getBaseTranslation() {
    const [parentWidth, parentHeight] = this.parentDimensions;
    const { _borderLineWidth } = AnnotationEditor;
    const x = _borderLineWidth / parentWidth;
    const y = _borderLineWidth / parentHeight;
    switch (this.rotation) {
      case 90:
        return [-x, y];
      case 180:
        return [x, y];
      case 270:
        return [x, -y];
      default:
        return [-x, -y];
    }
  }
Get the translation to take into account the editor border.
The CSS engine positions the element by taking the border into account so
we must apply the opposite translation to have the editor in the right
position.
@returns {Array<number>}