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

Question

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 a

Answer 1

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

Answer 2

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

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

Answer 3

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

Answer 4

SymPy has a builtin preview function that does this.

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

generates

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)

Answer 5

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.

Answer 6

Take a look at mathtex.