You can precisely layout text in data or axes (0,1) coordinates. This example shows you some of the alignment and rotation specifications for text layout.
import matplotlib.pyplot as plt
from matplotlib.lines import Line2D
from matplotlib.patches import Rectangle
# Build a rectangle in axes coords
left, width = .25, .5
bottom, height = .25, .5
right = left + width
top = bottom + height
ax = plt.gca()
p = plt.Rectangle((left, bottom), width, height, fill=False)
p.set_transform(ax.transAxes)
p.set_clip_on(False)
ax.add_patch(p)
ax.text(left, bottom, 'left top',
horizontalalignment='left',
verticalalignment='top',
transform=ax.transAxes)
ax.text(left, bottom, 'left bottom',
horizontalalignment='left',
verticalalignment='bottom',
transform=ax.transAxes)
ax.text(right, top, 'right bottom',
horizontalalignment='right',
verticalalignment='bottom',
transform=ax.transAxes)
ax.text(right, top, 'right top',
horizontalalignment='right',
verticalalignment='top',
transform=ax.transAxes)
ax.text(right, bottom, 'center top',
horizontalalignment='center',
verticalalignment='top',
transform=ax.transAxes)
ax.text(left, 0.5 * (bottom + top), 'right center',
horizontalalignment='right',
verticalalignment='center',
rotation='vertical',
transform=ax.transAxes)
ax.text(left, 0.5 * (bottom + top), 'left center',
horizontalalignment='left',
verticalalignment='center',
rotation='vertical',
transform=ax.transAxes)
ax.text(0.5 * (left + right), 0.5 * (bottom + top), 'middle',
horizontalalignment='center',
verticalalignment='center',
transform=ax.transAxes)
ax.text(right, 0.5 * (bottom + top), 'centered',
horizontalalignment='center',
verticalalignment='center',
rotation='vertical',
transform=ax.transAxes)
ax.text(left, top, 'rotated\nwith newlines',
horizontalalignment='center',
verticalalignment='center',
rotation=45,
transform=ax.transAxes)
plt.axis('off')
plt.show()