@ohos.multimodalAwareness.metadataBinding (Metadata Binding) (System API)

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';

metadataBinding.encodeImage

encodeImage(srcImage: image.PixelMap, metadata: string): Promise<image.PixelMap>

Encodes metadata into an image. This API uses a promise to return the result.

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 be encoded.

Return value

Type	Description
Promise<image.PixelMap>	Promise object, which is 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	Encode process fail. Possible causes: 1. Image processing error; 2. Channel coding error.

Example

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

metadataBinding.decodeImage

decodeImage(encodedImage: image.PixelMap): Promise<string>

Decodes the information carried in the image. This API uses a promise to return the result.

System capability: SystemCapability.MultimodalAwareness.metadataBinding

System API: This is a system API.

Parameters

Name	Type	Mandatory	Description
encodedImage	PixelMap	Yes	Image with metadata encoded.

Return value

Type	Description
Promise<string>	Promise object, which is 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 read failed.
32100003	Decode process fail. Possible causes: 1. Image is not an encoded Image; 2. Image destroyed, decoding failed.

Example

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

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

metadataBinding.notifyMetadataBindingEvent

notifyMetadataBindingEvent(bundleName: string): Promise<string>

Transfers metadata to the application or service that calls the encoding API. This API uses a promise to return the result.

System capability: SystemCapability.MultimodalAwareness.metadataBinding

System API: This is a system API.

Parameters

Name	Type	Mandatory	Description
bundleName	string	Yes	Bundle name used to obtain the application link.

Return value

Type	Description
Promise<string>	Promise used to return the application link information of the current page.

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. Obtain metadata failed.

Example

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

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