DOMMatrixReadOnly - Web APIs 编辑

The DOMMatrixReadOnly interface represents a read-only 4×4 matrix, suitable for 2D and 3D operations. The DOMMatrix interrface—which is based upon DOMMatrixReadOnly—adds mutability, allowing you to alter the matrix after creating it. A 4×4 matrix is suitable to describe any rotation and translation in 3D.

This interface should be available inside web workers, though some implementations doesn't allow it yet.

Properties

This interface doesn't inherit any properties.

is2D Read only

A Boolean flag whose value is true if the matrix was initialized as a 2D matrix. If false, the matrix is 3D.

isIdentity Read only

A Boolean whose value is true if the matrix is the identity matrix. The identity matrix is one in which every value is 0 except those on the main diagonal from top-left to bottom-right corner (in other words, where the offsets in each direction are equal).

m11, m12, m13, m14, m21, m22, m23, m24, m31, m32, m33, m34, m41, m42, m43, m44

Double-precision floating-point values representing each component of a 4×4 matrix, where m11 through m14 are the first column, m21 through m24 are the second column, and so forth.

a, b, c, d, e, f

Double-precision floating-point values representing the components of a 4×4 matrix which are required in order to perform 2D rotations and translations. These are aliases for specific components of a 4×4 matrix, as shown below.

2D	3D equivalent
a	m11
b	m12
c	m21
d	m22
e	m41
f	m42

Methods

This interface doesn't inherit any methods. None of the following methods alter the original matrix.

DOMMatrixReadOnly.flipX()

Returns a new DOMMatrix created by flipping the source matrix around its X-axis. This is equivalent to multiplying the matrix by  DOMMatrix(-1, 0, 0, 1, 0, 0). The original matrix is not modified.

DOMMatrixReadOnly.flipY()

Returns a new DOMMatrix created by flipping the source matrix around its Y-axis. This is equivalent to multiplying the matrix by  DOMMatrix(1, 0, 0, -1, 0, 0). The original matrix is not modified.

DOMMatrixReadOnly.inverse()

Returns a new DOMMatrix created by inverting the source matrix. If the matrix cannot be inverted, the new matrix's components are all set to NaN and its is2D property is set to false. The original matrix is not altered.

DOMMatrixReadOnly.multiply()

Returns a new DOMMatrix created by computing the dot product of the source matrix and the specified matrix: A⋅B. If no matrix is specified as the multiplier, the matrix is multiplied by a matrix in which every element is 0 except the bottom-right corner and the element immediately above and to its left: m33 and m34. These have the default value of 1. The original matrix is not modified.

DOMMatrixReadOnly.rotateAxisAngle()

Returns a new DOMMatrix created by rotating the source matrix by the given angle around the specified vector. The original matrix is not modified.

DOMMatrixReadOnly.rotate()

Returns a new DOMMatrix created by rotating the source matrix around each of its axes by the specified number of degrees. The original matrix is not altered.

DOMMatrixReadOnly.rotateFromVector()

Returns a new DOMMatrix created by rotating the source matrix by the angle between the specified vector and (1, 0). The original matrix is not modified.

DOMMatrixReadOnly.scale()

Returns a new DOMMatrix created by scaling the source matrix by the amount specified for each axis, centered on the given origin. By default, the X and Z axes are scaled by 1 and the Y axis has no default scaling value. The default origin is (0, 0, 0). The original matrix is not modified.

DOMMatrixReadOnly.scale3d()

Returns a new DOMMatrix created by scaling the source 3D matrix by the given factor along all its axes, centered on the specified origin point. The default origin is (0, 0, 0). The original matrix is not modified.

DOMMatrixReadOnly.scaleNonUniform()

Returns a new DOMMatrix created by applying the specified scaling on the X, Y, and Z axes, centered at the given origin. By default, the Y and Z axes' scaling factors are both 1, but the scaling factor for X must be specified. The default origin is (0, 0, 0). The original matrix is not changed.

DOMMatrixReadOnly.skewX()

Returns a new DOMMatrix created by applying the specified skew transformation to the source matrix along its X-axis. The original matrix is not modified.

DOMMatrixReadOnly.skewY()

Returns a new DOMMatrix created by applying the specified skew transformation to the source matrix along its Y-axis. The original matrix is not modified.

DOMMatrixReadOnly.toFloat32Array()

Returns a new Float32Array containing all 16 elements (m11, m12, m13, m14, m21, m22, m23, m24, m31, m32, m33, m34, m41, m42, m43, m44) which comprise the matrix. The elements are stored into the array as single-precision floating-point numbers in column-major (colexographical access, or "colex") order. (In other words, down the first column from top to bottom, then the second column, and so forth.)

DOMMatrixReadOnly.toFloat64Array()

Returns a new Float64Array containing all 16 elements (m11, m12, m13, m14, m21, m22, m23, m24, m31, m32, m33, m34, m41, m42, m43, m44) which comprise the matrix. The elements are stored into the array as double-precision floating-point numbers in column-major (colexographical access access or "colex") order. (In other words, down the first column from top to bottom, then the second column, and so forth.)

DOMMatrixReadOnly.toJSON()

Returns a JSON representation of the DOMMatrixReadOnly object.

DOMMatrixReadOnly.toString()

Creates and returns a DOMString object which contains a string representation of the matrix in CSS matrix syntax, using the appropriate CSS matrix notation. See the matrix() CSS function for details on this syntax. 

For a 2D matrix, the elements a through f are listed, for a total of six values and the form matrix(a, b, c, d, e, f).

For a 3D matrix, the returned string contains all 16 elements and takes the form matrix3d(m11, m12, m13, m14, m21, m22, m23, m24, m31, m32, m33, m34, m41, m42, m43, m44). See the CSS matrix3d() function for details on the 3D notation's syntax.

Throws an InvalidStateError exception if any of the elements in the matrix are non-finite (even if, in the case of a 2D matrix, the non-finite values are in elements not used by the 2D matrix representation).

DOMMatrixReadOnly.transformPoint()

Transforms the specified point using the matrix, returning a new DOMPoint object containing the transformed point. Neither the matrix nor the original point are altered.

DOMMatrixReadOnly.translate()

Returns a new DOMMatrix containing a matrix calculated by translating the source matrix using the specified vector. By default, the vector is (0, 0, 0). The original matrix is not changed.

Static methods

This interface inherits methods from DOMMatrixReadOnly.

fromFloat32Array()

Creates a new mutable DOMMatrix object given an array of single-precision (32-bit) floating-point values. If the array has six values, the result is a 2D matrix; if the array has 16 values, the result is a 3D matrix. Otherwise, a TypeError exception is thrown.

fromFloat64Array()

Creates a new mutable DOMMatrix object given an array of double-precision (64-bit) floating-point values. If the array has six values, the result is a 2D matrix; if the array has 16 values, the result is a 3D matrix. Otherwise, a TypeError exception is thrown.

fromMatrix()

Creates a new mutable DOMMatrix object given an existing matrix or a DOMMatrixInit dictionary which provides the values for its properties. If no matrix is specified, the matrix is initialized with every element set to 0 except the bottom-right corner and the element immediately above and to its left: m33 and m34. These have the default value of 1.

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• The mutable matrix type, DOMMatrix, which is based on this one.
• SVGMatrix and CSSMatrix, the SVG and CSS specific types that should be getting replaced by this interface.
• The CSS matrix() and matrix3d() functional notation that can be generated from this interface to be used in a CSS transform.