Allow customizing x and y axis bounds per dataset

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## To be released
 
+### Features
+
+* Add `Dataset.x_axis_bounds` and `Dataset.y_axis_bounds` to allow setting per-dataset axis bounds.
+
 ## v0.13.0 - 2020-11-14
 
 ### Features

examples/chart.rs

@@ -34,34 +34,69 @@ struct App {
     signal2: SinSignal,
     data2: Vec<(f64, f64)>,
     window: [f64; 2],
+    tick: usize,
+
+    signal3: SinSignal,
+    data3: Vec<(f64, f64)>,
+
+    signal4: SinSignal,
+    data4: Vec<(f64, f64)>,
+    window4: [f64; 2],
+}
+
+
+fn update_data(data: &mut Vec<(f64, f64)>, signal: &mut SinSignal, amount: usize) {
+    for _ in 0..amount {
+        data.remove(0);
+    }
+    data.extend(signal.by_ref().take(amount));
 }
 
 impl App {
     fn new() -> App {
         let mut signal1 = SinSignal::new(0.2, 3.0, 18.0);
         let mut signal2 = SinSignal::new(0.1, 2.0, 10.0);
+        let mut signal3 = SinSignal::new(0.2, 3.0, 18.0);
+        let mut signal4 = SinSignal::new(0.1, 2.0, 10.0);
         let data1 = signal1.by_ref().take(200).collect::<Vec<(f64, f64)>>();
         let data2 = signal2.by_ref().take(200).collect::<Vec<(f64, f64)>>();
+
+        let data3 = signal3.by_ref().take(200).collect::<Vec<(f64, f64)>>();
+        let data4 = signal4.by_ref().take(200).collect::<Vec<(f64, f64)>>();
+
         App {
             signal1,
             data1,
             signal2,
             data2,
             window: [0.0, 20.0],
+            tick: 0,
+            signal3,
+            data3,
+            signal4,
+            data4,
+            window4: [0.0, 20.0],
         }
     }
 
     fn update(&mut self) {
-        for _ in 0..5 {
-            self.data1.remove(0);
-        }
-        self.data1.extend(self.signal1.by_ref().take(5));
-        for _ in 0..10 {
-            self.data2.remove(0);
-        }
-        self.data2.extend(self.signal2.by_ref().take(10));
+        self.tick += 1;
+        update_data(&mut self.data1, &mut self.signal1, 5);
+        update_data(&mut self.data2, &mut self.signal2, 10);
+
+        update_data(&mut self.data3, &mut self.signal3, 5);
+
         self.window[0] += 1.0;
         self.window[1] += 1.0;
+
+        if self.tick == 5 {
+            self.tick = 0;
+
+            self.window4[0] += 1.0;
+            self.window4[1] += 1.0;
+
+            update_data(&mut self.data4, &mut self.signal4, 10);
+        }
     }
 }
 
@@ -92,6 +127,12 @@ fn main() -> Result<(), Box<dyn Error>> {
                     .as_ref(),
                 )
                 .split(size);
+
+            let bottom_chunks = Layout::default()
+                .direction(Direction::Horizontal)
+                .constraints([Constraint::Percentage(50), Constraint::Percentage(50)].as_ref())
+                .split(chunks[2]);
+
             let x_labels = vec![
                 Span::styled(
                     format!("{}", app.window[0]),
@@ -227,7 +268,45 @@ fn main() -> Result<(), Box<dyn Error>> {
                             Span::styled("5", Style::default().add_modifier(Modifier::BOLD)),
                         ]),
                 );
-            f.render_widget(chart, chunks[2]);
+            f.render_widget(chart, bottom_chunks[0]);
+
+            let datasets = vec![
+                Dataset::default()
+                    .name("data3")
+                    .marker(symbols::Marker::Braille)
+                    .style(Style::default().fg(Color::Yellow))
+                    .data(&app.data3).x_axis_bounds(app.window),
+                Dataset::default()
+                    .name("data3")
+                    .marker(symbols::Marker::Braille)
+                    .style(Style::default().fg(Color::Yellow))
+                    .data(&app.data4).x_axis_bounds(app.window4),
+            ];
+
+            let chart = Chart::new(datasets)
+                .block(
+                    Block::default()
+                        .title(Span::styled(
+                            "Chart 4",
+                            Style::default()
+                                .fg(Color::Cyan)
+                                .add_modifier(Modifier::BOLD),
+                        ))
+                        .borders(Borders::ALL),
+                )
+                .y_axis(
+                    Axis::default()
+                        .title("Y Axis")
+                        .style(Style::default().fg(Color::Gray))
+                        .labels(vec![
+                            Span::styled("-20", Style::default().add_modifier(Modifier::BOLD)),
+                            Span::raw("0"),
+                            Span::styled("20", Style::default().add_modifier(Modifier::BOLD)),
+                        ])
+                        .bounds([-20.0, 20.0]),
+                );
+            f.render_widget(chart, bottom_chunks[1]);
+
         })?;
 
         match events.next()? {

src/widgets/chart.rs

@@ -95,6 +95,9 @@ pub struct Dataset<'a> {
     graph_type: GraphType,
     /// Style used to plot this dataset
     style: Style,
+    ///
+    x_axis_bounds: Option<[f64; 2]>,
+    y_axis_bounds: Option<[f64; 2]>,
 }
 
 impl<'a> Default for Dataset<'a> {
@@ -105,6 +108,8 @@ impl<'a> Default for Dataset<'a> {
             marker: symbols::Marker::Dot,
             graph_type: GraphType::Scatter,
             style: Style::default(),
+            x_axis_bounds: None,
+            y_axis_bounds: None
         }
     }
 }
@@ -137,6 +142,16 @@ impl<'a> Dataset<'a> {
         self.style = style;
         self
     }
+
+    pub fn x_axis_bounds(mut self, bounds: [f64; 2]) -> Dataset<'a> {
+        self.x_axis_bounds = Some(bounds);
+        self
+    }
+
+    pub fn y_axis_bounds(mut self, bounds: [f64; 2]) -> Dataset<'a> {
+        self.y_axis_bounds = Some(bounds);
+        self
+    }
 }
 
 /// A container that holds all the infos about where to display each elements of the chart (axis,
@@ -442,8 +457,8 @@ impl<'a> Widget for Chart<'a> {
         for dataset in &self.datasets {
             Canvas::default()
                 .background_color(self.style.bg.unwrap_or(Color::Reset))
-                .x_bounds(self.x_axis.bounds)
-                .y_bounds(self.y_axis.bounds)
+                .x_bounds(dataset.x_axis_bounds.unwrap_or(self.x_axis.bounds))
+                .y_bounds(dataset.y_axis_bounds.unwrap_or(self.y_axis.bounds))
                 .marker(dataset.marker)
                 .paint(|ctx| {
                     ctx.draw(&Points {

tests/widgets_chart.rs

@@ -126,6 +126,46 @@ fn widgets_chart_can_have_empty_datasets() {
         .unwrap();
 }
 
+
+#[test]
+fn widgets_chart_disjoint_axis() {
+    let backend = TestBackend::new(100, 100);
+    let mut terminal = Terminal::new(backend).unwrap();
+
+    let dataset_1 = Dataset::default().data(&[(0.0, 0.0), (1.0, 1.0), (2.0, 2.0)]).x_axis_bounds([1.0, 2.0]).graph_type(Line);
+    let dataset_2 = Dataset::default().data(&[(0.0, 0.0), (1.0, 1.0)]).x_axis_bounds([0.0, 1.0]).graph_type(Line);
+    terminal
+        .draw(|f| {
+            let datasets = vec![dataset_1, dataset_2];
+            let chart = Chart::new(datasets)
+                .block(
+                    Block::default()
+                        .title("Empty Dataset With Line")
+                        .borders(Borders::ALL),
+                )
+                .x_axis(
+                    Axis::default()
+                        .bounds([0.0, 2.0])
+                        .labels(create_labels(&["0.0", "3.0"])),
+                )
+                .y_axis(
+                    Axis::default()
+                        .bounds([0.0, 3.0])
+                        .labels(create_labels(&["0.0", "3.0"])),
+                );
+            f.render_widget(
+                chart,
+                Rect {
+                    x: 0,
+                    y: 0,
+                    width: 100,
+                    height: 100,
+                },
+            );
+        })
+        .unwrap();
+}
+
 #[test]
 fn widgets_chart_can_have_a_legend() {
     let backend = TestBackend::new(60, 30);