code: @Pure
  	public double doc2fxY(double y) {
  		return this.centeringTransform.toCenterY(y) * this.scale.get() + this.canvasHeight.get() / 2.;
  	}
docs: Transform a document y coordinate to its JavaFX equivalent.
  
  @param y the document y coordinate.
  @return the JavaFX y coordinate.