code: public Color colorAt(Shape shape, float x, float y) {
  		if (local) {
  			return colorAt(x-shape.getCenterX(),y-shape.getCenterY());
  		} else {
  			return colorAt(x,y);
  		}
  	}
docs: Get the colour that should be applied at the specified location
  
  @param shape The shape being filled
  @param x The x coordinate of the point being coloured
  @param y The y coordinate of the point being coloured
  @return The colour that should be applied based on the control points of this gradient