Affine: R6 class representing an affine map.

In PlaneGeometry: Plane Geometry

R6 class representing an affine map.

Description

An affine map is given by a 2x2 matrix (a linear transformation) and a vector (the "intercept").

Active bindings

A

get or set the matrix A

b

get or set the vector b

Methods

Public methods

• Affine$new()

• Affine$print()

• Affine$get3x3matrix()

• Affine$inverse()

• Affine$compose()

• Affine$transform()

• Affine$transformLine()

• Affine$transformEllipse()

• Affine$clone()

---

Method new()

Create a new Affine object.

Usage

Affine$new(A, b)

Arguments

A

the 2x2 matrix of the affine map

b

the shift vector of the affine map

Returns

A new Affine object.

---

Method print()

Show instance of an Affine object.

Usage

Affine$print(...)

Arguments

...

ignored

Examples

Affine$new(rbind(c(3.5,2),c(0,4)), c(-1, 1.25))

---

Method get3x3matrix()

The 3x3 matrix representing the affine map.

Usage

Affine$get3x3matrix()

---

Method inverse()

The inverse affine transformation, if it exists.

Usage

Affine$inverse()

---

Method compose()

Compose the reference affine map with another affine map.

Usage

Affine$compose(transfo, left = TRUE)

Arguments

transfo

an Affine object

left

logical, whether to compose at left or at right (i.e. returns f1 o f0 or f0 o f1)

Returns

An Affine object.

---

Method transform()

Transform a point or several points by the reference affine map.

Usage

Affine$transform(M)

Arguments

M

a point or a two-column matrix of points, one point per row

---

Method transformLine()

Transform a line by the reference affine transformation (only for invertible affine maps).

Usage

Affine$transformLine(line)

Arguments

line

a Line object

Returns

A Line object.

---

Method transformEllipse()

Transform an ellipse by the reference affine transformation (only for an invertible affine map). The result is an ellipse.

Usage

Affine$transformEllipse(ell)

Arguments

ell

an Ellipse object or a Circle object

Returns

An Ellipse object.

---

Method clone()

The objects of this class are cloneable with this method.

Usage

Affine$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Examples

## ------------------------------------------------
## Method `Affine$print`
## ------------------------------------------------

Affine$new(rbind(c(3.5,2),c(0,4)), c(-1, 1.25))

PlaneGeometry documentation built on Aug. 10, 2023, 1:09 a.m.