Allow to specify text (label and/or value) location inside rectangles

[nmiranda]

Hello team,

I found it useful to modify the plot function by adding a loc argument that allows the user to specify the desired location of text inside the rectangles. Until now this location was always the center of the rectangles.

For instance:

import squarify
import matplotlib.pyplot as plt

labels = ['A', 'B', 'C', 'D', 'E']
values = [500.0, 433.0, 78.0, 25.0, 25.0]

fig, axes = plt.subplots(1, 1)
ax = squarify.plot(sizes=values,
              pad=True,
              ax=axes,
              label=labels,
              value=values,
              loc="top left",
              )
ax.axis("off")

fig, axes = plt.subplots(1, 1)
ax = squarify.plot(sizes=values,
              pad=True,
              ax=axes,
              label=labels,
              value=values,
              loc="center",
              )
ax.axis("off")

fig, axes = plt.subplots(1, 1)
ax = squarify.plot(sizes=values,
              pad=True,
              ax=axes,
              label=labels,
              value=values,
              loc="bottom right",
              )
ax.axis("off")

plt.show()

Output:

[laserson]

Thanks for the contribution @nmiranda! Could you add better user documentation to the valid possible loc strings and also perform error checking in case someone provides an invalid string? Also, please run the code through the black formatter.

[nmiranda]

-> Updated

• Added better documentation to the valid possible 'loc' strings.
• Performs error checking in case of invalid string.
• Ran code through black formatter.

[nmiranda]

-> Updated

• Include proposed changes by maintainer (thanks @laserson).
• Removed unnecessary imports.
• Invalid loc string check now references helper dictionary keys (to avoid duplication).

[laserson]

Closing as stale