@ohos.matrix4 (Matrix Transformation)

The matrix4 module provides APIs for matrix transformation. You can use these APIs to translate, rotate, and scale images.

NOTE

The initial APIs of this module are supported since API version 7. Updates will be marked with a superscript to indicate their earliest API version.

Modules to Import

import matrix4 from '@ohos.matrix4'

matrix4.init

init(options: [number,number,number,number,number,number,number,number,number,number,number,number,number,number,number,number]): Matrix4Transit

Matrix constructor, which is used to create a 4 x 4 matrix with the input parameters. Column-major order is used.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name Type Mandatory Description
option [number,number,number,number,
number,number,number,number,
number,number,number,number,
number,number,number,number]		 Yes A number array whose length is 16 (4 x 4). For details, see 4 x 4 matrix description.
Default value:
[1, 0, 0, 0,
0, 1, 0, 0,
0, 0, 1, 0,
0, 0, 0, 1]

Return value

Type Description
Matrix4Transit 4 x 4 matrix object created based on the input parameters.

4 x 4 matrix description

Name Type Mandatory Description
m00 number Yes Scaling value of the x-axis. The default value is 1 for the identity matrix.
m01 number Yes The second value, which is affected by the rotation of the x, y, and z axes.
m02 number Yes The third value, which is affected by the rotation of the x, y, and z axes.
m03 number Yes The fourth value, which is meaningless.
m10 number Yes The fifth value, which is affected by the rotation of the x, y, and z axes.
m11 number Yes Scaling value of the y-axis. The default value is 1 for the identity matrix.
m12 number Yes The seventh value, which is affected by the rotation of the x, y, and z axes.
m13 number Yes The eighth value, which is meaningless.
m20 number Yes The ninth value, which is affected by the rotation of the x, y, and z axes.
m21 number Yes The tenth value, which is affected by the rotation of the x, y, and z axes.
m22 number Yes Scaling value of the z-axis. The default value is 1 for the identity matrix.
m23 number Yes Meaningless value.
m30 number Yes Translation value of the x-axis, in px. The default value is 0 for the identity matrix.
m31 number Yes Translation value of the y-axis, in px. The default value is 0 for the identity matrix.
m32 number Yes Translation value of the z-axis, in px. The default value is 0 for the identity matrix.
m33 number Yes Valid in homogeneous coordinates, presenting the perspective projection effect.

Example

import matrix4 from '@ohos.matrix4'
// Create a 4 x 4 matrix.
let matrix = matrix4.init([1.0, 0.0, 0.0, 0.0,
                          0.0, 1.0, 0.0, 0.0,
                          0.0, 0.0, 1.0, 0.0,
                          0.0, 0.0, 0.0, 1.0])
@Entry
@Component
struct Tests {
  build() {
    Column() {
      Image($r("app.media.zh"))
        .width("40%")
        .height(100)
        .transform(matrix)
    }
  }
}

matrix4.identity

identity(): Matrix4Transit

Constructs an identity matrix.

System capability: SystemCapability.ArkUI.ArkUI.Full

Return value

Type Description
Matrix4Transit Identity matrix object.

Example

// The effect of matrix 1 is the same as that of matrix 2.
import matrix4 from '@ohos.matrix4'
let matrix1 = matrix4.init([1.0, 0.0, 0.0, 0.0,
                          0.0, 1.0, 0.0, 0.0,
                          0.0, 0.0, 1.0, 0.0,
                          0.0, 0.0, 0.0, 1.0])
let matrix2 = matrix4.identity()
@Entry
@Component
struct Tests {
  build() {
    Column() {
      Image($r("app.media.zh"))
        .width("40%")
        .height(100)
        .transform(matrix1)
      Image($r("app.media.zh"))
        .width("40%")
        .height(100)
        .margin({ top: 150 })
        .transform(matrix2)
    }
  }
}

Matrix4Transit

copy

copy(): Matrix4Transit

Copies this matrix object.

System capability: SystemCapability.ArkUI.ArkUI.Full

Return value

Type Description
Matrix4Transit Copy object of the current matrix.

Example

// xxx.ets
import matrix4 from '@ohos.matrix4'

@Entry
@Component
struct Test {
  private matrix1 = matrix4.identity().translate({ x: 200 })
  // Perform the scale operation on the copy matrix of matrix1, which does not affect matrix1.
  private matrix2 = this.matrix1.copy().scale({ x: 1.5 })

  build() {
    Column() {
      Image($r("app.media.test"))
        .width("40%")
        .height(100)
        .transform(this.matrix1)
      Image($r("app.media.test"))
        .width("40%")
        .height(100)
        .margin({ top: 50 })
        .transform(this.matrix2)
    }.alignItems(HorizontalAlign.Center)
    .height('100%')
    .justifyContent(FlexAlign.Center)
  }
}

en-us_image_0000001219744181

combine

combine(options: Matrix4Transit): Matrix4Transit

Combines the effects of two matrices to generate a new matrix object. The original matrix that calls this API will be changed.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name Type Mandatory Description
option Matrix4Transit Yes Matrix object to be combined.

Return value

Type Description
Matrix4Transit Object after matrix combination.

Example

// xxx.ets
import matrix4 from '@ohos.matrix4'

@Entry
@Component
struct Test {
  private matrix1 = matrix4.identity().translate({ x: 200 })
  private matrix2 = matrix4.identity().scale({ x: 2 })

  build() {
    Column() {
      // Before matrix transformation
      Image($r("app.media.icon"))
        .width("40%")
        .height(100)
        .margin({ top: 50 })
      // Translate the x-axis by 200px, and then scale it twice to obtain the resultant matrix.
      Image($r("app.media.icon"))
        .transform(this.matrix1.copy().combine(this.matrix2))
        .width("40%")
        .height(100)
        .margin({ top: 50 })
    }
  }
}

en-us_image_0000001118642902

invert

invert(): Matrix4Transit

Inverts this matrix object. The original matrix that calls this API will be changed.

System capability: SystemCapability.ArkUI.ArkUI.Full

Return value

Type Description
Matrix4Transit Inverse matrix object of the current matrix.

Example

import matrix4 from '@ohos.matrix4'
// The effect of matrix 1 (width scaled up by 2x) is opposite to that of matrix 2 (width scaled down by 2x).
let matrix1 = matrix4.identity().scale({ x: 2 })
let matrix2 = matrix1.copy().invert()

@Entry
@Component
struct Tests {
  build() {
    Column() {
      Image($r("app.media.zh"))
        .width(200)
        .height(100)
        .transform(matrix1)
        .margin({ top: 100 })
      Image($r("app.media.zh"))
        .width(200)
        .height(100)
        .margin({ top: 150 })
        .transform(matrix2)
    }
  }
}

translate

translate(options: TranslateOption): Matrix4Transit

Translates this matrix object along the x, y, and z axes. The original matrix that calls this API will be changed.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name Type Mandatory Description
option TranslateOption Yes Translation configuration.

Return value

Type Description
Matrix4Transit Matrix object after the translation.

Example

// xxx.ets
import matrix4 from '@ohos.matrix4'

@Entry
@Component
struct Test {
  private matrix1 = matrix4.identity().translate({ x: 100, y: 200, z: 30 })

  build() {
    Column() {
      Image($r("app.media.bg1")).transform(this.matrix1)
        .width("40%")
        .height(100)
    }
  }
}

en-us_image_0000001219662645

scale

scale(options: ScaleOption): Matrix4Transit

Scales this matrix object along the x, y, and z axes. The original matrix that calls this API will be changed.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name Type Mandatory Description
option ScaleOption Yes Scaling configuration.

Return value

Type Description
Matrix4Transit Matrix object after the scaling.

Example

// xxx.ets
import matrix4 from '@ohos.matrix4'
@Entry
@Component
struct Test {
  private matrix1 = matrix4.identity().scale({ x:2, y:3, z:4, centerX:50, centerY:50 })

  build() {
    Column() { 
      Image($r("app.media.bg1")).transform(this.matrix1)
        .width("40%")
        .height(100)
    }
  }
}

en-us_image_0000001219864131

rotate

rotate(options: RotateOption): Matrix4Transit

Rotates this matrix object along the x, y, and z axes. The original matrix that calls this API will be changed.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name Type Mandatory Description
option RotateOption Yes Rotation configuration.

Return value

Type Description
Matrix4Transit Matrix object after the rotation.

Example

// xxx.ets
import matrix4 from '@ohos.matrix4'

@Entry
@Component
struct Test {
  private matrix1 = matrix4.identity().rotate({ x: 1, y: 1, z: 2, angle: 30 })

  build() {
    Column() {
      Image($r("app.media.bg1")).transform(this.matrix1)
        .width("40%")
        .height(100)
    }.width("100%").margin({ top: 50 })
  }
}

en-us_image_0000001174422898

transformPoint

transformPoint(options: [number, number]): [number, number]

Applies the current transformation effect to a coordinate point.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name Type Mandatory Description
option [number, number] Yes Point to be transformed.

Return value

Type Description
[number, number] Point object after matrix transformation

Example

// xxx.ets
import matrix4 from '@ohos.matrix4'

@Entry
@Component
struct Test {
  private originPoint: number[] = [50, 50]
  private matrix_1 = matrix4.identity().translate({ x: 150, y: -50 })
  private transformPoint = this.matrix_1.transformPoint([this.originPoint[0], this.originPoint[1]])
  private matrix_2 = matrix4.identity().translate({ x: this.transformPoint[0], y: this.transformPoint[1] })

  build() {
    Column() {
      Text(`Coordinates before matrix transformation: [${this.originPoint}]`)
        .fontSize(16)
      Image($r("app.media.image"))
        .width('600px')
        .height('300px')
        .margin({ top: 50 })
      Text(`Coordinates after matrix transformation: [${this.transformPoint}]`)
        .fontSize(16)
        .margin({ top: 100 })
      Image($r("app.media.image"))
        .width('600px')
        .height('300px')
        .margin({ top: 50 })
        .transform(this.matrix_2)
    }.width("100%").padding(50)
  }
}

en-us_image_0000001219864133

TranslateOption

System capability: SystemCapability.ArkUI.ArkUI.Full

Name Type Mandatory Description
x number No Translation distance along the x-axis, in px.
Default value: 0
Value range: (-∞, +∞)
y number No Translation distance along the y-axis, in px.
Default value: 0
Value range: (-∞, +∞)
z number No Translation distance along the z-axis, in px.
Default value: 0
Value range: (-∞, +∞)

ScaleOption

System capability: SystemCapability.ArkUI.ArkUI.Full

Name Type Mandatory Description
x number No Scaling multiple along the x-axis. x > 1: The image is scaled up along the x-axis.
0 < x < 1: The image is scaled down along the x-axis.
x < 0: The image is scaled in the reverse direction of the x-axis.
Default value: 1
Value range: (-∞, +∞)
y number No Scaling multiple along the y-axis. y > 1: The image is scaled up along the y-axis.
0 < y < 1: The image is scaled down along the y-axis.
y < 0: The image is scaled in the reverse direction of the y-axis.
Default value: 1
Value range: (-∞, +∞)
z number No Scaling multiple along the z-axis. z > 1: The image is scaled up along the z-axis.
0 < z < 1: The image is scaled down along the z-axis.
z < 0: The image is scaled in the reverse direction of the z-axis.
Default value: 1
Value range: (-∞, +∞)
centerX number No X coordinate of the center point.
Default value: 0
Value range: (-∞, +∞)
centerY number No Y coordinate of the center point.
Default value: 0
Value range: (-∞, +∞)

RotateOption

System capability: SystemCapability.ArkUI.ArkUI.Full

Name Type Mandatory Description
x number No X coordinate of the rotation axis vector.
Default value: 0
Value range: (-∞, +∞)
y number No Y coordinate of the rotation axis vector.
Default value: 0
Value range: (-∞, +∞)
z number No Z coordinate of the rotation axis vector.
Default value: 0
Value range: (-∞, +∞)
NOTE
The rotation axis vector is valid only when at least one of x, y, and z is not 0.
angle number No Rotation angle.
Default value: 0
centerX number No X coordinate of the center point.
Default value: 0
centerY number No Y coordinate of the center point.
Default value: 0

matrix4.copy(deprecated)

copy(): Matrix4Transit

Copies this matrix object.

NOTE

This API is deprecated since API version 10. You are advised to use Matrix4Transit.copy instead.

System capability: SystemCapability.ArkUI.ArkUI.Full

Return value

Type Description
Matrix4Transit Copy object of the current matrix.

Example

// xxx.ets
import matrix4 from '@ohos.matrix4'

@Entry
@Component
struct Test {
  private matrix1 = matrix4.identity().translate({ x: 100 })
  // Perform the scale operation on the copy matrix of matrix1, which does not affect matrix1.
  private matrix2 = this.matrix1.copy().scale({ x: 2 })

  build() {
    Column() {
      Image($r("app.media.bg1"))
        .width("40%")
        .height(100)
        .transform(this.matrix1)
      Image($r("app.media.bg2"))
        .width("40%")
        .height(100)
        .margin({ top: 50 })
        .transform(this.matrix2)
    }
  }
}

en-us_image_0000001219744181

matrix4.invert(deprecated)

invert(): Matrix4Transit

Inverts this matrix object.

NOTE

This API is deprecated since API version 10. You are advised to use Matrix4Transit.invert instead.

System capability: SystemCapability.ArkUI.ArkUI.Full

Return value

Type Description
Matrix4Transit Inverse matrix object of the current matrix.

matrix4.combine(deprecated)

combine(options: Matrix4Transit): Matrix4Transit

Combines the effects of two matrices to generate a new matrix object.

NOTE

This API is deprecated since API version 10. You are advised to use Matrix4Transit.combine instead.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name Type Mandatory Description
option Matrix4Transit Yes Matrix object to be combined.

Return value

Type Description
Matrix4Transit Matrix object after combination.

matrix4.translate(deprecated)

translate(options: TranslateOption): Matrix4Transit

Translates this matrix object along the x, y, and z axes.

NOTE

This API is deprecated since API version 10. You are advised to use Matrix4Transit.translate instead.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name Type Mandatory Description
option TranslateOption Yes Translation configuration.

Return value

Type Description
Matrix4Transit Matrix object after translation.

matrix4.scale(deprecated)

scale(options: ScaleOption): Matrix4Transit

Scales this matrix object along the x, y, and z axes.

NOTE

This API is deprecated since API version 10. You are advised to use Matrix4Transit.scale instead.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name Type Mandatory Description
option ScaleOption Yes Scaling configuration.

Return value

Type Description
Matrix4Transit Matrix object after scaling.

matrix4.rotate(deprecated)

rotate(options: RotateOption): Matrix4Transit

Rotates this matrix object along the x, y, and z axes.

NOTE

This API is deprecated since API version 10. You are advised to use Matrix4Transit.rotate instead.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name Type Mandatory Description
option RotateOption Yes Rotation configuration.

Return value

Type Description
Matrix4Transit Matrix object after rotation.

matrix4.transformPoint(deprecated)

transformPoint(options: [number, number]): [number, number]

Applies the current transformation effect to a coordinate point.

NOTE

This API is deprecated since API version 10. You are advised to use Matrix4Transit.transformPoint instead.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name Type Mandatory Description
option [number, number] Yes Point to be transformed.

Return value

Type Description
[number, number] Point object after matrix transformation