code: public void setScaleFactors( double ...scaleFactors ) {
  		// see if the scale factors have not changed
  		if( scale != null && scale.length == scaleFactors.length ) {
  			boolean theSame = true;
  			for( int i = 0; i < scale.length; i++ ) {
  				if( scale[i] != scaleFactors[i] ) {
  					theSame = false;
  					break;
  				}
  			}
  			// no changes needed
  			if( theSame )
  				return;
  
  		}
  		// set width/height to zero to force the image to be redeclared
  		bottomWidth = bottomHeight = 0;
  		this.scale = scaleFactors.clone();
  		checkScales();
  	}
docs: Specifies the pyramid's structure.
  
  @param scaleFactors Change in scale factor for each layer in the pyramid.