The <radialGradient> element is used to define a radial gradient.
The <radialGradient> element must be nested within a <defs> tag. The <defs> tag is short
for definitions and contains definition of special
elements (such as gradients).
Example 1
Define an ellipse with a radial gradient from white to blue:
The id attribute of the <radialGradient> tag defines a unique name for the gradient
The cx, cy and r attributes define the outermost
circle and the fx and fy define the innermost circle
The color range for a gradient can be composed of two or more colors. Each color
is specified with a <stop> tag. The offset attribute is used to define where the gradient color begin and end
The fill attribute links the ellipse element to the gradient
Example 2
Define another ellipse with a radial gradient from white to blue: