matplotlib two different colors in the same annotate

Question

I am trying to create a figure in python and make is so that the same annonate text will have two colors, half of the annonate will be blue and the other half will be red.

I think the code explain itself. I have 3 lines 1 green with green annonate, 1 blue with blue annonate.

The 3rd is red its the summation of plot 1 and plot 2, and I want it to have half annonate blue and half green.

ipython -pylab

x=arange(0,4,0.1)  exp1 = e**(-x/5) exp2 = e**(-x/1) exp3 = e**(-x/5) +e**(-x/1)   figure() plot(x,exp1) plot(x,exp2) plot(x,exp1+exp2) title('Exponential Decay')   annotate(r'$e^{-x/5}$', xy=(x[10], exp1[10]), xytext=(-20,-35),           textcoords='offset points', ha='center', va='bottom',color='blue',           bbox=dict(boxstyle='round,pad=0.2', fc='yellow', alpha=0.3),           arrowprops=dict(arrowstyle='->', connectionstyle='arc3,rad=0.95',                              color='b'))  annotate(r'$e^{-x/1}$', xy=(x[10], exp2[10]), xytext=(-5,20),           textcoords='offset points', ha='center', va='bottom',color='green',           bbox=dict(boxstyle='round,pad=0.2', fc='yellow', alpha=0.3),           arrowprops=dict(arrowstyle='->', connectionstyle='arc3,rad=-0.5',                              color='g'))  annotate(r'$e^{-x/5} + e^{-x/1}$', xy=(x[10], exp2[10]+exp1[10]), xytext=(40,20),           textcoords='offset points', ha='center', va='bottom',           bbox=dict(boxstyle='round,pad=0.2', fc='yellow', alpha=0.3),           arrowprops=dict(arrowstyle='->', connectionstyle='arc3,rad=-0.5',                              color='red')) 

Is it possible?

Answer 1

You can use r'$\textcolor{blue}{e^{-x/5}} + \textcolor{green}{e^{-x/1}}$' to make the text half blue, half green. Using your own code for example:

The image is generated by the following code. Testd with matplotlib v2.1.2 with the default matplotlibrc settings.

import matplotlib as matplotlib matplotlib.use('pgf') matplotlib.rc('pgf', texsystem='pdflatex')  # from running latex -v preamble = matplotlib.rcParams.setdefault('pgf.preamble', []) preamble.append(r'\usepackage{color}')  from numpy import * from matplotlib.pyplot import *  x=arange(0,4,0.1)  exp1 = e**(-x/5) exp2 = e**(-x/1) exp3 = e**(-x/5) +e**(-x/1)   figure() plot(x,exp1) plot(x,exp2) plot(x,exp1+exp2) title('Exponential Decay')   annotate(r'$e^{-x/5}$', xy=(x[10], exp1[10]), xytext=(-20,-25),           textcoords='offset points', ha='center', va='bottom',color='blue',          bbox=dict(boxstyle='round,pad=0.2', fc='yellow', alpha=0.3),          arrowprops=dict(arrowstyle='->', connectionstyle='arc3,rad=0.95',                              color='b'))  annotate(r'$e^{-x/1}$', xy=(x[10], exp2[10]), xytext=(25,20),           textcoords='offset points', ha='center', va='bottom',color='green',          bbox=dict(boxstyle='round,pad=0.2', fc='yellow', alpha=0.3),          arrowprops=dict(arrowstyle='->', connectionstyle='arc3,rad=-0.5',                              color='g'))  annotate(r'$\textcolor{blue}{e^{-x/5}} + \textcolor[rgb]{0.0, 0.5, 0.0}{e^{-x/1}}$',           xy=(x[10], exp2[10]+exp1[10]), xytext=(40,20),           textcoords='offset points', ha='center', va='bottom',          bbox=dict(boxstyle='round,pad=0.2', fc='yellow', alpha=0.3),          arrowprops=dict(arrowstyle='->', connectionstyle='arc3,rad=-0.5',                              color='red'))  savefig('test.png') 

It is mainly your code with the following changes:

1. You need to use a pgf backend.
2. Usepackage color in pgf.preamble
3. There's some overlapping with the 1st and 2nd annotations, so xytext is changed.
4. The color='g' in te 2nd annotation actually didn't use the pure "Green" color like (0, 255, 0) of rgb. \textcolor[rgb]{0.0, 0.5, 0.0} makes it looking alike.