1 files changed, 155 insertions, 0 deletions
diff --git a/src/ratatui/widgets/sparkline.rs b/src/ratatui/widgets/sparkline.rs
new file mode 100644
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--- /dev/null
+++ b/src/ratatui/widgets/sparkline.rs
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+use crate::ratatui::{
+    buffer::Buffer,
+    layout::Rect,
+    style::Style,
+    symbols,
+    widgets::{Block, Widget},
+};
+use std::cmp::min;
+
+/// Widget to render a sparkline over one or more lines.
+///
+/// # Examples
+///
+/// ```
+/// # use ratatui::widgets::{Block, Borders, Sparkline};
+/// # use ratatui::style::{Style, Color};
+/// Sparkline::default()
+///     .block(Block::default().title("Sparkline").borders(Borders::ALL))
+///     .data(&[0, 2, 3, 4, 1, 4, 10])
+///     .max(5)
+///     .style(Style::default().fg(Color::Red).bg(Color::White));
+/// ```
+#[derive(Debug, Clone)]
+pub struct Sparkline<'a> {
+    /// A block to wrap the widget in
+    block: Option<Block<'a>>,
+    /// Widget style
+    style: Style,
+    /// A slice of the data to display
+    data: &'a [u64],
+    /// The maximum value to take to compute the maximum bar height (if nothing is specified, the
+    /// widget uses the max of the dataset)
+    max: Option<u64>,
+    /// A set of bar symbols used to represent the give data
+    bar_set: symbols::bar::Set,
+}
+
+impl<'a> Default for Sparkline<'a> {
+    fn default() -> Sparkline<'a> {
+        Sparkline {
+            block: None,
+            style: Default::default(),
+            data: &[],
+            max: None,
+            bar_set: symbols::bar::NINE_LEVELS,
+        }
+    }
+}
+
+impl<'a> Sparkline<'a> {
+    pub fn block(mut self, block: Block<'a>) -> Sparkline<'a> {
+        self.block = Some(block);
+        self
+    }
+
+    pub fn style(mut self, style: Style) -> Sparkline<'a> {
+        self.style = style;
+        self
+    }
+
+    pub fn data(mut self, data: &'a [u64]) -> Sparkline<'a> {
+        self.data = data;
+        self
+    }
+
+    pub fn max(mut self, max: u64) -> Sparkline<'a> {
+        self.max = Some(max);
+        self
+    }
+
+    pub fn bar_set(mut self, bar_set: symbols::bar::Set) -> Sparkline<'a> {
+        self.bar_set = bar_set;
+        self
+    }
+}
+
+impl<'a> Widget for Sparkline<'a> {
+    fn render(mut self, area: Rect, buf: &mut Buffer) {
+        let spark_area = match self.block.take() {
+            Some(b) => {
+                let inner_area = b.inner(area);
+                b.render(area, buf);
+                inner_area
+            }
+            None => area,
+        };
+
+        if spark_area.height < 1 {
+            return;
+        }
+
+        let max = match self.max {
+            Some(v) => v,
+            None => *self.data.iter().max().unwrap_or(&1u64),
+        };
+        let max_index = min(spark_area.width as usize, self.data.len());
+        let mut data = self
+            .data
+            .iter()
+            .take(max_index)
+            .map(|e| {
+                if max != 0 {
+                    e * u64::from(spark_area.height) * 8 / max
+                } else {
+                    0
+                }
+            })
+            .collect::<Vec<u64>>();
+        for j in (0..spark_area.height).rev() {
+            for (i, d) in data.iter_mut().enumerate() {
+                let symbol = match *d {
+                    0 => self.bar_set.empty,
+                    1 => self.bar_set.one_eighth,
+                    2 => self.bar_set.one_quarter,
+                    3 => self.bar_set.three_eighths,
+                    4 => self.bar_set.half,
+                    5 => self.bar_set.five_eighths,
+                    6 => self.bar_set.three_quarters,
+                    7 => self.bar_set.seven_eighths,
+                    _ => self.bar_set.full,
+                };
+                buf.get_mut(spark_area.left() + i as u16, spark_area.top() + j)
+                    .set_symbol(symbol)
+                    .set_style(self.style);
+
+                if *d > 8 {
+                    *d -= 8;
+                } else {
+                    *d = 0;
+                }
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn it_does_not_panic_if_max_is_zero() {
+        let widget = Sparkline::default().data(&[0, 0, 0]);
+        let area = Rect::new(0, 0, 3, 1);
+        let mut buffer = Buffer::empty(area);
+        widget.render(area, &mut buffer);
+    }
+
+    #[test]
+    fn it_does_not_panic_if_max_is_set_to_zero() {
+        let widget = Sparkline::default().data(&[0, 1, 2]).max(0);
+        let area = Rect::new(0, 0, 3, 1);
+        let mut buffer = Buffer::empty(area);
+        widget.render(area, &mut buffer);
+    }
+}