Function libeyelink_sys::eyelink_href_angle

pub unsafe extern "C" fn eyelink_href_angle(
    x1: f32, 
    y1: f32, 
    x2: f32, 
    y2: f32
) -> f32

@ingroup extra_data Convenient function to calculate the href angle. @param x1 Point 1 x. @param y1 Point 1 y. @param x2 Point 2 x. @param y2 Point 2 y.