Initializes a new instance of the LinearGradientBrush class that has the specified start Color, end Color, and angle.
The Color at offset 0.0.
The Color at offset 1.0.
A Double that represents the angle, in degrees, of the gradient. A value of 0.0 creates a horizontal gradient, and a value of 90.0 creates a vertical gradient.
The MappingMode of the brush is initialized to RelativeToBoundingBox.