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# Artist within an artist

Show how to override basic methods so an artist can contain another artist. In this case, the line contains a Text instance to label it.

    import numpy as np
    import matplotlib.pyplot as plt
    import matplotlib.lines as lines
    import matplotlib.transforms as mtransforms
    import matplotlib.text as mtext

    class MyLine(lines.Line2D):
        def __init__(self, *args, **kwargs):
            # we'll update the position when the line data is set
            self.text = mtext.Text(0, 0, '')
            lines.Line2D.__init__(self, *args, **kwargs)

            # we can't access the label attr until *after* the line is
            # inited
            self.text.set_text(self.get_label())

        def set_figure(self, figure):
            self.text.set_figure(figure)
            lines.Line2D.set_figure(self, figure)

        def set_axes(self, axes):
            self.text.set_axes(axes)
            lines.Line2D.set_axes(self, axes)

        def set_transform(self, transform):
            # 2 pixel offset
            texttrans = transform + mtransforms.Affine2D().translate(2, 2)
            self.text.set_transform(texttrans)
            lines.Line2D.set_transform(self, transform)

        def set_data(self, x, y):
            if len(x):
                self.text.set_position((x[-1], y[-1]))

            lines.Line2D.set_data(self, x, y)

        def draw(self, renderer):
            # draw my label at the end of the line with 2 pixel offset
            lines.Line2D.draw(self, renderer)
            self.text.draw(renderer)

    # Fixing random state for reproducibility
    np.random.seed(19680801)

    fig, ax = plt.subplots()
    x, y = np.random.rand(2, 20)
    line = MyLine(x, y, mfc='red', ms=12, label='line label')
    #line.text.set_text('line label')
    line.text.set_color('red')
    line.text.set_fontsize(16)

    ax.add_line(line)

    plt.show()

Total running time of the script: ( 0 minutes 0.032 seconds)

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