docs: public LocationInfo whatIsAtPoint( int pixelX , int pixelY , LocationInfo output ) {
  		if( output == null )
  			output = new LocationInfo();
  
  		int numCategories = confusion.getNumRows();
  
  		synchronized ( this ) {
  			if( pixelX >= gridWidth ) {
  				output.insideMatrix = false;
  				output.col = output.row = pixelY*numCategories/gridHeight;
  			} else {
  				output.insideMatrix = true;
  				output.row = pixelY*numCategories/gridHeight;
  				output.col = pixelX*numCategories/gridWidth;
  			}
  		}
  
  		return output;
  	}