Basic geometry functions

Overview

The geometry module provides basic geometry functions for computing 2D transformations and distances.

The following functions are available:

• translate()

• scale()

• rotate()

• colvector()

• vector_norm()

• vector_projection()

• vector_angle()

• compute_center()

• compute_rect_size()

• compute_distance()

• compute_angle()

Reference

plotpy.mathutils.geometry.translate(tx: float, ty: float) → ndarray

Return translation matrix

Parameters:

• tx – Translation along X-axis

• ty – Translation along Y-axis

Returns:

Translation matrix

plotpy.mathutils.geometry.scale(sx: float, sy: float) → ndarray

Return scale matrix

Parameters:

• sx – Scale along X-axis

• sy – Scale along Y-axis

Returns:

Scale matrix

plotpy.mathutils.geometry.rotate(alpha: float) → ndarray

Return rotation matrix

Parameters:

alpha – Rotation angle (in radians)

Returns:

Rotation matrix

plotpy.mathutils.geometry.colvector(x: float, y: float) → ndarray

Return vector from coordinates

Parameters:

• x – x-coordinate

• y – y-coordinate

Returns:

Vector

plotpy.mathutils.geometry.vector_norm(xa: float, ya: float, xb: float, yb: float) → float

Return vector norm

Parameters:

• xa – x-coordinate of first point

• ya – y-coordinate of first point

• xb – x-coordinate of second point

• yb – y-coordinate of second point

Returns:

Norm of vector (xa, xb)–>(ya, yb)

plotpy.mathutils.geometry.vector_projection(dv: ndarray, xa: float, ya: float, xb: float, yb: float) → ndarray

Return vector projection

Parameters:

• dv – vector to project

• xa – x-coordinate of first point

• ya – y-coordinate of first point

• xb – x-coordinate of second point

• yb – y-coordinate of second point

Returns:

Projection of dv on vector (xa, xb)–>(ya, yb)

plotpy.mathutils.geometry.vector_angle(dx: float, dy: float) → float

Return vector angle with X-axis

Parameters:

• dx – x-coordinate of vector

• dy – y-coordinate of vector

Returns:

Angle between vector and X-axis (in radians)

plotpy.mathutils.geometry.compute_center(x1: float, y1: float, x2: float, y2: float) → tuple[float, float]

Compute center of rectangle

Parameters:

• x1 – x-coordinate of top-left corner

• y1 – y-coordinate of top-left corner

• x2 – x-coordinate of bottom-right corner

• y2 – y-coordinate of bottom-right corner

Returns:

Tuple of (x, y) coordinates of center

plotpy.mathutils.geometry.compute_rect_size(x1: float, y1: float, x2: float, y2: float) → tuple[float, float]

Compute rectangle size

Parameters:

• x1 – x-coordinate of top-left corner

• y1 – y-coordinate of top-left corner

• x2 – x-coordinate of bottom-right corner

• y2 – y-coordinate of bottom-right corner

Returns:

Tuple of (width, height)

plotpy.mathutils.geometry.compute_distance(x1: float, y1: float, x2: float, y2: float) → float

Compute distance between two points

Parameters:

• x1 – x-coordinate of first point

• y1 – y-coordinate of first point

• x2 – x-coordinate of second point

• y2 – y-coordinate of second point

Returns:

Distance between points

plotpy.mathutils.geometry.compute_angle(x1: float, y1: float, x2: float, y2: float, reverse: bool = False) → float

Compute angle between two points

Parameters:

• x1 – x-coordinate of first point

• y1 – y-coordinate of first point

• x2 – x-coordinate of second point

• y2 – y-coordinate of second point

• reverse – If True, return the angle in the opposite direction

Returns:

Angle between points (in degrees)