"""
Compare the ellipse generated with arcs versus a polygonal approximation
"""
from basic_units import cm
import numpy as np
from matplotlib import patches
import matplotlib.pyplot as plt


xcenter, ycenter = 0.38*cm, 0.52*cm
#xcenter, ycenter = 0., 0.
width, height = 1e-1*cm, 3e-1*cm
angle = -30

theta = np.arange(0.0, 360.0, 1.0)*np.pi/180.0
x = 0.5 * width * np.cos(theta)
y = 0.5 * height * np.sin(theta)

rtheta = np.radians(angle)
R = np.array([
    [np.cos(rtheta), -np.sin(rtheta)],
    [np.sin(rtheta),  np.cos(rtheta)],
    ])


x, y = np.dot(R, np.array([x, y]))
x += xcenter
y += ycenter

fig = plt.figure()
ax = fig.add_subplot(211, aspect='auto')
ax.fill(x, y, alpha=0.2, facecolor='yellow', edgecolor='yellow', linewidth=1, zorder=1)

e1 = patches.Ellipse((xcenter, ycenter), width, height,
                     angle=angle, linewidth=2, fill=False, zorder=2)

ax.add_patch(e1)

ax = fig.add_subplot(212, aspect='equal')
ax.fill(x, y, alpha=0.2, facecolor='green', edgecolor='green', zorder=1)
e2 = patches.Ellipse((xcenter, ycenter), width, height,
                     angle=angle, linewidth=2, fill=False, zorder=2)


ax.add_patch(e2)

#fig.savefig('ellipse_compare.png')
fig.savefig('ellipse_compare')

fig = plt.figure()
ax = fig.add_subplot(211, aspect='auto')
ax.fill(x, y, alpha=0.2, facecolor='yellow', edgecolor='yellow', linewidth=1, zorder=1)

e1 = patches.Arc((xcenter, ycenter), width, height,
                 angle=angle, linewidth=2, fill=False, zorder=2)

ax.add_patch(e1)

ax = fig.add_subplot(212, aspect='equal')
ax.fill(x, y, alpha=0.2, facecolor='green', edgecolor='green', zorder=1)
e2 = patches.Arc((xcenter, ycenter), width, height,
                 angle=angle, linewidth=2, fill=False, zorder=2)


ax.add_patch(e2)

#fig.savefig('arc_compare.png')
fig.savefig('arc_compare')

plt.show() 

　このサンプルを実行するときに、basic_units_org.py が必要です。取り敢えず、実行時のカレント・ディレクトリに置けば動作します。

　

　

M:\______\ellipse_with_units.py:26: FutureWarning: 
  The input object of type 'TaggedValue' is an array-like implementing one of 
  the corresponding protocols (`__array__`, `__array_interface__` or 
  `__array_struct__`); but not a sequence (or 0-D). In the future, 
  this object will be coerced as if it was first converted using `np.array(obj)`. 
  To retain the old behaviour, you have to either modify the type 'TaggedValue', 
  or assign to an empty array created with `np.empty(correct_shape, dtype=object)`.
  x, y = np.dot(R, np.array([x, y]))
Traceback (most recent call last):
  File "M:\______\ellipse_with_units.py", line 26, in 
    x, y = np.dot(R, np.array([x, y]))
                     ^^^^^^^^^^^^^^^^
ValueError: setting an array element with a sequence. 
  The requested array has an inhomogeneous shape after 1 dimensions. 
  The detected shape was (2,) + inhomogeneous part.  

Traceback (most recent call last):
  File "C:\Program Files\Python312\Lib\site-packages\matplotlib\axis.py", 
    line 1769, in convert_units
    ret = self.converter.convert(x, self.units, self)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "E:\E_Home\usr\Python\Py-Support\76_units_Examples\94_ellipse_with_units\basic_units.py", line 341, in convert
    if units.ConversionInterface.is_numlike(val):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: type object 'ConversionInterface' has no attribute 'is_numlike'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "E:\______\ellipse_with_units.py", line 37, in 
    ax.add_patch(e1)
  File "C:\Program Files\Python312\Lib\site-packages\matplotlib\axes\_base.py", 
    line 2384, in add_patch
    self._update_patch_limits(p)
  File "C:\Program Files\Python312\Lib\site-packages\matplotlib\axes\_base.py", 
    line 2415, in _update_patch_limits
    patch_trf = patch.get_transform()
                ^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\site-packages\matplotlib\patches.py", 
    line 261, in get_transform
    return self.get_patch_transform() + artist.Artist.get_transform(self)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\site-packages\matplotlib\patches.py", 
    line 1581, in get_patch_transform
    self._recompute_transform()
  File "C:\Program Files\Python312\Lib\site-packages\matplotlib\patches.py", 
    line 1566, in _recompute_transform
    center = (self.convert_xunits(self._center[0]),
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\site-packages\matplotlib\artist.py", 
    line 279, in convert_xunits
    return ax.xaxis.convert_units(x)
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\site-packages\matplotlib\axis.py", 
    line 1771, in convert_units
    raise munits.ConversionError('Failed to convert value(s) to axis '
matplotlib.units.ConversionError: Failed to convert value(s) to axis units: 
  TaggedValue(0.38, BasicUnit(cm)) 

"""
==================
Ellipse with units
==================

Compare the ellipse generated with arcs versus a polygonal approximation.

.. only:: builder_html

   This example requires :download:`basic_units.py basic_units.py`
"""

from basic_units import cm

import matplotlib.pyplot as plt
import numpy as np

from matplotlib import patches

xcenter, ycenter = 0.38*cm, 0.52*cm
width, height = 1e-1*cm, 3e-1*cm
angle = -30

theta = np.deg2rad(np.arange(0.0, 360.0, 1.0))
x = 0.5 * width * np.cos(theta)
y = 0.5 * height * np.sin(theta)

rtheta = np.radians(angle)
R = np.array([
    [np.cos(rtheta), -np.sin(rtheta)],
    [np.sin(rtheta),  np.cos(rtheta)],
    ])


x, y = np.dot(R, [x, y])
x += xcenter
y += ycenter

# %%

fig = plt.figure()
ax = fig.add_subplot(211, aspect='auto')
ax.fill(x, y, alpha=0.2, facecolor='yellow',
        edgecolor='yellow', linewidth=1, zorder=1)

e1 = patches.Ellipse((xcenter, ycenter), width, height,
                     angle=angle, linewidth=2, fill=False, zorder=2)

ax.add_patch(e1)

ax = fig.add_subplot(212, aspect='equal')
ax.fill(x, y, alpha=0.2, facecolor='green', edgecolor='green', zorder=1)
e2 = patches.Ellipse((xcenter, ycenter), width, height,
                     angle=angle, linewidth=2, fill=False, zorder=2)


ax.add_patch(e2)
fig.savefig('ellipse_compare')

# %%

fig = plt.figure()
ax = fig.add_subplot(211, aspect='auto')
ax.fill(x, y, alpha=0.2, facecolor='yellow',
        edgecolor='yellow', linewidth=1, zorder=1)

e1 = patches.Arc((xcenter, ycenter), width, height,
                 angle=angle, linewidth=2, fill=False, zorder=2)

ax.add_patch(e1)

ax = fig.add_subplot(212, aspect='equal')
ax.fill(x, y, alpha=0.2, facecolor='green', edgecolor='green', zorder=1)
e2 = patches.Arc((xcenter, ycenter), width, height,
                 angle=angle, linewidth=2, fill=False, zorder=2)


ax.add_patch(e2)
fig.savefig('arc_compare')

plt.show() 

　Python 3.11.6 (matplotlib 3.7.1) 及び Python 3.12.0 (matplotlib 3.8.1) 共に、正常実行です。
　このサンプルを実行するときに、basic_units.py が必要です。取り敢えず、実行時のカレント・ディレクトリに置けば動作します。

　

　

　basic_units.py を新しいのに、入れ替えると、元の ellipse_with_units.py でも、正常に実行できます。

　

　

• 2023/12/12 Ver=1.04 Python 3.12.0 (matplotlib 3.8.1)で確認
• 2023/12/12 Ver=1.04 Python 3.11.6 (matplotlib 3.7.1)で確認
• 2023/04/06 Ver=1.03 Python 3.11.2 で確認
• 2020/11/03 Ver=1.01 Python 3.7.8 で確認
• 2018/12/08 Ver=1.01 初版リリース

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