harmony 鸿蒙@ohos.multimodalAwareness.metadataBinding (Metadata Binding)

2025-06-12
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@ohos.multimodalAwareness.metadataBinding (Metadata Binding)

The metadataBinding module provides the capability of adding metadata to images and parsing the metadata to complete information transfer.

NOTE

The initial APIs of this module are supported since API version 18. Newly added APIs will be marked with a superscript to indicate their earliest API version.

The APIs provided by this module are system APIs.

Modules to Import

import { metadataBinding } from '@kit.MultimodalAwarenessKit';

encodeImage(image.PixelMap, string)

encodeImage(srcImage: image.PixelMap, metadata: string): Promise;
Encodes metadata into an image. System capability: SystemCapability.MultimodalAwareness.metadataBinding System API: This is a system API.

Parameters

Name	Type	Mandatory	Description
srcImage	PixelMap	Yes	Source image.
metadata	string	Yes	Metadata to encoded.
Promise	Promise	Yes	Callback used to return the image with encoded metadata.

Error codes

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

ID	Error Message
202	Permission check failed. A non-system application uses the system API.
32100001	Internal handling failed. File creation failed.
32100002	Encoding failed. Possible causes: 1. Image processing error; 2. Channel coding error.

Example

import image from '@ohos.multimedia.image';
import { metadataBinding } from '@kit.MultimodalAwarenessKit';
import { BusinessError } from '@kit.BasicServicesKit';

let captureImage: image.PixelMap|undefined = undefined;
let metadata: string = "";
let srcImage: image.PixelMap|undefined = undefined;
metadataBinding.encodeImage(srcImage, metadata).then((pixelMap: image.PixelMap) =>{
	captureImage = pixelMap;
}).catch((error:BusinessError)=>{
	console.error("encode image error" + error);
});

decodeImage(image.PixelMap)

function decodeImage(encodedImage: image.PixelMap): Promise<string> Decodes the information carried in the image.

System capability: SystemCapability.MultimodalAwareness.metadataBinding System API: This is a system API.

Parameters

Name	Type	Mandatory	Description
encodedImage	PixelMap	Yes	Image with metadata encoded.
Promise	Promise<string>	Yes	Callback used to return the encoded metadata of the image.

Error codes

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

ID	Error Message
202	Permission check failed. A non-system application uses the system API.
32100001	Internal handling failed. File creation failed.
32100003	Decoding failed. Possible causes: 1. Image not encoded; 2. Image destroyed.

Example

import image from '@ohos.multimedia.image';
import { metadataBinding } from '@kit.MultimodalAwarenessKit';
import { BusinessError } from '@kit.BasicServicesKit';

let encodeImage: image.PixelMap|undefined = undefined;
let captrueMetadata: string = "";
metadataBinding.decodeImage(encodeImage).then((metadata: string) =>{
	captrueMetadata = metadata;
}).catch((error:BusinessError)=>{
	console.error("decode image error" + error);
});

notifyMetadataBindingEvent(string)

notifyMetadataBindingEvent(metadata: string): void; Transfers metadata to the application or service that calls the encoding API. System capability: SystemCapability.MultimodalAwareness.metadataBinding System API: This is a system API.

Parameters

Name	Type	Mandatory	Description
metadata	string	Yes	Metadata to be encoded.

Error codes

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

ID	Error Message
32100001	Internal handling failed. File creation failed.

Example

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

let metadata:string = '';
metadataBinding.notifyMetadataBindingEvent(metadata).catch((error: BusinessError)=>{
  console.error("notify metadata error" + error);
});