The grabFrame()
method of the ImageCapture
interface takes a snapshot of the live video in a MediaStreamTrack
and returns a Promise
that resolves with a ImageBitmap
containing the snapshot.
A Promise
that resolves to an ImageBitmap
object.
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 simplicity it does not show how to instantiate the ImageCapture
object.
let grabFrameButton = document.querySelector("button#grabFrame");
let canvas = document.querySelector("canvas");
grabFrameButton.onclick = grabFrame;
function grabFrame() {
imageCapture
.grabFrame()
.then((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((error) => {
console.error("grabFrame() error: ", error);
});
}