function getMaxSize (maxSize, isVR) {
  var aspectRatio;
  var size;
  var pixelRatio = window.devicePixelRatio;

  size = {height: document.body.offsetHeight, width: document.body.offsetWidth};
  if (!maxSize || isVR || (maxSize.width === -1 && maxSize.height === -1)) {
    return size;
  }

  if (size.width * pixelRatio < maxSize.width &&
    size.height * pixelRatio < maxSize.height) {
    return size;
  }

  aspectRatio = size.width / size.height;

  if ((size.width * pixelRatio) > maxSize.width && maxSize.width !== -1) {
    size.width = Math.round(maxSize.width / pixelRatio);
    size.height = Math.round(maxSize.width / aspectRatio / pixelRatio);
  }

  if ((size.height * pixelRatio) > maxSize.height && maxSize.height !== -1) {
    size.height = Math.round(maxSize.height / pixelRatio);
    size.width = Math.round(maxSize.height * aspectRatio / pixelRatio);
  }

  return size;
}
function getMaxSize (maxSize, isVR) {
  var aspectRatio;
  var size;
  var pixelRatio = window.devicePixelRatio;

  size = {height: document.body.offsetHeight, width: document.body.offsetWidth};
  if (!maxSize || isVR || (maxSize.width === -1 && maxSize.height === -1)) {
    return size;
  }

  if (size.width * pixelRatio < maxSize.width &&
    size.height * pixelRatio < maxSize.height) {
    return size;
  }

  aspectRatio = size.width / size.height;

  if ((size.width * pixelRatio) > maxSize.width && maxSize.width !== -1) {
    size.width = Math.round(maxSize.width / pixelRatio);
    size.height = Math.round(maxSize.width / aspectRatio / pixelRatio);
  }

  if ((size.height * pixelRatio) > maxSize.height && maxSize.height !== -1) {
    size.height = Math.round(maxSize.height / pixelRatio);
    size.width = Math.round(maxSize.height * aspectRatio / pixelRatio);
  }

  return size;
}
function getMaxSize ( maxSize , isVR ) { var aspectRatio ; var size ; var pixelRatio = window . devicePixelRatio ; size = { height : document . body . offsetHeight , width : document . body . offsetWidth } ; if ( ! maxSize || isVR || ( maxSize . width === - 1 && maxSize . height === - 1 ) ) { return size ; } if ( size . width * pixelRatio < maxSize . width && size . height * pixelRatio < maxSize . height ) { return size ; } aspectRatio = size . width / size . height ; if ( ( size . width * pixelRatio ) > maxSize . width && maxSize . width !== - 1 ) { size . width = Math . round ( maxSize . width / pixelRatio ) ; size . height = Math . round ( maxSize . width / aspectRatio / pixelRatio ) ; } if ( ( size . height * pixelRatio ) > maxSize . height && maxSize . height !== - 1 ) { size . height = Math . round ( maxSize . height / pixelRatio ) ; size . width = Math . round ( maxSize . height * aspectRatio / pixelRatio ) ; } return size ; }
Return the canvas size. Will be the window size unless that size is greater than the
maximum size (1920x1920 by default).  The constrained size will be returned in that case,
maintaining aspect ratio

@param {object} maxSize - Max size parameters (width and height).
@param {boolean} isVR - If in VR.
@returns {object} Width and height.
Return the canvas size . Will be the window size unless that size is greater than the maximum size ( 1920x1920 by default ) . The constrained size will be returned in that case maintaining aspect ratio
Get the maximum size of the page