The Darken method of the Color struct is used to darken the color by a specified fraction. This method adjusts the brightness of the color by reducing its intensity, making it appear darker.

To use the Darken method, call it on an instance of the Color struct, passing a float value as the fraction parameter. The fraction should be a value between 0 and 1, where 0 means no change and 1 means the color is completely darkened to black.

Example usage:

Color myColor = new Color(0.5f, 0.5f, 0.5f, 1.0f);
Color darkerColor = myColor.Darken(0.2f);

In this example, myColor is darkened by 20%, resulting in a new color stored in darkerColor.