feat(widgets/gauge): add `LineGauge` variant of `Gauge`

examples/demo/ui.rs

@@ -7,8 +7,8 @@ use tui::{
     text::{Span, Spans},
     widgets::canvas::{Canvas, Line, Map, MapResolution, Rectangle},
     widgets::{
-        Axis, BarChart, Block, Borders, Chart, Dataset, Gauge, List, ListItem, Paragraph, Row,
-        Sparkline, Table, Tabs, Wrap,
+        Axis, BarChart, Block, Borders, Chart, Dataset, Gauge, LineGauge, List, ListItem,
+        Paragraph, Row, Sparkline, Table, Tabs, Wrap,
     },
     Frame,
 };
@@ -42,8 +42,8 @@ where
     let chunks = Layout::default()
         .constraints(
             [
-                Constraint::Length(7),
-                Constraint::Min(7),
+                Constraint::Length(9),
+                Constraint::Min(8),
                 Constraint::Length(7),
             ]
             .as_ref(),
@@ -59,7 +59,14 @@ where
     B: Backend,
 {
     let chunks = Layout::default()
-        .constraints([Constraint::Length(2), Constraint::Length(3)].as_ref())
+        .constraints(
+            [
+                Constraint::Length(2),
+                Constraint::Length(3),
+                Constraint::Length(1),
+            ]
+            .as_ref(),
+        )
         .margin(1)
         .split(area);
     let block = Block::default().borders(Borders::ALL).title("Graphs");
@@ -88,6 +95,17 @@ where
             symbols::bar::THREE_LEVELS
         });
     f.render_widget(sparkline, chunks[1]);
+
+    let line_gauge = LineGauge::default()
+        .block(Block::default().title("LineGauge:"))
+        .gauge_style(Style::default().fg(Color::Magenta))
+        .line_set(if app.enhanced_graphics {
+            symbols::line::THICK
+        } else {
+            symbols::line::NORMAL
+        })
+        .ratio(app.progress);
+    f.render_widget(line_gauge, chunks[2]);
 }
 
 fn draw_charts<B>(f: &mut Frame<B>, app: &mut App, area: Rect)

src/widgets/gauge.rs

@@ -2,7 +2,8 @@ use crate::{
     buffer::Buffer,
     layout::Rect,
     style::{Color, Style},
-    text::Span,
+    symbols,
+    text::{Span, Spans},
     widgets::{Block, Widget},
 };
 
@@ -129,6 +130,137 @@ impl<'a> Widget for Gauge<'a> {
     }
 }
 
+/// A compact widget to display a task progress over a single line.
+///
+/// # Examples:
+///
+/// ```
+/// # use tui::widgets::{Widget, LineGauge, Block, Borders};
+/// # use tui::style::{Style, Color, Modifier};
+/// # use tui::symbols;
+/// LineGauge::default()
+///     .block(Block::default().borders(Borders::ALL).title("Progress"))
+///     .gauge_style(Style::default().fg(Color::White).bg(Color::Black).add_modifier(Modifier::BOLD))
+///     .line_set(symbols::line::THICK)
+///     .ratio(0.4);
+/// ```
+pub struct LineGauge<'a> {
+    block: Option<Block<'a>>,
+    ratio: f64,
+    label: Option<Spans<'a>>,
+    line_set: symbols::line::Set,
+    style: Style,
+    gauge_style: Style,
+}
+
+impl<'a> Default for LineGauge<'a> {
+    fn default() -> Self {
+        Self {
+            block: None,
+            ratio: 0.0,
+            label: None,
+            style: Style::default(),
+            line_set: symbols::line::NORMAL,
+            gauge_style: Style::default(),
+        }
+    }
+}
+
+impl<'a> LineGauge<'a> {
+    pub fn block(mut self, block: Block<'a>) -> Self {
+        self.block = Some(block);
+        self
+    }
+
+    pub fn ratio(mut self, ratio: f64) -> Self {
+        assert!(
+            ratio <= 1.0 && ratio >= 0.0,
+            "Ratio should be between 0 and 1 inclusively."
+        );
+        self.ratio = ratio;
+        self
+    }
+
+    pub fn line_set(mut self, set: symbols::line::Set) -> Self {
+        self.line_set = set;
+        self
+    }
+
+    pub fn label<T>(mut self, label: T) -> Self
+    where
+        T: Into<Spans<'a>>,
+    {
+        self.label = Some(label.into());
+        self
+    }
+
+    pub fn style(mut self, style: Style) -> Self {
+        self.style = style;
+        self
+    }
+
+    pub fn gauge_style(mut self, style: Style) -> Self {
+        self.gauge_style = style;
+        self
+    }
+}
+
+impl<'a> Widget for LineGauge<'a> {
+    fn render(mut self, area: Rect, buf: &mut Buffer) {
+        buf.set_style(area, self.style);
+        let gauge_area = match self.block.take() {
+            Some(b) => {
+                let inner_area = b.inner(area);
+                b.render(area, buf);
+                inner_area
+            }
+            None => area,
+        };
+
+        if gauge_area.height < 1 {
+            return;
+        }
+
+        let ratio = self.ratio;
+        let label = self
+            .label
+            .unwrap_or_else(move || Spans::from(format!("{:.0}%", ratio * 100.0)));
+        let (col, row) = buf.set_spans(
+            gauge_area.left(),
+            gauge_area.top(),
+            &label,
+            gauge_area.width,
+        );
+        let start = col + 1;
+        if start >= gauge_area.right() {
+            return;
+        }
+
+        let end = start
+            + (f64::from(gauge_area.right().saturating_sub(start)) * self.ratio).floor() as u16;
+        for col in start..end {
+            buf.get_mut(col, row)
+                .set_symbol(self.line_set.horizontal)
+                .set_style(Style {
+                    fg: self.gauge_style.fg,
+                    bg: None,
+                    add_modifier: self.gauge_style.add_modifier,
+                    sub_modifier: self.gauge_style.sub_modifier,
+                });
+        }
+        for col in end..gauge_area.right() {
+            buf.get_mut(col, row)
+                .set_symbol(self.line_set.horizontal)
+                .set_style(Style {
+                    fg: self.gauge_style.bg,
+                    bg: None,
+                    add_modifier: self.gauge_style.add_modifier,
+                    sub_modifier: self.gauge_style.sub_modifier,
+                });
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/widgets/mod.rs

@@ -32,7 +32,7 @@ pub use self::barchart::BarChart;
 pub use self::block::{Block, BorderType};
 pub use self::chart::{Axis, Chart, Dataset, GraphType};
 pub use self::clear::Clear;
-pub use self::gauge::Gauge;
+pub use self::gauge::{Gauge, LineGauge};
 pub use self::list::{List, ListItem, ListState};
 pub use self::paragraph::{Paragraph, Wrap};
 pub use self::sparkline::Sparkline;

tests/widgets_gauge.rs

@@ -1,8 +1,10 @@
 use tui::{
     backend::TestBackend,
     buffer::Buffer,
-    layout::{Constraint, Direction, Layout},
-    widgets::{Block, Borders, Gauge},
+    layout::{Constraint, Direction, Layout, Rect},
+    style::{Color, Style},
+    symbols,
+    widgets::{Block, Borders, Gauge, LineGauge},
     Terminal,
 };
 
@@ -42,3 +44,55 @@ fn widgets_gauge_renders() {
     ]);
     terminal.backend().assert_buffer(&expected);
 }
+
+#[test]
+fn widgets_line_gauge_renders() {
+    let backend = TestBackend::new(20, 4);
+    let mut terminal = Terminal::new(backend).unwrap();
+    terminal
+        .draw(|f| {
+            let gauge = LineGauge::default()
+                .gauge_style(Style::default().fg(Color::Green).bg(Color::White))
+                .ratio(0.43);
+            f.render_widget(
+                gauge,
+                Rect {
+                    x: 0,
+                    y: 0,
+                    width: 20,
+                    height: 1,
+                },
+            );
+            let gauge = LineGauge::default()
+                .block(Block::default().title("Gauge 2").borders(Borders::ALL))
+                .gauge_style(Style::default().fg(Color::Green))
+                .line_set(symbols::line::THICK)
+                .ratio(0.211_313_934_313_1);
+            f.render_widget(
+                gauge,
+                Rect {
+                    x: 0,
+                    y: 1,
+                    width: 20,
+                    height: 3,
+                },
+            );
+        })
+        .unwrap();
+    let mut expected = Buffer::with_lines(vec![
+        "43% ────────────────",
+        "┌Gauge 2───────────┐",
+        "│21% ━━━━━━━━━━━━━━│",
+        "└──────────────────┘",
+    ]);
+    for col in 4..10 {
+        expected.get_mut(col, 0).set_fg(Color::Green);
+    }
+    for col in 10..20 {
+        expected.get_mut(col, 0).set_fg(Color::White);
+    }
+    for col in 5..7 {
+        expected.get_mut(col, 2).set_fg(Color::Green);
+    }
+    terminal.backend().assert_buffer(&expected);
+}