我的情况是我必须为最终用户将 python 表达式转换为 Latex 位图(他们有足够的信心自己编写 python 函数，但更喜欢在 Latex 中观看结果)。

我正在使用 Matplotlib.mathtext 使用以下代码完成这项工作(来自翻译的 latex 原始字符串)。

import wx
import wx.lib.scrolledpanel as scrolled

import matplotlib as mpl
from matplotlib import cm 
from matplotlib import mathtext

class LatexBitmapFactory():
    """ Latex Expression to Bitmap """
    mpl.rc('image', origin='upper')
    parser = mathtext.MathTextParser("Bitmap")

    mpl.rc('text', usetex=True)
    DefaultProps = mpl.font_manager.FontProperties(family = "sans-serif",\
                                                    style = "normal",\
                                                    weight = "medium",\
                                                    size = 6)
    # size is changed from 6 to 7 
#-------------------------------------------------------------------------------
    def SetBitmap(self, _parent, _line, dpi = 150, prop = DefaultProps):
        bmp = self.mathtext_to_wxbitmap(_line, dpi, prop = prop)
        w,h = bmp.GetWidth(), bmp.GetHeight()
        return wx.StaticBitmap(_parent, -1, bmp, (80, 50), (w, h))
#-------------------------------------------------------------------------------
    def mathtext_to_wxbitmap(self, _s, dpi = 150, prop = DefaultProps):
        ftimage, depth = self.parser.parse(_s, dpi, prop)
        w,h = ftimage.get_width(), ftimage.get_height()
        return wx.BitmapFromBufferRGBA(w, h, ftimage.as_rgba_str())


EXP = r'$\left(\frac{A \cdot \left(vds \cdot rs + \operatorname{Vdp}\left(ri, Rn, Hr, Hd\right) \cdot rh\right) \cdot \left(rSurf + \left(1.0 - rSurf\right) \cdot ft\right) \cdot \left(1.0 - e^{- \left(\left(lr + \frac{\operatorname{Log}\left(2\right)}{tem \cdot 86400.0}\right)\right) \cdot tFr \cdot 3600.0}\right)}{rc \cdot \left(lr + \frac{\operatorname{Log}\left(2\right)}{tem \cdot 86400.0}\right) \cdot tFr \cdot 3600.0} + 1\right)$'

class aFrame(wx.Frame):
    def __init__(self, title="Edition"):
        wx.Frame.__init__(self, None, wx.ID_ANY, title=title, size=(600,400),
                          style=wx.DEFAULT_DIALOG_STYLE|wx.RESIZE_BORDER)
        self.SetBackgroundColour(wx.Colour(255,255,255))

        sizer = wx.FlexGridSizer(cols=25, vgap=4, hgap=4)
        panel = scrolled.ScrolledPanel(self)
        image_latex = LatexBitmapFactory().SetBitmap(panel, EXP)

        sizer.Add(image_latex, flag=wx.EXPAND|wx.ALL)
        panel.SetSizer(sizer)
        panel.SetAutoLayout(1)
        panel.SetupScrolling()


app = wx.App(redirect=True, filename="latexlog.txt")
frame = aFrame()
frame.Show()
app.MainLoop()

最佳答案

TL;DR mathtext.py的下一行有一个错误Line 727 .它涉及大小 Bigg 处的右括号到索引 '\x21' ，但这是感叹号的索引。带有一点上下文的行读取

_size_alternatives = {
    '('          : [('rm', '('), ('ex', '\xa1'), ('ex', '\xb3'),
                    ('ex', '\xb5'), ('ex', '\xc3')],
    ')'          : [('rm', ')'), ('ex', '\xa2'), ('ex', '\xb4'),
                    ('ex', '\xb6'), ('ex', '\x21')],

_size_alternatives = {
    '('          : [('rm', '('), ('ex', '\xa1'), ('ex', '\xb3'),
                    ('ex', '\xb5'), ('ex', '\x28')],
    ')'          : [('rm', ')'), ('ex', '\xa2'), ('ex', '\xb4'),
                    ('ex', '\xb6'), ('ex', '\x29')]

 import matplotlib.pyplot as plt
 import matplotlib as mpl

 mpl.rc('image', origin='upper')

 mpl.rc('text', usetex=True)
 DefaultProps = mpl.font_manager.FontProperties(family = "sans-serif",\
                                                 style = "normal",\
                                                 weight = "medium",\
                                                 size = 6)

 EXP = r'$\left(\frac{A \cdot \left(vds \cdot rs + \operatorname{Vdp}\left(ri, Rn, Hr, Hd\right) \cdot rh\right) \cdot \left(rSurf + \left(1.0 - rSurf\right) \cdot ft\right) \cdot \left(1.0 - e^{- \left(\left(lr + \frac{\operatorname{Log}\left(2\right)}{tem \cdot 86400.0}\right)\right) \cdot tFr \cdot 3600.0}\right)}{rc \cdot \left(lr + \frac{\operatorname{Log}\left(2\right)}{tem \cdot 86400.0}\right) \cdot tFr \cdot 3600.0} + 10589 \right)$'

 plt.title(EXP, fontsize=6)
 plt.gca().set_axis_off() # Get rid of the plotting axis for clarity

 plt.show()

    self.parser.to_png('D:\\math_out.png', _s, color=u'black', dpi=150)

Traceback (most recent call last):
  File "D:\baptiste_test.py", line 9, in <module>
    parser.to_png(filename, s, fontsize=size)
  File "C:\Python27\lib\site-packages\matplotlib\mathtext.py", line 3101, in to_
png
    rgba, depth = self.to_rgba(texstr, color=color, dpi=dpi, fontsize=fontsize)
  File "C:\Python27\lib\site-packages\matplotlib\mathtext.py", line 3066, in to_
rgba
    x, depth = self.to_mask(texstr, dpi=dpi, fontsize=fontsize)
  File "C:\Python27\lib\site-packages\matplotlib\mathtext.py", line 3039, in to_
mask
    ftimage, depth = self.parse(texstr, dpi=dpi, prop=prop)
  File "C:\Python27\lib\site-packages\matplotlib\mathtext.py", line 3012, in par
se
    box = self._parser.parse(s, font_output, fontsize, dpi)
  File "C:\Python27\lib\site-packages\matplotlib\mathtext.py", line 2339, in par
se
    print(result[0])
  File "C:\Python27\lib\site-packages\matplotlib\mathtext.py", line 1403, in __r
epr__
    ' '.join([repr(x) for x in self.children]))
  File "C:\Python27\lib\site-packages\matplotlib\mathtext.py", line 1403, in __r
epr__
    ' '.join([repr(x) for x in self.children]))
  File "C:\Python27\lib\site-packages\matplotlib\mathtext.py", line 1403, in __r
epr__
    ' '.join([repr(x) for x in self.children]))
  File "C:\Python27\lib\site-packages\matplotlib\mathtext.py", line 1403, in __r
epr__
    ' '.join([repr(x) for x in self.children]))
UnicodeEncodeError: 'ascii' codec can't encode character u'\xb3' in position 1:
ordinal not in range(128)

print('Getting glyph for symbol',repr(unicode(sym)))
print('Returning',cached_font, num, symbol_name, fontsize, slanted)

_size_alternatives = {
    '('          : [('rm', '('), ('ex', '\xa1'), ('ex', '\xb3'),
                    ('ex', '\xb5'), ('ex', '\xc3')],
    ')'          : [('rm', ')'), ('ex', '\xa2'), ('ex', '\xb4'),
                    ('ex', '\xb6'), ('ex', '\x21')],   ## <---- Incorrect line.

关于python - 为什么 matplotlib 在 latex 表达式中用 "!"替换右括号？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32826091/