Rectangle overflow

Cargo.toml

[package]
name = "druid-rectangle"
version = "0.1.0"
authors = ["Joe Neeman <joeneeman@gmail.com>"]
edition = "2018"

[dependencies]
druid = { git = "https://github.com/xi-editor/druid.git" }

main.rs

use druid::widget::prelude::*;
use druid::widget::Align;
use druid::{AppLauncher, Color, Env, LocalizedString, Point, Rect, Widget, WindowDesc};

const WINDOW_TITLE: LocalizedString<f64> = LocalizedString::new("Hello World!");

fn main() {
    let main_window = WindowDesc::new(build_root_widget)
        .title(WINDOW_TITLE)
        .window_size((400.0, 400.0));

    AppLauncher::with_window(main_window)
        .launch(1e7)
        .expect("Failed to launch application");
}

fn build_root_widget() -> impl Widget<f64> {
    Align::centered(RectangleWidget)
}

struct RectangleWidget;

impl Widget<f64> for RectangleWidget {
    fn event(&mut self, _: &mut EventCtx, _: &Event, _: &mut f64, _: &Env) {}
    fn lifecycle(&mut self, _: &mut LifeCycleCtx, _: &LifeCycle, _: &f64, _: &Env) {}
    fn update(&mut self, _: &mut UpdateCtx, _: &f64, _: &f64, _: &Env) {}
    fn layout(&mut self, _: &mut LayoutCtx, bc: &BoxConstraints, _: &f64, _: &Env) -> Size {
        bc.max()
    }

    fn paint(&mut self, ctx: &mut PaintCtx, width: &f64, _env: &Env) {
        let size = ctx.size();
        let widget_rect = Rect::from_origin_size(Point::ORIGIN, size);
        let draw_rect = Rect::from_origin_size((0.0, 50.0), (*width, size.height - 100.0))
            .to_rounded_rect(50.0);
        ctx.with_save(move |ctx| {
            ctx.clip(widget_rect);
            ctx.fill(draw_rect, &Color::rgb8(0, 0, 255));
        });
    }
}