chore(example): move demo2 to top level folder (#1524)

examples/README.md

@@ -42,3 +42,9 @@ This is the original demo example from the main README. It is available for each
 [Source](./apps/demo/).
 
 ![Demo](https://github.com/ratatui/ratatui/blob/images/examples/demo.gif?raw=true)
+
+## Demo2
+
+This is the demo example from the main README and crate page. [Source](./apps/demo2/).
+
+![Demo2](https://github.com/ratatui/ratatui/blob/images/examples/demo2.gif?raw=true)

examples/apps/demo/Cargo.toml

@@ -1,15 +1,7 @@
 [package]
 name = "demo"
 publish = false
-authors.workspace = true
-documentation.workspace = true
-repository.workspace = true
-homepage.workspace = true
-keywords.workspace = true
-categories.workspace = true
-readme.workspace = true
 license.workspace = true
-exclude.workspace = true
 edition.workspace = true
 rust-version.workspace = true
 

examples/apps/demo2/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "demo2"
+publish = false
+license.workspace = true
+edition.workspace = true
+rust-version.workspace = true
+
+[dependencies]
+color-eyre = "0.6.3"
+crossterm.workspace = true
+indoc.workspace = true
+itertools.workspace = true
+palette = "0.7.6"
+rand = "0.8.5"
+rand_chacha = "0.3.1"
+ratatui = { workspace = true, features = ["all-widgets"] }
+strum.workspace = true
+time = "0.3.36"
+unicode-width = "0.2.0"

examples/apps/demo2/README.md

@@ -0,0 +1,9 @@
+## Demo2
+
+This is the demo example from the main README and crate page. Source: [demo2](./demo2/).
+
+```shell
+cargo run -p demo2
+```
+
+![Demo2](https://github.com/ratatui/ratatui/blob/images/examples/demo2.gif?raw=true)

examples/apps/demo2/src/app.rs

@@ -0,0 +1,225 @@
+use std::time::Duration;
+
+use color_eyre::{eyre::Context, Result};
+use crossterm::event;
+use itertools::Itertools;
+use ratatui::{
+    buffer::Buffer,
+    crossterm::event::{Event, KeyCode, KeyEvent, KeyEventKind},
+    layout::{Constraint, Layout, Rect},
+    style::Color,
+    text::{Line, Span},
+    widgets::{Block, Tabs, Widget},
+    DefaultTerminal, Frame,
+};
+use strum::{Display, EnumIter, FromRepr, IntoEnumIterator};
+
+use crate::{
+    destroy,
+    tabs::{AboutTab, EmailTab, RecipeTab, TracerouteTab, WeatherTab},
+    THEME,
+};
+
+#[derive(Debug, Default, Clone, Copy, PartialEq, Eq)]
+pub struct App {
+    mode: Mode,
+    tab: Tab,
+    about_tab: AboutTab,
+    recipe_tab: RecipeTab,
+    email_tab: EmailTab,
+    traceroute_tab: TracerouteTab,
+    weather_tab: WeatherTab,
+}
+
+#[derive(Debug, Default, Clone, Copy, PartialEq, Eq)]
+enum Mode {
+    #[default]
+    Running,
+    Destroy,
+    Quit,
+}
+
+#[derive(Debug, Clone, Copy, Default, Display, EnumIter, FromRepr, PartialEq, Eq)]
+enum Tab {
+    #[default]
+    About,
+    Recipe,
+    Email,
+    Traceroute,
+    Weather,
+}
+
+impl App {
+    /// Run the app until the user quits.
+    pub fn run(mut self, mut terminal: DefaultTerminal) -> Result<()> {
+        while self.is_running() {
+            terminal
+                .draw(|frame| self.draw(frame))
+                .wrap_err("terminal.draw")?;
+            self.handle_events()?;
+        }
+        Ok(())
+    }
+
+    fn is_running(&self) -> bool {
+        self.mode != Mode::Quit
+    }
+
+    /// Draw a single frame of the app.
+    fn draw(&self, frame: &mut Frame) {
+        frame.render_widget(self, frame.area());
+        if self.mode == Mode::Destroy {
+            destroy::destroy(frame);
+        }
+    }
+
+    /// Handle events from the terminal.
+    ///
+    /// This function is called once per frame, The events are polled from the stdin with timeout of
+    /// 1/50th of a second. This was chosen to try to match the default frame rate of a GIF in VHS.
+    fn handle_events(&mut self) -> Result<()> {
+        let timeout = Duration::from_secs_f64(1.0 / 50.0);
+        if !event::poll(timeout)? {
+            return Ok(());
+        }
+        match event::read()? {
+            Event::Key(key) if key.kind == KeyEventKind::Press => self.handle_key_press(key),
+            _ => {}
+        }
+        Ok(())
+    }
+
+    fn handle_key_press(&mut self, key: KeyEvent) {
+        match key.code {
+            KeyCode::Char('q') | KeyCode::Esc => self.mode = Mode::Quit,
+            KeyCode::Char('h') | KeyCode::Left => self.prev_tab(),
+            KeyCode::Char('l') | KeyCode::Right => self.next_tab(),
+            KeyCode::Char('k') | KeyCode::Up => self.prev(),
+            KeyCode::Char('j') | KeyCode::Down => self.next(),
+            KeyCode::Char('d') | KeyCode::Delete => self.destroy(),
+            _ => {}
+        };
+    }
+
+    fn prev(&mut self) {
+        match self.tab {
+            Tab::About => self.about_tab.prev_row(),
+            Tab::Recipe => self.recipe_tab.prev(),
+            Tab::Email => self.email_tab.prev(),
+            Tab::Traceroute => self.traceroute_tab.prev_row(),
+            Tab::Weather => self.weather_tab.prev(),
+        }
+    }
+
+    fn next(&mut self) {
+        match self.tab {
+            Tab::About => self.about_tab.next_row(),
+            Tab::Recipe => self.recipe_tab.next(),
+            Tab::Email => self.email_tab.next(),
+            Tab::Traceroute => self.traceroute_tab.next_row(),
+            Tab::Weather => self.weather_tab.next(),
+        }
+    }
+
+    fn prev_tab(&mut self) {
+        self.tab = self.tab.prev();
+    }
+
+    fn next_tab(&mut self) {
+        self.tab = self.tab.next();
+    }
+
+    fn destroy(&mut self) {
+        self.mode = Mode::Destroy;
+    }
+}
+
+/// Implement Widget for &App rather than for App as we would otherwise have to clone or copy the
+/// entire app state on every frame. For this example, the app state is small enough that it doesn't
+/// matter, but for larger apps this can be a significant performance improvement.
+impl Widget for &App {
+    fn render(self, area: Rect, buf: &mut Buffer) {
+        let vertical = Layout::vertical([
+            Constraint::Length(1),
+            Constraint::Min(0),
+            Constraint::Length(1),
+        ]);
+        let [title_bar, tab, bottom_bar] = vertical.areas(area);
+
+        Block::new().style(THEME.root).render(area, buf);
+        self.render_title_bar(title_bar, buf);
+        self.render_selected_tab(tab, buf);
+        App::render_bottom_bar(bottom_bar, buf);
+    }
+}
+
+impl App {
+    fn render_title_bar(&self, area: Rect, buf: &mut Buffer) {
+        let layout = Layout::horizontal([Constraint::Min(0), Constraint::Length(43)]);
+        let [title, tabs] = layout.areas(area);
+
+        Span::styled("Ratatui", THEME.app_title).render(title, buf);
+        let titles = Tab::iter().map(Tab::title);
+        Tabs::new(titles)
+            .style(THEME.tabs)
+            .highlight_style(THEME.tabs_selected)
+            .select(self.tab as usize)
+            .divider("")
+            .padding("", "")
+            .render(tabs, buf);
+    }
+
+    fn render_selected_tab(&self, area: Rect, buf: &mut Buffer) {
+        match self.tab {
+            Tab::About => self.about_tab.render(area, buf),
+            Tab::Recipe => self.recipe_tab.render(area, buf),
+            Tab::Email => self.email_tab.render(area, buf),
+            Tab::Traceroute => self.traceroute_tab.render(area, buf),
+            Tab::Weather => self.weather_tab.render(area, buf),
+        };
+    }
+
+    fn render_bottom_bar(area: Rect, buf: &mut Buffer) {
+        let keys = [
+            ("H/←", "Left"),
+            ("L/→", "Right"),
+            ("K/↑", "Up"),
+            ("J/↓", "Down"),
+            ("D/Del", "Destroy"),
+            ("Q/Esc", "Quit"),
+        ];
+        let spans = keys
+            .iter()
+            .flat_map(|(key, desc)| {
+                let key = Span::styled(format!(" {key} "), THEME.key_binding.key);
+                let desc = Span::styled(format!(" {desc} "), THEME.key_binding.description);
+                [key, desc]
+            })
+            .collect_vec();
+        Line::from(spans)
+            .centered()
+            .style((Color::Indexed(236), Color::Indexed(232)))
+            .render(area, buf);
+    }
+}
+
+impl Tab {
+    fn next(self) -> Self {
+        let current_index = self as usize;
+        let next_index = current_index.saturating_add(1);
+        Self::from_repr(next_index).unwrap_or(self)
+    }
+
+    fn prev(self) -> Self {
+        let current_index = self as usize;
+        let prev_index = current_index.saturating_sub(1);
+        Self::from_repr(prev_index).unwrap_or(self)
+    }
+
+    fn title(self) -> String {
+        match self {
+            Self::About => String::new(),
+            tab => format!(" {tab} "),
+        }
+    }
+}

examples/apps/demo2/src/colors.rs

@@ -0,0 +1,35 @@
+use palette::{IntoColor, Okhsv, Srgb};
+use ratatui::{buffer::Buffer, layout::Rect, style::Color, widgets::Widget};
+
+/// A widget that renders a color swatch of RGB colors.
+///
+/// The widget is rendered as a rectangle with the hue changing along the x-axis from 0.0 to 360.0
+/// and the value changing along the y-axis (from 1.0 to 0.0). Each pixel is rendered as a block
+/// character with the top half slightly lighter than the bottom half.
+pub struct RgbSwatch;
+
+impl Widget for RgbSwatch {
+    #[allow(clippy::cast_precision_loss, clippy::similar_names)]
+    fn render(self, area: Rect, buf: &mut Buffer) {
+        for (yi, y) in (area.top()..area.bottom()).enumerate() {
+            let value = f32::from(area.height) - yi as f32;
+            let value_fg = value / f32::from(area.height);
+            let value_bg = (value - 0.5) / f32::from(area.height);
+            for (xi, x) in (area.left()..area.right()).enumerate() {
+                let hue = xi as f32 * 360.0 / f32::from(area.width);
+                let fg = color_from_oklab(hue, Okhsv::max_saturation(), value_fg);
+                let bg = color_from_oklab(hue, Okhsv::max_saturation(), value_bg);
+                buf[(x, y)].set_char('▀').set_fg(fg).set_bg(bg);
+            }
+        }
+    }
+}
+
+/// Convert a hue and value into an RGB color via the Oklab color space.
+///
+/// See <https://bottosson.github.io/posts/oklab/> for more details.
+pub fn color_from_oklab(hue: f32, saturation: f32, value: f32) -> Color {
+    let color: Srgb = Okhsv::new(hue, saturation, value).into_color();
+    let color = color.into_format();
+    Color::Rgb(color.red, color.green, color.blue)
+}

examples/apps/demo2/src/destroy.rs

@@ -0,0 +1,142 @@
+use rand::Rng;
+use rand_chacha::rand_core::SeedableRng;
+use ratatui::{
+    buffer::Buffer,
+    layout::{Flex, Layout, Rect},
+    style::{Color, Style},
+    text::Text,
+    widgets::Widget,
+    Frame,
+};
+
+/// delay the start of the animation so it doesn't start immediately
+const DELAY: usize = 120;
+/// higher means more pixels per frame are modified in the animation
+const DRIP_SPEED: usize = 500;
+/// delay the start of the text animation so it doesn't start immediately after the initial delay
+const TEXT_DELAY: usize = 180;
+
+/// Destroy mode activated by pressing `d`
+pub fn destroy(frame: &mut Frame<'_>) {
+    let frame_count = frame.count().saturating_sub(DELAY);
+    if frame_count == 0 {
+        return;
+    }
+
+    let area = frame.area();
+    let buf = frame.buffer_mut();
+
+    drip(frame_count, area, buf);
+    text(frame_count, area, buf);
+}
+
+/// Move a bunch of random pixels down one row.
+///
+/// Each pick some random pixels and move them each down one row. This is a very inefficient way to
+/// do this, but it works well enough for this demo.
+#[allow(
+    clippy::cast_possible_truncation,
+    clippy::cast_precision_loss,
+    clippy::cast_sign_loss
+)]
+fn drip(frame_count: usize, area: Rect, buf: &mut Buffer) {
+    // a seeded rng as we have to move the same random pixels each frame
+    let mut rng = rand_chacha::ChaCha8Rng::seed_from_u64(10);
+    let ramp_frames = 450;
+    let fractional_speed = frame_count as f64 / f64::from(ramp_frames);
+    let variable_speed = DRIP_SPEED as f64 * fractional_speed * fractional_speed * fractional_speed;
+    let pixel_count = (frame_count as f64 * variable_speed).floor() as usize;
+    for _ in 0..pixel_count {
+        let src_x = rng.gen_range(0..area.width);
+        let src_y = rng.gen_range(1..area.height - 2);
+        let src = buf[(src_x, src_y)].clone();
+        // 1% of the time, move a blank or pixel (10:1) to the top line of the screen
+        if rng.gen_ratio(1, 100) {
+            let dest_x = rng
+                .gen_range(src_x.saturating_sub(5)..src_x.saturating_add(5))
+                .clamp(area.left(), area.right() - 1);
+            let dest_y = area.top() + 1;
+
+            let dest = &mut buf[(dest_x, dest_y)];
+            // copy the cell to the new location about 1/10 of the time blank out the cell the rest
+            // of the time. This has the effect of gradually removing the pixels from the screen.
+            if rng.gen_ratio(1, 10) {
+                *dest = src;
+            } else {
+                dest.reset();
+            }
+        } else {
+            // move the pixel down one row
+            let dest_x = src_x;
+            let dest_y = src_y.saturating_add(1).min(area.bottom() - 2);
+            // copy the cell to the new location
+            buf[(dest_x, dest_y)] = src;
+        }
+    }
+}
+
+/// draw some text fading in and out from black to red and back
+#[allow(clippy::cast_possible_truncation, clippy::cast_precision_loss)]
+fn text(frame_count: usize, area: Rect, buf: &mut Buffer) {
+    let sub_frame = frame_count.saturating_sub(TEXT_DELAY);
+    if sub_frame == 0 {
+        return;
+    }
+
+    let logo = indoc::indoc! {"
+        ██████      ████    ██████    ████    ██████  ██    ██  ██
+        ██    ██  ██    ██    ██    ██    ██    ██    ██    ██  ██
+        ██████    ████████    ██    ████████    ██    ██    ██  ██
+        ██  ██    ██    ██    ██    ██    ██    ██    ██    ██  ██
+        ██    ██  ██    ██    ██    ██    ██    ██      ████    ██
+    "};
+    let logo_text = Text::styled(logo, Color::Rgb(255, 255, 255));
+    let area = centered_rect(area, logo_text.width() as u16, logo_text.height() as u16);
+
+    let mask_buf = &mut Buffer::empty(area);
+    logo_text.render(area, mask_buf);
+
+    let percentage = (sub_frame as f64 / 480.0).clamp(0.0, 1.0);
+
+    for row in area.rows() {
+        for col in row.columns() {
+            let cell = &mut buf[(col.x, col.y)];
+            let mask_cell = &mut mask_buf[(col.x, col.y)];
+            cell.set_symbol(mask_cell.symbol());
+
+            // blend the mask cell color with the cell color
+            let cell_color = cell.style().bg.unwrap_or(Color::Rgb(0, 0, 0));
+            let mask_color = mask_cell.style().fg.unwrap_or(Color::Rgb(255, 0, 0));
+
+            let color = blend(mask_color, cell_color, percentage);
+            cell.set_style(Style::new().fg(color));
+        }
+    }
+}
+
+fn blend(mask_color: Color, cell_color: Color, percentage: f64) -> Color {
+    let Color::Rgb(mask_red, mask_green, mask_blue) = mask_color else {
+        return mask_color;
+    };
+    let Color::Rgb(cell_red, cell_green, cell_blue) = cell_color else {
+        return mask_color;
+    };
+
+    let remain = 1.0 - percentage;
+
+    let red = f64::from(mask_red).mul_add(percentage, f64::from(cell_red) * remain);
+    let green = f64::from(mask_green).mul_add(percentage, f64::from(cell_green) * remain);
+    let blue = f64::from(mask_blue).mul_add(percentage, f64::from(cell_blue) * remain);
+
+    #[allow(clippy::cast_possible_truncation, clippy::cast_sign_loss)]
+    Color::Rgb(red as u8, green as u8, blue as u8)
+}
+
+/// a centered rect of the given size
+fn centered_rect(area: Rect, width: u16, height: u16) -> Rect {
+    let horizontal = Layout::horizontal([width]).flex(Flex::Center);
+    let vertical = Layout::vertical([height]).flex(Flex::Center);
+    let [area] = vertical.areas(area);
+    let [area] = horizontal.areas(area);
+    area
+}

examples/apps/demo2/src/main.rs

@@ -0,0 +1,54 @@
+//! # [Ratatui] Demo2 example
+//!
+//! The latest version of this example is available in the [examples] folder in the repository.
+//!
+//! Please note that the examples are designed to be run against the `main` branch of the Github
+//! repository. This means that you may not be able to compile with the latest release version on
+//! crates.io, or the one that you have installed locally.
+//!
+//! See the [examples readme] for more information on finding examples that match the version of the
+//! library you are using.
+//!
+//! [Ratatui]: https://github.com/ratatui/ratatui
+//! [examples]: https://github.com/ratatui/ratatui/blob/main/examples
+//! [examples readme]: https://github.com/ratatui/ratatui/blob/main/examples/README.md
+
+#![allow(
+    clippy::missing_errors_doc,
+    clippy::module_name_repetitions,
+    clippy::must_use_candidate
+)]
+
+mod app;
+mod colors;
+mod destroy;
+mod tabs;
+mod theme;
+
+use std::io::stdout;
+
+use app::App;
+use color_eyre::Result;
+use crossterm::{
+    execute,
+    terminal::{EnterAlternateScreen, LeaveAlternateScreen},
+};
+use ratatui::{layout::Rect, TerminalOptions, Viewport};
+
+pub use self::{
+    colors::{color_from_oklab, RgbSwatch},
+    theme::THEME,
+};
+
+fn main() -> Result<()> {
+    color_eyre::install()?;
+    // this size is to match the size of the terminal when running the demo
+    // using vhs in a 1280x640 sized window (github social preview size)
+    let viewport = Viewport::Fixed(Rect::new(0, 0, 81, 18));
+    let terminal = ratatui::init_with_options(TerminalOptions { viewport });
+    execute!(stdout(), EnterAlternateScreen).expect("failed to enter alternate screen");
+    let app_result = App::default().run(terminal);
+    execute!(stdout(), LeaveAlternateScreen).expect("failed to leave alternate screen");
+    ratatui::restore();
+    app_result
+}

examples/apps/demo2/src/tabs.rs

@@ -0,0 +1,11 @@
+mod about;
+mod email;
+mod recipe;
+mod traceroute;
+mod weather;
+
+pub use about::AboutTab;
+pub use email::EmailTab;
+pub use recipe::RecipeTab;
+pub use traceroute::TracerouteTab;
+pub use weather::WeatherTab;

examples/apps/demo2/src/tabs/about.rs

@@ -0,0 +1,165 @@
+use itertools::Itertools;
+use ratatui::{
+    buffer::Buffer,
+    layout::{Alignment, Constraint, Layout, Margin, Rect},
+    widgets::{Block, Borders, Clear, Padding, Paragraph, Widget, Wrap},
+};
+
+use crate::{RgbSwatch, THEME};
+
+const RATATUI_LOGO: [&str; 32] = [
+    "               ███              ",
+    "             ██████             ",
+    "            ███████             ",
+    "           ████████             ",
+    "          █████████             ",
+    "         ██████████             ",
+    "        ████████████            ",
+    "        █████████████           ",
+    "        █████████████     ██████",
+    "         ███████████    ████████",
+    "              █████ ███████████ ",
+    "               ███ ██ee████████ ",
+    "                █ █████████████ ",
+    "            ████ █████████████  ",
+    "           █████████████████    ",
+    "           ████████████████     ",
+    "           ████████████████     ",
+    "            ███ ██████████      ",
+    "          ██    █████████       ",
+    "         █xx█   █████████       ",
+    "        █xxxx█ ██████████       ",
+    "       █xx█xxx█ █████████       ",
+    "      █xx██xxxx█ ████████       ",
+    "     █xxxxxxxxxx█ ██████████    ",
+    "    █xxxxxxxxxxxx█ ██████████   ",
+    "   █xxxxxxx██xxxxx█ █████████   ",
+    "  █xxxxxxxxx██xxxxx█ ████  ███  ",
+    " █xxxxxxxxxxxxxxxxxx█ ██   ███  ",
+    "█xxxxxxxxxxxxxxxxxxxx█ █   ███  ",
+    "█xxxxxxxxxxxxxxxxxxxxx█   ███   ",
+    " █xxxxxxxxxxxxxxxxxxxxx█ ███    ",
+    "  █xxxxxxxxxxxxxxxxxxxxx█ █     ",
+];
+
+#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
+pub struct AboutTab {
+    row_index: usize,
+}
+
+impl AboutTab {
+    pub fn prev_row(&mut self) {
+        self.row_index = self.row_index.saturating_sub(1);
+    }
+
+    pub fn next_row(&mut self) {
+        self.row_index = self.row_index.saturating_add(1);
+    }
+}
+
+impl Widget for AboutTab {
+    fn render(self, area: Rect, buf: &mut Buffer) {
+        RgbSwatch.render(area, buf);
+        let horizontal = Layout::horizontal([Constraint::Length(34), Constraint::Min(0)]);
+        let [description, logo] = horizontal.areas(area);
+        render_crate_description(description, buf);
+        render_logo(self.row_index, logo, buf);
+    }
+}
+
+fn render_crate_description(area: Rect, buf: &mut Buffer) {
+    let area = area.inner(Margin {
+        vertical: 4,
+        horizontal: 2,
+    });
+    Clear.render(area, buf); // clear out the color swatches
+    Block::new().style(THEME.content).render(area, buf);
+    let area = area.inner(Margin {
+        vertical: 1,
+        horizontal: 2,
+    });
+    let text = "- cooking up terminal user interfaces -
+
+    Ratatui is a Rust crate that provides widgets (e.g. Paragraph, Table) and draws them to the \
+    screen efficiently every frame.";
+    Paragraph::new(text)
+        .style(THEME.description)
+        .block(
+            Block::new()
+                .title(" Ratatui ")
+                .title_alignment(Alignment::Center)
+                .borders(Borders::TOP)
+                .border_style(THEME.description_title)
+                .padding(Padding::new(0, 0, 0, 0)),
+        )
+        .wrap(Wrap { trim: true })
+        .scroll((0, 0))
+        .render(area, buf);
+}
+
+/// Use half block characters to render a logo based on the `RATATUI_LOGO` const.
+///
+/// The logo is rendered in three colors, one for the rat, one for the terminal, and one for the
+/// rat's eye. The eye color alternates between two colors based on the selected row.
+#[allow(clippy::cast_possible_truncation)]
+pub fn render_logo(selected_row: usize, area: Rect, buf: &mut Buffer) {
+    let eye_color = if selected_row % 2 == 0 {
+        THEME.logo.rat_eye
+    } else {
+        THEME.logo.rat_eye_alt
+    };
+    let area = area.inner(Margin {
+        vertical: 0,
+        horizontal: 2,
+    });
+    for (y, (line1, line2)) in RATATUI_LOGO.iter().tuples().enumerate() {
+        for (x, (ch1, ch2)) in line1.chars().zip(line2.chars()).enumerate() {
+            let x = area.left() + x as u16;
+            let y = area.top() + y as u16;
+            let cell = &mut buf[(x, y)];
+            let rat_color = THEME.logo.rat;
+            let term_color = THEME.logo.term;
+            match (ch1, ch2) {
+                ('█', '█') => {
+                    cell.set_char('█');
+                    cell.fg = rat_color;
+                    cell.bg = rat_color;
+                }
+                ('█', ' ') => {
+                    cell.set_char('▀');
+                    cell.fg = rat_color;
+                }
+                (' ', '█') => {
+                    cell.set_char('▄');
+                    cell.fg = rat_color;
+                }
+                ('█', 'x') => {
+                    cell.set_char('▀');
+                    cell.fg = rat_color;
+                    cell.bg = term_color;
+                }
+                ('x', '█') => {
+                    cell.set_char('▄');
+                    cell.fg = rat_color;
+                    cell.bg = term_color;
+                }
+                ('x', 'x') => {
+                    cell.set_char(' ');
+                    cell.fg = term_color;
+                    cell.bg = term_color;
+                }
+                ('█', 'e') => {
+                    cell.set_char('▀');
+                    cell.fg = rat_color;
+                    cell.bg = eye_color;
+                }
+                ('e', '█') => {
+                    cell.set_char('▄');
+                    cell.fg = rat_color;
+                    cell.bg = eye_color;
+                }
+                (_, _) => {}
+            };
+        }
+    }
+}

examples/apps/demo2/src/tabs/email.rs

@@ -0,0 +1,158 @@
+use itertools::Itertools;
+use ratatui::{
+    buffer::Buffer,
+    layout::{Constraint, Layout, Margin, Rect},
+    style::{Styled, Stylize},
+    text::Line,
+    widgets::{
+        Block, BorderType, Borders, Clear, List, ListItem, ListState, Padding, Paragraph,
+        Scrollbar, ScrollbarState, StatefulWidget, Tabs, Widget,
+    },
+};
+use unicode_width::UnicodeWidthStr;
+
+use crate::{RgbSwatch, THEME};
+
+#[derive(Debug, Default)]
+pub struct Email {
+    from: &'static str,
+    subject: &'static str,
+    body: &'static str,
+}
+
+const EMAILS: &[Email] = &[
+    Email {
+        from: "Alice <alice@example.com>",
+        subject: "Hello",
+        body: "Hi Bob,\nHow are you?\n\nAlice",
+    },
+    Email {
+        from: "Bob <bob@example.com>",
+        subject: "Re: Hello",
+        body: "Hi Alice,\nI'm fine, thanks!\n\nBob",
+    },
+    Email {
+        from: "Charlie <charlie@example.com>",
+        subject: "Re: Hello",
+        body: "Hi Alice,\nI'm fine, thanks!\n\nCharlie",
+    },
+    Email {
+        from: "Dave <dave@example.com>",
+        subject: "Re: Hello (STOP REPLYING TO ALL)",
+        body: "Hi Everyone,\nPlease stop replying to all.\n\nDave",
+    },
+    Email {
+        from: "Eve <eve@example.com>",
+        subject: "Re: Hello (STOP REPLYING TO ALL)",
+        body: "Hi Everyone,\nI'm reading all your emails.\n\nEve",
+    },
+];
+
+#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
+pub struct EmailTab {
+    row_index: usize,
+}
+
+impl EmailTab {
+    /// Select the previous email (with wrap around).
+    pub fn prev(&mut self) {
+        self.row_index = self.row_index.saturating_add(EMAILS.len() - 1) % EMAILS.len();
+    }
+
+    /// Select the next email (with wrap around).
+    pub fn next(&mut self) {
+        self.row_index = self.row_index.saturating_add(1) % EMAILS.len();
+    }
+}
+
+impl Widget for EmailTab {
+    fn render(self, area: Rect, buf: &mut Buffer) {
+        RgbSwatch.render(area, buf);
+        let area = area.inner(Margin {
+            vertical: 1,
+            horizontal: 2,
+        });
+        Clear.render(area, buf);
+        let vertical = Layout::vertical([Constraint::Length(5), Constraint::Min(0)]);
+        let [inbox, email] = vertical.areas(area);
+        render_inbox(self.row_index, inbox, buf);
+        render_email(self.row_index, email, buf);
+    }
+}
+fn render_inbox(selected_index: usize, area: Rect, buf: &mut Buffer) {
+    let vertical = Layout::vertical([Constraint::Length(1), Constraint::Min(0)]);
+    let [tabs, inbox] = vertical.areas(area);
+    let theme = THEME.email;
+    Tabs::new(vec![" Inbox ", " Sent ", " Drafts "])
+        .style(theme.tabs)
+        .highlight_style(theme.tabs_selected)
+        .select(0)
+        .divider("")
+        .render(tabs, buf);
+
+    let highlight_symbol = ">>";
+    let from_width = EMAILS
+        .iter()
+        .map(|e| e.from.width())
+        .max()
+        .unwrap_or_default();
+    let items = EMAILS.iter().map(|e| {
+        let from = format!("{:width$}", e.from, width = from_width).into();
+        ListItem::new(Line::from(vec![from, " ".into(), e.subject.into()]))
+    });
+    let mut state = ListState::default().with_selected(Some(selected_index));
+    StatefulWidget::render(
+        List::new(items)
+            .style(theme.inbox)
+            .highlight_style(theme.selected_item)
+            .highlight_symbol(highlight_symbol),
+        inbox,
+        buf,
+        &mut state,
+    );
+    let mut scrollbar_state = ScrollbarState::default()
+        .content_length(EMAILS.len())
+        .position(selected_index);
+    Scrollbar::default()
+        .begin_symbol(None)
+        .end_symbol(None)
+        .track_symbol(None)
+        .thumb_symbol("▐")
+        .render(inbox, buf, &mut scrollbar_state);
+}
+
+fn render_email(selected_index: usize, area: Rect, buf: &mut Buffer) {
+    let theme = THEME.email;
+    let email = EMAILS.get(selected_index);
+    let block = Block::new()
+        .style(theme.body)
+        .padding(Padding::new(2, 2, 0, 0))
+        .borders(Borders::TOP)
+        .border_type(BorderType::Thick);
+    let inner = block.inner(area);
+    block.render(area, buf);
+    if let Some(email) = email {
+        let vertical = Layout::vertical([Constraint::Length(3), Constraint::Min(0)]);
+        let [headers_area, body_area] = vertical.areas(inner);
+        let headers = vec![
+            Line::from(vec![
+                "From: ".set_style(theme.header),
+                email.from.set_style(theme.header_value),
+            ]),
+            Line::from(vec![
+                "Subject: ".set_style(theme.header),
+                email.subject.set_style(theme.header_value),
+            ]),
+            "-".repeat(inner.width as usize).dim().into(),
+        ];
+        Paragraph::new(headers)
+            .style(theme.body)
+            .render(headers_area, buf);
+        let body = email.body.lines().map(Line::from).collect_vec();
+        Paragraph::new(body)
+            .style(theme.body)
+            .render(body_area, buf);
+    } else {
+        Paragraph::new("No email selected").render(inner, buf);
+    }
+}

examples/apps/demo2/src/tabs/recipe.rs

@@ -0,0 +1,185 @@
+use itertools::Itertools;
+use ratatui::{
+    buffer::Buffer,
+    layout::{Alignment, Constraint, Layout, Margin, Rect},
+    style::{Style, Stylize},
+    text::Line,
+    widgets::{
+        Block, Clear, Padding, Paragraph, Row, Scrollbar, ScrollbarOrientation, ScrollbarState,
+        StatefulWidget, Table, TableState, Widget, Wrap,
+    },
+};
+
+use crate::{RgbSwatch, THEME};
+
+#[derive(Debug, Default, Clone, Copy)]
+struct Ingredient {
+    quantity: &'static str,
+    name: &'static str,
+}
+
+impl Ingredient {
+    #[allow(clippy::cast_possible_truncation)]
+    fn height(&self) -> u16 {
+        self.name.lines().count() as u16
+    }
+}
+
+impl From<Ingredient> for Row<'_> {
+    fn from(i: Ingredient) -> Self {
+        Row::new(vec![i.quantity, i.name]).height(i.height())
+    }
+}
+
+// https://www.realsimple.com/food-recipes/browse-all-recipes/ratatouille
+const RECIPE: &[(&str, &str)] = &[
+    (
+        "Step 1: ",
+        "Over medium-low heat, add the oil to a large skillet with the onion, garlic, and bay \
+        leaf, stirring occasionally, until the onion has softened.",
+    ),
+    (
+        "Step 2: ",
+        "Add the eggplant and cook, stirring occasionally, for 8 minutes or until the eggplant \
+        has softened. Stir in the zucchini, red bell pepper, tomatoes, and salt, and cook over \
+        medium heat, stirring occasionally, for 5 to 7 minutes or until the vegetables are \
+        tender. Stir in the basil and few grinds of pepper to taste.",
+    ),
+];
+
+const INGREDIENTS: &[Ingredient] = &[
+    Ingredient {
+        quantity: "4 tbsp",
+        name: "olive oil",
+    },
+    Ingredient {
+        quantity: "1",
+        name: "onion thinly sliced",
+    },
+    Ingredient {
+        quantity: "4",
+        name: "cloves garlic\npeeled and sliced",
+    },
+    Ingredient {
+        quantity: "1",
+        name: "small bay leaf",
+    },
+    Ingredient {
+        quantity: "1",
+        name: "small eggplant cut\ninto 1/2 inch cubes",
+    },
+    Ingredient {
+        quantity: "1",
+        name: "small zucchini halved\nlengthwise and cut\ninto thin slices",
+    },
+    Ingredient {
+        quantity: "1",
+        name: "red bell pepper cut\ninto slivers",
+    },
+    Ingredient {
+        quantity: "4",
+        name: "plum tomatoes\ncoarsely chopped",
+    },
+    Ingredient {
+        quantity: "1 tsp",
+        name: "kosher salt",
+    },
+    Ingredient {
+        quantity: "1/4 cup",
+        name: "shredded fresh basil\nleaves",
+    },
+    Ingredient {
+        quantity: "",
+        name: "freshly ground black\npepper",
+    },
+];
+
+#[derive(Debug, Default, Clone, Copy, PartialEq, Eq)]
+pub struct RecipeTab {
+    row_index: usize,
+}
+
+impl RecipeTab {
+    /// Select the previous item in the ingredients list (with wrap around)
+    pub fn prev(&mut self) {
+        self.row_index = self.row_index.saturating_add(INGREDIENTS.len() - 1) % INGREDIENTS.len();
+    }
+
+    /// Select the next item in the ingredients list (with wrap around)
+    pub fn next(&mut self) {
+        self.row_index = self.row_index.saturating_add(1) % INGREDIENTS.len();
+    }
+}
+
+impl Widget for RecipeTab {
+    fn render(self, area: Rect, buf: &mut Buffer) {
+        RgbSwatch.render(area, buf);
+        let area = area.inner(Margin {
+            vertical: 1,
+            horizontal: 2,
+        });
+        Clear.render(area, buf);
+        Block::new()
+            .title("Ratatouille Recipe".bold().white())
+            .title_alignment(Alignment::Center)
+            .style(THEME.content)
+            .padding(Padding::new(1, 1, 2, 1))
+            .render(area, buf);
+
+        let scrollbar_area = Rect {
+            y: area.y + 2,
+            height: area.height - 3,
+            ..area
+        };
+        render_scrollbar(self.row_index, scrollbar_area, buf);
+
+        let area = area.inner(Margin {
+            horizontal: 2,
+            vertical: 1,
+        });
+        let [recipe, ingredients] =
+            Layout::horizontal([Constraint::Length(44), Constraint::Min(0)]).areas(area);
+
+        render_recipe(recipe, buf);
+        render_ingredients(self.row_index, ingredients, buf);
+    }
+}
+
+fn render_recipe(area: Rect, buf: &mut Buffer) {
+    let lines = RECIPE
+        .iter()
+        .map(|(step, text)| Line::from(vec![step.white().bold(), text.gray()]))
+        .collect_vec();
+    Paragraph::new(lines)
+        .wrap(Wrap { trim: true })
+        .block(Block::new().padding(Padding::new(0, 1, 0, 0)))
+        .render(area, buf);
+}
+
+fn render_ingredients(selected_row: usize, area: Rect, buf: &mut Buffer) {
+    let mut state = TableState::default().with_selected(Some(selected_row));
+    let rows = INGREDIENTS.iter().copied();
+    let theme = THEME.recipe;
+    StatefulWidget::render(
+        Table::new(rows, [Constraint::Length(7), Constraint::Length(30)])
+            .block(Block::new().style(theme.ingredients))
+            .header(Row::new(vec!["Qty", "Ingredient"]).style(theme.ingredients_header))
+            .row_highlight_style(Style::new().light_yellow()),
+        area,
+        buf,
+        &mut state,
+    );
+}
+
+fn render_scrollbar(position: usize, area: Rect, buf: &mut Buffer) {
+    let mut state = ScrollbarState::default()
+        .content_length(INGREDIENTS.len())
+        .viewport_content_length(6)
+        .position(position);
+    Scrollbar::new(ScrollbarOrientation::VerticalRight)
+        .begin_symbol(None)
+        .end_symbol(None)
+        .track_symbol(None)
+        .thumb_symbol("▐")
+        .render(area, buf, &mut state);
+}

examples/apps/demo2/src/tabs/traceroute.rs

@@ -0,0 +1,206 @@
+use itertools::Itertools;
+use ratatui::{
+    buffer::Buffer,
+    layout::{Alignment, Constraint, Layout, Margin, Rect},
+    style::{Styled, Stylize},
+    symbols::Marker,
+    widgets::{
+        canvas::{self, Canvas, Map, MapResolution, Points},
+        Block, BorderType, Clear, Padding, Row, Scrollbar, ScrollbarOrientation, ScrollbarState,
+        Sparkline, StatefulWidget, Table, TableState, Widget,
+    },
+};
+
+use crate::{RgbSwatch, THEME};
+
+#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
+pub struct TracerouteTab {
+    row_index: usize,
+}
+
+impl TracerouteTab {
+    /// Select the previous row (with wrap around).
+    pub fn prev_row(&mut self) {
+        self.row_index = self.row_index.saturating_add(HOPS.len() - 1) % HOPS.len();
+    }
+
+    /// Select the next row (with wrap around).
+    pub fn next_row(&mut self) {
+        self.row_index = self.row_index.saturating_add(1) % HOPS.len();
+    }
+}
+
+impl Widget for TracerouteTab {
+    fn render(self, area: Rect, buf: &mut Buffer) {
+        RgbSwatch.render(area, buf);
+        let area = area.inner(Margin {
+            vertical: 1,
+            horizontal: 2,
+        });
+        Clear.render(area, buf);
+        Block::new().style(THEME.content).render(area, buf);
+        let horizontal = Layout::horizontal([Constraint::Ratio(1, 2), Constraint::Ratio(1, 2)]);
+        let vertical = Layout::vertical([Constraint::Min(0), Constraint::Length(3)]);
+        let [left, map] = horizontal.areas(area);
+        let [hops, pings] = vertical.areas(left);
+
+        render_hops(self.row_index, hops, buf);
+        render_ping(self.row_index, pings, buf);
+        render_map(self.row_index, map, buf);
+    }
+}
+
+fn render_hops(selected_row: usize, area: Rect, buf: &mut Buffer) {
+    let mut state = TableState::default().with_selected(Some(selected_row));
+    let rows = HOPS.iter().map(|hop| Row::new(vec![hop.host, hop.address]));
+    let block = Block::new()
+        .padding(Padding::new(1, 1, 1, 1))
+        .title_alignment(Alignment::Center)
+        .title("Traceroute bad.horse".bold().white());
+    StatefulWidget::render(
+        Table::new(rows, [Constraint::Max(100), Constraint::Length(15)])
+            .header(Row::new(vec!["Host", "Address"]).set_style(THEME.traceroute.header))
+            .row_highlight_style(THEME.traceroute.selected)
+            .block(block),
+        area,
+        buf,
+        &mut state,
+    );
+    let mut scrollbar_state = ScrollbarState::default()
+        .content_length(HOPS.len())
+        .position(selected_row);
+    let area = Rect {
+        width: area.width + 1,
+        y: area.y + 3,
+        height: area.height - 4,
+        ..area
+    };
+    Scrollbar::default()
+        .orientation(ScrollbarOrientation::VerticalLeft)
+        .begin_symbol(None)
+        .end_symbol(None)
+        .track_symbol(None)
+        .thumb_symbol("▌")
+        .render(area, buf, &mut scrollbar_state);
+}
+
+pub fn render_ping(progress: usize, area: Rect, buf: &mut Buffer) {
+    let mut data = [
+        8, 8, 8, 8, 7, 7, 7, 6, 6, 5, 4, 3, 3, 2, 2, 1, 1, 1, 2, 2, 3, 4, 5, 6, 7, 7, 8, 8, 8, 7,
+        7, 6, 5, 4, 3, 2, 1, 1, 1, 1, 1, 2, 4, 6, 7, 8, 8, 8, 8, 6, 4, 2, 1, 1, 1, 1, 2, 2, 2, 3,
+        3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7,
+    ];
+    let mid = progress % data.len();
+    data.rotate_left(mid);
+    Sparkline::default()
+        .block(
+            Block::new()
+                .title("Ping")
+                .title_alignment(Alignment::Center)
+                .border_type(BorderType::Thick),
+        )
+        .data(data)
+        .style(THEME.traceroute.ping)
+        .render(area, buf);
+}
+
+fn render_map(selected_row: usize, area: Rect, buf: &mut Buffer) {
+    let theme = THEME.traceroute.map;
+    let path: Option<(&Hop, &Hop)> = HOPS.iter().tuple_windows().nth(selected_row);
+    let map = Map {
+        resolution: MapResolution::High,
+        color: theme.color,
+    };
+    Canvas::default()
+        .background_color(theme.background_color)
+        .block(
+            Block::new()
+                .padding(Padding::new(1, 0, 1, 0))
+                .style(theme.style),
+        )
+        .marker(Marker::HalfBlock)
+        // picked to show Australia for the demo as it's the most interesting part of the map
+        // (and the only part with hops ;))
+        .x_bounds([112.0, 155.0])
+        .y_bounds([-46.0, -11.0])
+        .paint(|context| {
+            context.draw(&map);
+            if let Some(path) = path {
+                context.draw(&canvas::Line::new(
+                    path.0.location.0,
+                    path.0.location.1,
+                    path.1.location.0,
+                    path.1.location.1,
+                    theme.path,
+                ));
+                context.draw(&Points {
+                    color: theme.source,
+                    coords: &[path.0.location], // sydney
+                });
+                context.draw(&Points {
+                    color: theme.destination,
+                    coords: &[path.1.location], // perth
+                });
+            }
+        })
+        .render(area, buf);
+}
+
+#[derive(Debug)]
+struct Hop {
+    host: &'static str,
+    address: &'static str,
+    location: (f64, f64),
+}
+
+impl Hop {
+    const fn new(name: &'static str, address: &'static str, location: (f64, f64)) -> Self {
+        Self {
+            host: name,
+            address,
+            location,
+        }
+    }
+}
+
+const CANBERRA: (f64, f64) = (149.1, -35.3);
+const SYDNEY: (f64, f64) = (151.1, -33.9);
+const MELBOURNE: (f64, f64) = (144.9, -37.8);
+const PERTH: (f64, f64) = (115.9, -31.9);
+const DARWIN: (f64, f64) = (130.8, -12.4);
+const BRISBANE: (f64, f64) = (153.0, -27.5);
+const ADELAIDE: (f64, f64) = (138.6, -34.9);
+
+// Go traceroute bad.horse some time, it's fun. these locations are made up and don't correspond
+// to the actual IP addresses (which are in Toronto, Canada).
+const HOPS: &[Hop] = &[
+    Hop::new("home", "127.0.0.1", CANBERRA),
+    Hop::new("bad.horse", "162.252.205.130", SYDNEY),
+    Hop::new("bad.horse", "162.252.205.131", MELBOURNE),
+    Hop::new("bad.horse", "162.252.205.132", BRISBANE),
+    Hop::new("bad.horse", "162.252.205.133", SYDNEY),
+    Hop::new("he.rides.across.the.nation", "162.252.205.134", PERTH),
+    Hop::new("the.thoroughbred.of.sin", "162.252.205.135", DARWIN),
+    Hop::new("he.got.the.application", "162.252.205.136", BRISBANE),
+    Hop::new("that.you.just.sent.in", "162.252.205.137", ADELAIDE),
+    Hop::new("it.needs.evaluation", "162.252.205.138", DARWIN),
+    Hop::new("so.let.the.games.begin", "162.252.205.139", PERTH),
+    Hop::new("a.heinous.crime", "162.252.205.140", BRISBANE),
+    Hop::new("a.show.of.force", "162.252.205.141", CANBERRA),
+    Hop::new("a.murder.would.be.nice.of.course", "162.252.205.142", PERTH),
+    Hop::new("bad.horse", "162.252.205.143", MELBOURNE),
+    Hop::new("bad.horse", "162.252.205.144", DARWIN),
+    Hop::new("bad.horse", "162.252.205.145", MELBOURNE),
+    Hop::new("he-s.bad", "162.252.205.146", PERTH),
+    Hop::new("the.evil.league.of.evil", "162.252.205.147", BRISBANE),
+    Hop::new("is.watching.so.beware", "162.252.205.148", DARWIN),
+    Hop::new("the.grade.that.you.receive", "162.252.205.149", PERTH),
+    Hop::new("will.be.your.last.we.swear", "162.252.205.150", ADELAIDE),
+    Hop::new("so.make.the.bad.horse.gleeful", "162.252.205.151", SYDNEY),
+    Hop::new("or.he-ll.make.you.his.mare", "162.252.205.152", MELBOURNE),
+    Hop::new("o_o", "162.252.205.153", BRISBANE),
+    Hop::new("you-re.saddled.up", "162.252.205.154", DARWIN),
+    Hop::new("there-s.no.recourse", "162.252.205.155", PERTH),
+    Hop::new("it-s.hi-ho.silver", "162.252.205.156", SYDNEY),
+    Hop::new("signed.bad.horse", "162.252.205.157", CANBERRA),
+];

examples/apps/demo2/src/tabs/weather.rs

@@ -0,0 +1,164 @@
+use itertools::Itertools;
+use palette::Okhsv;
+use ratatui::{
+    buffer::Buffer,
+    layout::{Constraint, Direction, Layout, Margin, Rect},
+    style::{Color, Style, Stylize},
+    symbols,
+    widgets::{
+        calendar::{CalendarEventStore, Monthly},
+        Bar, BarChart, BarGroup, Block, Clear, LineGauge, Padding, Widget,
+    },
+};
+use time::OffsetDateTime;
+
+use crate::{color_from_oklab, RgbSwatch, THEME};
+
+#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
+pub struct WeatherTab {
+    pub download_progress: usize,
+}
+
+impl WeatherTab {
+    /// Simulate a download indicator by decrementing the row index.
+    pub fn prev(&mut self) {
+        self.download_progress = self.download_progress.saturating_sub(1);
+    }
+
+    /// Simulate a download indicator by incrementing the row index.
+    pub fn next(&mut self) {
+        self.download_progress = self.download_progress.saturating_add(1);
+    }
+}
+
+impl Widget for WeatherTab {
+    fn render(self, area: Rect, buf: &mut Buffer) {
+        RgbSwatch.render(area, buf);
+        let area = area.inner(Margin {
+            vertical: 1,
+            horizontal: 2,
+        });
+        Clear.render(area, buf);
+        Block::new().style(THEME.content).render(area, buf);
+
+        let area = area.inner(Margin {
+            horizontal: 2,
+            vertical: 1,
+        });
+        let [main, _, gauges] = Layout::vertical([
+            Constraint::Min(0),
+            Constraint::Length(1),
+            Constraint::Length(1),
+        ])
+        .areas(area);
+        let [calendar, charts] =
+            Layout::horizontal([Constraint::Length(23), Constraint::Min(0)]).areas(main);
+        let [simple, horizontal] =
+            Layout::vertical([Constraint::Length(29), Constraint::Min(0)]).areas(charts);
+
+        render_calendar(calendar, buf);
+        render_simple_barchart(simple, buf);
+        render_horizontal_barchart(horizontal, buf);
+        render_gauge(self.download_progress, gauges, buf);
+    }
+}
+
+fn render_calendar(area: Rect, buf: &mut Buffer) {
+    let date = OffsetDateTime::now_utc().date();
+    Monthly::new(date, CalendarEventStore::today(Style::new().red().bold()))
+        .block(Block::new().padding(Padding::new(0, 0, 2, 0)))
+        .show_month_header(Style::new().bold())
+        .show_weekdays_header(Style::new().italic())
+        .render(area, buf);
+}
+
+fn render_simple_barchart(area: Rect, buf: &mut Buffer) {
+    let data = [
+        ("Sat", 76),
+        ("Sun", 69),
+        ("Mon", 65),
+        ("Tue", 67),
+        ("Wed", 65),
+        ("Thu", 69),
+        ("Fri", 73),
+    ];
+    let data = data
+        .into_iter()
+        .map(|(label, value)| {
+            Bar::default()
+                .value(value)
+                // This doesn't actually render correctly as the text is too wide for the bar
+                // See https://github.com/ratatui/ratatui/issues/513 for more info
+                // (the demo GIFs hack around this by hacking the calculation in bars.rs)
+                .text_value(format!("{value}°"))
+                .style(if value > 70 {
+                    Style::new().fg(Color::Red)
+                } else {
+                    Style::new().fg(Color::Yellow)
+                })
+                .value_style(if value > 70 {
+                    Style::new().fg(Color::Gray).bg(Color::Red).bold()
+                } else {
+                    Style::new().fg(Color::DarkGray).bg(Color::Yellow).bold()
+                })
+                .label(label)
+        })
+        .collect_vec();
+    let group = BarGroup::default().bars(&data);
+    BarChart::default()
+        .data(group)
+        .bar_width(3)
+        .bar_gap(1)
+        .render(area, buf);
+}
+
+fn render_horizontal_barchart(area: Rect, buf: &mut Buffer) {
+    let bg = Color::Rgb(32, 48, 96);
+    let data = [
+        Bar::default().text_value("Winter 37-51").value(51),
+        Bar::default().text_value("Spring 40-65").value(65),
+        Bar::default().text_value("Summer 54-77").value(77),
+        Bar::default()
+            .text_value("Fall 41-71")
+            .value(71)
+            .value_style(Style::new().bold()), // current season
+    ];
+    let group = BarGroup::default().label("GPU").bars(&data);
+    BarChart::default()
+        .block(Block::new().padding(Padding::new(0, 0, 2, 0)))
+        .direction(Direction::Horizontal)
+        .data(group)
+        .bar_gap(1)
+        .bar_style(Style::new().fg(bg))
+        .value_style(Style::new().bg(bg).fg(Color::Gray))
+        .render(area, buf);
+}
+
+#[allow(clippy::cast_precision_loss)]
+pub fn render_gauge(progress: usize, area: Rect, buf: &mut Buffer) {
+    let percent = (progress * 3).min(100) as f64;
+
+    render_line_gauge(percent, area, buf);
+}
+
+#[allow(clippy::cast_possible_truncation)]
+fn render_line_gauge(percent: f64, area: Rect, buf: &mut Buffer) {
+    // cycle color hue based on the percent for a neat effect yellow -> red
+    let hue = 90.0 - (percent as f32 * 0.6);
+    let value = Okhsv::max_value();
+    let filled_color = color_from_oklab(hue, Okhsv::max_saturation(), value);
+    let unfilled_color = color_from_oklab(hue, Okhsv::max_saturation(), value * 0.5);
+    let label = if percent < 100.0 {
+        format!("Downloading: {percent}%")
+    } else {
+        "Download Complete!".into()
+    };
+    LineGauge::default()
+        .ratio(percent / 100.0)
+        .label(label)
+        .style(Style::new().light_blue())
+        .filled_style(Style::new().fg(filled_color))
+        .unfilled_style(Style::new().fg(unfilled_color))
+        .line_set(symbols::line::THICK)
+        .render(area, buf);
+}

examples/apps/demo2/src/theme.rs

@@ -0,0 +1,136 @@
+use ratatui::style::{Color, Modifier, Style};
+
+pub struct Theme {
+    pub root: Style,
+    pub content: Style,
+    pub app_title: Style,
+    pub tabs: Style,
+    pub tabs_selected: Style,
+    pub borders: Style,
+    pub description: Style,
+    pub description_title: Style,
+    pub key_binding: KeyBinding,
+    pub logo: Logo,
+    pub email: Email,
+    pub traceroute: Traceroute,
+    pub recipe: Recipe,
+}
+
+pub struct KeyBinding {
+    pub key: Style,
+    pub description: Style,
+}
+
+pub struct Logo {
+    pub rat: Color,
+    pub rat_eye: Color,
+    pub rat_eye_alt: Color,
+    pub term: Color,
+}
+
+pub struct Email {
+    pub tabs: Style,
+    pub tabs_selected: Style,
+    pub inbox: Style,
+    pub item: Style,
+    pub selected_item: Style,
+    pub header: Style,
+    pub header_value: Style,
+    pub body: Style,
+}
+
+pub struct Traceroute {
+    pub header: Style,
+    pub selected: Style,
+    pub ping: Style,
+    pub map: Map,
+}
+
+pub struct Map {
+    pub style: Style,
+    pub color: Color,
+    pub path: Color,
+    pub source: Color,
+    pub destination: Color,
+    pub background_color: Color,
+}
+
+pub struct Recipe {
+    pub ingredients: Style,
+    pub ingredients_header: Style,
+}
+
+pub const THEME: Theme = Theme {
+    root: Style::new().bg(DARK_BLUE),
+    content: Style::new().bg(DARK_BLUE).fg(LIGHT_GRAY),
+    app_title: Style::new()
+        .fg(WHITE)
+        .bg(DARK_BLUE)
+        .add_modifier(Modifier::BOLD),
+    tabs: Style::new().fg(MID_GRAY).bg(DARK_BLUE),
+    tabs_selected: Style::new()
+        .fg(WHITE)
+        .bg(DARK_BLUE)
+        .add_modifier(Modifier::BOLD)
+        .add_modifier(Modifier::REVERSED),
+    borders: Style::new().fg(LIGHT_GRAY),
+    description: Style::new().fg(LIGHT_GRAY).bg(DARK_BLUE),
+    description_title: Style::new().fg(LIGHT_GRAY).add_modifier(Modifier::BOLD),
+    logo: Logo {
+        rat: WHITE,
+        rat_eye: BLACK,
+        rat_eye_alt: RED,
+        term: BLACK,
+    },
+    key_binding: KeyBinding {
+        key: Style::new().fg(BLACK).bg(DARK_GRAY),
+        description: Style::new().fg(DARK_GRAY).bg(BLACK),
+    },
+    email: Email {
+        tabs: Style::new().fg(MID_GRAY).bg(DARK_BLUE),
+        tabs_selected: Style::new()
+            .fg(WHITE)
+            .bg(DARK_BLUE)
+            .add_modifier(Modifier::BOLD),
+        inbox: Style::new().bg(DARK_BLUE).fg(LIGHT_GRAY),
+        item: Style::new().fg(LIGHT_GRAY),
+        selected_item: Style::new().fg(LIGHT_YELLOW),
+        header: Style::new().add_modifier(Modifier::BOLD),
+        header_value: Style::new().fg(LIGHT_GRAY),
+        body: Style::new().bg(DARK_BLUE).fg(LIGHT_GRAY),
+    },
+    traceroute: Traceroute {
+        header: Style::new()
+            .bg(DARK_BLUE)
+            .add_modifier(Modifier::BOLD)
+            .add_modifier(Modifier::UNDERLINED),
+        selected: Style::new().fg(LIGHT_YELLOW),
+        ping: Style::new().fg(WHITE),
+        map: Map {
+            style: Style::new().bg(DARK_BLUE),
+            background_color: DARK_BLUE,
+            color: LIGHT_GRAY,
+            path: LIGHT_BLUE,
+            source: LIGHT_GREEN,
+            destination: LIGHT_RED,
+        },
+    },
+    recipe: Recipe {
+        ingredients: Style::new().bg(DARK_BLUE).fg(LIGHT_GRAY),
+        ingredients_header: Style::new()
+            .add_modifier(Modifier::BOLD)
+            .add_modifier(Modifier::UNDERLINED),
+    },
+};
+
+const DARK_BLUE: Color = Color::Rgb(16, 24, 48);
+const LIGHT_BLUE: Color = Color::Rgb(64, 96, 192);
+const LIGHT_YELLOW: Color = Color::Rgb(192, 192, 96);
+const LIGHT_GREEN: Color = Color::Rgb(64, 192, 96);
+const LIGHT_RED: Color = Color::Rgb(192, 96, 96);
+const RED: Color = Color::Rgb(215, 0, 0);
+const BLACK: Color = Color::Rgb(8, 8, 8); // not really black, often #080808
+const DARK_GRAY: Color = Color::Rgb(68, 68, 68);
+const MID_GRAY: Color = Color::Rgb(128, 128, 128);
+const LIGHT_GRAY: Color = Color::Rgb(188, 188, 188);
+const WHITE: Color = Color::Rgb(238, 238, 238); // not really white, often #eeeeee