ImageCapture.grabFrame

The grabFrame() property of the ImageCapture interface takes a snapshot of the live video in a MediaStreamTrack, returning an ImageBitmap, if successful.

Syntax

ImageCapture.grabFrame().then(function(imageBitmap) { ... })

Parameters

None.

Return value

A Promise that resolves to an ImageBitmap object.

Example

This example is extracted from this Simple Image Capture demo. It shows how to use the Promise returned by grabFrame() to copy the returned frame to a <canvas> element. For simplicy it does not show how to instantiate the image capture object.

var grabFrameButton = document.querySelector('button#grabFrame');
var canvas = document.querySelector('canvas');

grabFrameButton.onclick = grabFrame;

function grabFrame() {
  imageCapture.grabFrame()
  .then(function(imageBitmap) {
    console.log('Grabbed frame:', imageBitmap);
    canvas.width = imageBitmap.width;
    canvas.height = imageBitmap.height;
    canvas.getContext('2d').drawImage(imageBitmap, 0, 0);
    canvas.classList.remove('hidden');
  })
  .catch(function(error) {
    console.log('grabFrame() error: ', error);
  });
}

Specifications

Browser compatibilityUpdate compatibility data on GitHub