Function fromPixels

tfjs-backend-webgpu/src/kernels/FromPixels.ts:34–141

(args: {
  inputs: FromPixelsInputs,
  backend: WebGPUBackend,
  attrs: FromPixelsAttrs
})

let willReadFrequently = env().getBool('CANVAS2D_WILL_READ_FREQUENTLY_FOR_GPU');

export function fromPixels(args: {
  inputs: FromPixelsInputs,
  backend: WebGPUBackend,
  attrs: FromPixelsAttrs
}): TensorInfo {
  const {inputs, backend, attrs} = args;
  let {pixels} = inputs;
  const {numChannels} = attrs;

  if (pixels == null) {
    throw new Error('pixels passed to tf.browser.fromPixels() can not be null');
  }

  const isVideo = typeof (HTMLVideoElement) !== 'undefined' &&
      pixels instanceof HTMLVideoElement;
  const isImage = typeof (HTMLImageElement) !== 'undefined' &&
      pixels instanceof HTMLImageElement;
  const isCanvas = (typeof (HTMLCanvasElement) !== 'undefined' &&
                    pixels instanceof HTMLCanvasElement) ||
      (typeof (OffscreenCanvas) !== 'undefined' &&
       pixels instanceof OffscreenCanvas);
  const isImageBitmap =
      typeof (ImageBitmap) !== 'undefined' && pixels instanceof ImageBitmap;

  const [width, height] = isVideo ?
      [
        (pixels as HTMLVideoElement).videoWidth,
        (pixels as HTMLVideoElement).videoHeight
      ] :
      [pixels.width, pixels.height];
  const outputShape = [height, width, numChannels];

  const importVideo =
      env().getBool('WEBGPU_IMPORT_EXTERNAL_TEXTURE') && isVideo;
  const isVideoOrImage = isVideo || isImage;
  if (isImageBitmap || isCanvas || isVideoOrImage) {
    let resource;
    if (importVideo) {
      resource = backend.device.importExternalTexture(
          {source: pixels as HTMLVideoElement});
    } else {
      if (isVideoOrImage) {
        const newWillReadFrequently =
            env().getBool('CANVAS2D_WILL_READ_FREQUENTLY_FOR_GPU');
        if (fromPixels2DContext == null ||
            newWillReadFrequently !== willReadFrequently) {
          willReadFrequently = newWillReadFrequently;
          fromPixels2DContext = document.createElement('canvas').getContext(
              '2d', {willReadFrequently});
        }
        fromPixels2DContext.canvas.width = width;
        fromPixels2DContext.canvas.height = height;
        fromPixels2DContext.drawImage(
            pixels as HTMLVideoElement | HTMLImageElement, 0, 0, width, height);
        pixels = fromPixels2DContext.canvas;
      }

      const usage = GPUTextureUsage.COPY_DST |