how to zoom in video camera when use qr scanner nodejs from browser

QR Scanner Camera Zoom
https://github.com/zxing-js/browser/issues/34
https://googlechrome.github.io/samples/image-capture/update-camera-zoom.html

binsarjr121@gmail.com
how to zoom in video camera when use qr scanner nodejs from browser

Unfortunately, I'm not sure I fully understand your question. However, I'll do my best to provide an answer based on my understanding.

Assuming you're using a web browser to scan a QR code using a camera connected to your computer or device, and you want to know how to zoom in the camera while scanning the QR code using Node.js, here's what you can do:

1. Check if the camera you're using supports zooming in. Some cameras have a zoom-in feature, while others don't.
2. If your camera supports zooming in, you can use the getUserMedia() API in JavaScript to access the camera stream and apply a zoom effect to it.
3. You can use the MediaStreamTrack.applyConstraints() method to apply the zoom effect to the camera stream.

Here's an example of how to apply a zoom effect to the camera stream in JavaScript:

navigator.mediaDevices.getUserMedia({ video: true })
  .then(function(stream) {
    var video = document.querySelector('video');
    var track = stream.getVideoTracks()[0];
    var constraints = track.getConstraints();
    constraints.advanced = [{ zoom: 2.0 }];
    track.applyConstraints(constraints);
    video.srcObject = stream;
  })
  .catch(function(error) {
    console.log('Error accessing camera: ' + error);
  });

In this example, we're accessing the camera using the getUserMedia() API, getting the video track, and applying a zoom constraint to it using the applyConstraints() method.

Note that the specific syntax and functionality of the getUserMedia() and applyConstraints() APIs may vary depending on the browser you're using.

Source: chatgpt

mentahan pake svlete dan zxing

<script lang="ts">
	import { onMount } from 'svelte';
	import { BrowserCodeReader, BrowserQRCodeReader } from '@zxing/browser';
	import { browser } from '$app/environment';

	let selectedDeviceId: string;
	const codeReader = new BrowserQRCodeReader();
  let video: HTMLVideoElement
  let track:MediaStreamTrack

	let result = '';
	const load = async () => {
		// choose your media device (webcam, frontal camera, back camera, etc.)

		console.log(`Started decode from camera with id ${selectedDeviceId}`);

    


		// you can use the controls to stop() the scan or switchTorch() if available
		const controls = await codeReader.decodeFromVideoDevice(
			selectedDeviceId,
			video,
			(_result, error, controls) => {
				result = _result?.toString() || '';
				// console.log(result, 'bro');
				// use the result and error values to choose your actions
				// you can also use controls API in this scope like the controls
				// returned from the method.
			}
		);
	};
	$:if(selectedDeviceId && browser) {
	  load()
	}
	let range = 1;
	onMount(async () => {
    video = document.getElementById('video') as HTMLVideoElement
		await load();
    // navigator.mediaDevices
		// 	.getUserMedia({ video: true })
		// 	.then(function (stream) {
		// 		track = stream.getVideoTracks().find(vl =>vl.id==selectedDeviceId)!;
    //     // video=stream
				
		// 	})
		// 	.catch(function (error) {
		// 		console.log('Error accessing camera: ' + error);
		// 	});
	});

  const change =async (e) => {
    selectedDeviceId= e.target.value
    await load()
    resize()
  }
  
  let rangeId:any
const resize = () => {

    console.log('range',range)
    rangeId && clearTimeout(rangeId)
		rangeId= setTimeout(() => {


      navigator.mediaDevices.getUserMedia({ video: {
        advanced: [{
          deviceId: selectedDeviceId
        }]
      } })
  .then(async function(stream) {
    let track = stream.getVideoTracks()[0];
    

    console.log(track,selectedDeviceId,'track')
    let constraints = track.getConstraints();
    constraints.advanced = [{ zoom: range}];
    await track.applyConstraints(constraints);
    console.log('ok')
    video.srcObject = stream;
  })
  .catch(function(error) {
    console.log('Error accessing camera: ' + error);
  });


     }, 500);
		// 		const constraints = track.getConstraints();
    // constraints.advanced = [{ zoom: range }];
		// 		console.log(constraints,track,'plo');
		// 		track.applyConstraints(constraints);
			
	}
</script>

<select bind:value={selectedDeviceId} on:change={change}>
	{#await BrowserCodeReader.listVideoInputDevices() then videoInputDevices}
		{#each videoInputDevices as videoInputDevice, i}
			<option
				value={videoInputDevice.deviceId}
				selected={selectedDeviceId == videoInputDevice.deviceId}>{videoInputDevice.label}</option
			>
		{/each}
	{/await}
</select>
<video id="video" />
<input type="range" id="zoom-slider" on:input={resize} min="1" max="5" bind:value={range} step="0.1" />

<p>result {result}</p>

<p>range {range}</p>