let canvas = |
#background_color: &[Color, null] = &null,
#marker: &[Marker, null] = &null,
#x_bounds: &{ max: f64, min: f64 },
#y_bounds: &{ max: f64, min: f64 },
shapes: &Array<&CanvasShape>
| -> Tui `Canvas({
background_color,
marker,
shapes,
x_bounds,
y_bounds
})