Available in Chrome 56+ | View on GitHub | Browse Samples
The ImageCapture Web API allows web developers to capture images from camera
in the form of a Blob with takePhoto()
or as a ImageBitmap with
grabFrame()
.
var imageCapture;
function onGetUserMediaButtonClick() {
navigator.mediaDevices.getUserMedia({video: true})
.then(mediaStream => {
document.querySelector('video').srcObject = mediaStream;
const track = mediaStream.getVideoTracks()[0];
imageCapture = new ImageCapture(track);
})
.catch(error => ChromeSamples.log(error));
}
function onGrabFrameButtonClick() {
imageCapture.grabFrame()
.then(imageBitmap => {
const canvas = document.querySelector('#grabFrameCanvas');
drawCanvas(canvas, imageBitmap);
})
.catch(error => ChromeSamples.log(error));
}
function onTakePhotoButtonClick() {
imageCapture.takePhoto()
.then(blob => createImageBitmap(blob))
.then(imageBitmap => {
const canvas = document.querySelector('#takePhotoCanvas');
drawCanvas(canvas, imageBitmap);
})
.catch(error => ChromeSamples.log(error));
}
/* Utils */
function drawCanvas(canvas, img) {
canvas.width = getComputedStyle(canvas).width.split('px')[0];
canvas.height = getComputedStyle(canvas).height.split('px')[0];
let ratio = Math.min(canvas.width / img.width, canvas.height / img.height);
let x = (canvas.width - img.width * ratio) / 2;
let y = (canvas.height - img.height * ratio) / 2;
canvas.getContext('2d').clearRect(0, 0, canvas.width, canvas.height);
canvas.getContext('2d').drawImage(img, 0, 0, img.width, img.height,
x, y, img.width * ratio, img.height * ratio);
}
document.querySelector('video').addEventListener('play', function() {
document.querySelector('#grabFrameButton').disabled = false;
document.querySelector('#takePhotoButton').disabled = false;
});