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pythonlatex
Mark Roddy
Mark Roddy

Reputation: 27986

Converting latex code to Images (or other displayble format) with Python

I have a function I am consuming that returns a string of latex code. I need to generate an image from this. Most of the methods I have seen for doing so suggest calling an external application via say the subprocess module which will generate the image for me.

However, management is not keen on this as it will require external users to install additional software in addition to our own which, with our user base, is not something we can assume to be a simple task.

So are there any python libraries that will accomplish the task of taking latex into a format (such as an image file) which is displayable in a GUI?

Upvotes: 32

Views: 28884

Answers (8)

Enrique Pérez Herrero
Enrique Pérez Herrero

Reputation: 3882

In a Jupyter notebook, you can use the rendering features to display images generated with LaTeX.:

from IPython.display import Math
latex_string = r"""
$$
\left(
      \begin{array}{ r  r  r }
         1 & 0 & 0 \\ 
         0 & 1 & 0 \\ 
         0 & 0 & 1 \\ 
      \end{array}
\right)$$"""


Math(latex_string)

matrix

If you want to save the image to a file you can use this function:

def latex2png(latex, filename, fontsize=300):
    """
    Render latex code to png image
    """
    from sympy import preview
    return preview(latex,
                   viewer='file',
                   filename=filename,
                   euler=False,
                   dvioptions=['-D', f'{str(fontsize)}'])

Upvotes: 0

Andrew Slabko
Andrew Slabko

Reputation: 720

This is a bit ugly solution I often use, but I found it easiest to use in many cases.

import matplotlib.pyplot as plt
import io
from PIL import Image, ImageChops

white = (255, 255, 255, 255)

def latex_to_img(tex):
    buf = io.BytesIO()
    plt.rc('text', usetex=True)
    plt.rc('font', family='serif')
    plt.axis('off')
    plt.text(0.05, 0.5, f'${tex}$', size=40)
    plt.savefig(buf, format='png')
    plt.close()

    im = Image.open(buf)
    bg = Image.new(im.mode, im.size, white)
    diff = ImageChops.difference(im, bg)
    diff = ImageChops.add(diff, diff, 2.0, -100)
    bbox = diff.getbbox()
    return im.crop(bbox)

latex_to_img(r'\frac{x}{y^2}').save('img.png')

Keep in mind, it requires pillow and matplotlib.

pip install matplotlib pillow

Upvotes: 8

asmeurer
asmeurer

Reputation: 91590

SymPy has a builtin preview function that does this.

expr = sin(sqrt(x**2 + 20)) + 1
preview(expr, viewer='file', filename='output.png')

generates

enter image description here

There are lots of options to preview to change the format of the output (for instance, if you don't like the Euler font you can set euler=False).

preview also accepts a LaTeX string instead of a SymPy expression if you have that

preview(r'$$\int_0^1 e^x\,dx$$', viewer='file', filename='test.png', euler=False)

enter image description here

Upvotes: 39

mulllhausen
mulllhausen

Reputation: 4435

this answer might not have been available at the time when the question was asked, but i will add it for those seeking a solution as of 2015.

you can use matplotlib.pyplot to render an equation in a graph with axes, and then remove the axes manually. you can also generate the latex with sympy:

#!/usr/bin/env python2.7                                                        

import matplotlib.pyplot as plt                                                 
import sympy                                                                    

x = sympy.symbols('x')                                                          
y = 1 + sympy.sin(sympy.sqrt(x**2 + 20))                                         
lat = sympy.latex(y)                                                            

#add text                                                                       
plt.text(0, 0.6, r"$%s$" % lat, fontsize = 50)                                  

#hide axes                                                                      
fig = plt.gca()                                                                 
fig.axes.get_xaxis().set_visible(False)                                         
fig.axes.get_yaxis().set_visible(False)                                         
plt.draw() #or savefig                                                          
plt.show()

tested with sympy 0.7.6 and matplotlib 1.4.3

Upvotes: 19

Bastien Léonard
Bastien Léonard

Reputation: 61753

Maybe you could use an online service such as this one: http://www.codecogs.com/components/equationeditor/equationeditor.php.

Following Joel A. Christophel's suggestion, here's a working similar website: http://arachnoid.com/latex/

Upvotes: 1

Jouni K. Seppänen
Jouni K. Seppänen

Reputation: 44132

Take a look at mathtex.

Upvotes: 5

Eduardo Leoni
Eduardo Leoni

Reputation: 9050

If it is just math equations that you need, you will probably have better luck finding a mathml renderer in python. This page might provide some clues, including some latex-mathml translators.

Upvotes: 0

D'Nabre
D'Nabre

Reputation: 2262

You're going to need to use LaTeX to process to string. The process of rendering LaTex/TeX is very involved (it generally takes a 100+MB package to do the work), you're just not going to be able toss in a little python module to get the work done.

Upvotes: -1

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