Hi, this is a small snippet and shows how to use the QR code scanner from here:

https://raw.githubusercontent.com/nimiq/qr-scanner/master/qr-scanner.legacy.min.js

unit qrscanner;

interface

uses
  qtx.sysutils, qtx.classes, qtx.dom.widgets, qtx.dom.types;

type
 TQTXQRScanner = class;
 TQTXQRScannerConstructor = procedure (QTXScanner: TQTXQRScanner);

 TOnGetQRCode = procedure(Sender: TObject; Result: String);

 TQTXQRScanner = class(TQTXWidget)
 private
  FOnGetQRCode: TOnGetQRCode;
  FVideoElement: THandle;
  FScanner: THandle;
 public
  constructor Create(AOwner: TQTXComponent; CB: TQTXQRScannerConstructor); reintroduce; virtual;

  property OnGetQRCode: TOnGetQRCode read FOnGetQRCode write FOnGetQRCode;
 end;

implementation

constructor TQTXQRScanner.Create(AOwner: TQTXComponent; CB: TQTXQRScannerConstructor);

 procedure Callback(AResult: Variant);
 begin
  if assigned(FOnGetQRCode) then FOnGetQRCode(Self, AResult.data);
 end;

begin
  inherited Create(AOwner, procedure(Widget: TQTXWidget)
  begin
   Style.width := '100%';
   Style.height := '100%';

   asm
    const video = document.createElement('video');
    video.id = 'qr-video';

    @self.FVideoElement = video;
   end;
   Widget.Handle.appendChild(FVideoElement);
   if assigned(CB) then CB(self);

   TQTXDispatch.Execute(procedure()
   begin
    asm
      const scanner = new QrScanner(video, result => {
         @Callback(result);
        }, {
          highlightScanRegion: true,
          highlightCodeOutline: true,
        });

     @self.FScanner = scanner;
     scanner.start();
    end;
   end,1000);
  end);
end;

end.