JavaScript API Reference
The primary class of the library is LabelRecognizer
. The following code snippets shows the basic usage.
- Recognize a still image
let labelRecognizer = await Dynamsoft.DLR.LabelRecognizer.createInstance();
let results = await labelRecognizer.recognize(imagePath);
for (let result of results) {
for (let lineResult of result.lineResults) {
console.log(lineResult.text);
}
}
- Recognize continuous video frames
let cameraEnhancer = await Dynamsoft.DCE.CameraEnhancer.createInstance();
await cameraEnhancer.setUIElement(document.getElementById('div-ui-container'));
let recognizer = await Dynamsoft.DLR.LabelRecognizer.createInstance();
recognizer.setImageSource(cameraEnhancer);
await recognizer.updateRuntimeSettingsFromString("video-MRZ");
recognizer.onImageRead = results => {
for (let result of results) {
for (let lineResult of result.lineResults) {
console.log(lineResult.text);
}
}
};
recognizer.startScanning(true);
The APIs for this class include
Initialization Control
The following static methods and properties help to set up the runtime environment for the library.
API Name | Description |
---|---|
engineResourcePath | Specifies the path from where the recognition engine and models, etc. can be loaded. |
loadWasm() | Loads the recognition engine and models. |
isWasmLoaded() | Returns whether the recognition engine and models have been loaded. |
getVersion() | Returns the version of the library. |
detectEnvironment() | Assess the running environment regarding the features the library requires to run. |
Create and Destroy Instances
API Name | Description |
---|---|
createInstance() | Creates a LabelRecognizer instance. |
destroyContext() | Destroies the LabelRecognizer instance. |
isContextDestroyed() | Returns whether the instance has been destroyed. |
License Control
API Name | Description |
---|---|
license | Use an alphanumeric string to specify the license. |
Recognition
Recognize Labels from Still Images
API Name | Description |
---|---|
recognize() | Decodes labels from an image. |
recognizeBase64String() | Decodes labels from a base64-encoded image (with or without MIME). |
recognizeUrl() | Decodes labels from an image specified by its URL. |
recognizeBuffer() | Decodes labels from raw image data. |
Recognize Labels from Video Frames
API Name | Description |
---|---|
setImageSource | Sets an image source for continous scanning. |
onUniqueRead | This event is triggered when a new, unduplicated label is found when scanning via video. |
onImageRead | This event is triggered after the library finishes scanning an image. |
onMRZRead | This event is triggered after the library finishes scanning a frame with the built-in templates passportMRZ , video-passportMRZ , visaMRZ , video-visaMRZ , MRZ or video-MRZ . |
onVINRead | This event is triggered after the library finishes scanning an image based on one of the built-in templates VIN , video-VIN , VIN_NA or video-VIN_NA . |
startScanning() | Starts continuous scanning of incoming images. |
stopScanning() | Stops continuous scanning. |
pauseScanning() | Pause continuous scanning but keep the video stream. |
resumeScanning() | Resumes continuous scanning. |
Settings
Scan Settings
API Name | Description |
---|---|
getScanSettings() | Returns the current scan settings. |
updateScanSettings() | Changes scan settings with the object passed in. |
Runtime Settings
API Name | Description |
---|---|
updateRuntimeSettingsFromString() | Updates runtime settings with a template represented by a JSON string. |
outputRuntimeSettingsToString() | Output the current runtime settings to a JSON string. |
updateReferenceRegionFromBarcodeResults() | Updates reference region which is defined with source type DLR_LST_BARCODE . |
Auxiliary
API Name | Description |
---|---|
ifSaveOriginalImageInACanvas | Whether to save the original image into a < canvas> element. |
getOriginalImageInACanvas() | Returns an HTMLCanvasElement that holds the original image. |
onResourcesLoadStarted | This event is triggered when the resource file (.data) for a particular template starts to load. |
onResourcesLoadProgress | This event is triggered multiple times when the resource file (.data) for a particular template is being loaded. |
onResourcesLoaded | This event is triggered when the resource file (.data) for a particular template finishes loading. |
Interfaces and Enumerations
In order to make the code more predictable and readable, the library defines a series of supporting interfaces and enumerations.
Interfaces
- DLRLineResult
- Point
- Quadrilateral
- DLRReferenceRegion
- DLRResult
- DLRRuntimeSettings
- ImageSource
- DSImage