matplotlib - 无法在 matplotlib 的绘图上绘制具有“宽度”属性的边界框？

Question

我正在尝试在文本中绘制一个边界框，例如：

from matplotlib.pyplot import text
from matplotlib.patches import FancyBboxPatch
import matplotlib.transforms as mtransforms

import numpy as np
import matplotlib.pyplot as plt



def draw_bbox(ax, bb):
    # boxstyle=square with pad=0, i.e. bbox itself.
    p_bbox = FancyBboxPatch((bb.xmin, bb.ymin),
                            abs(bb.width), abs(bb.height),
                            boxstyle="round,pad=0.1, rounding_size=0.2",
                            ec="k", fc="none", zorder=10.,facecolor='pink')
    ax.add_patch(p_bbox)

np.random.seed(19680801)

fig, ax = plt.subplots()
x = 30*np.random.randn(10000)
mu = x.mean()
median = np.median(x)
sigma = x.std()
textstr = '\n'.join((
    r'$\mu=%.2f$' % (mu, ),
    r'$\mathrm{median}=%.2f$' % (median, ),
    r'$\sigma=%.2f$' % (sigma, )))

ax.hist(x, 50)

# these are matplotlib.patch.Patch properties
props = dict(boxstyle='square, pad=0.2', facecolor='wheat', alpha=0.5 )

# place a text box in upper left in axes coords
ax.text(0.05, 0.95, textstr, transform=ax.transAxes, fontsize=14,
        verticalalignment='top', bbox=props
       )

plt.show()

在文档matplotlib.pyplot.text中返回一个可以采用 kwarg ' bbox ' 的 Text 实例。这个 bbox 参数接受一个 dict() 类型的对象，该对象具有 patch.FancyBboxPatch 的属性。FancyBboxPatch 有一个位置 arg 宽度，如果我想给出，

props2 =FancyBboxPatch(xy=(0., 0.),width=1.,height=1.,boxstyle='Round, pad=0.2', facecolor='pink', alpha=0.5 )
ax.text(0.1, 0.95, textstr, transform=ax.transAxes, fontsize=14,
        verticalalignment='top', bbox=props2
       )

它给出了以下错误：

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-59-0c8ad0d773a9> in <module>
     32 props2 =FancyBboxPatch((0., 0.),1.,1.,boxstyle='Round, pad=0.2', facecolor='pink', alpha=0.5 )
     33 ax.text(0.1, 0.95, textstr, transform=ax.transAxes, fontsize=14,
---> 34         verticalalignment='top', bbox=props2
     35        )
     36 

~\AppData\Local\Continuum\anaconda3\envs\automation_work\lib\site-packages\matplotlib\cbook\deprecation.py in wrapper(*args, **kwargs)
    367                 f"%(removal)s.  If any parameter follows {name!r}, they "
    368                 f"should be pass as keyword, not positionally.")
--> 369         return func(*args, **kwargs)
    370 
    371     return wrapper

~\AppData\Local\Continuum\anaconda3\envs\automation_work\lib\site-packages\matplotlib\axes\_axes.py in text(self, x, y, s, fontdict, withdash, **kwargs)
    781         else:
    782             t = mtext.Text(x, y, text=s)
--> 783         t.update(effective_kwargs)
    784 
    785         t.set_clip_path(self.patch)

~\AppData\Local\Continuum\anaconda3\envs\automation_work\lib\site-packages\matplotlib\text.py in update(self, kwargs)
    177         super().update(kwargs)
    178         if bbox is not sentinel:
--> 179             self.set_bbox(bbox)
    180 
    181     def __getstate__(self):

~\AppData\Local\Continuum\anaconda3\envs\automation_work\lib\site-packages\matplotlib\text.py in set_bbox(self, rectprops)
    443 
    444         if rectprops is not None:
--> 445             props = rectprops.copy()
    446             boxstyle = props.pop("boxstyle", None)
    447             pad = props.pop("pad", None)

AttributeError: 'FancyBboxPatch' object has no attribute 'copy'

这个错误对我没有意义。我觉得这是 FancyBboxPatch 实现中的错误？任何人都可以帮助找到问题吗？

Answer 1

以下将在轴的左上角添加两个彼此下方的文本。框的宽度为 200 像素，与文本大小无关。

import matplotlib.pyplot as plt
from matplotlib.offsetbox import AnchoredOffsetbox, HPacker, VPacker, TextArea, PaddedBox

fig, ax = plt.subplots()

text1 = TextArea("Short\nText")
of1 = HPacker(width=200, height=None, pad=2, sep=5, align="center", mode="expand", children=[text1])
pb1 = PaddedBox(of1, pad=4, draw_frame=True)

text2 = TextArea("Long text in one line")
of2 = HPacker(width=200, height=None, pad=2, sep=5, align="center", mode="expand",  children=[text2])
pb2 = PaddedBox(of2, pad=4, draw_frame=True)

oft = VPacker(width=200, height=None, pad=2, sep=5, align="baseline", children=[pb1, pb2])
t = AnchoredOffsetbox("upper left", pad=0.4, frameon=False, child=oft)

ax.add_artist(t)

plt.show()