code: protected Integer getYFor(Number value) {
  		double offset = zeroBased ? 0.0 : getTickInfo(ValueDimension.Y).getFirstTick();
  		return getPaintingRegion().getBottomLeft().y - (int) Math.round((value.doubleValue()-offset)*getPaintingRegion().getUnit(ValueDimension.Y));
  	}
docs: Returns the Y-coordinate for a given value of the second dimension (Y),
  considering the actual operation-mode {@link #zeroBased}.<br>
  This implementation simply returns a value that reflects the position of the given value with respect to the coordinate axis Y.
  @param value Value of the maintained Y-dimension
  @return Y-coordinate for the given value