Add gauge, fix rendering and cleanup code

examples/prototype.rs

@@ -5,6 +5,7 @@ extern crate log4rs;
 extern crate termion;
 
 use std::thread;
+use std::time;
 use std::sync::mpsc;
 use std::io::{Write, stdin};
 
@@ -18,7 +19,7 @@ use log4rs::encode::pattern::PatternEncoder;
 use log4rs::config::{Appender, Config, Logger, Root};
 
 use tui::Terminal;
-use tui::widgets::{Widget, Block, List, Border};
+use tui::widgets::{Widget, Block, List, Gauge, border};
 use tui::layout::{Group, Direction, Alignment, Size};
 
 struct App {
@@ -27,26 +28,24 @@ struct App {
     items: Vec<String>,
     selected: usize,
     show_episodes: bool,
+    progress: u16,
 }
 
 enum Event {
     Input(event::Key),
+    Tick,
 }
 
 fn main() {
 
     let log = FileAppender::builder()
-        .encoder(Box::new(PatternEncoder::new("{d} - {m}{n}")))
+        .encoder(Box::new(PatternEncoder::new("{l} / {d(%H:%M:%S)} / {M}:{L}{n}{m}{n}{n}")))
         .build("prototype.log")
         .unwrap();
 
     let config = Config::builder()
         .appender(Appender::builder().build("log", Box::new(log)))
-        .logger(Logger::builder()
-            .appender("log")
-            .additive(false)
-            .build("log", LogLevelFilter::Info))
-        .build(Root::builder().appender("log").build(LogLevelFilter::Info))
+        .build(Root::builder().appender("log").build(LogLevelFilter::Debug))
         .unwrap();
 
     let handle = log4rs::init_config(config).unwrap();
@@ -58,21 +57,30 @@ fn main() {
         items: ["1", "2", "3"].into_iter().map(|e| String::from(*e)).collect(),
         selected: 0,
         show_episodes: false,
+        progress: 0,
     };
     let (tx, rx) = mpsc::channel();
+    let input_tx = tx.clone();
 
     thread::spawn(move || {
-        let tx = tx.clone();
         let stdin = stdin();
         for c in stdin.keys() {
             let evt = c.unwrap();
-            tx.send(Event::Input(evt)).unwrap();
+            input_tx.send(Event::Input(evt)).unwrap();
             if evt == event::Key::Char('q') {
                 break;
             }
         }
     });
 
+    thread::spawn(move || {
+        let tx = tx.clone();
+        loop {
+            tx.send(Event::Tick).unwrap();
+            thread::sleep(time::Duration::from_millis(1000));
+        }
+    });
+
     let mut terminal = Terminal::new().unwrap();
     terminal.clear();
     terminal.hide_cursor();
@@ -102,6 +110,12 @@ fn main() {
                     _ => {}
                 }
             }
+            Event::Tick => {
+                app.progress += 5;
+                if app.progress > 100 {
+                    app.progress = 0;
+                }
+            }
         }
     }
     terminal.show_cursor();
@@ -112,12 +126,22 @@ fn draw(terminal: &mut Terminal, app: &App) {
     let ui = Group::default()
         .direction(Direction::Vertical)
         .alignment(Alignment::Left)
-        .chunks(&[Size::Fixed(3), Size::Percent(100), Size::Fixed(3)])
+        .chunks(&[Size::Fixed(5), Size::Percent(80), Size::Fixed(10)])
         .render(&terminal.area(), |chunks, tree| {
-            tree.add(Block::default()
-                .borders(Border::ALL)
-                .title("Header")
-                .render(&chunks[0]));
+            tree.add(Block::default().borders(border::ALL).title("Gauges").render(&chunks[0]));
+            tree.add(Group::default()
+                .direction(Direction::Vertical)
+                .alignment(Alignment::Left)
+                .margin(1)
+                .chunks(&[Size::Fixed(1), Size::Fixed(1), Size::Fixed(1)])
+                .render(&chunks[0], |chunks, tree| {
+                    tree.add(Gauge::new()
+                        .percent(app.progress)
+                        .render(&chunks[0]));
+                    tree.add(Gauge::new()
+                        .percent(app.progress)
+                        .render(&chunks[2]));
+                }));
             let sizes = if app.show_episodes {
                 vec![Size::Percent(50), Size::Percent(50)]
             } else {
@@ -130,7 +154,7 @@ fn draw(terminal: &mut Terminal, app: &App) {
                 .render(&chunks[1], |chunks, tree| {
                     tree.add(List::default()
                         .block(|b| {
-                            b.borders(Border::ALL).title("Podcasts");
+                            b.borders(border::ALL).title("Podcasts");
                         })
                         .items(&app.items)
                         .select(app.selected)
@@ -141,12 +165,12 @@ fn draw(terminal: &mut Terminal, app: &App) {
                         .render(&chunks[0]));
                     if app.show_episodes {
                         tree.add(Block::default()
-                            .borders(Border::ALL)
+                            .borders(border::ALL)
                             .title("Episodes")
                             .render(&chunks[1]));
                     }
                 }));
-            tree.add(Block::default().borders(Border::ALL).title("Footer").render(&chunks[2]));
+            tree.add(Block::default().borders(border::ALL).title("Footer").render(&chunks[2]));
         });
     terminal.render(ui);
 }

src/.lib.rs.rustfmt

@@ -0,0 +1,22 @@
+extern crate termion;
+#[macro_use]
+extern crate bitflags;
+#[macro_use]
+extern crate log;
+extern crate cassowary;
+
+mod buffer;
+mod util;
+pub mod symbols;
+pub mod terminal;
+pub mod widgets;
+pub mod style;
+pub mod layout;
+
+pub use self::terminal::Terminal;
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {}
+}

src/buffer.rs

@@ -94,6 +94,15 @@ impl Buffer {
         self.content[i].symbol = symbol;
     }
 
+    pub fn set_fg(&mut self, x: u16, y: u16, color: Color) {
+        let i = self.index_of(x, y);
+        self.content[i].fg = color;
+    }
+    pub fn set_bg(&mut self, x: u16, y: u16, color: Color) {
+        let i = self.index_of(x, y);
+        self.content[i].bg = color;
+    }
+
     pub fn set_string(&mut self, x: u16, y: u16, string: &str) {
         let mut cursor = (x, y);
         for c in string.chars() {

src/layout.rs

@@ -3,9 +3,8 @@ use std::collections::HashMap;
 
 use cassowary::{Solver, Variable, Constraint};
 use cassowary::WeightedRelation::*;
-use cassowary::strength::{WEAK, MEDIUM, STRONG, REQUIRED};
+use cassowary::strength::{WEAK, MEDIUM, REQUIRED};
 
-use util::hash;
 use buffer::Buffer;
 use widgets::WidgetType;
 
@@ -24,7 +23,7 @@ pub enum Direction {
     Vertical,
 }
 
-#[derive(Debug, Clone, Copy, PartialEq)]
+#[derive(Hash, Debug, Clone, Copy, Eq, PartialEq)]
 pub struct Rect {
     pub x: u16,
     pub y: u16,
@@ -46,10 +45,10 @@ impl Default for Rect {
 impl Rect {
     pub fn new(x: u16, y: u16, width: u16, height: u16) -> Rect {
         Rect {
-            x: 0,
-            y: 0,
-            width: 0,
-            height: 0,
+            x: x,
+            y: y,
+            width: width,
+            height: height,
         }
     }
 
@@ -57,15 +56,15 @@ impl Rect {
         self.width * self.height
     }
 
-    pub fn inner(&self, spacing: u16) -> Rect {
-        if self.width - spacing < 0 || self.height - spacing < 0 {
+    pub fn inner(&self, margin: u16) -> Rect {
+        if self.width < 2 * margin || self.height < 2 * margin {
             Rect::default()
         } else {
             Rect {
-                x: self.x + spacing,
-                y: self.y + spacing,
-                width: self.width - 2 * spacing,
-                height: self.height - 2 * spacing,
+                x: self.x + margin,
+                y: self.y + margin,
+                width: self.width - 2 * margin,
+                height: self.height - 2 * margin,
             }
         }
     }
@@ -114,16 +113,25 @@ pub enum Size {
 /// use tui::layout::{Rect, Size, Alignment, Direction, split};
 ///
 /// fn main() {
-///     let chunks = split(&Rect{x: 2, y: 2, width: 10, height: 10}, Direction::Vertical,
-///     Alignment::Left, &[Size::Fixed(5.0), Size::Percent(80.0)]);
+///     let chunks = split(&Rect{x: 2, y: 2, width: 10, height: 10},
+///                        &Direction::Vertical,
+///                        &Alignment::Left,
+///                        0,
+///                        &[Size::Fixed(5), Size::Percent(80)]);
 /// }
 ///
 /// ```
-pub fn split(area: &Rect, dir: &Direction, align: &Alignment, sizes: &[Size]) -> Vec<Rect> {
+pub fn split(area: &Rect,
+             dir: &Direction,
+             align: &Alignment,
+             margin: u16,
+             sizes: &[Size])
+             -> Vec<Rect> {
     let mut solver = Solver::new();
     let mut vars: HashMap<Variable, (usize, usize)> = HashMap::new();
-    let elements = sizes.iter().map(|e| Element::new()).collect::<Vec<Element>>();
-    let mut results = sizes.iter().map(|e| Rect::default()).collect::<Vec<Rect>>();
+    let elements = sizes.iter().map(|_| Element::new()).collect::<Vec<Element>>();
+    let mut results = sizes.iter().map(|_| Rect::default()).collect::<Vec<Rect>>();
+    let dest_area = area.inner(margin);
     for (i, e) in elements.iter().enumerate() {
         vars.insert(e.x, (i, 0));
         vars.insert(e.y, (i, 1));
@@ -131,20 +139,19 @@ pub fn split(area: &Rect, dir: &Direction, align: &Alignment, sizes: &[Size]) ->
         vars.insert(e.height, (i, 3));
     }
     let mut constraints: Vec<Constraint> = Vec::new();
-    if let Some(size) = sizes.first() {
+    if let Some(first) = elements.first() {
         constraints.push(match *dir {
-            Direction::Horizontal => elements[0].x | EQ(REQUIRED) | area.x as f64,
-            Direction::Vertical => elements[0].y | EQ(REQUIRED) | area.y as f64,
+            Direction::Horizontal => first.x | EQ(REQUIRED) | dest_area.x as f64,
+            Direction::Vertical => first.y | EQ(REQUIRED) | dest_area.y as f64,
         })
     }
-    if let Some(size) = sizes.last() {
-        let last = elements.last().unwrap();
+    if let Some(last) = elements.last() {
         constraints.push(match *dir {
             Direction::Horizontal => {
-                last.x + last.width | EQ(REQUIRED) | (area.x + area.width) as f64
+                last.x + last.width | EQ(REQUIRED) | (dest_area.x + dest_area.width) as f64
             }
             Direction::Vertical => {
-                last.y + last.height | EQ(REQUIRED) | (area.y + area.height) as f64
+                last.y + last.height | EQ(REQUIRED) | (dest_area.y + dest_area.height) as f64
             }
         })
     }
@@ -154,12 +161,13 @@ pub fn split(area: &Rect, dir: &Direction, align: &Alignment, sizes: &[Size]) ->
                 constraints.push(pair[0].x + pair[0].width | LE(REQUIRED) | pair[1].x);
             }
             for (i, size) in sizes.iter().enumerate() {
-                let cs = [elements[i].y | EQ(REQUIRED) | area.y as f64,
-                          elements[i].height | EQ(REQUIRED) | area.height as f64,
+                let cs = [elements[i].y | EQ(REQUIRED) | dest_area.y as f64,
+                          elements[i].height | EQ(REQUIRED) | dest_area.height as f64,
                           match *size {
-                              Size::Fixed(f) => elements[i].width | EQ(REQUIRED) | f as f64,
+                              Size::Fixed(f) => elements[i].width | EQ(MEDIUM) | f as f64,
                               Size::Percent(p) => {
-                                  elements[i].width | EQ(WEAK) | (area.width * p) as f64 / 100.0
+                                  elements[i].width | EQ(WEAK) |
+                                  (dest_area.width * p) as f64 / 100.0
                               }
                           }];
                 constraints.extend_from_slice(&cs);
@@ -170,12 +178,13 @@ pub fn split(area: &Rect, dir: &Direction, align: &Alignment, sizes: &[Size]) ->
                 constraints.push(pair[0].y + pair[0].height | LE(REQUIRED) | pair[1].y);
             }
             for (i, size) in sizes.iter().enumerate() {
-                let cs = [elements[i].x | EQ(REQUIRED) | area.x as f64,
-                          elements[i].width | EQ(REQUIRED) | area.width as f64,
+                let cs = [elements[i].x | EQ(REQUIRED) | dest_area.x as f64,
+                          elements[i].width | EQ(REQUIRED) | dest_area.width as f64,
                           match *size {
                               Size::Fixed(f) => elements[i].height | EQ(REQUIRED) | f as f64,
                               Size::Percent(p) => {
-                                  elements[i].height | EQ(WEAK) | (area.height * p) as f64 / 100.0
+                                  elements[i].height | EQ(WEAK) |
+                                  (dest_area.height * p) as f64 / 100.0
                               }
                           }];
                 constraints.extend_from_slice(&cs);
@@ -286,6 +295,7 @@ pub struct Leaf {
 pub struct Group {
     direction: Direction,
     alignment: Alignment,
+    margin: u16,
     chunks: Vec<Size>,
 }
 
@@ -294,6 +304,7 @@ impl Default for Group {
         Group {
             direction: Direction::Horizontal,
             alignment: Alignment::Left,
+            margin: 0,
             chunks: Vec::new(),
         }
     }
@@ -310,6 +321,11 @@ impl Group {
         self
     }
 
+    pub fn margin(&mut self, margin: u16) -> &mut Group {
+        self.margin = margin;
+        self
+    }
+
     pub fn chunks(&mut self, chunks: &[Size]) -> &mut Group {
         self.chunks = Vec::from(chunks);
         self
@@ -317,9 +333,13 @@ impl Group {
     pub fn render<F>(&self, area: &Rect, f: F) -> Tree
         where F: Fn(&[Rect], &mut Node)
     {
-        let chunks = split(area, &self.direction, &self.alignment, &self.chunks);
+        let chunks = split(area,
+                           &self.direction,
+                           &self.alignment,
+                           self.margin,
+                           &self.chunks);
         let mut node = Node { children: Vec::new() };
-        let results = f(&chunks, &mut node);
+        f(&chunks, &mut node);
         Tree::Node(node)
     }
 }

src/lib.rs

@@ -7,6 +7,7 @@ extern crate cassowary;
 
 mod buffer;
 mod util;
+pub mod symbols;
 pub mod terminal;
 pub mod widgets;
 pub mod style;

src/symbols.rs

@@ -0,0 +1,10 @@
+pub mod block {
+    pub const FULL: char = '█';
+    pub const SEVEN_EIGHTHS: char = '▉';
+    pub const THREE_QUATERS: char = '▊';
+    pub const FIVE_EIGHTHS: char = '▋';
+    pub const HALF: char = '▌';
+    pub const THREE_EIGHTHS: char = '▍';
+    pub const ONE_QUATER: char = '▎';
+    pub const ONE_EIGHTH: char = '▏';
+}

src/terminal.rs

@@ -1,4 +1,3 @@
-use std::iter;
 use std::io;
 use std::io::Write;
 use std::collections::HashMap;
@@ -8,13 +7,13 @@ use termion::raw::{IntoRawMode, RawTerminal};
 
 use buffer::Buffer;
 use widgets::WidgetType;
-use layout::{Rect, Tree, Node, Leaf};
+use layout::{Rect, Tree};
 
 pub struct Terminal {
     width: u16,
     height: u16,
     stdout: RawTerminal<io::Stdout>,
-    previous: HashMap<(WidgetType, u64), Rect>,
+    previous: HashMap<(WidgetType, Rect), u64>,
 }
 
 impl Terminal {
@@ -39,29 +38,33 @@ impl Terminal {
     }
 
     pub fn render(&mut self, ui: Tree) {
-        info!("Render");
+        debug!("Render Pass");
         let mut buffers: Vec<Buffer> = Vec::new();
-        let mut previous: HashMap<(WidgetType, u64), Rect> = HashMap::new();
+        let mut previous: HashMap<(WidgetType, Rect), u64> = HashMap::new();
         for node in ui.into_iter() {
             let area = *node.buffer.area();
-            match self.previous.remove(&(node.widget_type, node.hash)) {
-                Some(r) => {
-                    if r != area {
+            match self.previous.remove(&(node.widget_type, area)) {
+                Some(h) => {
+                    if h == node.hash {
+                        debug!("Skip {:?} at {:?}", node.widget_type, area);
+                    } else {
+                        debug!("Update {:?} at {:?}", node.widget_type, area);
                         buffers.push(node.buffer);
                     }
                 }
                 None => {
                     buffers.push(node.buffer);
+                    debug!("Render {:?} at {:?}", node.widget_type, area);
                 }
             }
-            previous.insert((node.widget_type, node.hash), area);
+            previous.insert((node.widget_type, area), node.hash);
         }
-        for (_, area) in &self.previous {
-            buffers.insert(0, Buffer::empty(*area));
+        for (&(t, a), h) in &self.previous {
+            buffers.insert(0, Buffer::empty(a));
+            debug!("Erased {:?} at {:?}", t, a);
         }
         for buf in buffers {
             self.render_buffer(&buf);
-            info!("{:?}", buf.area());
         }
         self.previous = previous;
     }

src/util.rs

@@ -1,7 +1,10 @@
 use std::hash::{Hash, SipHasher, Hasher};
 
-pub fn hash<T: Hash>(t: &T) -> u64 {
+use layout::Rect;
+
+pub fn hash<T: Hash>(t: &T, area: &Rect) -> u64 {
     let mut s = SipHasher::new();
     t.hash(&mut s);
+    area.hash(&mut s);
     s.finish()
 }

src/widgets/block.rs

@@ -2,12 +2,12 @@
 use buffer::Buffer;
 use layout::Rect;
 use style::Color;
-use widgets::{Widget, WidgetType, Border, Line, vline, hline};
+use widgets::{Widget, WidgetType, border, Line, vline, hline};
 
-#[derive(Hash)]
+#[derive(Hash, Clone, Copy)]
 pub struct Block<'a> {
     title: Option<&'a str>,
-    borders: Border::Flags,
+    borders: border::Flags,
     border_fg: Color,
     border_bg: Color,
 }
@@ -16,7 +16,7 @@ impl<'a> Default for Block<'a> {
     fn default() -> Block<'a> {
         Block {
             title: None,
-            borders: Border::NONE,
+            borders: border::NONE,
             border_fg: Color::White,
             border_bg: Color::Black,
         }
@@ -29,35 +29,31 @@ impl<'a> Block<'a> {
         self
     }
 
-    pub fn borders(&mut self, flag: Border::Flags) -> &mut Block<'a> {
+    pub fn borders(&mut self, flag: border::Flags) -> &mut Block<'a> {
         self.borders = flag;
         self
     }
 }
 
 impl<'a> Widget for Block<'a> {
-    fn buffer(&self, area: &Rect) -> Buffer {
+    fn _buffer(&self, area: &Rect) -> Buffer {
 
         let mut buf = Buffer::empty(*area);
 
-        if area.area() == 0 {
-            return buf;
-        }
-
-        if self.borders == Border::NONE {
+        if self.borders == border::NONE {
             return buf;
         }
 
         // Sides
-        if self.borders.intersects(Border::LEFT) {
+        if self.borders.intersects(border::LEFT) {
             let line = vline(area.x, area.y, area.height, self.border_fg, self.border_bg);
             buf.merge(&line);
         }
-        if self.borders.intersects(Border::TOP) {
+        if self.borders.intersects(border::TOP) {
             let line = hline(area.x, area.y, area.width, self.border_fg, self.border_bg);
             buf.merge(&line);
         }
-        if self.borders.intersects(Border::RIGHT) {
+        if self.borders.intersects(border::RIGHT) {
             let line = vline(area.x + area.width - 1,
                              area.y,
                              area.height,
@@ -65,7 +61,7 @@ impl<'a> Widget for Block<'a> {
                              self.border_bg);
             buf.merge(&line);
         }
-        if self.borders.intersects(Border::BOTTOM) {
+        if self.borders.intersects(border::BOTTOM) {
             let line = hline(area.x,
                              area.y + area.height - 1,
                              area.width,
@@ -75,16 +71,16 @@ impl<'a> Widget for Block<'a> {
         }
 
         // Corners
-        if self.borders.contains(Border::LEFT | Border::TOP) {
+        if self.borders.contains(border::LEFT | border::TOP) {
             buf.set_symbol(0, 0, Line::TopLeft.get());
         }
-        if self.borders.contains(Border::RIGHT | Border::TOP) {
+        if self.borders.contains(border::RIGHT | border::TOP) {
             buf.set_symbol(area.width - 1, 0, Line::TopRight.get());
         }
-        if self.borders.contains(Border::BOTTOM | Border::LEFT) {
+        if self.borders.contains(border::BOTTOM | border::LEFT) {
             buf.set_symbol(0, area.height - 1, Line::BottomLeft.get());
         }
-        if self.borders.contains(Border::BOTTOM | Border::RIGHT) {
+        if self.borders.contains(border::BOTTOM | border::RIGHT) {
             buf.set_symbol(area.width - 1, area.height - 1, Line::BottomRight.get());
         }
         if let Some(ref title) = self.title {

src/widgets/gauge.rs

@@ -0,0 +1,75 @@
+use widgets::{Widget, WidgetType, Block};
+use buffer::Buffer;
+use style::Color;
+use layout::Rect;
+
+/// Progress bar widget
+///
+/// # Examples:
+///
+/// ```
+/// extern crate tui;
+/// use tui::widgets::{Widget, Gauge, Block, border};
+///
+/// fn main() {
+///     Gauge::new()
+///         .block(*Block::default().borders(border::ALL).title("Progress"))
+///         .percent(20);
+/// }
+/// ```
+#[derive(Hash)]
+pub struct Gauge<'a> {
+    block: Option<Block<'a>>,
+    percent: u16,
+    fg: Color,
+    bg: Color,
+}
+
+impl<'a> Gauge<'a> {
+    pub fn new() -> Gauge<'a> {
+        Gauge {
+            block: None,
+            percent: 0,
+            bg: Color::White,
+            fg: Color::Black,
+        }
+    }
+
+    pub fn block(&'a mut self, block: Block<'a>) -> &mut Gauge<'a> {
+        self.block = Some(block);
+        self
+    }
+
+    pub fn percent(&mut self, percent: u16) -> &mut Gauge<'a> {
+        self.percent = percent;
+        self
+    }
+}
+
+impl<'a> Widget for Gauge<'a> {
+    fn _buffer(&self, area: &Rect) -> Buffer {
+        let (mut buf, gauge_area) = match self.block {
+            Some(ref b) => (b._buffer(area), area.inner(1)),
+            None => (Buffer::empty(*area), *area),
+        };
+        if gauge_area.height < 1 {
+            return buf;
+        } else {
+            let margin = gauge_area.x - area.x;
+            let width = (gauge_area.width * self.percent) / 100;
+            for i in 0..width {
+                buf.set_bg(margin + i, margin, self.bg);
+                buf.set_fg(margin + i, margin, self.fg);
+            }
+            let percent_string = format!("{}%", self.percent);
+            let len = percent_string.len() as u16;
+            let middle = gauge_area.width / 2 - len / 2;
+            buf.set_string(middle, margin, &percent_string);
+        }
+        buf
+    }
+
+    fn widget_type(&self) -> WidgetType {
+        WidgetType::Gauge
+    }
+}

src/widgets/list.rs

@@ -1,10 +1,9 @@
-use std::cmp::{min, max};
+use std::cmp::min;
 use std::fmt::Display;
 use std::hash::{Hash, Hasher};
 
 use buffer::Buffer;
 use widgets::{Widget, WidgetType, Block};
-use style::Color;
 use layout::Rect;
 
 pub struct List<'a, T> {
@@ -29,7 +28,7 @@ impl<'a, T> Default for List<'a, T> {
         List {
             block: Block::default(),
             selected: 0,
-            formatter: Box::new(|e: &T, selected: bool| String::from("")),
+            formatter: Box::new(|_, _| String::from("")),
             items: Vec::new(),
         }
     }
@@ -66,7 +65,7 @@ impl<'a, T> List<'a, T>
 impl<'a, T> Widget for List<'a, T>
     where T: Display + Hash
 {
-    fn buffer(&self, area: &Rect) -> Buffer {
+    fn _buffer(&self, area: &Rect) -> Buffer {
         let mut buf = self.block.buffer(area);
         if area.area() == 0 {
             return buf;

src/widgets/mod.rs

@@ -1,9 +1,12 @@
 mod block;
 mod list;
+mod gauge;
 
 pub use self::block::Block;
 pub use self::list::List;
-use std::hash::{Hash, SipHasher, Hasher};
+pub use self::gauge::Gauge;
+
+use std::hash::Hash;
 
 use util::hash;
 use buffer::{Buffer, Cell};
@@ -23,7 +26,7 @@ enum Line {
     HorizontalUp,
 }
 
-pub mod Border {
+pub mod border {
     bitflags! {
         pub flags Flags: u32 {
             const NONE  = 0b00000001,
@@ -53,7 +56,6 @@ impl Line {
     }
 }
 
-
 fn hline<'a>(x: u16, y: u16, len: u16, fg: Color, bg: Color) -> Buffer {
     Buffer::filled(Rect {
                        x: x,
@@ -85,14 +87,21 @@ fn vline<'a>(x: u16, y: u16, len: u16, fg: Color, bg: Color) -> Buffer {
 pub enum WidgetType {
     Block,
     List,
+    Gauge,
 }
 
 pub trait Widget: Hash {
-    fn buffer(&self, area: &Rect) -> Buffer;
+    fn _buffer(&self, area: &Rect) -> Buffer;
+    fn buffer(&self, area: &Rect) -> Buffer {
+        match area.area() {
+            0 => Buffer::empty(*area),
+            _ => self._buffer(area),
+        }
+    }
     fn widget_type(&self) -> WidgetType;
     fn render(&self, area: &Rect) -> Tree {
         let widget_type = self.widget_type();
-        let hash = hash(&self);
+        let hash = hash(&self, area);
         let buffer = self.buffer(area);
         Tree::Leaf(Leaf {
             widget_type: widget_type,