Function two_point_conical_gradient 

pub fn two_point_conical_gradient<'a>(
    (start, start_radius): (impl Into<Point>, scalar),
    (end, end_radius): (impl Into<Point>, scalar),
    gradient: &Gradient<'_>,
    local_matrix: impl Into<Option<&'a Matrix>>,
) -> Option<Shader>

Returns a shader that generates a conical gradient given two circles.

The gradient interprets the two circles according to the following HTML spec: http://dev.w3.org/html5/2dcontext/#dom-context-2d-createradialgradient

• start: The center of the start circle
• start_radius: Must be positive. The radius of the start circle
• end: The center of the end circle
• end_radius: Must be positive. The radius of the end circle
• gradient: Description of the colors and interpolation method
• local_matrix: Optional local matrix