Matrix

An affine transform performs a linear mapping from 2D coordinates to other 2D coordinates that preserves the "straightness" and "parallelness" of lines.

Such a coordinate transformation can be represented by a 3 row by 3 column matrix with an implied last row of [ 0 0 1 ]. This matrix transforms source coordinates (x,y) into destination coordinates (x',y') by considering them to be a column vector and multiplying the coordinate vector by the matrix according to the following process:

     [ x']   [  m00  m01  m02  ] [ x ]   [ m00x + m01y + m02 ]
     [ y'] = [  m10  m11  m12  ] [ y ] = [ m10x + m11y + m12 ]
     [ 1 ]   [   0    0    1   ] [ 1 ]   [         1         ]

This class is optimized for speed and minimizes calculations based on its knowledge of the underlying matrix (as opposed to say simply performing matrix multiplication).

Constructors

Matrix(m00, m10, m01, m11, m02, m12)

Matrix(m00, m10, m01, m11, m02, m12)

Creates a 2D affine transform.

Parameters:

m00: Number — The m00 coordinate of the transform.
m10: Number — The m10 coordinate of the transform.
m01: Number — The m01 coordinate of the transform.
m11: Number — The m11 coordinate of the transform.
m02: Number — The m02 coordinate of the transform.
m12: Number — The m12 coordinate of the transform.

Methods

set(m00, m10, m01, m11, m02, m12)

set(m00, m10, m01, m11, m02, m12)

Sets this transform to the matrix specified by the 6 values.

Parameters:

m00: Number — The m00 coordinate of the transform.
m10: Number — The m10 coordinate of the transform.
m01: Number — The m01 coordinate of the transform.
m11: Number — The m11 coordinate of the transform.
m02: Number — The m02 coordinate of the transform.
m12: Number — The m12 coordinate of the transform.

Returns:

Matrix — This affine transform.

scale(scale[, center])

scale(sx, sy[, center])

scale(sx, sy[, center])

Concatentates this transform with a scaling transformation.

Parameters:

sx: Number — The x-axis scaling factor.
sy: Number — The y-axis scaling factor.
center: Point — The center for the scaling transformation. — optional

Returns:

Matrix — This affine transform.

translate(point)

translate(dx, dy)

translate(dx, dy)

Concatentates this transform with a translate transformation.

Parameters:

dx: Number — The distance to translate in the x direction.
dy: Number — The distance to translate in the y direction.

Returns:

Matrix — This affine transform.

rotate(angle, center)

rotate(angle, center)

Concatentates this transform with a rotation transformation around an anchor point.

Parameters:

angle: Number — The angle of rotation measured in degrees.
center: Point — The anchor point to rotate around.

Returns:

Matrix — This affine transform.

rotate(angle, x, y)

rotate(angle, x, y)

Concatentates this transform with a rotation transformation around an anchor point.

Parameters:

angle: Number — The angle of rotation measured in degrees.
x: Number — The x coordinate of the anchor point.
y: Number — The y coordinate of the anchor point.

Returns:

Matrix — This affine transform.

shear(point[, center])

shear(point[, center])

Concatentates this transform with a shear transformation.

Parameters:

point: Point — The shear factor in x and y direction.
center: Point — The center for the shear transformation. — optional

Returns:

Matrix — This affine transform.

shear(shx, shy[, center])

shear(shx, shy[, center])

Concatentates this transform with a shear transformation.

Parameters:

shx: Number — The x shear factor.
shy: Number — The y shear factor.
center: Point — The center for the shear transformation. — optional

Returns:

Matrix — This affine transform.

concatenate(mx)

preConcatenate(mx)

transform(point, src, srcOff, dst, dstOff, numPts)

transform(point, src, srcOff, dst, dstOff, numPts)

Transforms a point or an array of coordinates by this matrix and returns the result. If an array is transformed, the the result is stored into a destination array.

Parameters:

point: Point — The point to be transformed.
src: Number — The array containing the source points as x, y value pairs.
srcOff: Number — The offset to the first point to be transformed.
dst: Number — The array into which to store the transformed point pairs.
dstOff: Number — The offset of the location of the first transformed point in the destination array.
numPts: Number — The number of points to tranform.

getDeterminant()

getRotation()

isInvertible()

createInverse()

setToScale(sx, sy)

setToTranslation(dx, dy)

setToTranslation(dx, dy)

Sets this transform to a translation transformation.

Parameters:

dx: Number — The distance to translate in the x direction.
dy: Number — The distance to translate in the y direction.

Returns:

Matrix — This affine transform.

setToShear(shx, shy)

setToRotation(angle, x, y)

setToRotation(angle, x, y)

Sets this transform to a rotation transformation.

Parameters:

angle: Number — The angle of rotation measured in degrees.
x: Number — The x coordinate of the anchor point.
y: Number — The y coordinate of the anchor point.

Returns:

Matrix — This affine transform.

applyToContext(ctx[, reset])

Static Methods

Matrix.getScaleInstance(sx, sy)

Matrix.getScaleInstance(sx, sy)

Creates a transform representing a scaling transformation.

Parameters:

sx: Number — The x-axis scaling factor.
sy: Number — The y-axis scaling factor.

Returns:

Matrix — A transform representing a scaling transformation.

Matrix.getTranslateInstance(dx, dy)

Matrix.getTranslateInstance(dx, dy)

Creates a transform representing a translation transformation.

Parameters:

dx: Number — The distance to translate in the x direction.
dy: Number — The distance to translate in the y direction.

Returns:

Matrix — A transform representing a translation transformation.

Matrix.getShearInstance(shx, shy, center)

Matrix.getShearInstance(shx, shy, center)

Creates a transform representing a shearing transformation.

Parameters:

shx: Number — The x-axis shear factor.
shy: Number — The y-axis shear factor.
center:

Returns:

Matrix — A transform representing a shearing transformation.

Matrix.getRotateInstance(angle, x, y)

Matrix.getRotateInstance(angle, x, y)

Creates a transform representing a rotation transformation.

Parameters:

angle: Number — The angle of rotation measured in degrees.
x: Number — The x coordinate of the anchor point.
y: Number — The y coordinate of the anchor point.

Returns:

Matrix — A transform representing a rotation transformation.