MutableAffineTransform

public final class MutableAffineTransform extends AffineTransform

java.lang.Object
   ↳ androidx.ink.geometry.AffineTransform
     ↳ androidx.ink.geometry.MutableAffineTransform

An affine transformation in the plane. The transformation can be thought of as a 3x3 matrix:

⎡m00  m10  m20⎤
⎢m01  m11  m21⎥
⎣ 0    0    1 ⎦

Applying the transformation can be thought of as a matrix multiplication, with the to-be-transformed point represented as a column vector with an extra 1:

⎡m00  m10  m20⎤   ⎡x⎤   ⎡m00*x + m10*y + m20⎤
⎢m01  m11  m21⎥ * ⎢y⎥ = ⎢m01*x + m11*y + m21⎥
⎣ 0    0    1 ⎦   ⎣1⎦   ⎣         1         ⎦

Transformations are composed via multiplication. Multiplication is not commutative (i.e. AB != BA), and the left-hand transformation is composed "after" the right hand transformation. E.g., if you have:

val rotate = ImmutableAffineTransform.rotate(Angle.degreesToRadians(45))
val translate = ImmutableAffineTransform.translate(Vec(10, 0))

then rotate * translate first translates 10 units in the positive x-direction, then rotates 45° about the origin.

See ImmutableAffineTransform for an immutable alternative to this class.

Summary

Public constructors

Constructs an identity MutableAffineTransform:

Public methods
boolean
equals(Object other)

Component-wise equality operator for MutableAffineTransform.
int
final void
setValues(@Size(min = 6) @NonNull float[] values)

Like setValues, but accepts a FloatArray instead of individual float values.
final void
setValues(float m00, float m10, float m20, float m01, float m11, float m21)

Populates this transform with the given values, starting with the top left corner of the matrix and proceeding in row-major order.
@NonNull String

Inherited methods
From androidx.ink.geometry.AffineTransform
final @NonNull MutableParallelogram
applyTransform(
    @NonNull Box box,
    @NonNull MutableParallelogram outParallelogram
)

Apply the AffineTransform to the Box and store the result in the MutableParallelogram.
final @NonNull MutableParallelogram
applyTransform(
    @NonNull Parallelogram parallelogram,
    @NonNull MutableParallelogram outParallelogram
)

Apply the AffineTransform to the Parallelogram and store the result in the MutableParallelogram.
final @NonNull MutableSegment
applyTransform(
    @NonNull Segment segment,
    @NonNull MutableSegment outSegment
)

Apply the AffineTransform to the Segment and store the result in the MutableSegment.
final @NonNull MutableTriangle
applyTransform(
    @NonNull Triangle triangle,
    @NonNull MutableTriangle outTriangle
)

Apply the AffineTransform to the Triangle and store the result in the MutableTriangle.
final @NonNull MutableVec

Apply the AffineTransform to the Vec and store the result in the MutableVec.
final @NonNull MutableAffineTransform

Populates outAffineTransform with the inverse of this AffineTransform.
final @Size(min = 6) @NonNull float[]
getValues(@Size(min = 6) @NonNull float[] outArray)

Populates the first 6 elements of outArray with the values of this transform, starting with the top left corner of the matrix and proceeding in row-major order.

Public constructors

MutableAffineTransform

Added in 1.0.0-alpha01
public MutableAffineTransform()

Constructs an identity MutableAffineTransform:

⎡1  0  0⎤
⎢0  1  0⎥
⎣0  0  1⎦

This is useful when pre-allocating a scratch instance to be filled later.

Public methods

equals

public boolean equals(Object other)

Component-wise equality operator for MutableAffineTransform.

Due to the propagation floating point precision errors, operations that may be equivalent over the real numbers are not always equivalent for floats, and might return false for equals in some cases.

hashCode

public int hashCode()

setValues

Added in 1.0.0-alpha01
public final void setValues(@Size(min = 6) @NonNull float[] values)

Like setValues, but accepts a FloatArray instead of individual float values.

setValues

Added in 1.0.0-alpha01
public final void setValues(float m00, float m10, float m20, float m01, float m11, float m21)

Populates this transform with the given values, starting with the top left corner of the matrix and proceeding in row-major order.

Prefer to modify this object with functions that apply specific transform operations, such as populateFromScale or populateFromRotate, rather than directly setting the actual numeric values of this transform. This function is useful for when the values are needed to be provided in bulk, for example for serialization.

To access these values in the same order as they are set here, use AffineTransform.getValues.

toString

public @NonNull String toString()