bordado.rotate_coordinates

bordado.rotate_coordinates(coordinates, angle, *, rotation_center=(0, 0))

Rotate coordinates in 2-dimensional space.

Apply a rotation matrix to the vectors defined by the given coordinates in a 2D space. The rotation is counterclockwise and performed around the origin of the coordinate system or optionally around a specified point (see rotation_center below).

Parameters:

coordinatestuple = (easting, northing)

Tuple of arrays with the coordinates of each point. Should have 2 elements. Arrays can be Python lists. Arrays can be of any shape but must all have the same shape.

anglefloat

The angle of rotation in degrees.

rotation_centertuple = (easting, northing)

The center of the rotation, represented by a tuple of 2 floats. By default, rotate around the origin of the coordinate system at point (0, 0).

Returns:

rotated_coordinatestuple

A tuple of arrays containing the rotated coordinates. The returned arrays will have the same shape as the input coordinate arrays.

Examples

Let’s say we have points that fall on a line along the first dimension:

>>> coordinates = ([1, 2, 3], [0, 0, 0])

Rotating these points by 90° should align them with the second dimension:

>>> rotated = rotate_coordinates(coordinates, angle=90)
>>> print("First coordinate:", ", ".join(f"{x:.2f}" for x in rotated[0]))
First coordinate: 0.00, 0.00, 0.00
>>> print("Second coordinate:", ", ".join(f"{x:.2f}" for x in rotated[1]))
Second coordinate: 1.00, 2.00, 3.00

And rotating them clockwise (-90°) should align them with the negative part of the second dimension:

>>> rotated = rotate_coordinates(coordinates, angle=-90)
>>> print("First coordinate:", ", ".join(f"{x:.2f}" for x in rotated[0]))
First coordinate: 0.00, 0.00, 0.00
>>> print("Second coordinate:", ", ".join(f"{x:.2f}" for x in rotated[1]))
Second coordinate: -1.00, -2.00, -3.00

By default, the rotation is done around the origin. But we can also specify a custom rotation center:

>>> rotated = rotate_coordinates(
...     coordinates, angle=90, rotation_center=(2, 0),
... )
>>> print("First coordinate:", ", ".join(f"{x:.2f}" for x in rotated[0]))
First coordinate: 2.00, 2.00, 2.00
>>> print("Second coordinate:", ", ".join(f"{x:.2f}" for x in rotated[1]))
Second coordinate: -1.00, 0.00, 1.00

The coordinates can have any shape but there can only be 2 of them:

>>> coordinates = ([[1, 2], [3, 4]], [[0, 0], [0, 0]])
>>> rotated = rotate_coordinates(coordinates, angle=90)
>>> for line in rotated[0]:
...     print(", ".join(f"{x:.2f}" for x in line))
0.00, 0.00
0.00, 0.00
>>> for line in rotated[1]:
...     print(", ".join(f"{x:.2f}" for x in line))
1.00, 2.00
3.00, 4.00