Function render_option 

pub fn render_option(
    context: &impl IsA<StyleContext>,
    cr: &Context,
    x: f64,
    y: f64,
    width: f64,
    height: f64,
)

Renders an option mark (as in a RadioButton), the StateFlags::CHECKED state will determine whether the option is on or off, and StateFlags::INCONSISTENT whether it should be marked as undefined.

Typical option mark rendering:

context

a StyleContext

cr

a cairo::Context

x

X origin of the rectangle

y

Y origin of the rectangle

width

rectangle width

height

rectangle height