Is it possible to control the camera light on a phone via a website?
I fixed Daniel's answer and now button works properly on Android phones. IOS is still unsupported.
https://jsfiddle.net/nzw5tv1q/
//have a console on mobile
const consoleOutput = document.getElementById("console");
const log = function (msg) {
consoleOutput.innerText = `${consoleOutput.innerText}\n${msg}`;
console.log(msg);
}
//Test browser support
const SUPPORTS_MEDIA_DEVICES = 'mediaDevices' in navigator;
if (SUPPORTS_MEDIA_DEVICES) {
//Get the environment camera (usually the second one)
navigator.mediaDevices.enumerateDevices().then(devices => {
const cameras = devices.filter((device) => device.kind === 'videoinput');
if (cameras.length === 0) {
log('No camera found on this device.');
}
// Create stream and get video track
navigator.mediaDevices.getUserMedia({
video: {
facingMode: 'environment',
}
}).then(stream => {
const track = stream.getVideoTracks()[0];
//Create image capture object and get camera capabilities
const imageCapture = new ImageCapture(track)
imageCapture.getPhotoCapabilities().then(capabilities => {
//let there be light!
const btn = document.querySelector('.switch');
const torchSupported = !!capabilities.torch || (
'fillLightMode' in capabilities &&
capabilities.fillLightMode.length != 0 &&
capabilities.fillLightMode != 'none'
);
if (torchSupported) {
let torch = false;
btn.addEventListener('click', function (e) {
try {
track.applyConstraints({
advanced: [{
torch: (torch = !torch)
}]
});
} catch (err) {
log(err);
}
});
} else {
log("No torch found");
}
}).catch(log);
}).catch(log);
}).catch(log);
//The light will be on as long the track exists
}
<button class="switch">On / Off</button>
<h2>
Console output
</h2>
<div id="console">
</div>
Here is a little "torch-app" for a website:
Edit 1: I also made a jsfiddle
//Test browser support
const SUPPORTS_MEDIA_DEVICES = 'mediaDevices' in navigator;
if (SUPPORTS_MEDIA_DEVICES) {
//Get the environment camera (usually the second one)
navigator.mediaDevices.enumerateDevices().then(devices => {
const cameras = devices.filter((device) => device.kind === 'videoinput');
if (cameras.length === 0) {
throw 'No camera found on this device.';
}
const camera = cameras[cameras.length - 1];
// Create stream and get video track
navigator.mediaDevices.getUserMedia({
video: {
deviceId: camera.deviceId,
facingMode: ['user', 'environment'],
height: {ideal: 1080},
width: {ideal: 1920}
}
}).then(stream => {
const track = stream.getVideoTracks()[0];
//Create image capture object and get camera capabilities
const imageCapture = new ImageCapture(track)
const photoCapabilities = imageCapture.getPhotoCapabilities().then(() => {
//todo: check if camera has a torch
//let there be light!
const btn = document.querySelector('.switch');
btn.addEventListener('click', function(){
track.applyConstraints({
advanced: [{torch: true}]
});
});
});
});
});
//The light will be on as long the track exists
}
<button class="switch">On / Off</button>
The code is heavily inspired by this repository, this webseries and this blog-post
Edit 2: This does only works in Chrome (and maybe Opera). It does not work in Chrome on iOS, because Chrome cannot access the camera. I cannot test it on android for now. I created a new jsfiddle, with an output. If you have an android phone and it does not work for you, it will maybe tell why: https://jsfiddle.net/jpa1vwed/
Feel free to debug, comment and edit.
You can use the MediaStream Image Capture API by creating an ImageCapture from a VideoStreamTrack and setting the option "fillLightMode" to "flash" or "torch". Example:
<video autoplay="true"></video>
<img />
<button onclick="takePhoto()">Take Photo</button>
<script type="text/javascript">
var imageCapture = null;
var deviceConfig = {
video: {
width: 480,
height: 640,
facingMode: "environment", /* may not work, see https://bugs.chromium.org/p/chromium/issues/detail?id=290161 */
deviceId: null
}
};
var imageCaptureConfig = {
fillLightMode: "torch", /* or "flash" */
focusMode: "continuous"
};
// get the available video input devices and choose the one that represents the backside camera
navigator.mediaDevices.enumerateDevices()
/* replacement for not working "facingMode: 'environment'": use filter to get the backside camera with the flash light */
.then(mediaDeviceInfos => mediaDeviceInfos.filter(mediaDeviceInfo => ((mediaDeviceInfo.kind === 'videoinput')/* && mediaDeviceInfo.label.includes("back")*/)))
.then(mediaDeviceInfos => {
console.log("mediaDeviceInfos[0].label: " + mediaDeviceInfos[0].label);
// get the device ID of the backside camera and use it for media stream initialization
deviceConfig.video.deviceId = mediaDeviceInfos[0].deviceId;
navigator.mediaDevices.getUserMedia(deviceConfig)
.then(_gotMedia)
.catch(err => console.error('getUserMedia() failed: ', err));
});
function takePhoto () {
imageCapture.takePhoto()
.then(blob => {
console.log('Photo taken: ' + blob.type + ', ' + blob.size + 'B');
// get URL for blob data and use as source for the image element
const image = document.querySelector('img');
image.src = URL.createObjectURL(blob);
})
.catch(err => console.error('takePhoto() failed: ', err));
}
function _gotMedia (mediastream) {
// use the media stream as source for the video element
const video = document.querySelector('video');
video.srcObject = mediastream;
// create an ImageCapture from the first video track
const track = mediastream.getVideoTracks()[0];
imageCapture = new ImageCapture(track);
// set the image capture options (e.g. flash light, autofocus, ...)
imageCapture.setOptions(imageCaptureConfig)
.catch(err => console.error('setOptions(' + JSON.stringify(imageCaptureConfig) + ') failed: ', err));
}
</script>
Note:
- As of this writing the API is still under development and may change in the future.
- For enabling ImageCapture in Chrome the flag "chrome://flags/#enable-experimental-web-platform-features" has to be set to "true"
- For enabling ImageCapture in Firefox the flag "dom.imagecapture.enabled" in "about:config" has to be set to "true". But "setOptions" is not supported as of this writing!
See also:
- Mediastream Image Capture on GitHub
- NPM module ImageCapture polyfill
Here, it is a static class for handling flashlight. You can call flashlightHandler.accessFlashlight()
when the window loads. And then use the flashlightHandler.setFlashlightStatus()
method, passing it true
or false
, as you want the flashlight status.
class flashlightHandler {
static track; //the video track which is used to turn on/off the flashlight
static accessFlashlight() {
//Test browser support
if (!('mediaDevices' in window.navigator)) {
alert("Media Devices not available. Use HTTPS!");
return;
};
//Get the environment camera (usually the second one)
window.navigator.mediaDevices.enumerateDevices().then((devices) => {
const cameras = devices.filter((device) => device.kind === 'videoinput');
if (cameras.length === 0) {
alert("No camera found. If your device has camera available, check permissions.");
return;
};
const camera = cameras[cameras.length - 1];
window.navigator.mediaDevices.getUserMedia({
video: {
deviceId: camera.deviceId
}
}).then((stream) => {
this.track = stream.getVideoTracks()[0];
if (!(this.track.getCapabilities().torch)) {
alert("No torch available.");
};
});
});
}
static setFlashlightStatus(status) {
this.track.applyConstraints({
advanced: [{
torch: status
}]
});
}
}