Function triangle 

pub fn triangle<T: Padded + 'static>(
    id: Arc<SourceID>,
    props: T,
    border: f32,
    blur: f32,
    corners: [f32; 3],
    offset: f32,
    fill: sRGB,
    outline: sRGB,
    size: DAbsPoint,
) -> Shape<T, { _ }>