<p>您可以使用<code>r'$\textcolor{blue}{e^{-x/5}} + \textcolor{green}{e^{-x/1}}$'</code>将文本设置为半蓝色、半绿色。例如,使用您自己的代码:</p>
<p><a href="https://i.stack.imgur.com/hxUlU.png" rel="noreferrer"><img src="https://i.stack.imgur.com/hxUlU.png" alt="enter image description here"/></a></p>
<p>图像由以下代码生成。使用matplotlib v2.1.2和默认的<code>matplotlibrc</code>设置进行测试。</p>
<pre><code>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')
</code></pre>
<p>主要是您的代码,有以下更改:</p>
<ol>
<li>您需要使用<code>pgf</code>后端。</li>
<li>在<code>pgf.preamble</code>中使用包<code>color</code></li>
<li>与第一个和第二个注释有一些重叠,因此<code>xytext</code>被更改。</li>
<li>te 2nd注释中的<code>color='g'</code>实际上没有使用像rgb的(0,255,0)那样的纯“绿色”。<code>\textcolor[rgb]{0.0, 0.5, 0.0}</code>让它看起来很像。</li>
</ol>