The color gradient is a smooth shading of colors from the center point of the path to the outside boundary edge of the path. Blend factors, positions, and style affect where the gradient starts and ends, and how fast it changes shade.
Path gradient brushes do not obey the SmoothingMode property of the Graphics object used to do the drawing. Areas filled using a PathGradientBrush object are rendered the same way (aliased) regardless of the smoothing mode.