Python - Color coding labels without using ax.text?

Question

While using the legends module for matplotlib is fine for labeling my plots distinguishably, I want to label my plots using a color labeling like (without the lines):

If I where to go about this with my plot, I use the text module to put in the labels with the same color. For example, from my plot:

fig6 = plt.figure()
VelCumullog = fig6.add_subplot(111)


VelCumullog.plot(VelCumu[0], VelCumu[1], color = 'slateblue', label = 'Illustris-1')
VelCumullog.plot(VelCumuD[0], VelCumuD[1], color = 'crimson',  label = 'Illustris-1-Dark')
VelCumullog.set_xscale('log')
VelCumullog.set_yscale('log')
VelCumullog.set_xlim(50,500)
VelCumullog.set_ylim(1,5000)
VelCumullog.set_xlabel('$\mathrm{Velocity\ Relative\ to\ Host}\ [\mathrm{km}\ \mathrm{s}^{-1}]$')
VelCumullog.set_ylabel('$N\ (>v_{\mathrm{rel}})$ ', labelpad=-1)
VelCumullog.set_xticks([100, 1000])
VelCumullog.set_yticks([10, 100, 1000])
VelCumullog.get_xaxis().set_major_formatter(tic.ScalarFormatter())
VelCumullog.get_yaxis().set_major_formatter(tic.ScalarFormatter())
#VelCumullog.legend(loc='upper left', frameon=False)
VelCumullog.text(60, 2800, 'Illustris-1', color='slateblue')
VelCumullog.text(60, 1800, 'Illustris-1-Dark', color='crimson')

Where you see me just use text instead of legend.

But as you see, if I where to do this method for other plots, it can get pretty tedious to porperly place the labels on the plot, since I have to define their coordinates. Especially if the spacing between the text are off in comparison to the other texts in plots.

I was wondering if their would be another method in what I am wanting to do, like using the legends module, or something else that makes my life easier.

Douglas Dawson · Accepted Answer · 2017-03-04 18:31:33Z

1

If I understand correctly, you want your legends to have no lines, and have the text colored. We can do that by setting handlelength=0 when calling legend and manually changing the text color.

The following works for me:

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.patches import Rectangle
import matplotlib.ticker as tic
fig6 = plt.figure()
VelCumullog = fig6.add_subplot(111)

VelCumu = [np.arange(0,1000,1.0)]
VelCumu.append(1000-2.0*VelCumu[0])
VelCumuD = [np.arange(0,1000,1.0)]
VelCumuD.append(1200-2.0*VelCumu[0])

VelCumullog.plot(VelCumu[0], VelCumu[1], color = 'slateblue', label = 'Illustris-1')
VelCumullog.plot(VelCumuD[0], VelCumuD[1], color = 'crimson',  label = 'Illustris-1-Dark')
VelCumullog.set_xscale('log')
VelCumullog.set_yscale('log')
VelCumullog.set_xlim(50,500)
VelCumullog.set_ylim(1,5000)
VelCumullog.set_xlabel('$\mathrm{Velocity\ Relative\ to\ Host}\ [\mathrm{km}\ \mathrm{s}^{-1}]$')
VelCumullog.set_ylabel('$N\ (>v_{\mathrm{rel}})$ ', labelpad=-1)
VelCumullog.set_xticks([100, 1000])
VelCumullog.set_yticks([10, 100, 1000])
VelCumullog.get_xaxis().set_major_formatter(tic.ScalarFormatter())
VelCumullog.get_yaxis().set_major_formatter(tic.ScalarFormatter())
l = VelCumullog.legend(loc='upper left', frameon=False, handlelength=0)
l.get_texts()[0].set_color('slateblue')
l.get_texts()[1].set_color('crimson')

plt.show()

If that does not work, you can try to change the Artists that draw the legend graphic to an invisible box:

empty = Rectangle((0, 0), 0, 0, alpha=0.0)
l = VelCumullog.legend([empty, empty], ['Illustris-1', 'Illustris-1-Dark'], loc='upper left', frameon=False, handlelength=0, handletextpad=0)
l.get_texts()[0].set_color('slateblue')
l.get_texts()[1].set_color('crimson')

Notice I also set handletextpad=0 which might help some alignment issues (removes the space between the invisible Artist and the label).

edited Mar 4, 2017 at 18:31

answered Mar 3, 2017 at 21:44

Douglas Dawson

5562 silver badges9 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

iron2man Over a year ago

+1 for trying to reproduce my plot! Question: What do I do when I set the handle length to zero, i still get a small portion of my handle/line?

Douglas Dawson Over a year ago

I added some information on how to make an invisible artist instead of a line in the legend. Does this help?

Collectives™ on Stack Overflow

Python - Color coding labels without using ax.text?

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related