html5-qrcode.ts
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/**
* @module
* HTML5 QR code & barcode scanning library.
* - Decode QR Code.
* - Decode different kinds of barcodes.
* - Decode using web cam, smart phone camera or using images on local file
* system.
*
* @author mebjas <minhazav@gmail.com>
*
* The word "QR Code" is registered trademark of DENSO WAVE INCORPORATED
* http://www.denso-wave.com/qrcode/faqpatent-e.html
*/
import {
QrcodeErrorCallback,
QrcodeSuccessCallback,
Logger,
BaseLoggger,
Html5QrcodeResultFactory,
Html5QrcodeErrorFactory,
Html5QrcodeSupportedFormats,
RobustQrcodeDecoderAsync,
isValidHtml5QrcodeSupportedFormats,
Html5QrcodeConstants,
Html5QrcodeResult,
isNullOrUndefined,
QrDimensions,
QrDimensionFunction
} from "./core";
import { Html5QrcodeStrings } from "./strings";
import { VideoConstraintsUtil } from "./utils";
import { Html5QrcodeShim } from "./code-decoder";
import { CameraFactory } from "./camera/factories";
import {
CameraDevice,
CameraCapabilities,
CameraRenderingOptions,
RenderedCamera,
RenderingCallbacks
} from "./camera/core";
import { CameraRetriever } from "./camera/retriever";
import { ExperimentalFeaturesConfig } from "./experimental-features";
import {
StateManagerProxy,
StateManagerFactory,
StateManagerTransaction,
Html5QrcodeScannerState
} from "./state-manager";
class Constants extends Html5QrcodeConstants {
//#region static constants
static DEFAULT_WIDTH = 300;
static DEFAULT_WIDTH_OFFSET = 2;
static FILE_SCAN_MIN_HEIGHT = 300;
static FILE_SCAN_HIDDEN_CANVAS_PADDING = 100;
static MIN_QR_BOX_SIZE = 50;
static SHADED_LEFT = 1;
static SHADED_RIGHT = 2;
static SHADED_TOP = 3;
static SHADED_BOTTOM = 4;
static SHADED_REGION_ELEMENT_ID = "qr-shaded-region";
static VERBOSE = false;
static BORDER_SHADER_DEFAULT_COLOR = "#ffffff";
static BORDER_SHADER_MATCH_COLOR = "rgb(90, 193, 56)";
//#endregion
}
/**
* Interface for configuring {@link Html5Qrcode} class instance.
*/
export interface Html5QrcodeConfigs {
/**
* Array of formats to support of type {@link Html5QrcodeSupportedFormats}.
*
* All invalid values would be ignored. If null or underfined all supported
* formats will be used for scanning. Unless you want to limit the scan to
* only certain formats or want to improve performance, you should not set
* this value.
*/
formatsToSupport?: Array<Html5QrcodeSupportedFormats> | undefined;
/**
* {@link BarcodeDetector} is being implemented by browsers at the moment.
* It has very limited browser support but as it gets available it could
* enable faster native code scanning experience.
*
* Set this flag to true, to enable using {@link BarcodeDetector} if
* supported. This is true by default.
*
* Documentations:
* - https://developer.mozilla.org/en-US/docs/Web/API/BarcodeDetector
* - https://web.dev/shape-detection/#barcodedetector
*/
useBarCodeDetectorIfSupported?: boolean | undefined;
/**
* Config for experimental features.
*
* Everything is false by default.
*/
experimentalFeatures?: ExperimentalFeaturesConfig | undefined;
}
/**
* Interface for full configuration of {@link Html5Qrcode}.
*
* Notes: Ideally we don't need to have two interfaces for this purpose, but
* since the public APIs before version 2.0.8 allowed passing a boolean verbose
* flag to constructor we need to allow users to pass Html5QrcodeFullConfig or
* boolean flag to be backward compatible.
* In future versions these two interfaces can be merged.
*/
export interface Html5QrcodeFullConfig extends Html5QrcodeConfigs {
/**
* If true, all logs would be printed to console. False by default.
*/
verbose: boolean | undefined;
}
/**
* Configuration type for scanning QR code with camera.
*/
export interface Html5QrcodeCameraScanConfig {
/**
* Optional, Expected framerate of qr code scanning. example `{ fps: 2 }` means the
* scanning would be done every `500 ms`.
*/
fps: number | undefined;
/**
* Optional, edge size, dimension or calculator function for QR scanning
* box, the value or computed value should be smaller than the width and
* height of the full region.
*
* This would make the scanner look like this:
* ----------------------
* |********************|
* |******,,,,,,,,,*****| <--- shaded region
* |******| |*****| <--- non shaded region would be
* |******| |*****| used for QR code scanning.
* |******|_______|*****|
* |********************|
* |********************|
* ----------------------
*
* Instance of {@link QrDimensions} can be passed to construct a non
* square rendering of scanner box. You can also pass in a function of type
* {@link QrDimensionFunction} that takes in the width and height of the
* video stream and return QR box size of type {@link QrDimensions}.
*
* If this value is not set, no shaded QR box will be rendered and the
* scanner will scan the entire area of video stream.
*/
qrbox?: number | QrDimensions | QrDimensionFunction | undefined;
/**
* Optional, Desired aspect ratio for the video feed. Ideal aspect ratios
* are 4:3 or 16:9. Passing very wrong aspect ratio could lead to video feed
* not showing up.
*/
aspectRatio?: number | undefined;
/**
* Optional, if `true` flipped QR Code won't be scanned. Only use this
* if you are sure the camera cannot give mirrored feed if you are facing
* performance constraints.
*/
disableFlip?: boolean | undefined;
/**
* Optional, @beta(this config is not well supported yet).
*
* Important: When passed this will override other parameters like
* 'cameraIdOrConfig' or configurations like 'aspectRatio'.
* 'videoConstraints' should be of type {@link MediaTrackConstraints} as
* defined in
* https://developer.mozilla.org/en-US/docs/Web/API/MediaTrackConstraints
* and is used to specify a variety of video or camera controls like:
* aspectRatio, facingMode, frameRate, etc.
*/
videoConstraints?: MediaTrackConstraints | undefined;
}
/**
* Internal implementation of {@link Html5QrcodeConfig} with util & factory
* methods.
*
* @hidden
*/
class InternalHtml5QrcodeConfig implements Html5QrcodeCameraScanConfig {
public readonly fps: number;
public readonly disableFlip: boolean;
public readonly qrbox: number | QrDimensions | QrDimensionFunction | undefined;
public readonly aspectRatio: number | undefined;
public readonly videoConstraints: MediaTrackConstraints | undefined;
private logger: Logger;
private constructor(
config: Html5QrcodeCameraScanConfig | undefined,
logger: Logger) {
this.logger = logger;
this.fps = Constants.SCAN_DEFAULT_FPS;
if (!config) {
this.disableFlip = Constants.DEFAULT_DISABLE_FLIP;
} else {
if (config.fps) {
this.fps = config.fps;
}
this.disableFlip = config.disableFlip === true;
this.qrbox = config.qrbox;
this.aspectRatio = config.aspectRatio;
this.videoConstraints = config.videoConstraints;
}
}
public isMediaStreamConstraintsValid(): boolean {
if (!this.videoConstraints) {
this.logger.logError(
"Empty videoConstraints", /* experimental= */ true);
return false;
}
return VideoConstraintsUtil.isMediaStreamConstraintsValid(
this.videoConstraints, this.logger);
}
public isShadedBoxEnabled(): boolean {
return !isNullOrUndefined(this.qrbox);
}
/**
* Create instance of {@link Html5QrcodeCameraScanConfig}.
*
* Create configuration by merging default and input settings.
*/
static create(config: Html5QrcodeCameraScanConfig | undefined, logger: Logger)
: InternalHtml5QrcodeConfig {
return new InternalHtml5QrcodeConfig(config, logger);
}
}
/** @hidden */
interface QrcodeRegionBounds {
x: number,
y: number,
width: number,
height: number
}
/**
* Low level APIs for building web based QR and Barcode Scanner.
*
* Supports APIs for camera as well as file based scanning.
*
* Depending of the configuration, the class will help render code
* scanning UI on the provided parent HTML container.
*/
export class Html5Qrcode {
//#region Private fields.
private readonly logger: Logger;
private readonly elementId: string;
private readonly verbose: boolean;
private readonly qrcode: RobustQrcodeDecoderAsync;
private shouldScan: boolean;
// Nullable elements
// TODO(mebjas): Reduce the state-fulness of this mammoth class, by splitting
// into independent classes for better separation of concerns and reducing
// error prone nature of a large stateful class.
private element: HTMLElement | null = null;
private canvasElement: HTMLCanvasElement | null = null;
private scannerPausedUiElement: HTMLDivElement | null = null;
private hasBorderShaders: boolean | null = null;
private borderShaders: Array<HTMLElement> | null = null;
private qrMatch: boolean | null = null;
private renderedCamera: RenderedCamera | null = null;
private foreverScanTimeout: any;
private qrRegion: QrcodeRegionBounds | null = null;
private context: CanvasRenderingContext2D | null = null;
private lastScanImageFile: string | null = null;
//#endregion
private stateManagerProxy: StateManagerProxy;
// TODO(mebjas): deprecate this.
/** @hidden */
public isScanning: boolean = false;
/**
* Initialize the code scanner.
*
* @param elementId Id of the HTML element.
* @param configOrVerbosityFlag optional, config object of type {@link
* Html5QrcodeFullConfig} or a boolean verbosity flag (to maintain backward
* compatibility). If nothing is passed, default values would be used.
* If a boolean value is used, it'll be used to set verbosity. Pass a
* config value to configure the Html5Qrcode scanner as per needs.
*
* Use of `configOrVerbosityFlag` as a boolean value is being
* deprecated since version 2.0.7.
*
* TODO(mebjas): Deprecate the verbosity boolean flag completely.
*/
public constructor(elementId: string,
configOrVerbosityFlag?: boolean | Html5QrcodeFullConfig | undefined) {
if (!document.getElementById(elementId)) {
throw `HTML Element with id=${elementId} not found`;
}
this.elementId = elementId;
this.verbose = false;
let experimentalFeatureConfig : ExperimentalFeaturesConfig | undefined;
let configObject: Html5QrcodeFullConfig | undefined;
if (typeof configOrVerbosityFlag == "boolean") {
this.verbose = configOrVerbosityFlag === true;
} else if (configOrVerbosityFlag) {
configObject = configOrVerbosityFlag;
this.verbose = configObject.verbose === true;
experimentalFeatureConfig = configObject.experimentalFeatures;
}
this.logger = new BaseLoggger(this.verbose);
this.qrcode = new Html5QrcodeShim(
this.getSupportedFormats(configOrVerbosityFlag),
this.getUseBarCodeDetectorIfSupported(configObject),
this.verbose,
this.logger);
this.foreverScanTimeout;
this.shouldScan = true;
this.stateManagerProxy = StateManagerFactory.create();
}
//#region start()
/**
* Start scanning QR codes or bar codes for a given camera.
*
* @param cameraIdOrConfig Identifier of the camera, it can either be the
* camera id retrieved from {@link Html5Qrcode#getCameras()} method or
* object with facing mode constraint.
* @param configuration Extra configurations to tune the code scanner.
* @param qrCodeSuccessCallback Callback called when an instance of a QR
* code or any other supported bar code is found.
* @param qrCodeErrorCallback Callback called in cases where no instance of
* QR code or any other supported bar code is found.
*
* @returns Promise for starting the scan. The Promise can fail if the user
* doesn't grant permission or some API is not supported by the browser.
*/
public start(
cameraIdOrConfig: string | MediaTrackConstraints,
configuration: Html5QrcodeCameraScanConfig | undefined,
qrCodeSuccessCallback: QrcodeSuccessCallback | undefined,
qrCodeErrorCallback: QrcodeErrorCallback | undefined,
): Promise<null> {
// Code will be consumed as javascript.
if (!cameraIdOrConfig) {
throw "cameraIdOrConfig is required";
}
if (!qrCodeSuccessCallback
|| typeof qrCodeSuccessCallback != "function") {
throw "qrCodeSuccessCallback is required and should be a function.";
}
let qrCodeErrorCallbackInternal: QrcodeErrorCallback;
if (qrCodeErrorCallback) {
qrCodeErrorCallbackInternal = qrCodeErrorCallback;
} else {
qrCodeErrorCallbackInternal
= this.verbose ? this.logger.log : () => {};
}
const internalConfig = InternalHtml5QrcodeConfig.create(
configuration, this.logger);
this.clearElement();
// Check if videoConstraints is passed and valid
let videoConstraintsAvailableAndValid = false;
if (internalConfig.videoConstraints) {
if (!internalConfig.isMediaStreamConstraintsValid()) {
this.logger.logError(
"'videoConstraints' is not valid 'MediaStreamConstraints, "
+ "it will be ignored.'",
/* experimental= */ true);
} else {
videoConstraintsAvailableAndValid = true;
}
}
const areVideoConstraintsEnabled = videoConstraintsAvailableAndValid;
// qr shaded box
const element = document.getElementById(this.elementId)!;
const rootElementWidth = element.clientWidth
? element.clientWidth : Constants.DEFAULT_WIDTH;
element.style.position = "relative";
this.shouldScan = true;
this.element = element;
const $this = this;
const toScanningStateChangeTransaction: StateManagerTransaction
= this.stateManagerProxy.startTransition(
Html5QrcodeScannerState.SCANNING);
return new Promise((resolve, reject) => {
const videoConstraints = areVideoConstraintsEnabled
? internalConfig.videoConstraints
: $this.createVideoConstraints(cameraIdOrConfig);
if (!videoConstraints) {
toScanningStateChangeTransaction.cancel();
reject("videoConstraints should be defined");
return;
}
let cameraRenderingOptions: CameraRenderingOptions = {};
if (!areVideoConstraintsEnabled || internalConfig.aspectRatio) {
cameraRenderingOptions.aspectRatio = internalConfig.aspectRatio;
}
let renderingCallbacks: RenderingCallbacks = {
onRenderSurfaceReady: (viewfinderWidth, viewfinderHeight) => {
$this.setupUi(
viewfinderWidth, viewfinderHeight, internalConfig);
$this.isScanning = true;
$this.foreverScan(
internalConfig,
qrCodeSuccessCallback,
qrCodeErrorCallbackInternal!);
}
};
// TODO(minhazav): Flatten this flow.
CameraFactory.failIfNotSupported().then((factory) => {
factory.create(videoConstraints).then((camera) => {
return camera.render(
this.element!, cameraRenderingOptions, renderingCallbacks)
.then((renderedCamera) => {
$this.renderedCamera = renderedCamera;
toScanningStateChangeTransaction.execute();
resolve(/* Void */ null);
})
.catch((error) => {
toScanningStateChangeTransaction.cancel();
reject(error);
});
}).catch((error) => {
toScanningStateChangeTransaction.cancel();
reject(Html5QrcodeStrings.errorGettingUserMedia(error));
});
}).catch((_) => {
toScanningStateChangeTransaction.cancel();
reject(Html5QrcodeStrings.cameraStreamingNotSupported());
});
});
}
//#endregion
//#region Other state related public APIs
/**
* Pauses the ongoing scan.
*
* @param shouldPauseVideo (Optional, default = false) If true the
* video will be paused.
*
* @throws error if method is called when scanner is not in scanning state.
*/
public pause(shouldPauseVideo?: boolean) {
if (!this.stateManagerProxy.isStrictlyScanning()) {
throw "Cannot pause, scanner is not scanning.";
}
this.stateManagerProxy.directTransition(Html5QrcodeScannerState.PAUSED);
this.showPausedState();
if (isNullOrUndefined(shouldPauseVideo) || shouldPauseVideo !== true) {
shouldPauseVideo = false;
}
if (shouldPauseVideo && this.renderedCamera) {
this.renderedCamera.pause();
}
}
/**
* Resumes the paused scan.
*
* If the video was previously paused by setting `shouldPauseVideo``
* to `true` in {@link Html5Qrcode#pause(shouldPauseVideo)}, calling
* this method will resume the video.
*
* Note: with this caller will start getting results in success and error
* callbacks.
*
* @throws error if method is called when scanner is not in paused state.
*/
public resume() {
if (!this.stateManagerProxy.isPaused()) {
throw "Cannot result, scanner is not paused.";
}
if (!this.renderedCamera) {
throw "renderedCamera doesn't exist while trying resume()";
}
const $this = this;
const transitionToScanning = () => {
$this.stateManagerProxy.directTransition(
Html5QrcodeScannerState.SCANNING);
$this.hidePausedState();
}
if (!this.renderedCamera.isPaused()) {
transitionToScanning();
return;
}
this.renderedCamera.resume(() => {
// Transition state, when the video playback has resumed.
transitionToScanning();
});
}
/**
* Gets state of the camera scan.
*
* @returns state of type {@link ScannerState}.
*/
public getState(): Html5QrcodeScannerState {
return this.stateManagerProxy.getState();
}
/**
* Stops streaming QR Code video and scanning.
*
* @returns Promise for safely closing the video stream.
*/
public stop(): Promise<void> {
if (!this.stateManagerProxy.isScanning()) {
throw "Cannot stop, scanner is not running or paused.";
}
const toStoppedStateTransaction: StateManagerTransaction
= this.stateManagerProxy.startTransition(
Html5QrcodeScannerState.NOT_STARTED);
this.shouldScan = false;
if (this.foreverScanTimeout) {
clearTimeout(this.foreverScanTimeout);
}
// Removes the shaded region if exists.
const removeQrRegion = () => {
if (!this.element) {
return;
}
let childElement = document.getElementById(Constants.SHADED_REGION_ELEMENT_ID);
if (childElement) {
this.element.removeChild(childElement);
}
};
let $this = this;
return this.renderedCamera!.close().then(() => {
$this.renderedCamera = null;
if ($this.element) {
$this.element.removeChild($this.canvasElement!);
$this.canvasElement = null;
}
removeQrRegion();
if ($this.qrRegion) {
$this.qrRegion = null;
}
if ($this.context) {
$this.context = null;
}
toStoppedStateTransaction.execute();
$this.hidePausedState();
$this.isScanning = false;
return Promise.resolve();
});
}
//#endregion
//#region File scan related public APIs
/**
* Scans an Image File for QR Code.
*
* This feature is mutually exclusive to camera-based scanning, you should
* call stop() if the camera-based scanning was ongoing.
*
* @param imageFile a local file with Image content.
* @param showImage if true the Image will be rendered on given
* element.
*
* @returns Promise with decoded QR code string on success and error message
* on failure. Failure could happen due to different reasons:
* 1. QR Code decode failed because enough patterns not found in image.
* 2. Input file was not image or unable to load the image or other image
* load errors.
*/
public scanFile(
imageFile: File, /* default=true */ showImage?: boolean): Promise<string> {
return this.scanFileV2(imageFile, showImage)
.then((html5qrcodeResult) => html5qrcodeResult.decodedText);
}
/**
* Scans an Image File for QR Code & returns {@link Html5QrcodeResult}.
*
* This feature is mutually exclusive to camera-based scanning, you should
* call stop() if the camera-based scanning was ongoing.
*
* @param imageFile a local file with Image content.
* @param showImage if true the Image will be rendered on given
* element.
*
* @returns Promise which resolves with result of type
* {@link Html5QrcodeResult}.
*
* @beta This is a WIP method, it's available as a public method but not
* documented.
* TODO(mebjas): Replace scanFile with ScanFileV2
*/
public scanFileV2(imageFile: File, /* default=true */ showImage?: boolean)
: Promise<Html5QrcodeResult> {
if (!imageFile || !(imageFile instanceof File)) {
throw "imageFile argument is mandatory and should be instance "
+ "of File. Use 'event.target.files[0]'.";
}
if (isNullOrUndefined(showImage)) {
showImage = true;
}
if (!this.stateManagerProxy.canScanFile()) {
throw "Cannot start file scan - ongoing camera scan";
}
return new Promise((resolve, reject) => {
this.possiblyCloseLastScanImageFile();
this.clearElement();
this.lastScanImageFile = URL.createObjectURL(imageFile);
const inputImage = new Image;
inputImage.onload = () => {
const imageWidth = inputImage.width;
const imageHeight = inputImage.height;
const element = document.getElementById(this.elementId)!;
const containerWidth = element.clientWidth
? element.clientWidth : Constants.DEFAULT_WIDTH;
// No default height anymore.
const containerHeight = Math.max(
element.clientHeight ? element.clientHeight : imageHeight,
Constants.FILE_SCAN_MIN_HEIGHT);
const config = this.computeCanvasDrawConfig(
imageWidth, imageHeight, containerWidth, containerHeight);
if (showImage) {
const visibleCanvas = this.createCanvasElement(
containerWidth, containerHeight, "qr-canvas-visible");
visibleCanvas.style.display = "inline-block";
element.appendChild(visibleCanvas);
const context = visibleCanvas.getContext("2d");
if (!context) {
throw "Unable to get 2d context from canvas";
}
context.canvas.width = containerWidth;
context.canvas.height = containerHeight;
// More reference
// https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/drawImage
context.drawImage(
inputImage,
/* sx= */ 0,
/* sy= */ 0,
/* sWidth= */ imageWidth,
/* sHeight= */ imageHeight,
/* dx= */ config.x,
/* dy= */ config.y,
/* dWidth= */ config.width,
/* dHeight= */ config.height);
}
// Hidden canvas should be at-least as big as the image.
// This could get really troublesome for large images like 12MP
// images or 48MP images captured on phone.
let padding = Constants.FILE_SCAN_HIDDEN_CANVAS_PADDING;
let hiddenImageWidth = Math.max(inputImage.width, config.width);
let hiddenImageHeight = Math.max(inputImage.height, config.height);
let hiddenCanvasWidth = hiddenImageWidth + 2 * padding;
let hiddenCanvasHeight = hiddenImageHeight + 2 * padding;
// Try harder for file scan.
// TODO(minhazav): Fallback to mirroring, 90 degree rotation and
// color inversion.
const hiddenCanvas = this.createCanvasElement(
hiddenCanvasWidth, hiddenCanvasHeight);
element.appendChild(hiddenCanvas);
const context = hiddenCanvas.getContext("2d");
if (!context) {
throw "Unable to get 2d context from canvas";
}
context.canvas.width = hiddenCanvasWidth;
context.canvas.height = hiddenCanvasHeight;
context.drawImage(
inputImage,
/* sx= */ 0,
/* sy= */ 0,
/* sWidth= */ imageWidth,
/* sHeight= */ imageHeight,
/* dx= */ padding,
/* dy= */ padding,
/* dWidth= */ hiddenImageWidth,
/* dHeight= */ hiddenImageHeight);
try {
this.qrcode.decodeRobustlyAsync(hiddenCanvas)
.then((result) => {
resolve(
Html5QrcodeResultFactory.createFromQrcodeResult(
result));
})
.catch(reject);
} catch (exception) {
reject(`QR code parse error, error = ${exception}`);
}
};
inputImage.onerror = reject;
inputImage.onabort = reject;
inputImage.onstalled = reject;
inputImage.onsuspend = reject;
inputImage.src = URL.createObjectURL(imageFile);
});
}
//#endregion
/**
* Clears the existing canvas.
*
* Note: in case of ongoing web cam based scan, it needs to be explicitly
* closed before calling this method, else it will throw exception.
*/
public clear(): void {
this.clearElement();
}
/**
* Returns list of {@link CameraDevice} supported by the device.
*
* @returns array of camera devices on success.
*/
public static getCameras(): Promise<Array<CameraDevice>> {
return CameraRetriever.retrieve();
}
/**
* Returns the capabilities of the running video track.
*
* Read more: https://developer.mozilla.org/en-US/docs/Web/API/MediaStreamTrack/getConstraints
*
* Important:
* 1. Must be called only if the camera based scanning is in progress.
*
* @returns capabilities of the running camera.
* @throws error if the scanning is not in running state.
*/
public getRunningTrackCapabilities(): MediaTrackCapabilities {
return this.getRenderedCameraOrFail().getRunningTrackCapabilities();
}
/**
* Returns the object containing the current values of each constrainable
* property of the running video track.
*
* Read more: https://developer.mozilla.org/en-US/docs/Web/API/MediaStreamTrack/getSettings
*
* Important:
* 1. Must be called only if the camera based scanning is in progress.
*
* @returns settings of the running media track.
*
* @throws error if the scanning is not in running state.
*/
public getRunningTrackSettings(): MediaTrackSettings {
return this.getRenderedCameraOrFail().getRunningTrackSettings();
}
/**
* Returns {@link CameraCapabilities} of the running video track.
*
* TODO(minhazav): Document this API, currently hidden.
*
* @returns capabilities of the running camera.
* @throws error if the scanning is not in running state.
*/
public getRunningTrackCameraCapabilities(): CameraCapabilities {
return this.getRenderedCameraOrFail().getCapabilities();
}
/**
* Apply a video constraints on running video track from camera.
*
* Important:
* 1. Must be called only if the camera based scanning is in progress.
* 2. Changing aspectRatio while scanner is running is not yet supported.
*
* @param {MediaTrackConstraints} specifies a variety of video or camera
* controls as defined in
* https://developer.mozilla.org/en-US/docs/Web/API/MediaTrackConstraints
* @returns a Promise which succeeds if the passed constraints are applied,
* fails otherwise.
* @throws error if the scanning is not in running state.
*/
public applyVideoConstraints(videoConstaints: MediaTrackConstraints)
: Promise<void> {
if (!videoConstaints) {
throw "videoConstaints is required argument.";
} else if (!VideoConstraintsUtil.isMediaStreamConstraintsValid(
videoConstaints, this.logger)) {
throw "invalid videoConstaints passed, check logs for more details";
}
return this.getRenderedCameraOrFail().applyVideoConstraints(
videoConstaints);
}
//#region Private methods.
private getRenderedCameraOrFail() {
if (this.renderedCamera == null) {
throw "Scanning is not in running state, call this API only when"
+ " QR code scanning using camera is in running state.";
}
return this.renderedCamera!;
}
/**
* Construct list of supported formats and returns based on input args.
* `configOrVerbosityFlag` optional, config object of type {@link
* Html5QrcodeFullConfig} or a boolean verbosity flag (to maintain backward
* compatibility). If nothing is passed, default values would be used.
* If a boolean value is used, it'll be used to set verbosity. Pass a
* config value to configure the Html5Qrcode scanner as per needs.
*
* Use of `configOrVerbosityFlag` as a boolean value is being
* deprecated since version 2.0.7.
*
* TODO(mebjas): Deprecate the verbosity boolean flag completely.
*/
private getSupportedFormats(
configOrVerbosityFlag: boolean | Html5QrcodeFullConfig | undefined)
: Array<Html5QrcodeSupportedFormats> {
const allFormats: Array<Html5QrcodeSupportedFormats> = [
Html5QrcodeSupportedFormats.QR_CODE,
Html5QrcodeSupportedFormats.AZTEC,
Html5QrcodeSupportedFormats.CODABAR,
Html5QrcodeSupportedFormats.CODE_39,
Html5QrcodeSupportedFormats.CODE_93,
Html5QrcodeSupportedFormats.CODE_128,
Html5QrcodeSupportedFormats.DATA_MATRIX,
Html5QrcodeSupportedFormats.MAXICODE,
Html5QrcodeSupportedFormats.ITF,
Html5QrcodeSupportedFormats.EAN_13,
Html5QrcodeSupportedFormats.EAN_8,
Html5QrcodeSupportedFormats.PDF_417,
Html5QrcodeSupportedFormats.RSS_14,
Html5QrcodeSupportedFormats.RSS_EXPANDED,
Html5QrcodeSupportedFormats.UPC_A,
Html5QrcodeSupportedFormats.UPC_E,
Html5QrcodeSupportedFormats.UPC_EAN_EXTENSION,
];
if (!configOrVerbosityFlag
|| typeof configOrVerbosityFlag == "boolean") {
return allFormats;
}
if (!configOrVerbosityFlag.formatsToSupport) {
return allFormats;
}
if (!Array.isArray(configOrVerbosityFlag.formatsToSupport)) {
throw "configOrVerbosityFlag.formatsToSupport should be undefined "
+ "or an array.";
}
if (configOrVerbosityFlag.formatsToSupport.length === 0) {
throw "Atleast 1 formatsToSupport is needed.";
}
const supportedFormats: Array<Html5QrcodeSupportedFormats> = [];
for (const format of configOrVerbosityFlag.formatsToSupport) {
if (isValidHtml5QrcodeSupportedFormats(format)) {
supportedFormats.push(format);
} else {
this.logger.warn(
`Invalid format: ${format} passed in config, ignoring.`);
}
}
if (supportedFormats.length === 0) {
throw "None of formatsToSupport match supported values.";
}
return supportedFormats;
}
/**
* Returns `true` if `useBarCodeDetectorIfSupported` is
* enabled in the config.
*/
/*eslint complexity: ["error", 10]*/
private getUseBarCodeDetectorIfSupported(
config: Html5QrcodeConfigs | undefined) : boolean {
// Default value is true.
if (isNullOrUndefined(config)) {
return true;
}
if (!isNullOrUndefined(config!.useBarCodeDetectorIfSupported)) {
// Default value is false.
return config!.useBarCodeDetectorIfSupported !== false;
}
if (isNullOrUndefined(config!.experimentalFeatures)) {
return true;
}
let experimentalFeatures = config!.experimentalFeatures!;
if (isNullOrUndefined(
experimentalFeatures.useBarCodeDetectorIfSupported)) {
return true;
}
return experimentalFeatures.useBarCodeDetectorIfSupported !== false;
}
/**
* Validates if the passed config for qrbox is correct.
*/
private validateQrboxSize(
viewfinderWidth: number,
viewfinderHeight: number,
internalConfig: InternalHtml5QrcodeConfig) {
const qrboxSize = internalConfig.qrbox!;
this.validateQrboxConfig(qrboxSize);
let qrDimensions = this.toQrdimensions(
viewfinderWidth, viewfinderHeight, qrboxSize);
const validateMinSize = (size: number) => {
if (size < Constants.MIN_QR_BOX_SIZE) {
throw "minimum size of 'config.qrbox' dimension value is"
+ ` ${Constants.MIN_QR_BOX_SIZE}px.`;
}
};
/**
* The 'config.qrbox.width' shall be overriden if it's larger than the
* width of the root element.
*
* Based on the verbosity settings, this will be logged to the logger.
*
* @param configWidth the width of qrbox set by users in the config.
*/
const correctWidthBasedOnRootElementSize = (configWidth: number) => {
if (configWidth > viewfinderWidth) {
this.logger.warn("`qrbox.width` or `qrbox` is larger than the"
+ " width of the root element. The width will be truncated"
+ " to the width of root element.");
configWidth = viewfinderWidth;
}
return configWidth;
};
validateMinSize(qrDimensions.width);
validateMinSize(qrDimensions.height);
qrDimensions.width = correctWidthBasedOnRootElementSize(
qrDimensions.width);
// Note: In this case if the height of the qrboxSize turns out to be
// greater than the height of the root element (which should later be
// based on the aspect ratio of the camera stream), it would be silently
// ignored with a warning.
}
/**
* Validates if the `qrboxSize` is a valid value.
*
* It's expected to be either a number or of type {@link QrDimensions}.
*/
private validateQrboxConfig(
qrboxSize: number | QrDimensions | QrDimensionFunction) {
if (typeof qrboxSize === "number") {
return;
}
if (typeof qrboxSize === "function") {
// This is a valid format.
return;
}
// Alternatively, the config is expected to be of type QrDimensions.
if (qrboxSize.width === undefined || qrboxSize.height === undefined) {
throw "Invalid instance of QrDimensions passed for "
+ "'config.qrbox'. Both 'width' and 'height' should be set.";
}
}
/**
* Possibly converts `qrboxSize` to an object of type
* {@link QrDimensions}.
*/
private toQrdimensions(
viewfinderWidth: number,
viewfinderHeight: number,
qrboxSize: number | QrDimensions | QrDimensionFunction): QrDimensions {
if (typeof qrboxSize === "number") {
return { width: qrboxSize, height: qrboxSize};
} else if (typeof qrboxSize === "function") {
try {
return qrboxSize(viewfinderWidth, viewfinderHeight);
} catch (error) {
throw new Error(
"qrbox config was passed as a function but it failed with "
+ "unknown error" + error);
}
}
return qrboxSize;
}
//#region Documented private methods for camera based scanner.
/**
* Setups the UI elements, changes the state of this class.
*
* @param viewfinderWidth derived width of viewfinder.
* @param viewfinderHeight derived height of viewfinder.
*/
private setupUi(
viewfinderWidth: number,
viewfinderHeight: number,
internalConfig: InternalHtml5QrcodeConfig): void {
// Validate before insertion
if (internalConfig.isShadedBoxEnabled()) {
this.validateQrboxSize(
viewfinderWidth, viewfinderHeight, internalConfig);
}
// If `qrbox` size is not set, it will default to the dimensions of the
// viewfinder.
const qrboxSize = isNullOrUndefined(internalConfig.qrbox) ?
{width: viewfinderWidth, height: viewfinderHeight}: internalConfig.qrbox!;
this.validateQrboxConfig(qrboxSize);
let qrDimensions = this.toQrdimensions(viewfinderWidth, viewfinderHeight, qrboxSize);
if (qrDimensions.height > viewfinderHeight) {
this.logger.warn("[Html5Qrcode] config.qrbox has height that is"
+ "greater than the height of the video stream. Shading will be"
+ " ignored");
}
const shouldShadingBeApplied
= internalConfig.isShadedBoxEnabled()
&& qrDimensions.height <= viewfinderHeight;
const defaultQrRegion: QrcodeRegionBounds = {
x: 0,
y: 0,
width: viewfinderWidth,
height: viewfinderHeight
};
const qrRegion = shouldShadingBeApplied
? this.getShadedRegionBounds(viewfinderWidth, viewfinderHeight, qrDimensions)
: defaultQrRegion;
const canvasElement = this.createCanvasElement(
qrRegion.width, qrRegion.height);
// Tell user agent that this canvas will be read frequently.
// More info:
// https://html.spec.whatwg.org/multipage/canvas.html#concept-canvas-will-read-frequently
const contextAttributes: any = { willReadFrequently: true };
// Casting canvas to any, as Microsoft's interface definition hasn't
// caught up with latest definition for 'CanvasRenderingContext2DSettings'.
const context: CanvasRenderingContext2D
= (<any>canvasElement).getContext("2d", contextAttributes)!;
context.canvas.width = qrRegion.width;
context.canvas.height = qrRegion.height;
// Insert the canvas
this.element!.append(canvasElement);
if (shouldShadingBeApplied) {
this.possiblyInsertShadingElement(
this.element!, viewfinderWidth, viewfinderHeight, qrDimensions);
}
this.createScannerPausedUiElement(this.element!);
// Update local states
this.qrRegion = qrRegion;
this.context = context;
this.canvasElement = canvasElement;
}
// TODO(mebjas): Convert this to a standard message viewer.
private createScannerPausedUiElement(rootElement: HTMLElement) {
const scannerPausedUiElement = document.createElement("div");
scannerPausedUiElement.innerText = Html5QrcodeStrings.scannerPaused();
scannerPausedUiElement.style.display = "none";
scannerPausedUiElement.style.position = "absolute";
scannerPausedUiElement.style.top = "0px";
scannerPausedUiElement.style.zIndex = "1";
scannerPausedUiElement.style.background = "rgba(9, 9, 9, 0.46)";
scannerPausedUiElement.style.color = "#FFECEC";
scannerPausedUiElement.style.textAlign = "center";
scannerPausedUiElement.style.width = "100%";
rootElement.appendChild(scannerPausedUiElement);
this.scannerPausedUiElement = scannerPausedUiElement;
}
/**
* Scans current context using the qrcode library.
*
* <p>This method call would result in callback being triggered by the
* qrcode library. This method also handles the border coloring.
*
* @returns true if scan match is found, false otherwise.
*/
private scanContext(
qrCodeSuccessCallback: QrcodeSuccessCallback,
qrCodeErrorCallback: QrcodeErrorCallback
): Promise<boolean> {
if (this.stateManagerProxy.isPaused()) {
return Promise.resolve(false);
}
return this.qrcode.decodeAsync(this.canvasElement!)
.then((result) => {
qrCodeSuccessCallback(
result.text,
Html5QrcodeResultFactory.createFromQrcodeResult(
result));
this.possiblyUpdateShaders(/* qrMatch= */ true);
return true;
}).catch((error) => {
this.possiblyUpdateShaders(/* qrMatch= */ false);
let errorMessage = Html5QrcodeStrings.codeParseError(error);
qrCodeErrorCallback(
errorMessage, Html5QrcodeErrorFactory.createFrom(errorMessage));
return false;
});
}
/**
* Forever scanning method.
*/
private foreverScan(
internalConfig: InternalHtml5QrcodeConfig,
qrCodeSuccessCallback: QrcodeSuccessCallback,
qrCodeErrorCallback: QrcodeErrorCallback) {
if (!this.shouldScan) {
// Stop scanning.
return;
}
if (!this.renderedCamera) {
return;
}
// There is difference in size of rendered video and one that is
// considered by the canvas. Need to account for scaling factor.
const videoElement = this.renderedCamera!.getSurface();
const widthRatio
= videoElement.videoWidth / videoElement.clientWidth;
const heightRatio
= videoElement.videoHeight / videoElement.clientHeight;
if (!this.qrRegion) {
throw "qrRegion undefined when localMediaStream is ready.";
}
const sWidthOffset = this.qrRegion.width * widthRatio;
const sHeightOffset = this.qrRegion.height * heightRatio;
const sxOffset = this.qrRegion.x * widthRatio;
const syOffset = this.qrRegion.y * heightRatio;
// Only decode the relevant area, ignore the shaded area,
// More reference:
// https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/drawImage
this.context!.drawImage(
videoElement,
/* sx= */ sxOffset,
/* sy= */ syOffset,
/* sWidth= */ sWidthOffset,
/* sHeight= */ sHeightOffset,
/* dx= */ 0,
/* dy= */ 0,
/* dWidth= */ this.qrRegion.width,
/* dHeight= */ this.qrRegion.height);
const triggerNextScan = () => {
this.foreverScanTimeout = setTimeout(() => {
this.foreverScan(
internalConfig, qrCodeSuccessCallback, qrCodeErrorCallback);
}, this.getTimeoutFps(internalConfig.fps));
};
// Try scanning normal frame and in case of failure, scan
// the inverted context if not explictly disabled.
// TODO(mebjas): Move this logic to decoding library.
this.scanContext(qrCodeSuccessCallback, qrCodeErrorCallback)
.then((isSuccessfull) => {
// Previous scan failed and disableFlip is off.
if (!isSuccessfull && internalConfig.disableFlip !== true) {
this.context!.translate(this.context!.canvas.width, 0);
this.context!.scale(-1, 1);
this.scanContext(qrCodeSuccessCallback, qrCodeErrorCallback)
.finally(() => {
triggerNextScan();
});
} else {
triggerNextScan();
}
}).catch((error) => {
this.logger.logError(
"Error happend while scanning context", error);
triggerNextScan();
});
}
private createVideoConstraints(
cameraIdOrConfig: string | MediaTrackConstraints)
: MediaTrackConstraints | undefined {
if (typeof cameraIdOrConfig == "string") {
// If it's a string it should be camera device Id.
return { deviceId: { exact: cameraIdOrConfig } };
} else if (typeof cameraIdOrConfig == "object") {
const facingModeKey = "facingMode";
const deviceIdKey = "deviceId";
const allowedFacingModeValues
= { "user" : true, "environment" : true};
const exactKey = "exact";
const isValidFacingModeValue = (value: string) => {
if (value in allowedFacingModeValues) {
// Valid config
return true;
} else {
// Invalid config
throw "config has invalid 'facingMode' value = "
+ `'${value}'`;
}
};
const keys = Object.keys(cameraIdOrConfig);
if (keys.length !== 1) {
throw "'cameraIdOrConfig' object should have exactly 1 key,"
+ ` if passed as an object, found ${keys.length} keys`;
}
const key:string = Object.keys(cameraIdOrConfig)[0];
if (key !== facingModeKey && key !== deviceIdKey) {
throw `Only '${facingModeKey}' and '${deviceIdKey}' `
+ " are supported for 'cameraIdOrConfig'";
}
if (key === facingModeKey) {
/**
* Supported scenarios:
* - { facingMode: "user" }
* - { facingMode: "environment" }
* - { facingMode: { exact: "environment" } }
* - { facingMode: { exact: "user" } }
*/
const facingMode: any = cameraIdOrConfig.facingMode;
if (typeof facingMode == "string") {
if (isValidFacingModeValue(facingMode)) {
return { facingMode: facingMode };
}
} else if (typeof facingMode == "object") {
if (exactKey in facingMode) {
if (isValidFacingModeValue(facingMode[`${exactKey}`])) {
return {
facingMode: {
exact: facingMode[`${exactKey}`]
}
};
}
} else {
throw "'facingMode' should be string or object with"
+ ` ${exactKey} as key.`;
}
} else {
const type = (typeof facingMode);
throw `Invalid type of 'facingMode' = ${type}`;
}
} else {
/**
* key == deviceIdKey; Supported scenarios:
* - { deviceId: { exact: "a76afe74e95e3.....38627b3bde" }
* - { deviceId: "a76afe74e95e3....065c9cd89438627b3bde" }
*/
const deviceId: any = cameraIdOrConfig.deviceId;
if (typeof deviceId == "string") {
return { deviceId: deviceId };
} else if (typeof deviceId == "object") {
if (exactKey in deviceId) {
return {
deviceId : { exact: deviceId[`${exactKey}`] }
};
} else {
throw "'deviceId' should be string or object with"
+ ` ${exactKey} as key.`;
}
} else {
const type = (typeof deviceId);
throw `Invalid type of 'deviceId' = ${type}`;
}
}
}
// invalid type
const type = (typeof cameraIdOrConfig);
throw `Invalid type of 'cameraIdOrConfig' = ${type}`;
}
//#endregion
//#region Documented private methods for file based scanner.
private computeCanvasDrawConfig(
imageWidth: number,
imageHeight: number,
containerWidth: number,
containerHeight: number): QrcodeRegionBounds {
if (imageWidth <= containerWidth
&& imageHeight <= containerHeight) {
// no downsampling needed.
const xoffset = (containerWidth - imageWidth) / 2;
const yoffset = (containerHeight - imageHeight) / 2;
return {
x: xoffset,
y: yoffset,
width: imageWidth,
height: imageHeight
};
} else {
const formerImageWidth = imageWidth;
const formerImageHeight = imageHeight;
if (imageWidth > containerWidth) {
imageHeight = (containerWidth / imageWidth) * imageHeight;
imageWidth = containerWidth;
}
if (imageHeight > containerHeight) {
imageWidth = (containerHeight / imageHeight) * imageWidth;
imageHeight = containerHeight;
}
this.logger.log(
"Image downsampled from "
+ `${formerImageWidth}X${formerImageHeight}`
+ ` to ${imageWidth}X${imageHeight}.`);
return this.computeCanvasDrawConfig(
imageWidth, imageHeight, containerWidth, containerHeight);
}
}
//#endregion
private clearElement(): void {
if (this.stateManagerProxy.isScanning()) {
throw "Cannot clear while scan is ongoing, close it first.";
}
const element = document.getElementById(this.elementId);
if (element) {
element.innerHTML = "";
}
}
private possiblyUpdateShaders(qrMatch: boolean) {
if (this.qrMatch === qrMatch) {
return;
}
if (this.hasBorderShaders
&& this.borderShaders
&& this.borderShaders.length) {
this.borderShaders.forEach((shader) => {
shader.style.backgroundColor = qrMatch
? Constants.BORDER_SHADER_MATCH_COLOR
: Constants.BORDER_SHADER_DEFAULT_COLOR;
});
}
this.qrMatch = qrMatch;
}
private possiblyCloseLastScanImageFile() {
if (this.lastScanImageFile) {
URL.revokeObjectURL(this.lastScanImageFile);
this.lastScanImageFile = null;
}
}
private createCanvasElement(
width: number, height: number, customId?: string): HTMLCanvasElement {
const canvasWidth = width;
const canvasHeight = height;
const canvasElement = document.createElement("canvas");
canvasElement.style.width = `${canvasWidth}px`;
canvasElement.style.height = `${canvasHeight}px`;
canvasElement.style.display = "none";
canvasElement.id = isNullOrUndefined(customId)
? "qr-canvas" : customId!;
return canvasElement;
}
private getShadedRegionBounds(
width: number, height: number, qrboxSize: QrDimensions)
: QrcodeRegionBounds {
if (qrboxSize.width > width || qrboxSize.height > height) {
throw "'config.qrbox' dimensions should not be greater than the "
+ "dimensions of the root HTML element.";
}
return {
x: (width - qrboxSize.width) / 2,
y: (height - qrboxSize.height) / 2,
width: qrboxSize.width,
height: qrboxSize.height
};
}
private possiblyInsertShadingElement(
element: HTMLElement,
width: number,
height: number,
qrboxSize: QrDimensions) {
if ((width - qrboxSize.width) < 1 || (height - qrboxSize.height) < 1) {
return;
}
const shadingElement = document.createElement("div");
shadingElement.style.position = "absolute";
const rightLeftBorderSize = (width - qrboxSize.width) / 2;
const topBottomBorderSize = (height - qrboxSize.height) / 2;
shadingElement.style.borderLeft
= `${rightLeftBorderSize}px solid rgba(0, 0, 0, 0.48)`;
shadingElement.style.borderRight
= `${rightLeftBorderSize}px solid rgba(0, 0, 0, 0.48)`;
shadingElement.style.borderTop
= `${topBottomBorderSize}px solid rgba(0, 0, 0, 0.48)`;
shadingElement.style.borderBottom
= `${topBottomBorderSize}px solid rgba(0, 0, 0, 0.48)`;
shadingElement.style.boxSizing = "border-box";
shadingElement.style.top = "0px";
shadingElement.style.bottom = "0px";
shadingElement.style.left = "0px";
shadingElement.style.right = "0px";
shadingElement.id = `${Constants.SHADED_REGION_ELEMENT_ID}`;
// Check if div is too small for shadows. As there are two 5px width
// borders the needs to have a size above 10px.
if ((width - qrboxSize.width) < 11
|| (height - qrboxSize.height) < 11) {
this.hasBorderShaders = false;
} else {
const smallSize = 5;
const largeSize = 40;
this.insertShaderBorders(
shadingElement,
/* width= */ largeSize,
/* height= */ smallSize,
/* top= */ -smallSize,
/* bottom= */ null,
/* side= */ 0,
/* isLeft= */ true);
this.insertShaderBorders(
shadingElement,
/* width= */ largeSize,
/* height= */ smallSize,
/* top= */ -smallSize,
/* bottom= */ null,
/* side= */ 0,
/* isLeft= */ false);
this.insertShaderBorders(
shadingElement,
/* width= */ largeSize,
/* height= */ smallSize,
/* top= */ null,
/* bottom= */ -smallSize,
/* side= */ 0,
/* isLeft= */ true);
this.insertShaderBorders(
shadingElement,
/* width= */ largeSize,
/* height= */ smallSize,
/* top= */ null,
/* bottom= */ -smallSize,
/* side= */ 0,
/* isLeft= */ false);
this.insertShaderBorders(
shadingElement,
/* width= */ smallSize,
/* height= */ largeSize + smallSize,
/* top= */ -smallSize,
/* bottom= */ null,
/* side= */ -smallSize,
/* isLeft= */ true);
this.insertShaderBorders(
shadingElement,
/* width= */ smallSize,
/* height= */ largeSize + smallSize,
/* top= */ null,
/* bottom= */ -smallSize,
/* side= */ -smallSize,
/* isLeft= */ true);
this.insertShaderBorders(
shadingElement,
/* width= */ smallSize,
/* height= */ largeSize + smallSize,
/* top= */ -smallSize,
/* bottom= */ null,
/* side= */ -smallSize,
/* isLeft= */ false);
this.insertShaderBorders(
shadingElement,
/* width= */ smallSize,
/* height= */ largeSize + smallSize,
/* top= */ null,
/* bottom= */ -smallSize,
/* side= */ -smallSize,
/* isLeft= */ false);
this.hasBorderShaders = true;
}
element.append(shadingElement);
}
private insertShaderBorders(
shaderElem: HTMLDivElement,
width: number,
height: number,
top: number | null,
bottom: number | null,
side: number,
isLeft: boolean) {
const elem = document.createElement("div");
elem.style.position = "absolute";
elem.style.backgroundColor = Constants.BORDER_SHADER_DEFAULT_COLOR;
elem.style.width = `${width}px`;
elem.style.height = `${height}px`;
if (top !== null) {
elem.style.top = `${top}px`;
}
if (bottom !== null) {
elem.style.bottom = `${bottom}px`;
}
if (isLeft) {
elem.style.left = `${side}px`;
} else {
elem.style.right = `${side}px`;
}
if (!this.borderShaders) {
this.borderShaders = [];
}
this.borderShaders.push(elem);
shaderElem.appendChild(elem);
}
private showPausedState() {
if (!this.scannerPausedUiElement) {
throw "[internal error] scanner paused UI element not found";
}
this.scannerPausedUiElement.style.display = "block";
}
private hidePausedState() {
if (!this.scannerPausedUiElement) {
throw "[internal error] scanner paused UI element not found";
}
this.scannerPausedUiElement.style.display = "none";
}
private getTimeoutFps(fps: number) {
return 1000 / fps;
}
//#endregion
}