在圖例文字中使用matplotlib分散標記以及乳膠

Question

我有一個插圖的情節。後者有一個傳說，我想在其中使用matplotlib分散標記。我也希望能夠在所有標籤和傳說的同時使用LaTeX。我提到這個的原因是因爲我看了this thread，那裏的解決方案對我不起作用。我會解釋爲什麼波紋管。

下面是一個例子代碼（對不起，我繪製功能，想不出任何東西）

# -*- coding: utf-8 -*- 
import numpy as np 
import matplotlib.pyplot as plt 
from mpl_toolkits.axes_grid.inset_locator import (inset_axes, InsetPosition, mark_inset) 
from matplotlib import rc 
rc('text', usetex=True) 

N = 50 
x = np.random.rand(N) 
y = np.random.rand(N) 

fig, ax1 = plt.subplots() 

ax1.scatter(x, np.cos(x), color = 'blue', marker = "D", s=47.5, label = r'$\cos$') 
ax1.scatter(y, np.sin(y), color = 'cyan', marker = "*", alpha = 0.85, label = r'$\sin$') 
ax1box = ax1.get_position() 
x_value = -0.13 
y_value = 0.675 
legend=ax1.legend(loc = (ax1box.x0 + x_value, ax1box.y0 + y_value), handletextpad=0.1, prop={'size':8}) 
frame = legend.get_frame() 
frame.set_alpha(0) 
frame.set_linewidth(0) 

ax2 = plt.axes([0.5,0.5,0.5,0.5]) 
ip = InsetPosition(ax1, [0.55,0,0.45,0.40]) 
ax2.set_axes_locator(ip) 
ax2.scatter(x, np.tan(x), color = 'gray', marker = "v", s=15, label = r'Insert blue square marker here') 
ax2.scatter(y, np.log(y)+1, color = 'brown', marker = "4", s=15, label = r'Insert cyan star marker here') 
ax2.xaxis.tick_top() 
ax2.xaxis.set_label_position('top') 
ax2.yaxis.tick_right() 
legend2=ax2.legend(loc = 'lower right', handletextpad=0.1, prop={'size':7}) 
frame2 = legend2.get_frame() 
frame2.set_alpha(0) 
frame2.set_linewidth(0) 

plt.show() 

如果我與建議去here約乳膠和與

嘗試

ax2.scatter(x, np.tan(x), color = 'gray', marker = "v", s=15, label = r'$\square$') 

該圖顯示插圖中沒有圖例。

相反，如果我決定實施統一的解決方案

ax2.scatter(x, np.tan(x), color = 'gray', marker = "v", s=15, label = '●') 

我收到以下錯誤

Exception in Tkinter callback 
Traceback (most recent call last): 
    File "/usr/lib/python3.5/tkinter/__init__.py", line 1562, in __call__ 
    return self.func(*args) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/backends/backend_tkagg.py", line 280, in resize 
    self.show() 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/backends/backend_tkagg.py", line 351, in draw 
    FigureCanvasAgg.draw(self) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/backends/backend_agg.py", line 464, in draw 
    self.figure.draw(self.renderer) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/artist.py", line 63, in draw_wrapper 
    draw(artist, renderer, *args, **kwargs) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/figure.py", line 1144, in draw 
    renderer, self, dsu, self.suppressComposite) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/image.py", line 139, in _draw_list_compositing_images 
    a.draw(renderer) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/artist.py", line 63, in draw_wrapper 
    draw(artist, renderer, *args, **kwargs) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/axes/_base.py", line 2426, in draw 
    mimage._draw_list_compositing_images(renderer, self, dsu) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/image.py", line 139, in _draw_list_compositing_images 
    a.draw(renderer) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/artist.py", line 63, in draw_wrapper 
    draw(artist, renderer, *args, **kwargs) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/legend.py", line 471, in draw 
    bbox = self._legend_box.get_window_extent(renderer) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/offsetbox.py", line 269, in get_window_extent 
    w, h, xd, yd, offsets = self.get_extent_offsets(renderer) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/offsetbox.py", line 391, in get_extent_offsets 
    for c in self.get_visible_children()] 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/offsetbox.py", line 391, in <listcomp> 
    for c in self.get_visible_children()] 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/offsetbox.py", line 262, in get_extent 
    w, h, xd, yd, offsets = self.get_extent_offsets(renderer) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/offsetbox.py", line 462, in get_extent_offsets 
    for c in self.get_visible_children()] 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/offsetbox.py", line 462, in <listcomp> 
    for c in self.get_visible_children()] 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/offsetbox.py", line 262, in get_extent 
    w, h, xd, yd, offsets = self.get_extent_offsets(renderer) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/offsetbox.py", line 391, in get_extent_offsets 
    for c in self.get_visible_children()] 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/offsetbox.py", line 391, in <listcomp> 
    for c in self.get_visible_children()] 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/offsetbox.py", line 262, in get_extent 
    w, h, xd, yd, offsets = self.get_extent_offsets(renderer) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/offsetbox.py", line 462, in get_extent_offsets 
    for c in self.get_visible_children()] 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/offsetbox.py", line 462, in <listcomp> 
    for c in self.get_visible_children()] 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/offsetbox.py", line 835, in get_extent 
    bbox, info, d = self._text._get_layout(renderer) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/text.py", line 362, in _get_layout 
    ismath=ismath) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/backends/backend_agg.py", line 230, in get_text_width_height_descent 
    renderer=self) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/texmanager.py", line 676, in get_text_width_height_descent 
    dvifile = self.make_dvi(tex, fontsize) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/texmanager.py", line 399, in make_dvi 
    texfile = self.make_tex(tex, fontsize) 
    File "/usr/local/lib/python3.5/dist-packages/matplotlib/texmanager.py", line 314, in make_tex 
    fh.write(s.encode('ascii')) 
UnicodeEncodeError: 'ascii' codec can't encode character '\u25cf' in position 226: ordinal not in range(128) 

這似乎是來自於事實，我現在用的乳膠，因爲如果我註釋掉

# from matplotlib import rc 
# rc('text', usetex=True) 

然後我得到一切正常，但沒有LaTeX。 （我得到的這個圈子是黑色的，我還沒有考慮是否有可能改變它的顏色）。儘管如此，我確實需要LaTeX，所以這對我並不好。

Answer 1

由於The Great, Big List of LaTeX Symbols告訴我們，\square是一個AMS符號。因此，爲了使用它，你必須把\usepackage{amssymb}在你的序言，這是可以做到的

rc('text', usetex=True) 
rc('text.latex', preamble=r'\usepackage{amssymb}')