Joshua Sierles / Apr 30 2018
with Martin Kavalar, Micah P. Dombrowski and Andrea Amantini

Using Matplotlib with Plotly and SVG

You can plot here in two ways with Matplotlib: via interactive Plotly.js plots, or SVG images.

These examples are drawn from the Matplotlib documentation.

First, let's setup our environment.

import matplotlib.pyplot as plt
import numpy as np
import plotly.tools as tls

# redefine some plotting methods for Nextjournal support

plt.show = plt.gcf
0.0s
setup
Python

1.
Simple Line Plot

# Data for plotting
t = np.arange(0.0, 2.0, 0.01)
s = 1 + np.sin(2 * np.pi * t)

# Note that using plt.subplots below is equivalent to using
# fig = plt.figure and then ax = fig.add_subplot(111)
fig, ax = plt.subplots()
ax.plot(t, s)

ax.set(xlabel='time (s)', ylabel='voltage (mV)',
       title='About as simple as it gets, folks')
ax.grid()

plt.show()
0.7s
simple svg
Python

Let's plot with Plot.ly for interactivity.

tls.mpl_to_plotly(fig)
0.2s
twilight-frog
Python

2.
Image tutorial

Our original stinkbug image

mkdir -p /images
cp 
stinkbug.png
 /images/stinkbug.png
ls -lsa /images
0.6s
copy image
Bash in Python


import matplotlib.image as mpimg
img = mpimg.imread("/images/stinkbug.png")
print(img)
0.6s
load image
Python


plt.imshow(img)
plt.show()
0.8s
display image
Python


lum_img = img[:, :, 0]

# This is array slicing.  You can read more in the `Numpy tutorial
# <https://docs.scipy.org/doc/numpy-dev/user/quickstart.html>`_.

plt.imshow(lum_img)
plt.show()
0.7s
lum image
Python


plt.imshow(lum_img, cmap="hot")
plt.show()
0.7s
shiny-dust
Python


imgplot = plt.imshow(lum_img)
imgplot.set_cmap('nipy_spectral')
plt.gcf
0.0s
patient-recipe
Python


imgplot = plt.imshow(lum_img)
plt.colorbar()
plt.show()
0.9s
withered-cloud
Python


plt.clf()
plt.hist(lum_img.ravel(), bins=256, range=(0.0, 1.0), fc='k', ec='k')
plt.show()
1.2s
summer-darkness
Python
fig = plt.figure()
a = fig.add_subplot(1, 2, 1)
imgplot = plt.imshow(lum_img)
a.set_title('Before')
plt.colorbar(ticks=[0.1, 0.3, 0.5, 0.7], orientation='horizontal')
a = fig.add_subplot(1, 2, 2)
imgplot = plt.imshow(lum_img)
imgplot.set_clim(0.0, 0.7)
a.set_title('After')
plt.colorbar(ticks=[0.1, 0.3, 0.5, 0.7], orientation='horizontal')
plt.gcf()
0.8s
misty-surf
Python