"""
================
Polygon Selector
================

Shows how to create a polygon programmatically or interactively
"""

import matplotlib.pyplot as plt
from matplotlib.widgets import PolygonSelector

###############################################################################
#
# To create the polygon programmatically
fig, ax = plt.subplots()
fig.show()

selector = PolygonSelector(ax, lambda *args: None)

# Add three vertices
selector.verts = [(0.1, 0.4), (0.5, 0.9), (0.3, 0.2)]


###############################################################################
#
# To create the polygon interactively

fig2, ax2 = plt.subplots()
fig2.show()

selector2 = PolygonSelector(ax2, lambda *args: None)

print("Click on the figure to create a polygon.")
print("Press the 'esc' key to start a new polygon.")
print("Try holding the 'shift' key to move all of the vertices.")
print("Try holding the 'ctrl' key to move a single vertex.")


#############################################################################
#
# .. admonition:: References
#
#    The use of the following functions, methods, classes and modules is shown
#    in this example:
#
#    - `matplotlib.widgets.PolygonSelector`