a05065e9创建于 4月20日历史提交

Interface (Metadata)

The Metadata class provides APIs for storing image metadata. For details about the supported metadata types, see MetadataType.

NOTE

The initial APIs of this module are supported since API version 6. Newly added APIs will be marked with a superscript to indicate their earliest API version.

The initial APIs of this interface are supported since API version 13.

Modules to Import

import { image } from '@kit.ImageKit';

getProperties¹³⁺

getProperties(key: Array<string>): Promise<Record<string, string | null>>

Obtains the values of properties from the image's metadata. This API uses a promise to return the result.

For details about how to query the property values, see PropertyKey, FragmentMapPropertyKey, GifPropertyKey, and HeifsPropertyKey.

System capability: SystemCapability.Multimedia.Image.Core

Parameters

Name	Type	Mandatory	Description
key	Array<string>	Yes	Names of the properties.

Return value

Type	Description
Promise<Record<string, string \| null>>	Promise used to return the property values. If the operation fails, an error code is returned.

Error codes

For details about the error codes, see Universal Error Codes and Image Error Codes.

ID	Error Message
401	Parameter error.Possible causes:1.Mandatory parameters are left unspecified;2.Incorrect parameter types;3.Parameter verification failed;
7600202	Unsupported metadata. Possible causes: 1. Unsupported metadata type. 2. The metadata type does not match the auxiliary picture type.

Example

import { BusinessError } from '@kit.BasicServicesKit';

async function GetProperties(context: Context) {
  const resourceMgr = context.resourceManager;
  const rawFile = await resourceMgr.getRawFileContent("exif.jpg"); // An image containing Exif metadata is required.
  let ops: image.SourceOptions = {
    sourceDensity: 98,
  }
  let imageSource: image.ImageSource = image.createImageSource(rawFile.buffer as ArrayBuffer, ops);
  let commodityPixelMap: image.PixelMap = await imageSource.createPixelMap();
  let pictureObj: image.Picture = image.createPicture(commodityPixelMap);
  let metadataType: image.MetadataType = image.MetadataType.EXIF_METADATA;
  let metaData: image.Metadata | null = await pictureObj.getMetadata(metadataType);
  if (metaData != null) {
    await metaData.getProperties(["ImageWidth", "ImageLength"]).then((data2) => {
      console.info('Get properties ',JSON.stringify(data2));
    }).catch((error: BusinessError) => {
      console.error(`Get properties failed error.code is ${error.code}, error.message is ${error.message}`);
    });
  } else {
    console.error('Metadata is null.');
  }
}

setProperties¹³⁺

setProperties(records: Record<string, string | null>): Promise<void>

Sets the values of properties for the image's metadata. This API uses a promise to return the result.

For details about how to query the property values, see PropertyKey, FragmentMapPropertyKey, GifPropertyKey, and HeifsPropertyKey.

System capability: SystemCapability.Multimedia.Image.Core

Parameters

Name	Type	Mandatory	Description
records	Record<string, string \| null>	Yes	Array of properties and their values.

Return value

Type	Description
Promise<void>	Promise that returns no value. If the operation fails, an error code is returned.

Error codes

For details about the error codes, see Universal Error Codes and Image Error Codes.

ID	Error Message
401	Parameter error.Possible causes:1.Mandatory parameters are left unspecified;2.Incorrect parameter types;3.Parameter verification failed;
7600202	Unsupported metadata. Possible causes: 1. Unsupported metadata type. 2. The metadata type does not match the auxiliary picture type.

Example

import { BusinessError } from '@kit.BasicServicesKit';

async function SetProperties(context: Context) {
  const resourceMgr = context.resourceManager;
  const rawFile = await resourceMgr.getRawFileContent("exif.jpg"); // An image containing Exif metadata is required.
  let ops: image.SourceOptions = {
    sourceDensity: 98,
  }
  let imageSource: image.ImageSource = image.createImageSource(rawFile.buffer as ArrayBuffer, ops);
  let commodityPixelMap: image.PixelMap = await imageSource.createPixelMap();
  let pictureObj: image.Picture = image.createPicture(commodityPixelMap);
  let metadataType: image.MetadataType = image.MetadataType.EXIF_METADATA;
  let metaData: image.Metadata | null = await pictureObj.getMetadata(metadataType);
  if (metaData != null) {
    let setkey: Record<string, string | null> = {
      "ImageWidth": "200",
      "ImageLength": "300"
    };
    await metaData.setProperties(setkey).then(async () => {
      console.info('Set AuxPictureObj properties success.');
    }).catch((error: BusinessError) => {
      console.error(`Failed to set metadata Properties. code is ${error.code}, message is ${error.message}`);
    })
  } else {
    console.error('AuxPictureObj metadata is null. ');
  }
}

getAllProperties¹³⁺

getAllProperties(): Promise<Record<string, string | null>>

Obtains all properties and values from the image's metadata. This API uses a promise to return the result.

For details about how to query the property values, see PropertyKey, FragmentMapPropertyKey, GifPropertyKey, and HeifsPropertyKey.

System capability: SystemCapability.Multimedia.Image.Core

Return value

Type	Description
Promise<Record<string, string \| null>>	Promise used to return the values of all properties.

Example

import { BusinessError } from '@kit.BasicServicesKit';

async function GetAllProperties(context: Context) {
  const resourceMgr = context.resourceManager;
  const rawFile = await resourceMgr.getRawFileContent("exif.jpg"); // An image containing Exif metadata is required.
  let ops: image.SourceOptions = {
    sourceDensity: 98,
  }
  let imageSource: image.ImageSource = image.createImageSource(rawFile.buffer as ArrayBuffer, ops);
  let commodityPixelMap: image.PixelMap = await imageSource.createPixelMap();
  let pictureObj: image.Picture = image.createPicture(commodityPixelMap);
  let metadataType: image.MetadataType = image.MetadataType.EXIF_METADATA;
  let metaData: image.Metadata | null = await pictureObj.getMetadata(metadataType);
  if (metaData != null) {
    await metaData.getAllProperties().then((data2) => {
      const count = Object.keys(data2).length;
      console.info('Metadata have ', count, ' properties');
      console.info(`Get metadata all properties: ${data2}`);
    }).catch((error: BusinessError) => {
      console.error(`Get metadata all properties failed error.code is ${error.code}, error.message is ${error.message}`);
    });
  } else {
    console.error('Metadata is null.');
  }
}

clone¹³⁺

clone(): Promise<Metadata>

Clones the metadata. This API uses a promise to return the result.

System capability: SystemCapability.Multimedia.Image.Core

Return value

Type	Description
Promise<Metadata>	Promise used to return the metadata instance.

Example

import { BusinessError } from '@kit.BasicServicesKit';

async function Clone(context: Context) {
  const resourceMgr = context.resourceManager;
  const rawFile = await resourceMgr.getRawFileContent("exif.jpg"); // An image containing Exif metadata is required.
  let ops: image.SourceOptions = {
    sourceDensity: 98,
  }
  let imageSource: image.ImageSource = image.createImageSource(rawFile.buffer as ArrayBuffer, ops);
  let commodityPixelMap: image.PixelMap = await imageSource.createPixelMap();
  let pictureObj: image.Picture = image.createPicture(commodityPixelMap);
  let metadataType: image.MetadataType = image.MetadataType.EXIF_METADATA;
  let metaData: image.Metadata | null = await pictureObj.getMetadata(metadataType);
  if (metaData != null) {
    let new_metadata: image.Metadata = await metaData.clone();
    new_metadata.getProperties(["ImageWidth"]).then((data1) => {
      console.info(`Clone new_metadata and get Properties: ${data1}`);
    }).catch((err: BusinessError) => {
      console.error(`Clone new_metadata failed, error : ${err}`);
    });
  } else {
    console.error('Metadata is null.');
  }
}

getBlob²³⁺

getBlob(): Promise<ArrayBuffer>

Obtains the metadata in binary format. This API uses a promise to return the result.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.Multimedia.Image.Core

Return value

Type	Description
Promise<ArrayBuffer>	Promise that returns the binary data of the metadata.

Example

import { fileIo } from '@kit.CoreFileKit';

function getFileFd(context: Context): number | undefined {
  const filePath: string = context.cacheDir + '/exif.jpg'; // An image containing Exif metadata is required.
  const file: fileIo.File = fileIo.openSync(filePath, fileIo.OpenMode.READ_WRITE);
  const fd: number = file?.fd;
  return fd;
}

async function GetBlob(context: Context) {
  let fd = getFileFd(context);
  let imageSource = image.createImageSource(fd);
  let pictureObj: image.Picture = await imageSource.createPicture();
  let metadataType: image.MetadataType = image.MetadataType.EXIF_METADATA;
  let metaData: image.Metadata | null = await pictureObj.getMetadata(metadataType);
  if (metaData != null) {
    let blob = await metaData.getBlob();
    if (blob != undefined) {
      console.info("get blob success");
    }
  }
}

setBlob²³⁺

setBlob(blob: ArrayBuffer): Promise<void>

Replaces the current metadata with binary data. This API uses a promise to return the result.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.Multimedia.Image.Core

Parameters

Name	Type	Mandatory	Description
blob	ArrayBuffer	Yes	Binary data used to replace the metadata.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Error codes

For details about the error codes, see Image Error Codes.

ID	Error Message
7600206	Invalid parameter. Possible causes: The blob is empty or has a length of 0.

Example

import { fileIo } from '@kit.CoreFileKit';

function getFileFd(context: Context): number | undefined {
  const filePath: string = context.cacheDir + '/exif.jpg'; // An image containing Exif metadata is required.
  const file: fileIo.File = fileIo.openSync(filePath, fileIo.OpenMode.READ_WRITE);
  const fd: number = file?.fd;
  return fd;
}

async function setBlob(context: Context) {
  let fd = getFileFd(context);
  let imageSource = image.createImageSource(fd);
  let pictureObj: image.Picture = await imageSource.createPicture();
  let metadataType: image.MetadataType = image.MetadataType.EXIF_METADATA;
  let metaData: image.Metadata | null = await pictureObj.getMetadata(metadataType);
  if (metaData != null) {
    let blob = await metaData.getBlob();
    if (blob != undefined) {
      console.info("get blob success");
      metaData.setBlob(blob);
    }
    let new_blob = metaData.getBlob();
    if (new_blob != undefined) {
      console.info("new_blob is not undefined");
    }
  }
}

Interface (Metadata)

Modules to Import

getProperties13+

setProperties13+

getAllProperties13+

clone13+

getBlob23+

setBlob23+

getProperties¹³⁺

setProperties¹³⁺

getAllProperties¹³⁺

clone¹³⁺

getBlob²³⁺

setBlob²³⁺