Initialization Control

The following methods and properties help with the initialization of the library.

License Control

Create and Destroy Instances

Set Up the Environment

defaultUIElementURL

[Deprecated]

Returns or sets the URL of the .html file that defines the default UI Element. The URL can only be set before the API createInstance is called.

static defaultUIElementURL: string

Code Snippet

// The following line is actually not useful anymore if Dynamsoft Camera Enhancer v3.0.0+ is used.
Dynamsoft.DLR.LabelRecognizer.defaultUIElementURL = "https://cdn.jsdelivr.net/npm/dynamsoft-label-recognizer@2.2.11/dist/dlr.ui.html";
let cameraEnhancer = await Dynamsoft.DCE.CameraEnhancer.createInstance();
let options = {
    resultsHighlightBaseShapes: Dynamsoft.DCE.DrawingItem
};
await recognizer.setImageSource(enhancer, options);
let recognizer = await Dynamsoft.DLR.LabelRecognizer.createInstance({
    runtimeSettings: "video-passportMRZ"
});
await recognizer.startScanning();

license

An online license or an offline license can be set here. Most license formats are supported. Dynamsoft usually provides an online license.

license needs to be set before createInstance() or loadWasm().

static license: string

Note:

Handshake Code and Organization ID

When you are using the online licenses, the license items can’t be used directly. You need to use either a “Handshake Code” or an “Organization ID” instead.

The “Handshake Code” refers to an array of license items. When an “Handshake Code” is set, these license items will be consumed in a preset order.

When an “Organization ID” is set, the default “Handshake Code” of the “Organization ID” will be used.

Generally, the first “Handshake Code” ever created for an organization is the default one. However, you can always configure another “Handshake Code” as the default.

“Handshake Codes” can be configured in the customer portal.

Code Snippet

Dynamsoft.DLR.LabelRecognizer.license =
  "YOUR-ORGANIZATION-ID or YOUR-HANDSHAKECODE or AN-OFFLINE-LICENSE or ANY-OTHER-TYPE-OF-SUPPORTED-LICENSE-STRING";
let scanner = await Dynamsoft.DLR.LabelRecognizer.createInstance();

For convenience, you can even set license in the script tag.

<script src="/dist/dlr.js" data-license=
  "YOUR-ORGANIZATION-ID or YOUR-HANDSHAKECODE or AN-OFFLINE-LICENSE or ANY-OTHER-TYPE-OF-SUPPORTED-LICENSE-STRING"></script>

createInstance

Creates a LabelRecognizer instance.

static createInstance(config?: any): Promise<LabelRecognizer>

Parameters

config : Configures how to create the instance. At present, it only specifies one of the built-in runtimeSettings templates which include

When recognizing from video input, add the prefix “video-“ for a slightly different template optimized for continuous frame recognition. For example, use video-passportMRZ to read the MRZ on passports with a camera.

Return value

A promise resolving to the created LabelRecognizer object.

Code Snippet

let recognizer = await Dynamsoft.DLR.LabelRecognizer.createInstance({
    runtimeSettings: "video-MRZ"
});
await recognizer.startScanning();

destroyContext

Destroys the LabelRecognizer instance. If your page needs to create a new instance from time to time, don’t forget to destroy unused old instances.

destroyContext(): void

Return value

A promise that resolves when the operation succeeds.

Code Snippet

let recognizer = await Dynamsoft.DLR.LabelRecognizer.createInstance();
// ... decode ...
recognizer.destroyContext();

isContextDestroyed

Returns whether the instance has been destroyed.

isContextDestroyed(): boolean

engineResourcePath

Specifies the path to find the engine(s). The property needs to be set before loadWasm. If not specified, the library will try to find the engine in the same location as the main JavaScript file (dlr.js).

static engineResourcePath: string

Code Snippet

Dynamsoft.DLR.LabelRecognizer.engineResourcePath = "https://cdn.jsdelivr.net/npm/dynamsoft-label-recognizer@2.2.11/dist/";
await Dynamsoft.DLR.LabelRecognizer.loadWasm();

loadWasm

Downloads and compiles the engine to get it loaded/ready for a LabelRecognizer instance to be created. You can call this API to silently set the operating environment of the library as soon as the page is loaded, avoiding unnecessary waiting time when using the library later.

If this API is not called beforehand, it will be called automatically when creating a LabelRecognizer instance.

static loadWasm(): Promise<void>

Code Snippet

window.addEventListener('DOMContentLoaded', (event) => {
    Dynamsoft.DLR.LabelRecognizer.loadWasm();
});

isWasmLoaded

Returns whether the engine is loaded/ready.

static isWasmLoaded(): boolean

getVersion

Returns the version of the library including the detailed version numbers of the engine and the main JavaScript code.

The engine version only valid after loadWasm has been called.

static getVersion(): string

Code Snippet

console.log(Dynamsoft.DLR.LabelRecognizer.getVersion());
// loading...(JS 2.2.0.20211011)
await Dynamsoft.DLR.LabelRecognizer.loadWasm();
console.log(Dynamsoft.DLR.LabelRecognizer.getVersion());
// 2.2.0.11051(JS 2.2.0.20211011)

detectEnvironment

Returns a report on the current running environments.

static detectEnvironment(): Promise<any>

Code Snippet

console.log(Dynamsoft.DLR.LabelRecognizer.detectEnvironment());
// {"wasm":true, "worker":true, "getUserMedia":true, "camera":true, 
// "browser":"Chrome", "version":90, "OS":"Windows"}