getViewportSizeMinusPadding_(rotation) {
    let size = this.getViewportSize_(rotation);
    const padding = this.padding_;
    if (padding) {
      size = [
        size[0] - padding[1] - padding[3],
        size[1] - padding[0] - padding[2],
      ];
    }
    return size;
  }
Returns the size of the viewport minus padding.
@private
@param {number} [rotation] Take into account the rotation of the viewport when giving the size
@return {import("./size.js").Size} Viewport size reduced by the padding.