Files
qr-scanner/qr-scanner.min.js
T
Danielandshrpne b3713f2b38 Remove canplay logic
The manual call of play() just after setting the video stream introduced in
the previous commit seems to suffice without the need to wait for the
canplay event.

Co-authored-by: shrpne <shrpne@gmail.com>
2020-07-05 13:45:29 +02:00

13 lines
5.2 KiB
JavaScript

class e{static hasCamera(){return!!navigator.mediaDevices&&navigator.mediaDevices.enumerateDevices().then((a)=>a.some((a)=>"videoinput"===a.kind)).catch(()=>!1)}constructor(a,c,b=e.DEFAULT_CANVAS_SIZE){this.$video=a;this.$canvas=document.createElement("canvas");this._onDecode=c;this._paused=this._active=!1;this.$canvas.width=b;this.$canvas.height=b;this._sourceRect={x:0,y:0,width:b,height:b};this._onPlay=this._onPlay.bind(this);this._onVisibilityChange=this._onVisibilityChange.bind(this);
this.$video.addEventListener("play",this._onPlay);document.addEventListener("visibilitychange",this._onVisibilityChange);this._qrWorker=new Worker(e.WORKER_PATH)}destroy(){this.$video.removeEventListener("play",this._onPlay);document.removeEventListener("visibilitychange",this._onVisibilityChange);this.stop();this._qrWorker.postMessage({type:"close"})}start(){if(this._active&&!this._paused)return Promise.resolve();"https:"!==window.location.protocol&&console.warn("The camera stream is only accessible if the page is transferred via https.");
this._active=!0;this._paused=!1;if(document.hidden)return Promise.resolve();clearTimeout(this._offTimeout);this._offTimeout=null;if(this.$video.srcObject)return this.$video.play(),Promise.resolve();let a="environment";return this._getCameraStream("environment",!0).catch(()=>{a="user";return this._getCameraStream()}).then((c)=>{this.$video.srcObject=c;this.$video.play();this._setVideoMirror(a)}).catch((a)=>{this._active=!1;throw a;})}stop(){this.pause();this._active=!1}pause(){this._paused=!0;this._active&&
(this.$video.pause(),this._offTimeout||(this._offTimeout=setTimeout(()=>{let a=this.$video.srcObject&&this.$video.srcObject.getTracks()[0];a&&(a.stop(),this._offTimeout=this.$video.srcObject=null)},300)))}static scanImage(a,c=null,b=null,d=null,f=!1,g=!1){let h=!1,l=new Promise((l,g)=>{b||(b=new Worker(e.WORKER_PATH),h=!0,b.postMessage({type:"inversionMode",data:"both"}));let n,m,k;m=(a)=>{"qrResult"===a.data.type&&(b.removeEventListener("message",m),b.removeEventListener("error",k),clearTimeout(n),
null!==a.data.data?l(a.data.data):g("QR code not found."))};k=(a)=>{b.removeEventListener("message",m);b.removeEventListener("error",k);clearTimeout(n);g("Scanner error: "+(a?a.message||a:"Unknown Error"))};b.addEventListener("message",m);b.addEventListener("error",k);n=setTimeout(()=>k("timeout"),3E3);e._loadImage(a).then((a)=>{a=e._getImageData(a,c,d,f);b.postMessage({type:"decode",data:a},[a.data.buffer])}).catch(k)});c&&g&&(l=l.catch(()=>e.scanImage(a,null,b,d,f)));return l=l.finally(()=>{h&&
b.postMessage({type:"close"})})}setGrayscaleWeights(a,c,b,d=!0){this._qrWorker.postMessage({type:"grayscaleWeights",data:{red:a,green:c,blue:b,useIntegerApproximation:d}})}setInversionMode(a){this._qrWorker.postMessage({type:"inversionMode",data:a})}_onPlay(){this._updateSourceRect();this._scanFrame()}_onVisibilityChange(){document.hidden?this.pause():this._active&&this.start()}_updateSourceRect(){let a=Math.round(2/3*Math.min(this.$video.videoWidth,this.$video.videoHeight));this._sourceRect.width=
this._sourceRect.height=a;this._sourceRect.x=(this.$video.videoWidth-a)/2;this._sourceRect.y=(this.$video.videoHeight-a)/2}_scanFrame(){if(!this._active||this.$video.paused||this.$video.ended)return!1;requestAnimationFrame(()=>{e.scanImage(this.$video,this._sourceRect,this._qrWorker,this.$canvas,!0).then(this._onDecode,(a)=>{this._active&&"QR code not found."!==a&&console.error(a)}).then(()=>this._scanFrame())})}_getCameraStream(a,c=!1){let b=[{width:{min:1024}},{width:{min:768}},{}];a&&(c&&(a={exact:a}),
b.forEach((b)=>b.facingMode=a));return this._getMatchingCameraStream(b)}_getMatchingCameraStream(a){return navigator.mediaDevices&&0!==a.length?navigator.mediaDevices.getUserMedia({video:a.shift()}).catch(()=>this._getMatchingCameraStream(a)):Promise.reject("Camera not found.")}_setVideoMirror(a){this.$video.style.transform="scaleX("+("user"===a?-1:1)+")"}static _getImageData(a,c=null,b=null,d=!1){b=b||document.createElement("canvas");let f=c&&c.x?c.x:0,g=c&&c.y?c.y:0,h=c&&c.width?c.width:a.width||
a.videoWidth;c=c&&c.height?c.height:a.height||a.videoHeight;d||b.width===h&&b.height===c||(b.width=h,b.height=c);d=b.getContext("2d",{alpha:!1});d.imageSmoothingEnabled=!1;d.drawImage(a,f,g,h,c,0,0,b.width,b.height);return d.getImageData(0,0,b.width,b.height)}static _loadImage(a){if(a instanceof HTMLCanvasElement||a instanceof HTMLVideoElement||window.ImageBitmap&&a instanceof window.ImageBitmap||window.OffscreenCanvas&&a instanceof window.OffscreenCanvas)return Promise.resolve(a);if(a instanceof
Image)return e._awaitImageLoad(a).then(()=>a);if(a instanceof File||a instanceof URL||"string"===typeof a){let c=new Image;c.src=a instanceof File?URL.createObjectURL(a):a;return e._awaitImageLoad(c).then(()=>{a instanceof File&&URL.revokeObjectURL(c.src);return c})}return Promise.reject("Unsupported image type.")}static _awaitImageLoad(a){return new Promise((c,b)=>{if(a.complete&&0!==a.naturalWidth)c();else{let d,f;d=()=>{a.removeEventListener("load",d);a.removeEventListener("error",f);c()};f=()=>
{a.removeEventListener("load",d);a.removeEventListener("error",f);b("Image load error")};a.addEventListener("load",d);a.addEventListener("error",f)}})}}e.DEFAULT_CANVAS_SIZE=400;e.WORKER_PATH="qr-scanner-worker.min.js";export default e;
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