bezier.curved_polygon module

Curved polygon and associated helpers.

A curved polygon (in \(\mathbf{R}^2\)) is defined by the collection of Bézier curves that determine the boundary.

class bezier.curved_polygon.CurvedPolygon(*edges)

Bases: object

Represents an object defined by its curved boundary.

The boundary is a piecewise defined collection of Bézier curves.

Note

The direction of the nodes in each Curve on the boundary is important: we check that one curve begins where the last one ended.

>>> import bezier
>>> edge0 = bezier.Curve(np.array([
...     [0.0,  0.0],
...     [1.0, -1.0],
...     [2.0,  0.0],
... ]))
>>> edge1 = bezier.Curve(np.array([
...     [2.0, 0.0],
...     [2.0, 1.0],
... ]))
>>> edge2 = bezier.Curve(np.array([
...     [2.0, 1.0],
...     [1.0, 2.0],
...     [0.0, 1.0],
... ]))
>>> edge3 = bezier.Curve(np.array([
...     [0.0, 1.0],
...     [0.0, 0.0],
... ]))
>>> curved_poly = bezier.CurvedPolygon(
...     edge0, edge1, edge2, edge3)
>>> curved_poly
<CurvedPolygon (num_sides=4)>

Though the endpoints of edge pair of edges are verified to match, the curved polygon as a whole is not verified, so creating a curved polygon with self-intersections is possible:

>>> edge0 = bezier.Curve(np.array([
...     [0.0, 0.0],
...     [1.0, 0.0],
... ]))
>>> edge1 = bezier.Curve(np.array([
...     [1.0 , 0.0],
...     [1.25, 0.5],
...     [1.0 , 1.0],
... ]))
>>> edge2 = bezier.Curve(np.array([
...     [1.0, 1.0],
...     [2.0, 1.0],
... ]))
>>> edge3 = bezier.Curve(np.array([
...     [2.0, 1.0 ],
...     [1.0, 0.75],
...     [0.0, 0.0 ],
... ]))
>>> curved_poly = bezier.CurvedPolygon(
...     edge0, edge1, edge2, edge3)
>>> curved_poly
<CurvedPolygon (num_sides=4)>

Parameters:edges (Tuple [ Curve, ... ]) – The boundary edges of the curved polygon.

num_sides

int: The number of sides in the current polygon.

__repr__()

Representation of current object.

Returns:Object representation. Return type:str

plot(pts_per_edge, color=None, ax=None, show=False)

Plot the current curved polygon.

Parameters:

• pts_per_edge (int) – Number of points to plot per curved edge.
• color (Optional [ Tuple [ float, float, float ] ]) – Color as RGB profile.
• ax (Optional [ matplotlib.artist.Artist ]) – matplotlib axis object to add plot to.
• show (Optional [ bool ]) – Flag indicating if the plot should be shown.

Returns:

The axis containing the plot. This may be a newly created axis.

Return type:

matplotlib.artist.Artist