matplotlib中文本的部分着色

Question

在matplotlib中是否有办法部分指定字符串的颜色？

示例：

plt.ylabel("Today is cloudy.")

如何将“今天”显示为红色，“是”显示为绿色和“阴天”。为蓝色？

感谢。

Answer 1

我只知道如何以非交互方式进行此操作，即使只是使用'PS'后端。

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

以下是执行此操作的示例：

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转换为png，所以我可以在这里发布）：

Answer 2

这是交互式版本（我发布到the list的同一个版本）

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

延长Yann的答案，LaTeX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")

请注意，此python脚本有时会在第一次尝试时失败，并显示Undefined control sequence个错误。然后再次运行它是成功的。