face-api/src/dom/imageTensorToCanvas.ts

import * as tf from '../../dist/tfjs.esm.js';

import { env } from '../env/index';
import { isTensor4D } from '../utils/index';

export async function imageTensorToCanvas(
  imgTensor: tf.Tensor,
  canvas?: HTMLCanvasElement,
): Promise<HTMLCanvasElement> {
  const targetCanvas = canvas || env.getEnv().createCanvasElement();

  const [height, width, numChannels] = imgTensor.shape.slice(isTensor4D(imgTensor) ? 1 : 0);
  const imgTensor3D = tf.tidy(() => imgTensor.as3D(height, width, numChannels).toInt());
  await tf.browser.toPixels(imgTensor3D, targetCanvas);

  imgTensor3D.dispose();

  return targetCanvas;
}