use gpui::{    Background, Bounds, ColorSpace, Context, Path, PathBuilder, Pixels, Render, TitlebarOptions,    Window, WindowBounds, WindowOptions, canvas, div, linear_color_stop, linear_gradient, point,    prelude::*, px, rgb, size,};use gpui_platform::application; const DEFAULT_WINDOW_WIDTH: Pixels = px(1024.0);const DEFAULT_WINDOW_HEIGHT: Pixels = px(768.0); struct PaintingViewer {    default_lines: Vec<(Path<Pixels>, Background)>,    _painting: bool,} impl PaintingViewer {    fn new(_window: &mut Window, _cx: &mut Context<Self>) -> Self {        let mut lines = vec![];         // draw a lightening bolt ⚡        for _ in 0..2000 {            // draw a ⭐            let mut builder = PathBuilder::fill();            builder.move_to(point(px(350.), px(100.)));            builder.line_to(point(px(370.), px(160.)));            builder.line_to(point(px(430.), px(160.)));            builder.line_to(point(px(380.), px(200.)));            builder.line_to(point(px(400.), px(260.)));            builder.line_to(point(px(350.), px(220.)));            builder.line_to(point(px(300.), px(260.)));            builder.line_to(point(px(320.), px(200.)));            builder.line_to(point(px(270.), px(160.)));            builder.line_to(point(px(330.), px(160.)));            builder.line_to(point(px(350.), px(100.)));            let path = builder.build().unwrap();            lines.push((                path,                linear_gradient(                    180.,                    linear_color_stop(rgb(0xFACC15), 0.7),                    linear_color_stop(rgb(0xD56D0C), 1.),                )                .color_space(ColorSpace::Oklab),            ));        }         Self {            default_lines: lines,            _painting: false,        }    }} impl Render for PaintingViewer {    fn render(&mut self, window: &mut Window, _: &mut Context<Self>) -> impl IntoElement {        window.request_animation_frame();        let lines = self.default_lines.clone();        div().size_full().child(            canvas(                move |_, _, _| {},                move |_, _, window, _| {                    for (path, color) in lines {                        window.paint_path(path, color);                    }                },            )            .size_full(),        )    }} fn main() {    application().run(|cx| {        cx.open_window(            WindowOptions {                titlebar: Some(TitlebarOptions {                    title: Some("Vulkan".into()),                    ..Default::default()                }),                focus: true,                window_bounds: Some(WindowBounds::Windowed(Bounds::centered(                    None,                    size(DEFAULT_WINDOW_WIDTH, DEFAULT_WINDOW_HEIGHT),                    cx,                ))),                ..Default::default()            },            |window, cx| cx.new(|cx| PaintingViewer::new(window, cx)),        )        .unwrap();        cx.activate(true);    });}