Plot a LaTeX equation as a matplotlib figure

plot_equation.py

# Majority of credit goes to Chris Holdgraf, @choldgraf, and this StackOverflow
# post: http://stackoverflow.com/questions/5320205/matplotlib-text-dimensions

import pylab as plt
import numpy as np

def plot_equation(eq, fontsize=50, outfile=None, padding=0.1, **kwargs):
    """Plot an equation as a matplotlib figure.
    Parameters
    ----------
    eq : string
        The equation that you wish to plot. Should be plottable with
        latex. If `$` is included, they will be stripped.
    fontsize : number
        The fontsize passed to plt.text()
    outfile : string
        Name of the file to save the figure to.
    padding : float
        Amount of padding around the equation in inches.
    Returns
    -------
    ax : matplotlib axis
        The axis with your equation.
    """
    # clean equation string
    eq = eq.strip('$').replace(' ', '')
    
    # set up figure
    f = plt.figure()
    ax = plt.axes([0,0,1,1])    
    r = f.canvas.get_renderer()

    # display equation
    t = ax.text(0.5, 0.5, '${}$'.format(eq), fontsize=fontsize,
        horizontalalignment='center',verticalalignment='center')
    
    # resize figure to fit equation
    bb = t.get_window_extent(renderer=r)
    w,h = bb.width/f.dpi,np.ceil(bb.height/f.dpi)
    f.set_size_inches((padding+w,padding+h))

    # set axis limits so equation is centered
    plt.xlim([0,1])
    plt.ylim([0,1])
    ax.grid(False)
    ax.set_axis_off()

    if outfile is not None:
        plt.savefig(outfile, **kwargs)

    return ax

plot_equation('x = \\frac{-b \\pm \\sqrt{b^2 - 4ac}}{2a}',outfile='test',padding=0.1)

Very valuable for me. Thank you very much!
Is it possible to set DPI resolution?

Yes, I just slightly modified the code to take **kwargs and pass them to savefig.

So you should be able to do plot_equation(..., outfile="test.png", dpi=500).