Rainbow text

The example shows how to string together several text objects.

History

On the matplotlib-users list back in February 2012, Gökhan Sever asked the following question:

Is there a way in matplotlib to partially specify the color of a string?

Example:

plt.ylabel("Today is cloudy.")

How can I show "today" as red, "is" as green and "cloudy." as blue?

Thanks.

The solution below is modified from Paul Ivanov's original answer.

import matplotlib.pyplot as plt
from matplotlib.transforms import Affine2D, offset_copy


def rainbow_text(x, y, strings, colors, orientation='horizontal',
                 ax=None, **kwargs):
    """
    Take a list of *strings* and *colors* and place them next to each
    other, with text strings[i] being shown in colors[i].

    Parameters
    ----------
    x, y : float
        Text position in data coordinates.
    strings : list of str
        The strings to draw.
    colors : list of color
        The colors to use.
    orientation : {'horizontal', 'vertical'}
    ax : Axes, optional
        The Axes to draw into. If None, the current axes will be used.
    **kwargs
        All other keyword arguments are passed to plt.text(), so you can
        set the font size, family, etc.
    """
    if ax is None:
        ax = plt.gca()
    t = ax.transData
    fig = ax.figure
    canvas = fig.canvas

    assert orientation in ['horizontal', 'vertical']
    if orientation == 'vertical':
        kwargs.update(rotation=90, verticalalignment='bottom')

    for s, c in zip(strings, colors):
        text = ax.text(x, y, s + " ", color=c, transform=t, **kwargs)

        # Need to draw to update the text position.
        text.draw(canvas.get_renderer())
        ex = text.get_window_extent()
        # Convert window extent from pixels to inches
        # to avoid issues displaying at different dpi
        ex = fig.dpi_scale_trans.inverted().transform_bbox(ex)

        if orientation == 'horizontal':
            t = text.get_transform() + \
                offset_copy(Affine2D(), fig=fig, x=ex.width, y=0)
        else:
            t = text.get_transform() + \
                offset_copy(Affine2D(), fig=fig, x=0, y=ex.height)


words = "all unicorns poop rainbows ! ! !".split()
colors = ['red', 'orange', 'gold', 'lawngreen', 'lightseagreen', 'royalblue',
          'blueviolet']
plt.figure(figsize=(6, 6))
rainbow_text(0.1, 0.05, words, colors, size=18)
rainbow_text(0.05, 0.1, words, colors, orientation='vertical', size=18)

plt.show()