qr-scanner/qr-scanner.min.js

'use strict';export default class QrScanner{constructor(video,onDecode,canvasSize=QrScanner.DEFAULT_CANVAS_SIZE){this.$video=video;this.$canvas=document.createElement("canvas");this._onDecode=onDecode;this._active=false;this.$canvas.width=canvasSize;this.$canvas.height=canvasSize;this._sourceRect={x:0,y:0,width:canvasSize,height:canvasSize};this.$video.addEventListener("canplay",()=>this._updateSourceRect());this.$video.addEventListener("play",()=>{this._updateSourceRect();this._scanFrame()},false);
this._qrWorker=new Worker("/qr-scanner/qr-scanner-worker.min.js")}_updateSourceRect(){const smallestDimension=Math.min(this.$video.videoWidth,this.$video.videoHeight);const sourceRectSize=Math.round(2/3*smallestDimension);this._sourceRect.width=this._sourceRect.height=sourceRectSize;this._sourceRect.x=(this.$video.videoWidth-sourceRectSize)/2;this._sourceRect.y=(this.$video.videoHeight-sourceRectSize)/2}_scanFrame(){if(this.$video.paused||this.$video.ended)return false;requestAnimationFrame(()=>{QrScanner.scanImage(this.$video,
this._sourceRect,this._qrWorker,this.$canvas,true).then(this._onDecode,(error)=>{if(error!=="QR code not found.")console.error(error)}).then(()=>this._scanFrame())})}set active(active){if(active&&!this._active){this._cameraOn();this._active=true}else{this._cameraOff();this._active=false}}_getCameraStream(facingMode,exact=false){const constraintsToTry=[{width:{min:1024}},{width:{min:768}},{}];if(facingMode){if(exact)facingMode={exact:facingMode};constraintsToTry.forEach((constraint)=>constraint.facingMode=
facingMode)}return this._getMatchingCameraStream(constraintsToTry)}_getMatchingCameraStream(constraintsToTry){if(constraintsToTry.length===0)return Promise.reject("Camera not found.");return navigator.mediaDevices.getUserMedia({video:constraintsToTry.shift()}).catch(()=>this._getMatchingCameraStream(constraintsToTry))}_cameraOn(){clearTimeout(this._offTimeout);let facingMode="environment";this._getCameraStream("environment",true).catch(()=>{facingMode="user";return this._getCameraStream()}).then((stream)=>
{this.$video.srcObject=stream;this._setVideoMirror(facingMode)})}_cameraOff(){this.$video.pause();this._offTimeout=setTimeout(()=>{this.$video.srcObject.getTracks()[0].stop();this.$video.srcObject=null},3E3)}_setVideoMirror(facingMode){const scaleFactor=facingMode==="user"?-1:1;this.$video.style.transform="scaleX("+scaleFactor+")"}setGrayscaleWeights(red,green,blue){this._qrWorker.postMessage({type:"grayscaleWeights",data:{red,green,blue}})}static scanImage(imageOrFileOrUrl,sourceRect=null,worker=
null,canvas=null,fixedCanvasSize=false,alsoTryWithoutSourceRect=false){const promise=new Promise((resolve,reject)=>{worker=worker||new Worker("/qr-scanner/qr-scanner-worker.min.js");let timeout,onMessage,onError;onMessage=(event)=>{if(event.data.type!=="qrResult")return;worker.removeEventListener("message",onMessage);worker.removeEventListener("error",onError);clearTimeout(timeout);if(event.data.data!==null)resolve(event.data.data);else reject("QR code not found.")};onError=()=>{worker.removeEventListener("message",
onMessage);worker.removeEventListener("error",onError);clearTimeout(timeout);reject("Worker error.")};worker.addEventListener("message",onMessage);worker.addEventListener("error",onError);timeout=setTimeout(onError,3E3);QrScanner._loadImage(imageOrFileOrUrl).then((image)=>{const imageData=QrScanner._getImageData(image,sourceRect,canvas,fixedCanvasSize);worker.postMessage({type:"decode",data:imageData},[imageData.data.buffer])}).catch(reject)});if(sourceRect&&alsoTryWithoutSourceRect)return promise.catch(()=>
QrScanner.scanImage(imageOrFileOrUrl,null,worker,canvas,fixedCanvasSize));else return promise}static _getImageData(image,sourceRect=null,canvas=null,fixedCanvasSize=false){canvas=canvas||document.createElement("canvas");const sourceRectX=sourceRect&&sourceRect.x?sourceRect.x:0;const sourceRectY=sourceRect&&sourceRect.y?sourceRect.y:0;const sourceRectWidth=sourceRect&&sourceRect.width?sourceRect.width:image.width||image.videoWidth;const sourceRectHeight=sourceRect&&sourceRect.height?sourceRect.height:
image.height||image.videoHeight;if(!fixedCanvasSize&&(canvas.width!==sourceRectWidth||canvas.height!==sourceRectHeight)){canvas.width=sourceRectWidth;canvas.height=sourceRectHeight}const context=canvas.getContext("2d",{alpha:false});context.imageSmoothingEnabled=false;context.drawImage(image,sourceRectX,sourceRectY,sourceRectWidth,sourceRectHeight,0,0,canvas.width,canvas.height);return context.getImageData(0,0,canvas.width,canvas.height)}static _loadImage(imageOrFileOrUrl){if(imageOrFileOrUrl instanceof
HTMLCanvasElement||imageOrFileOrUrl instanceof HTMLVideoElement||window.ImageBitmap&&imageOrFileOrUrl instanceof window.ImageBitmap||window.OffscreenCanvas&&imageOrFileOrUrl instanceof window.OffscreenCanvas)return Promise.resolve(imageOrFileOrUrl);else if(imageOrFileOrUrl instanceof Image)return QrScanner._awaitImageLoad(imageOrFileOrUrl).then(()=>imageOrFileOrUrl);else if(imageOrFileOrUrl instanceof File||imageOrFileOrUrl instanceof URL||typeof imageOrFileOrUrl==="string"){const image=new Image;
if(imageOrFileOrUrl instanceof File)image.src=URL.createObjectURL(imageOrFileOrUrl);else image.src=imageOrFileOrUrl;return QrScanner._awaitImageLoad(image).then(()=>{if(imageOrFileOrUrl instanceof File)URL.revokeObjectURL(image.src);return image})}else return Promise.reject("Unsupported image type.")}static _awaitImageLoad(image){return new Promise((resolve,reject)=>{if(image.complete&&image.naturalWidth!==0)resolve();else{let onLoad,onError;onLoad=()=>{image.removeEventListener("load",onLoad);image.removeEventListener("error",
onError);resolve()};onError=()=>{image.removeEventListener("load",onLoad);image.removeEventListener("error",onError);reject("Image load error")};image.addEventListener("load",onLoad);image.addEventListener("error",onError)}})}}QrScanner.DEFAULT_CANVAS_SIZE=400;

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