthB=1.,
lengthA=0.2, lengthB=0.2, angleA=0, angleB=0, scaleA=None,
scaleB=None):
"""
Parameters
----------
head_length : float, default: 0.4
Length of the arrow head, relative to *mutation_size*.
head_width : float, default: 0.2
Width of the arrow head, relative to *mutation_size*.
widthA, widthB : float, default: 1.0
Width of the bracket.
lengthA, lengthB : float, default: 0.2
Length of the bracket.
angleA, angleB : float, default: 0
Orientation of the bracket, as a counterclockwise angle.
0 degrees means perpendicular to the line.
scaleA, scaleB : float, default: *mutation_size*
The scale of the brackets.
"""
self.head_length, self.head_width = head_length, head_width
self.widthA, self.widthB = widthA, widthB
self.lengthA, self.lengthB = lengthA, lengthB
self.angleA, self.angleB = angleA, angleB
self.scaleA, self.scaleB = scaleA, scaleB
self._beginarrow_head = False
self._beginarrow_bracket = False
self._endarrow_head = False
self._endarrow_bracket = False
if "-" not in self.arrow:
raise ValueError("arrow must have the '-' between "
"the two heads")
beginarrow, endarrow = self.arrow.split("-", 1)
if beginarrow == "<":
self._beginarrow_head = True
self._beginarrow_bracket = False
elif beginarrow == "<|":
self._beginarrow_head = True
self._beginarrow_bracket = False
self.fillbegin = True
elif beginarrow in ("]", "|"):
self._beginarrow_head = False
self._beginarrow_bracket = True
if endarrow == ">":
self._endarrow_head = True
self._endarrow_bracket = False
elif endarrow == "|>":
self._endarrow_head = True
self._endarrow_bracket = False
self.fillend = True
elif endarrow in ("[", "|"):
self._endarrow_head = False
self._endarrow_bracket = True
super().__init__()
def _get_arrow_wedge(self, x0, y0, x1, y1,
head_dist, cos_t, sin_t, linewidth):
"""
Return the paths for arrow heads. Since arrow lines are
drawn with capstyle=projected, The arrow goes beyond the
desired point. This method also returns the amount of the path
to be shrunken so that it does not overshoot.
"""
# arrow from x0, y0 to x1, y1
dx, dy = x0 - x1, y0 - y1
cp_distance = np.hypot(dx, dy)
# pad_projected : amount of pad to account the
# overshooting of the projection of the wedge
pad_projected = (.5 * linewidth / sin_t)
# Account for division by zero
if cp_distance == 0:
cp_distance = 1
# apply pad for projected edge
ddx = pad_projected * dx / cp_distance
ddy = pad_projected * dy / cp_distance
# offset for arrow wedge
dx = dx / cp_distance * head_dist
dy = dy / cp_distance * head_dist
dx1, dy1 = cos_t * dx + sin_t * dy, -sin_t * dx + cos_t * dy
dx2, dy2 = cos_t * dx - sin_t * dy, sin_t * dx + cos_t * dy
vertices_arrow = [(x1 + ddx + dx1, y1 + ddy + dy1),
(x1 + ddx, y1 + ddy),
(x1 + ddx + dx2, y1 + ddy + dy2)]
codes_arrow = [Path.MOVETO,
Path.LINETO,
Path.LINETO]
return vertices_arrow, codes_arrow, ddx, ddy
def _get_bracket(self, x0, y0,
x1, y1, width, length, angle):
cos_t, sin_t = get_cos_sin(x1, y1, x0, y0)
# arrow from x0, y0 to x1, y1
from matplotlib.bezier import get_normal_points
x1, y1, x2, y2 = get_normal_points(x0, y0, cos_t, sin_t, width)
dx, dy = length * cos_t, length * sin_t
vertices_arrow = [(x1 + dx, y1 + dy),
(x1, y1),
(x2, y2),
(x2 + dx, y2 + dy)]
codes_arrow = [Path.MOVETO,
Path.LINETO,
Path.LINETO,
Path.LINETO]
if angle:
trans = transforms.Affine2D().rotate_deg_around(x0, y0, angle)
vertices_arrow = trans.transform(vertices_arrow)
return vertices_arrow, codes_arrow
def transmute(self, path, mutation_size, linewidth):
# docstring inherited
if self._beginarrow_head or self._endarrow_head:
head_length = self.head_length * mutation_size
head_width = self.head_width * mutation_size
head_dist = np.hypot(head_length, head_width)
cos_t, sin_t = head_length / head_dist, head_width / head_dist
scaleA = mutation_size if self.scaleA is None else self.scaleA
scaleB = mutation_size if self.scaleB is None else self.scaleB
# begin arrow
x0, y0 = path.vertices[0]
x1, y1 = path.vertices[1]
# If there is no room for an arrow and a line, then skip the arrow
has_begin_arrow = self._beginarrow_head and (x0, y0) != (x1, y1)
verticesA, codesA, ddxA, ddyA = (
self._get_arrow_wedge(x1, y1, x0, y0,
head_dist, cos_t, sin_t, linewidth)
if has_begin_arrow
else ([], [], 0, 0)
)
# end arrow
x2, y2 = path.vertices[-2]
x3, y3 = path.vertices[-1]
# If there is no room for an arrow and a line, then skip the arrow
has_end_arrow = self._endarrow_head and (x2, y2) != (x3, y3)
verticesB, codesB, ddxB, ddyB = (
self._get_arrow_wedge(x2, y2, x3, y3,
head_dist, cos_t, sin_t, linewidth)
if has_end_arrow
else ([], [], 0, 0)
)
# This simple code will not work if ddx, ddy is greater than the
# separation between vertices.
paths = [Path(np.concatenate([[(x0 + ddxA, y0 + ddyA)],
path.vertices[1:-1],
[(x3 + ddxB, y3 + ddyB)]]),
path.codes)]
fills = [False]
if has_begin_arrow:
if self.fillbegin:
paths.append(
Path([*verticesA, (0, 0)], [*codesA, Path.CLOSEPOLY]))
fills.append(True)
else:
paths.append(Path(verticesA, codesA))
fills.append(False)
elif self._beginarrow_bracket:
x0, y0 = path.vertices[0]
x1, y1 = path.vertices[1]
verticesA, codesA = self._get_bracket(x0, y0, x1, y1,
self.widthA * scaleA,
self.lengthA * scaleA,
self.angleA)
paths.append(Path(verticesA, codesA))
fills.append(False)
if has_end_arrow:
if self.fillend:
fills.append(True)
paths.append(
Path([*verticesB, (0, 0)], [*codesB, Path.CLOSEPOLY]))
else:
fills.append(False)
paths.append(Path(verticesB, codesB))
elif self._endarrow_bracket:
x0, y0 = path.vertices[-1]
x1, y1 = path.vertices[-2]
verticesB, codesB = self._get_bracket(x0, y0, x1, y1,
self.widthB * scaleB,
self.lengthB * scaleB,
self.angleB)
paths.append(Path(verticesB, codesB))
fills.append(False)
return paths, fills
@_register_style(_style_list, name="-")
class Curve(_Curve):
"""A simple curve without any arrow head."""
def __init__(self): # hide head_length, head_width
# These attributes (whose values come from backcompat) only matter
# if someone modifies beginarrow/etc. on an ArrowStyle instance.
super().__init__(head_length=.2, head_width=.1)
@_register_style(_style_list, name="<-")
class CurveA(_Curve):
"""An arrow with a head at its start point."""
arrow = "<-"
@_register_style(_style_list, name="->")
class CurveB(_Curve):
"""An arrow with a head at its end point."""
arrow = "->"
@_register_style(_style_list, name="<->")
class CurveAB(_Curve):
"""An arrow with heads both at the start and the end point."""
arrow = "<->"
@_register_style(_style_list, name="<|-")
class CurveFilledA(_Curve):
"""An arrow with filled triangle head at the start."""
arrow = "<|-"
@_register_style(_style_list, name="-|>")
class CurveFilledB(_Curve):
"""An arrow with filled triangle head at the end."""
arrow = "-|>"
@_register_style(_style_list, name="<|-|>")
class CurveFilledAB(_Curve):
"""An arrow with filled triangle heads at both ends."""
arrow = "<|-|>"
@_register_style(_style_list, name="]-")
class BracketA(_Curve):
"""An arrow with an outward square bracket at its start."""
arrow = "]-"
def __init__(self, widthA=1., lengthA=0.2, angleA=0):
"""
Parameters
----------
widthA : float, default: 1.0
Width of the bracket.
lengthA : float, default: 0.2
Length of the bracket.
angleA : float, default: 0 degrees
Orientation of the bracket, as a counterclockwise angle.
0 degrees means perpendicular to the line.
"""
super().__init__(widthA=widthA, lengthA=lengthA, angleA=angleA)
@_register_style(_style_list, name="-[")
class BracketB(_Curve):
"""An arrow with an outward square bracket at its end."""
arrow = "-["
def __init__(self, widthB=1., lengthB=0.2, angleB=0):
"""
Parameters
----------
widthB : float, default: 1.0
Width of the bracket.
lengthB : float, default: 0.2
Length of the bracket.
angleB : float, default: 0 degrees
Orientation of the bracket, as a counterclockwise angle.
0 degrees means perpendicular to the line.
"""
super().__init__(widthB=widthB, lengthB=lengthB, angleB=angleB)
@_register_style(_style_list, name="]-[")
class BracketAB(_Curve):
"""An arrow with outward square brackets at both ends."""
arrow = "]-["
def __init__(self,
widthA=1., lengthA=0.2, angleA=0,
widthB=1., lengthB=0.2, angleB=0):
"""
Parameters
----------
widthA, widthB : float, default: 1.0
Width of the bracket.
lengthA, lengthB : float, default: 0.2
Length of the bracket.
angleA, angleB : float, default: 0 degrees
Orientation of the bracket, as a counterclockwise angle.
0 degrees means perpendicular to the line.
"""
super().__init__(widthA=widthA, lengthA=lengthA, angleA=angleA,
widthB=widthB, lengthB=lengthB, angleB=angleB)
@_register_style(_style_list, name="|-|")
class BarAB(_Curve):
"""An arrow with vertical bars ``|`` at both ends."""
arrow = "|-|"
def __init__(self, widthA=1., angleA=0, widthB=1., angleB=0):
"""
Parameters
----------
widthA, widthB : float, default: 1.0
Width of the bracket.
angleA, angleB : float, default: 0 degrees
Orientation of the bracket, as a counterclockwise angle.
0 degrees means perpendicular to the line.
"""
super().__init__(widthA=widthA, lengthA=0, angleA=angleA,
widthB=widthB, lengthB=0, angleB=angleB)
@_register_style(_style_list, name=']->')
class BracketCurve(_Curve):
"""
An arrow with an outward square bracket at its start and a head at
the end.
"""
arrow = "]->"
def __init__(self, widthA=1., lengthA=0.2, angleA=None):
"""
Parameters
----------
widthA : float, default: 1.0
Width of the bracket.
lengthA : float, default: 0.2
Length of the bracket.
angleA : float, default: 0 degrees
Orientation of the bracket, as a counterclockwise angle.
0 degrees means perpendicular to the line.
"""
super().__init__(widthA=widthA, lengthA=lengthA, angleA=angleA)
@_register_style(_style_list, name='<-[')
class CurveBracket(_Curve):
"""
An arrow with an outward square bracket at its end and a head at
the start.
"""
arrow = "<-["
def __init__(self, widthB=1., lengthB=0.2, angleB=None):
"""
Parameters
----------
widthB : float, default: 1.0
Width of the bracket.
lengthB : float, default: 0.2
Length of the bracket.
angleB : float, default: 0 degrees
Orientation of the bracket, as a counterclockwise angle.
0 degrees means perpendicular to the line.
"""
super().__init__(widthB=widthB, lengthB=lengthB, angleB=angleB)
@_register_style(_style_list)
class Simple(_Base):
"""A simple arrow. Only works with a quadratic Bézier curve."""
def __init__(self, head_length=.5, head_width=.5, tail_width=.2):
"""
Parameters
----------
head_length : float, default: 0.5
Length of the arrow head.
head_width : float, default: 0.5
Width of the arrow head.
tail_width : float, default: 0.2
Width of the arrow tail.
"""
self.head_length, self.head_width, self.tail_width = \
head_length, head_width, tail_width
super().__init__()
def transmute(self, path, mutation_size, linewidth):
# docstring inherited
x0, y0, x1, y1, x2, y2 = self.ensure_quadratic_bezier(path)
# divide the path into a head and a tail
head_length = self.head_length * mutation_size
in_f = inside_circle(x2, y2, head_length)
arrow_path = [(x0, y0), (x1, y1), (x2, y2)]
try:
arrow_out, arrow_in = \
split_bezier_intersecting_with_closedpath(arrow_path, in_f)
except NonIntersectingPathException:
# if this happens, make a straight line of the head_length
# long.
x0, y0 = _point_along_a_line(x2, y2, x1, y1, head_length)
x1n, y1n = 0.5 * (x0 + x2), 0.5 * (y0 + y2)
arrow_in = [(x0, y0), (x1n, y1n), (x2, y2)]
arrow_out = None
# head
head_width = self.head_width * mutation_size
head_left, head_right = make_wedged_bezier2(arrow_in,
head_width / 2., wm=.5)
# tail
if arrow_out is not None:
tail_width = self.tail_width * mutation_size
tail_left, tail_right = get_parallels(arrow_out,
tail_width / 2.)
patch_path = [(Path.MOVETO, tail_right[0]),
(Path.CURVE3, tail_right[1]),
(Path.CURVE3, tail_right[2]),
(Path.LINETO, head_right[0]),
(Path.CURVE3, head_right[1]),
(Path.CURVE3, head_right[2]),
(Path.CURVE3, head_left[1]),
(Path.CURVE3, head_left[0]),
(Path.LINETO, tail_left[2]),
(Path.CURVE3, tail_left[1]),
(Path.CURVE3, tail_left[0]),
(Path.LINETO, tail_right[0]),
(Path.CLOSEPOLY, tail_right[0]),
]
else:
patch_path = [(Path.MOVETO, head_right[0]),
(Path.CURVE3, head_right[1]),
(Path.CURVE3, head_right[2]),
(Path.CURVE3, head_left[1]),
(Path.CURVE3, head_left[0]),
(Path.CLOSEPOLY, head_left[0]),
]
path = Path([p for c, p in patch_path], [c for c, p in patch_path])
return path, True
@_register_style(_style_list)
class Fancy(_Base):
"""A fancy arrow. Only works with a quadratic Bézier curve."""
def __init__(self, head_length=.4, head_width=.4, tail_width=.4):
"""
Parameters
----------
head_length : float, default: 0.4
Length of the arrow head.
head_width : float, default: 0.4
Width of the arrow head.
tail_width : float, default: 0.4
Width of the arrow tail.
"""
self.head_length, self.head_width, self.tail_width = \
head_length, head_width, tail_width
super().__init__()
def transmute(self, path, mutation_size, linewidth):
# docstring inherited
x0, y0, x1, y1, x2, y2 = self.ensure_quadratic_bezier(path)
# divide the path into a head and a tail
head_length = self.head_length * mutation_size
arrow_path = [(x0, y0), (x1, y1), (x2, y2)]
# path for head
in_f = inside_circle(x2, y2, head_length)
try:
path_out, path_in = split_bezier_intersecting_with_closedpath(
arrow_path, in_f)
except NonIntersectingPathException:
# if this happens, make a straight line of the head_length
# long.
x0, y0 = _point_along_a_line(x2, y2, x1, y1, head_length)
x1n, y1n = 0.5 * (x0 + x2), 0.5 * (y0 + y2)
arrow_path = [(x0, y0), (x1n, y1n), (x2, y2)]
path_head = arrow_path
else:
path_head = path_in
# path for head
in_f = inside_circle(x2, y2, head_length * .8)
path_out, path_in = split_bezier_intersecting_with_closedpath(
arrow_path, in_f)
path_tail = path_out
# head
head_width = self.head_width * mutation_size
head_l, head_r = make_wedged_bezier2(path_head,
head_width / 2.,
wm=.6)
# tail
tail_width = self.tail_width * mutation_size
tail_left, tail_right = make_wedged_bezier2(path_tail,
tail_width * .5,
w1=1., wm=0.6, w2=0.3)
# path for head
in_f = inside_circle(x0, y0, tail_width * .3)
path_in, path_out = split_bezier_intersecting_with_closedpath(
arrow_path, in_f)
tail_start = path_in[-1]
head_right, head_left = head_r, head_l
patch_path = [(Path.MOVETO, tail_start),
(Path.LINETO, tail_right[0]),
(Path.CURVE3, tail_right[1]),
(Path.CURVE3, tail_right[2]),
(Path.LINETO, head_right[0]),
(Path.CURVE3, head_right[1]),
(Path.CURVE3, head_right[2]),
(Path.CURVE3, head_left[1]),
(Path.CURVE3, head_left[0]),
(Path.LINETO, tail_left[2]),
(Path.CURVE3, tail_left[1]),
(Path.CURVE3, tail_left[0]),
(Path.LINETO, tail_start),
(Path.CLOSEPOLY, tail_start),
]
path = Path([p for c, p in patch_path], [c for c, p in patch_path])
return path, True
@_register_style(_style_list)
class Wedge(_Base):
"""
Wedge(?) shape. Only works with a quadratic Bézier curve. The
start point has a width of the *tail_width* and the end point has a
width of 0. At the middle, the width is *shrink_factor*x*tail_width*.
"""
def __init__(self, tail_width=.3, shrink_factor=0.5):
"""
Parameters
----------
tail_width : float, default: 0.3
Width of the tail.
shrink_factor : float, default: 0.5
Fraction of the arrow width at the middle point.
"""
self.tail_width = tail_width
self.shrink_factor = shrink_factor
super().__init__()
def transmute(self, path, mutation_size, linewidth):
# docstring inherited
x0, y0, x1, y1, x2, y2 = self.ensure_quadratic_bezier(path)
arrow_path = [(x0, y0), (x1, y1), (x2, y2)]
b_plus, b_minus = make_wedged_bezier2(
arrow_path,
self.tail_width * mutation_size / 2.,
wm=self.shrink_factor)
patch_path = [(Path.MOVETO, b_plus[0]),
(Path.CURVE3, b_plus[1]),
(Path.CURVE3, b_plus[2]),
(Path.LINETO, b_minus[2]),
(Path.CURVE3, b_minus[1]),
(Path.CURVE3, b_minus[0]),
(Path.CLOSEPOLY, b_minus[0]),
]
path = Path([p for c, p in patch_path], [c for c, p in patch_path])
return path, True
class FancyBboxPatch(Patch):
"""
A fancy box around a rectangle with lower left at *xy* = (*x*, *y*)
with specified width and height.
`.FancyBboxPatch` is similar to `.Rectangle`, but it draws a fancy box
around the rectangle. The transformation of the rectangle box to the
fancy box is delegated to the style classes defined in `.BoxStyle`.
"""
_edge_default = True
def __str__(self):
s = self.__class__.__name__ + "((%g, %g), width=%g, height=%g)"
return s % (self._x, self._y, self._width, self._height)
@_docstring.dedent_interpd
def __init__(self, xy, width, height, boxstyle="round", *,
mutation_scale=1, mutation_aspect=1, **kwargs):
"""
Parameters
----------
xy : (float, float)
The lower left corner of the box.
width : float
The width of the box.
height : float
The height of the box.
boxstyle : str or `~matplotlib.patches.BoxStyle`
The style of the fancy box. This can either be a `.BoxStyle`
instance or a string of the style name and optionally comma
separated attributes (e.g. "Round, pad=0.2"). This string is
passed to `.BoxStyle` to construct a `.BoxStyle` object. See
there for a full documentation.
The following box styles are available:
%(BoxStyle:table)s
mutation_scale : float, default: 1
Scaling factor applied to the attributes of the box style
(e.g. pad or rounding_size).
mutation_aspect : float, default: 1
The height of the rectangle will be squeezed by this value before
the mutation and the mutated box will be stretched by the inverse
of it. For example, this allows different horizontal and vertical
padding.
Other Parameters
----------------
**kwargs : `~matplotlib.patches.Patch` properties
%(Patch:kwdoc)s
"""
super().__init__(**kwargs)
self._x, self._y = xy
self._width = width
self._height = height
self.set_boxstyle(boxstyle)
self._mutation_scale = mutation_scale
self._mutation_aspect = mutation_aspect
self.stale = True
@_docstring.dedent_interpd
def set_boxstyle(self, boxstyle=None, **kwargs):
"""
Set the box style, possibly with further attributes.
Attributes from the previous box style are not reused.
Without argument (or with ``boxstyle=None``), the available box styles
are returned as a human-readable string.
Parameters
----------
boxstyle : str or `~matplotlib.patches.BoxStyle`
The style of the box: either a `.BoxStyle` instance, or a string,
which is the style name and optionally comma separated attributes
(e.g. "Round,pad=0.2"). Such a string is used to construct a
`.BoxStyle` object, as documented in that class.
The following box styles are available:
%(BoxStyle:table_and_accepts)s
**kwargs
Additional attributes for the box style. See the table above for
supported parameters.
Examples
--------
::
set_boxstyle("Round,pad=0.2")
set_boxstyle("round", pad=0.2)
"""
if boxstyle is None:
return BoxStyle.pprint_styles()
self._bbox_transmuter = (
BoxStyle(boxstyle, **kwargs)
if isinstance(boxstyle, str) else boxstyle)
self.stale = True
def get_boxstyle(self):
"""Return the boxstyle object."""
return self._bbox_transmuter
def set_mutation_scale(self, scale):
"""
Set the mutation scale.
Parameters
----------
scale : float
"""
self._mutation_scale = scale
self.stale = True
def get_mutation_scale(self):
"""Return the mutation scale."""
return self._mutation_scale
def set_mutation_aspect(self, aspect):
"""
Set the aspect ratio of the bbox mutation.
Parameters
----------
aspect : float
"""
self._mutation_aspect = aspect
self.stale = True
def get_mutation_aspect(self):
"""Return the aspect ratio of the bbox mutation."""
return (self._mutation_aspect if self._mutation_aspect is not None
else 1) # backcompat.
def get_path(self):
"""Return the mutated path of the rectangle."""
boxstyle = self.get_boxstyle()
m_aspect = self.get_mutation_aspect()
# Call boxstyle with y, height squeezed by aspect_ratio.
path = boxstyle(self._x, self._y / m_aspect,
self._width, self._height / m_aspect,
self.get_mutation_scale())
return Path(path.vertices * [1, m_aspect], path.codes) # Unsqueeze y.
# Following methods are borrowed from the Rectangle class.
def get_x(self):
"""Return the left coord of the rectangle."""
return self._x
def get_y(self):
"""Return the bottom coord of the rectangle."""
return self._y
def get_width(self):
"""Return the width of the rectangle."""
return self._width
def get_height(self):
"""Return the height of the rectangle."""
return self._height
def set_x(self, x):
"""
Set the left coord of the rectangle.
Parameters
----------
x : float
"""
self._x = x
self.stale = True
def set_y(self, y):
"""
Set the bottom coord of the rectangle.
Parameters
----------
y : float
"""
self._y = y
self.stale = True
def set_width(self, w):
"""
Set the rectangle width.
Parameters
----------
w : float
"""
self._width = w
self.stale = True
def set_height(self, h):
"""
Set the rectangle height.
Parameters
----------
h : float
"""
self._height = h
self.stale = True
def set_bounds(self, *args):
"""
Set the bounds of the rectangle.
Call signatures::
set_bounds(left, bottom, width, height)
set_bounds((left, bottom, width, height))
Parameters
----------
left, bottom : float
The coordinates of the bottom left corner of the rectangle.
width, height : float
The width/height of the rectangle.
"""
if len(args) == 1:
l, b, w, h = args[0]
else:
l, b, w, h = args
self._x = l
self._y = b
self._width = w
self._height = h
self.stale = True
def get_bbox(self):
"""Return the `.Bbox`."""
return transforms.Bbox.from_bounds(self._x, self._y,
self._width, self._height)
class FancyArrowPatch(Patch):
"""
A fancy arrow patch. It draws an arrow using the `ArrowStyle`.
The head and tail positions are fixed at the specified start and end points
of the arrow, but the size and shape (in display coordinates) of the arrow
does not change when the axis is moved or zoomed.
"""
_edge_default = True
def __str__(self):
if self._posA_posB is not None:
(x1, y1), (x2, y2) = self._posA_posB
return f"{type(self).__name__}(({x1:g}, {y1:g})->({x2:g}, {y2:g}))"
else:
return f"{type(self).__name__}({self._path_original})"
@_docstring.dedent_interpd
@_api.make_keyword_only("3.6", name="path")
def __init__(self, posA=None, posB=None, path=None,
arrowstyle="simple", connectionstyle="arc3",
patchA=None, patchB=None,
shrinkA=2, shrinkB=2,
mutation_scale=1, mutation_aspect=1,
**kwargs):
"""
There are two ways for defining an arrow:
- If *posA* and *posB* are given, a path connecting two points is
created according to *connectionstyle*. The path will be
clipped with *patchA* and *patchB* and further shrunken by
*shrinkA* and *shrinkB*. An arrow is drawn along this
resulting path using the *arrowstyle* parameter.
- Alternatively if *path* is provided, an arrow is drawn along this
path and *patchA*, *patchB*, *shrinkA*, and *shrinkB* are ignored.
Parameters
----------
posA, posB : (float, float), default: None
(x, y) coordinates of arrow tail and arrow head respectively.
path : `~matplotlib.path.Path`, default: None
If provided, an arrow is drawn along this path and *patchA*,
*patchB*, *shrinkA*, and *shrinkB* are ignored.
arrowstyle : str or `.ArrowStyle`, default: 'simple'
The `.ArrowStyle` with which the fancy arrow is drawn. If a
string, it should be one of the available arrowstyle names, with
optional comma-separated attributes. The optional attributes are
meant to be scaled with the *mutation_scale*. The following arrow
styles are available:
%(ArrowStyle:table)s
connectionstyle : str or `.ConnectionStyle` or None, optional, \
default: 'arc3'
The `.ConnectionStyle` with which *posA* and *posB* are connected.
If a string, it should be one of the available connectionstyle
names, with optional comma-separated attributes. The following
connection styles are available:
%(ConnectionStyle:table)s
patchA, patchB : `~matplotlib.patches.Patch`, default: None
Head and tail patches, respectively.
shrinkA, shrinkB : float, default: 2
Shrinking factor of the tail and head of the arrow respectively.
mutation_scale : float, default: 1
Value with which attributes of *arrowstyle* (e.g., *head_length*)
will be scaled.
mutation_aspect : None or float, default: None
The height of the rectangle will be squeezed by this value before
the mutation and the mutated box will be stretched by the inverse
of it.
Other Parameters
----------------
**kwargs : `~matplotlib.patches.Patch` properties, optional
Here is a list of available `.Patch` properties:
%(Patch:kwdoc)s
In contrast to other patches, the default ``capstyle`` and
``joinstyle`` for `FancyArrowPatch` are set to ``"round"``.
"""
# Traditionally, the cap- and joinstyle for FancyArrowPatch are round
kwargs.setdefault("joinstyle", JoinStyle.round)
kwargs.setdefault("capstyle", CapStyle.round)
super().__init__(**kwargs)
if posA is not None and posB is not None and path is None:
self._posA_posB = [posA, posB]
if connectionstyle is None:
connectionstyle = "arc3"
self.set_connectionstyle(connectionstyle)
elif posA is None and posB is None and path is not None:
self._posA_posB = None
else:
raise ValueError("Either posA and posB, or path need to provided")
self.patchA = patchA
self.patchB = patchB
self.shrinkA = shrinkA
self.shrinkB = shrinkB
self._path_original = path
self.set_arrowstyle(arrowstyle)
self._mutation_scale = mutation_scale
self._mutation_aspect = mutation_aspect
self._dpi_cor = 1.0
def set_positions(self, posA, posB):
"""
Set the start and end positions of the connecting path.
Parameters
----------
posA, posB : None, tuple
(x, y) coordinates of arrow tail and arrow head respectively. If
`None` use current value.
"""
if posA is not None:
self._posA_posB[0] = posA
if posB is not None:
self._posA_posB[1] = posB
self.stale = True
def set_patchA(self, patchA):
"""
Set the tail patch.
Parameters
----------
patchA : `.patches.Patch`
"""
self.patchA = patchA
self.stale = True
def set_patchB(self, patchB):
"""
Set the head patch.
Parameters
----------
patchB : `.patches.Patch`
"""
self.patchB = patchB
self.stale = True
@_docstring.dedent_interpd
def set_connectionstyle(self, connectionstyle=None, **kwargs):
"""
Set the connection style, possibly with further attributes.
Attributes from the previous connection style are not reused.
Without argument (or with ``connectionstyle=None``), the available box
styles are returned as a human-readable string.
Parameters
----------
connectionstyle : str or `~matplotlib.patches.ConnectionStyle`
The style of the connection: either a `.ConnectionStyle` instance,
or a string, which is the style name and optionally comma separated
attributes (e.g. "Arc,armA=30,rad=10"). Such a string is used to
construct a `.ConnectionStyle` object, as documented in that class.
The following connection styles are available:
%(ConnectionStyle:table_and_accepts)s
**kwargs
Additional attributes for the connection style. See the table above
for supported parameters.
Examples
--------
::
set_connectionstyle("Arc,armA=30,rad=10")
set_connectionstyle("arc", armA=30, rad=10)
"""
if connectionstyle is None:
return ConnectionStyle.pprint_styles()
self._connector = (
ConnectionStyle(connectionstyle, **kwargs)
if isinstance(connectionstyle, str) else connectionstyle)
self.stale = True
def get_connectionstyle(self):
"""Return the `ConnectionStyle` used."""
return self._connector
def set_arrowstyle(self, arrowstyle=None, **kwargs):
"""
Set the arrow style, possibly with further attributes.
Attributes from the previous arrow style are not reused.
Without argument (or with ``arrowstyle=None``), the available box
styles are returned as a human-readable string.
Parameters
----------
arrowstyle : str or `~matplotlib.patches.ArrowStyle`
The style of the arrow: either a `.ArrowStyle` instance, or a
string, which is the style name and optionally comma separated
attributes (e.g. "Fancy,head_length=0.2"). Such a string is used to
construct a `.ArrowStyle` object, as documented in that class.
The following arrow styles are available:
%(ArrowStyle:table_and_accepts)s
**kwargs
Additional attributes for the arrow style. See the table above for
supported parameters.
Examples
--------
::
set_arrowstyle("Fancy,head_length=0.2")
set_arrowstyle("fancy", head_length=0.2)
"""
if arrowstyle is None:
return ArrowStyle.pprint_styles()
self._arrow_transmuter = (
ArrowStyle(arrowstyle, **kwargs)
if isinstance(arrowstyle, str) else arrowstyle)
self.stale = True
def get_arrowstyle(self):
"""Return the arrowstyle object."""
return self._arrow_transmuter
def set_mutation_scale(self, scale):
"""
Set the mutation scale.
Parameters
----------
scale : float
"""
self._mutation_scale = scale
self.stale = True
def get_mutation_scale(self):
"""
Return the mutation scale.
Returns
-------
scalar
"""
return self._mutation_scale
def set_mutation_aspect(self, aspect):
"""
Set the aspect ratio of the bbox mutation.
Parameters
----------
aspect : float
"""
self._mutation_aspect = aspect
self.stale = True
def get_mutation_aspect(self):
"""Return the aspect ratio of the bbox mutation."""
return (self._mutation_aspect if self._mutation_aspect is not None
else 1) # backcompat.
def get_path(self):
"""Return the path of the arrow in the data coordinates."""
# The path is generated in display coordinates, then converted back to
# data coordinates.
_path, fillable = self._get_path_in_displaycoord()
if np.iterable(fillable):
_path = Path.make_compound_path(*_path)
return self.get_transform().inverted().transform_path(_path)
def _get_path_in_displaycoord(self):
"""Return the mutated path of the arrow in display coordinates."""
dpi_cor = self._dpi_cor
if self._posA_posB is not None:
posA = self._convert_xy_units(self._posA_posB[0])
posB = self._convert_xy_units(self._posA_posB[1])
(posA, posB) = self.get_transform().transform((posA, posB))
_path = self.get_connectionstyle()(posA, posB,
patchA=self.patchA,
patchB=self.patchB,
shrinkA=self.shrinkA * dpi_cor,
shrinkB=self.shrinkB * dpi_cor
)
else:
_path = self.get_transform().transform_path(self._path_original)
_path, fillable = self.get_arrowstyle()(
_path,
self.get_mutation_scale() * dpi_cor,
self.get_linewidth() * dpi_cor,
self.get_mutation_aspect())
return _path, fillable
def draw(self, renderer):
if not self.get_visible():
return
# FIXME: dpi_cor is for the dpi-dependency of the linewidth. There
# could be room for improvement. Maybe _get_path_in_displaycoord could
# take a renderer argument, but get_path should be adapted too.
self._dpi_cor = renderer.points_to_pixels(1.)
path, fillable = self._get_path_in_displaycoord()
if not np.iterable(fillable):
path = [path]
fillable = [fillable]
affine = transforms.IdentityTransform()
self._draw_paths_with_artist_properties(
renderer,
[(p, affine, self._facecolor if f and self._facecolor[3] else None)
for p, f in zip(path, fillable)])
class ConnectionPatch(FancyArrowPatch):
"""A patch that connects two points (possibly in different axes)."""
def __str__(self):
return "ConnectionPatch((%g, %g), (%g, %g))" % \
(self.xy1[0], self.xy1[1], self.xy2[0], self.xy2[1])
@_docstring.dedent_interpd
@_api.make_keyword_only("3.6", name="axesA")
def __init__(self, xyA, xyB, coordsA, coordsB=None,
axesA=None, axesB=None,
arrowstyle="-",
connectionstyle="arc3",
patchA=None,
patchB=None,
shrinkA=0.,
shrinkB=0.,
mutation_scale=10.,
mutation_aspect=None,
clip_on=False,
**kwargs):
"""
Connect point *xyA* in *coordsA* with point *xyB* in *coordsB*.
Valid keys are
=============== ======================================================
Key Description
=============== ======================================================
arrowstyle the arrow style
connectionstyle the connection style
relpos default is (0.5, 0.5)
patchA default is bounding box of the text
patchB default is None
shrinkA default is 2 points
shrinkB default is 2 points
mutation_scale default is text size (in points)
mutation_aspect default is 1.
? any key for `matplotlib.patches.PathPatch`
=============== ======================================================
*coordsA* and *coordsB* are strings that indicate the
coordinates of *xyA* and *xyB*.
==================== ==================================================
Property Description
==================== ==================================================
'figure points' points from the lower left corner of the figure
'figure pixels' pixels from the lower left corner of the figure
'figure fraction' 0, 0 is lower left of figure and 1, 1 is upper
right
'subfigure points' points from the lower left corner of the subfigure
'subfigure pixels' pixels from the lower left corner of the subfigure
'subfigure fraction' fraction of the subfigure, 0, 0 is lower left.
'axes points' points from lower left corner of axes
'axes pixels' pixels from lower left corner of axes
'axes fraction' 0, 0 is lower left of axes and 1, 1 is upper right
'data' use the coordinate system of the object being
annotated (default)
'offset points' offset (in points) from the *xy* value
'polar' you can specify *theta*, *r* for the annotation,
even in cartesian plots. Note that if you are
using a polar axes, you do not need to specify
polar for the coordinate system since that is the
native "data" coordinate system.
==================== ==================================================
Alternatively they can be set to any valid
`~matplotlib.transforms.Transform`.
Note that 'subfigure pixels' and 'figure pixels' are the same
for the parent figure, so users who want code that is usable in
a subfigure can use 'subfigure pixels'.
.. note::
Using `ConnectionPatch` across two `~.axes.Axes` instances
is not directly compatible with :doc:`constrained layout
</tutorials/intermediate/constrainedlayout_guide>`. Add the artist
directly to the `.Figure` instead of adding it to a specific Axes,
or exclude it from the layout using ``con.set_in_layout(False)``.
.. code-block:: default
fig, ax = plt.subplots(1, 2, constrained_layout=True)
con = ConnectionPatch(..., axesA=ax[0], axesB=ax[1])
fig.add_artist(con)
"""
if coordsB is None:
coordsB = coordsA
# we'll draw ourself after the artist we annotate by default
self.xy1 = xyA
self.xy2 = xyB
self.coords1 = coordsA
self.coords2 = coordsB
self.axesA = axesA
self.axesB = axesB
super().__init__(posA=(0, 0), posB=(1, 1),
arrowstyle=arrowstyle,
connectionstyle=connectionstyle,
patchA=patchA, patchB=patchB,
shrinkA=shrinkA, shrinkB=shrinkB,
mutation_scale=mutation_scale,
mutation_aspect=mutation_aspect,
clip_on=clip_on,
**kwargs)
# if True, draw annotation only if self.xy is inside the axes
self._annotation_clip = None
def _get_xy(self, xy, s, axes=None):
"""Calculate the pixel position of given point."""
s0 = s # For the error message, if needed.
if axes is None:
axes = self.axes
xy = np.array(xy)
if s in ["figure points", "axes points"]:
xy *= self.figure.dpi / 72
s = s.replace("points", "pixels")
elif s == "figure fraction":
s = self.figure.transFigure
elif s == "subfigure fraction":
s = self.figure.transSubfigure
elif s == "axes fraction":
s = axes.transAxes
x, y = xy
if s == 'data':
trans = axes.transData
x = float(self.convert_xunits(x))
y = float(self.convert_yunits(y))
return trans.transform((x, y))
elif s == 'offset points':
if self.xycoords == 'offset points': # prevent recursion
return self._get_xy(self.xy, 'data')
return (
self._get_xy(self.xy, self.xycoords) # converted data point
+ xy * self.figure.dpi / 72) # converted offset
elif s == 'polar':
theta, r = x, y
x = r * np.cos(theta)
y = r * np.sin(theta)
trans = axes.transData
return trans.transform((x, y))
elif s == 'figure pixels':
# pixels from the lower left corner of the figure
bb = self.figure.figbbox
x = bb.x0 + x if x >= 0 else bb.x1 + x
y = bb.y0 + y if y >= 0 else bb.y1 + y
return x, y
elif s == 'subfigure pixels':
# pixels from the lower left corner of the figure
bb = self.figure.bbox
x = bb.x0 + x if x >= 0 else bb.x1 + x
y = bb.y0 + y if y >= 0 else bb.y1 + y
return x, y
elif s == 'axes pixels':
# pixels from the lower left corner of the axes
bb = axes.bbox
x = bb.x0 + x if x >= 0 else bb.x1 + x
y = bb.y0 + y if y >= 0 else bb.y1 + y
return x, y
elif isinstance(s, transforms.Transform):
return s.transform(xy)
else:
raise ValueError(f"{s0} is not a valid coordinate transformation")
def set_annotation_clip(self, b):
"""
Set the annotation's clipping behavior.
Parameters
----------
b : bool or None
- True: The annotation will be clipped when ``self.xy`` is
outside the axes.
- False: The annotation will always be drawn.
- None: The annotation will be clipped when ``self.xy`` is
outside the axes and ``self.xycoords == "data"``.
"""
self._annotation_clip = b
self.stale = True
def get_annotation_clip(self):
"""
Return the clipping behavior.
See `.set_annotation_clip` for the meaning of the return value.
"""
return self._annotation_clip
def _get_path_in_displaycoord(self):
"""Return the mutated path of the arrow in display coordinates."""
dpi_cor = self._dpi_cor
posA = self._get_xy(self.xy1, self.coords1, self.axesA)
posB = self._get_xy(self.xy2, self.coords2, self.axesB)
path = self.get_connectionstyle()(
posA, posB,
patchA=self.patchA, patchB=self.patchB,
shrinkA=self.shrinkA * dpi_cor, shrinkB=self.shrinkB * dpi_cor,
)
path, fillable = self.get_arrowstyle()(
path,
self.get_mutation_scale() * dpi_cor,
self.get_linewidth() * dpi_cor,
self.get_mutation_aspect()
)
return path, fillable
def _check_xy(self, renderer):
"""Check whether the annotation needs to be drawn."""
b = self.get_annotation_clip()
if b or (b is None and self.coords1 == "data"):
xy_pixel = self._get_xy(self.xy1, self.coords1, self.axesA)
if self.axesA is None:
axes = self.axes
else:
axes = self.axesA
if not axes.contains_point(xy_pixel):
return False
if b or (b is None and self.coords2 == "data"):
xy_pixel = self._get_xy(self.xy2, self.coords2, self.axesB)
if self.axesB is None:
axes = self.axes
else:
axes = self.axesB
if not axes.contains_point(xy_pixel):
return False
return True
def draw(self, renderer):
if renderer is not None:
self._renderer = renderer
if not self.get_visible() or not self._check_xy(renderer):
return
super().draw(renderer)