Beginning Web Development, Silverlight, and ASP.NET AJAX

CHAPTER 16 ■ PROGRAMMING SILVERLIGHT WITH XAML AND JAVASCRIPT 381
The RadialGradientBrush
This is similar to the LinearGradientBrush in that is paints a space using a gradient, but it
does it in a circular manner, with 0 marking the center of the circle and 1 being its radius.
Thus, if you have two colors defined, it will look a lot like the effect of a spotlight of the
first color being shown on a wall of the second color, whereby the center of the circle will
be the color of the light, the outer edge of the circle will be the color of the wall, and a gradient
between the two will fill the space.
When using the RadialGradientBrush, you don’t need to specify a start point or endpoint,
as the gradient direction will always be from the center of the circle to its outside
edge.
Gradient stops are used in the same manner as the LinearGradientBrush, with the
Offset indicating the unit distance from the center.
Here’s an example of a RadialGradientBrush using the same rainbow colors as the
previous rectangle:
The RadialGradientBrush gives you some extra control over how the gradient is
painted. The GradientOrigin allows you to set the point at which the gradient emanates. It
doesn’t have to be the center of the circle, so setting it to a different value will “stretch”
the gradient from the center of the circle to the specified point. You set it using a normalized
(x,y) value, where (0.5,0.5) is the center of the circle, (1,1) is the lower right-hand side