matplotlib中文本的部分着色

Question

matplotlib中有一种方法可以部分指定字符串的颜色吗？

例子：

plt.ylabel("Today is cloudy.") 

我怎样才能显示 “今天” 红 “是” 绿色和 “龙龙”。如蓝色？

谢谢。

Answer 1

我只知道如何以非交互方式做到这一点，即使这样只有'PS'后端。

为此，我将使用Latex格式化文本。然后，我会包含'颜色'包，并根据需要设置颜色。

下面是这样的一个例子：

import matplotlib 
matplotlib.use('ps') 
from matplotlib import rc 

rc('text',usetex=True) 
rc('text.latex', preamble='\usepackage{color}') 
import matplotlib.pyplot as plt 

plt.figure() 
plt.ylabel(r'\textcolor{red}{Today} '+ 
      r'\textcolor{green}{is} '+ 
      r'\textcolor{blue}{cloudy.}') 
plt.savefig('test.ps') 

这导致（使用ImageMagick从PS到PNG转换，这样我就可以在这里发布）：

Answer 2

这里的互动版（同一个我张贴到the list）

import matplotlib.pyplot as plt 
from matplotlib import transforms 

def rainbow_text(x,y,ls,lc,**kw): 
    """ 
    Take a list of strings ``ls`` and colors ``lc`` and place them next to each 
    other, with text ls[i] being shown in color lc[i]. 

    This example shows how to do both vertical and horizontal text, and will 
    pass all keyword arguments to plt.text, so you can set the font size, 
    family, etc. 
    """ 
    t = plt.gca().transData 
    fig = plt.gcf() 
    plt.show() 

    #horizontal version 
    for s,c in zip(ls,lc): 
     text = plt.text(x,y," "+s+" ",color=c, transform=t, **kw) 
     text.draw(fig.canvas.get_renderer()) 
     ex = text.get_window_extent() 
     t = transforms.offset_copy(text._transform, x=ex.width, units='dots') 

    #vertical version 
    for s,c in zip(ls,lc): 
     text = plt.text(x,y," "+s+" ",color=c, transform=t, 
       rotation=90,va='bottom',ha='center',**kw) 
     text.draw(fig.canvas.get_renderer()) 
     ex = text.get_window_extent() 
     t = transforms.offset_copy(text._transform, y=ex.height, units='dots') 


plt.figure() 
rainbow_text(0.5,0.5,"all unicorns poop rainbows ! ! !".split(), 
     ['red', 'orange', 'brown', 'green', 'blue', 'purple', 'black'], 
     size=40) 

Answer 3

扩展晏的回答，乳胶着色现在also works with PDF export：

import matplotlib 
from matplotlib.backends.backend_pgf import FigureCanvasPgf 
matplotlib.backend_bases.register_backend('pdf', FigureCanvasPgf) 

import matplotlib.pyplot as plt 

pgf_with_latex = { 
    "text.usetex": True,   # use LaTeX to write all text 
    "pgf.rcfonts": False,   # Ignore Matplotlibrc 
    "pgf.preamble": [ 
     r'\usepackage{color}'  # xcolor for colours 
    ] 
} 
matplotlib.rcParams.update(pgf_with_latex) 

plt.figure() 
plt.ylabel(r'\textcolor{red}{Today} '+ 
      r'\textcolor{green}{is} '+ 
      r'\textcolor{blue}{cloudy.}') 
plt.savefig("test.pdf") 

注意这个python脚本有时会失败，在第一次尝试Undefined control sequence错误。再次运行它是成功的。