setColor(color) {
    this.color = getRgbColor(color);
  }
Set the color and take care of color space conversion.
The default value is black, in RGB color space.

@public
@memberof Annotation
@param {Array} color - The color array containing either 0
                       (transparent), 1 (grayscale), 3 (RGB) or
                       4 (CMYK) elements