Geometric Utilities (lib601.util)

class lib601.util.Pose(x, y, theta)

Represent the x, y, theta pose of an object in 2D space

diff(pose)
Parameters:pose – an instance of lib601.util.Pose
Returns:a pose that is the difference between self and pose (in x, y, and theta)
distance(pose)
Parameters:pose – an instance of lib601.util.Pose
Returns:the distance between the x,y part of self and the x,y part of pose.
inverse()

Return a pose corresponding to the transformation matrix that is the inverse of the transform associated with this pose. If this pose’s transformation maps points from frame X to frame Y, the inverse maps points from frame Y to frame X.

is_near(pose, distEps, angleEps)
Returns:True if pose is within distEps and angleEps of self
point()

Return just the x, y parts represented as an instance of lib601.util.Point

transform()

Return a transformation matrix that corresponds to rotating by theta and then translating by x,y (in the original coordinate frame).

transform_delta(point)

Does the rotation by theta of the pose but does not add the x,y offset. This is useful in transforming the difference(delta) between two points.

Parameters:point – an instance of lib601.util.Point
Returns:a lib601.util.Point.
transform_point(point)

Applies the pose.transform to point and returns new point.

Parameters:point – an instance of lib601.util.Point
transform_pose(pose)

Make self into a transformation matrix and apply it to pose.

Returns:Af new util.pose.
xyt_tuple()
Returns:a representation of this pose as a tuple of x, y, theta values
theta = 0.0

rotation in radians

x = 0.0

x coordinate

y = 0.0

y coordinate

class lib601.util.Point(x, y)

Represent a point with its x, y values

add(point)

Vector addition

angle_to(p)
Parameters:p – instance of lib601.util.Point or lib601.util.Pose
Returns:angle in radians of vector from self to p
distance(point)
Parameters:point – instance of lib601.util.Point
Returns:Euclidean distance between self and lib601.util.Point
dot(p)

Dot product

magnitude()
Returns:Magnitude of this point, interpreted as a vector in 2-space
near(point, dist_eps)
Parameters:
Returns:

true if the distance between self and lib601.util.Point is less than dist_eps
scale(s)

Vector scaling

sub(point)

Vector subtraction

xy_tuple()
Returns:pair of x, y values
x = 0.0

x coordinate

y = 0.0

y coordinate

class lib601.util.Transform(matrix=None)

Rotation and translation represented as 3 x 3 matrix

apply_to_point(point)

Transform a point into a new point.

apply_to_pose(pose)

Transform a pose into a new pose.

compose(trans)

Returns composition of self and trans

inverse()

Returns transformation matrix that is the inverse of this one

pose()

Convert to Pose

matrix = None

matrix representation of transform

class lib601.util.Line(p1, p2)

Line in 2D space

Initialize with two points that are on the line. Actually, store a normal and an offset from the origin

angle_of()

Angle between line from (p1 to p2) and x-axis in radians

closest_point(p)

Return the point on the line that is closest to point p

distance_from_line(p)

Return (signed) distance of point p from line

intersection(other)

Return a lib601.util.Point where self intersects other. Returns None if there is no intersection. :param other: a util.Line

point_on_line(p, eps)

Return true if point p is within eps of the line

nx = None

x component of normal vector

ny = None

y component of normal vector

off = None

offset along normal

class lib601.util.LineSeg(p1, p2)

Line segment in 2D space

Initialize with two points that are on the line. Store one of the points and the vector between them.

closest_point(p)

Return the point on the line that is closest to point p

dist_to_point(p)

Shortest distance between point p and this line

intersection(other)

Return a lib601.util.Point where self intersects other. Returns False if there is no intersection. :param other: a util.LineSeg

M = None

Vector from the stored point to the other point

p1 = None

One point

p2 = None

Other point

lib601.util.line_indices(xxx_todo_changeme, xxx_todo_changeme1)

Takes two cells in the grid (each described by a pair of integer indices), and returns a list of the cells in the grid that are on the line segment between the cells.

lib601.util.line_indices_conservative(xxx_todo_changeme2, xxx_todo_changeme3)

Takes two cells in the grid (each described by a pair of integer indices), and returns a list of the cells in the grid that are on the line segment between the cells. This is a conservative version.