绘制 Matplotlib 绘图时出错（缺少字体指标文件：cmss17）

Question

我知道有一些与此相关的类似问题，但我完全不知道该怎么做。我在这方面绝对是新手，所以如果可能的话，分步指南将非常有帮助。 所以我一直尝试在Jupyter笔记本中编写一个简单的代码：

import numpy as np
import matplotlib.pyplot as plt
from matplotlib import rc
rc('text', usetex=True)
plt.rcParams.update({'font.size': 22})

zeta = np.arange(10**-6,10**4,1000)
N0 = 50
ns = 1-(3*(1+16*zeta*N0/3))/(N0*(1+8*zeta*N0))

plt.plot(zeta,ns)
plt.show()

这是我的代码。我收到以下错误：

FileNotFoundError                         Traceback (most recent call last)
~\anaconda3\lib\site-packages\IPython\core\formatters.py in __call__(self, obj)
    339                 pass
    340             else:
--> 341                 return printer(obj)
    342             # Finally look for special method names
    343             method = get_real_method(obj, self.print_method)

~\anaconda3\lib\site-packages\IPython\core\pylabtools.py in print_figure(fig, fmt, bbox_inches, base64, **kwargs)
    149         FigureCanvasBase(fig)
    150 
--> 151     fig.canvas.print_figure(bytes_io, **kw)
    152     data = bytes_io.getvalue()
    153     if fmt == 'svg':

~\anaconda3\lib\site-packages\matplotlib\backend_bases.py in print_figure(self, filename, dpi, facecolor, edgecolor, orientation, format, bbox_inches, pad_inches, bbox_extra_artists, backend, **kwargs)
   2228                        else suppress())
   2229                 with ctx:
-> 2230                     self.figure.draw(renderer)
   2231 
   2232             if bbox_inches:

~\anaconda3\lib\site-packages\matplotlib\artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
     72     @wraps(draw)
     73     def draw_wrapper(artist, renderer, *args, **kwargs):
---> 74         result = draw(artist, renderer, *args, **kwargs)
     75         if renderer._rasterizing:
     76             renderer.stop_rasterizing()

~\anaconda3\lib\site-packages\matplotlib\artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
     49                 renderer.start_filter()
     50 
---> 51             return draw(artist, renderer, *args, **kwargs)
     52         finally:
     53             if artist.get_agg_filter() is not None:

~\anaconda3\lib\site-packages\matplotlib\figure.py in draw(self, renderer)
   2788 
   2789             self.patch.draw(renderer)
-> 2790             mimage._draw_list_compositing_images(
   2791                 renderer, self, artists, self.suppressComposite)
   2792 

~\anaconda3\lib\site-packages\matplotlib\image.py in _draw_list_compositing_images(renderer, parent, artists, suppress_composite)
    130     if not_composite or not has_images:
    131         for a in artists:
--> 132             a.draw(renderer)
    133     else:
    134         # Composite any adjacent images together

~\anaconda3\lib\site-packages\matplotlib\artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
     49                 renderer.start_filter()
     50 
---> 51             return draw(artist, renderer, *args, **kwargs)
     52         finally:
     53             if artist.get_agg_filter() is not None:

~\anaconda3\lib\site-packages\matplotlib\_api\deprecation.py in wrapper(*inner_args, **inner_kwargs)
    429                          else deprecation_addendum,
    430                 **kwargs)
--> 431         return func(*inner_args, **inner_kwargs)
    432 
    433     return wrapper

~\anaconda3\lib\site-packages\matplotlib\axes\_base.py in draw(self, renderer, inframe)
   2919             renderer.stop_rasterizing()
   2920 
-> 2921         mimage._draw_list_compositing_images(renderer, self, artists)
   2922 
   2923         renderer.close_group('axes')

~\anaconda3\lib\site-packages\matplotlib\image.py in _draw_list_compositing_images(renderer, parent, artists, suppress_composite)
    130     if not_composite or not has_images:
    131         for a in artists:
--> 132             a.draw(renderer)
    133     else:
    134         # Composite any adjacent images together

~\anaconda3\lib\site-packages\matplotlib\artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
     49                 renderer.start_filter()
     50 
---> 51             return draw(artist, renderer, *args, **kwargs)
     52         finally:
     53             if artist.get_agg_filter() is not None:

~\anaconda3\lib\site-packages\matplotlib\axis.py in draw(self, renderer, *args, **kwargs)
   1140 
   1141         ticks_to_draw = self._update_ticks()
-> 1142         ticklabelBoxes, ticklabelBoxes2 = self._get_tick_bboxes(ticks_to_draw,
   1143                                                                 renderer)
   1144 

~\anaconda3\lib\site-packages\matplotlib\axis.py in _get_tick_bboxes(self, ticks, renderer)
   1066     def _get_tick_bboxes(self, ticks, renderer):
   1067         """Return lists of bboxes for ticks' label1's and label2's."""
-> 1068         return ([tick.label1.get_window_extent(renderer)
   1069                  for tick in ticks if tick.label1.get_visible()],
   1070                 [tick.label2.get_window_extent(renderer)

~\anaconda3\lib\site-packages\matplotlib\axis.py in <listcomp>(.0)
   1066     def _get_tick_bboxes(self, ticks, renderer):
   1067         """Return lists of bboxes for ticks' label1's and label2's."""
-> 1068         return ([tick.label1.get_window_extent(renderer)
   1069                  for tick in ticks if tick.label1.get_visible()],
   1070                 [tick.label2.get_window_extent(renderer)

~\anaconda3\lib\site-packages\matplotlib\text.py in get_window_extent(self, renderer, dpi)
    901 
    902         with cbook._setattr_cm(self.figure, dpi=dpi):
--> 903             bbox, info, descent = self._get_layout(self._renderer)
    904             x, y = self.get_unitless_position()
    905             x, y = self.get_transform().transform((x, y))

~\anaconda3\lib\site-packages\matplotlib\text.py in _get_layout(self, renderer)
    304 
    305         # Full vertical extent of font, including ascenders and descenders:
--> 306         _, lp_h, lp_d = renderer.get_text_width_height_descent(
    307             "lp", self._fontproperties,
    308             ismath="TeX" if self.get_usetex() else False)

~\anaconda3\lib\site-packages\matplotlib\backends\backend_agg.py in get_text_width_height_descent(self, s, prop, ismath)
    227             texmanager = self.get_texmanager()
    228             fontsize = prop.get_size_in_points()
--> 229             w, h, d = texmanager.get_text_width_height_descent(
    230                 s, fontsize, renderer=self)
    231             return w, h, d

~\anaconda3\lib\site-packages\matplotlib\texmanager.py in get_text_width_height_descent(self, tex, fontsize, renderer)
    399             dvifile = self.make_dvi(tex, fontsize)
    400             with dviread.Dvi(dvifile, 72 * dpi_fraction) as dvi:
--> 401                 page, = dvi
    402             # A total height (including the descent) needs to be returned.
    403             return page.width, page.height + page.descent, page.descent

~\anaconda3\lib\site-packages\matplotlib\dviread.py in __iter__(self)
    249             integers.
    250         """
--> 251         while self._read():
    252             yield self._output()
    253 

~\anaconda3\lib\site-packages\matplotlib\dviread.py in _read(self)
    329         while True:
    330             byte = self.file.read(1)[0]
--> 331             self._dtable[byte](self, byte)
    332             downs += self._dtable[byte].__name__ == "_down"
    333             if (self._baseline_v is None

~\anaconda3\lib\site-packages\matplotlib\dviread.py in wrapper(self, byte)
    172             if state is not None and self.state != state:
    173                 raise ValueError("state precondition failed")
--> 174             return method(self, *[f(self, byte-min) for f in get_args])
    175         if max is None:
    176             table[min] = wrapper

~\anaconda3\lib\site-packages\matplotlib\dviread.py in _fnt_def(self, k, c, s, d, a, l)
    474     @_dispatch(min=243, max=246, args=('olen1', 'u4', 'u4', 'u4', 'u1', 'u1'))
    475     def _fnt_def(self, k, c, s, d, a, l):
--> 476         self._fnt_def_real(k, c, s, d, a, l)
    477 
    478     def _fnt_def_real(self, k, c, s, d, a, l):

~\anaconda3\lib\site-packages\matplotlib\dviread.py in _fnt_def_real(self, k, c, s, d, a, l)
    481         tfm = _tfmfile(fontname)
    482         if tfm is None:
--> 483             raise FileNotFoundError("missing font metrics file: %s" % fontname)
    484         if c != 0 and tfm.checksum != 0 and c != tfm.checksum:
    485             raise ValueError('tfm checksum mismatch: %s' % n)

FileNotFoundError: missing font metrics file: cmss17

我不确定是否应该将整个错误放在这里，但这就是我尝试绘制图表时得到的结果。我唯一能想到的是，一些用于在图表上写入内容的文件丢失了，但我不知道如何解决这个问题。任何帮助将不胜感激。 谢谢。

Answer 1

我刚刚遇到了同样的错误，就我而言，我需要使用乳胶。我发现，如果正确安装了其他字体，更改默认字体可以解决该问题：

plt.rcParams.update({
"text.usetex": True,
"font.family": "sans-serif",
"font.sans-serif": ["Helvetica"]})

您可以在代码的第 6 行插入此脚本，看看是否有帮助。

Answer 2

我没有从您发布的内容中得出您想要的字体大小 22，因此这适用于轴刻度的标签。
您发布的内容的简单版本：

import numpy as np
import matplotlib.pyplot as plt

zeta = np.arange(10**-6,10**4,1000)
N0 = 50
ns = 1-(3*(1+16*zeta*N0/3))/(N0*(1+8*zeta*N0))
plt.plot(zeta,ns)
plt.tick_params(labelsize=22)
plt.show()

您可以在我的评论中转到此处，会话启动后打开笔记本，并在那里测试该代码。您应该会看到它应该有效。如果它的工作方式与您尝试的方式不同，那么您的东西就已经过时了。

刻度格式基础知识在 Matplotlib 的顶部进行了说明在第一个代码块中勾选格式化程序文档。在大多数情况下，您不再需要 rc 或 rcParams 。现在语法更加明显了。使用它的任何答案要么已经过时，因为它们没有使用提供的路线，要么它们涵盖了异常/边缘情况。