Add HJoin and VJoin widgets

src/ui/widgets.rs

@@ -1,5 +1,6 @@
 pub mod background;
 pub mod empty;
+pub mod join;
 pub mod list;
 pub mod rules;
 pub mod text;

src/ui/widgets/join.rs

@@ -0,0 +1,134 @@
+use async_trait::async_trait;
+use toss::frame::{Frame, Pos, Size};
+
+use super::Widget;
+
+pub struct Segment {
+    widget: Box<dyn Widget + Send>,
+    expanding: bool,
+}
+
+impl Segment {
+    pub fn new<W: 'static + Widget + Send>(widget: W) -> Self {
+        Self {
+            widget: Box::new(widget),
+            expanding: false,
+        }
+    }
+
+    pub fn expanding(mut self, active: bool) -> Self {
+        self.expanding = active;
+        self
+    }
+}
+
+fn expand(amounts: &mut [(u16, bool)], total: u16) {
+    // Weirdly, rustc needs this type annotation while rust-analyzer manages to
+    // derive the correct type in an inlay hint.
+    let actual: u16 = amounts.iter().map(|(a, _)| *a).sum();
+    if actual < total {
+        let mut remaining = total - actual;
+        while remaining > 0 {
+            for (amount, expanding) in amounts.iter_mut() {
+                if *expanding {
+                    if remaining > 0 {
+                        *amount += 1;
+                        remaining -= 1;
+                    } else {
+                        break;
+                    }
+                }
+            }
+        }
+    }
+}
+
+/// Place multiple widgets next to each other horizontally.
+pub struct HJoin {
+    segments: Vec<Segment>,
+}
+
+impl HJoin {
+    pub fn new(segments: Vec<Segment>) -> Self {
+        Self { segments }
+    }
+}
+
+#[async_trait]
+impl Widget for HJoin {
+    fn size(&self, frame: &mut Frame, _max_width: Option<u16>, max_height: Option<u16>) -> Size {
+        let mut size = Size::ZERO;
+        for segment in &self.segments {
+            let widget_size = segment.widget.size(frame, None, max_height);
+            size.width += widget_size.width;
+            size.height = size.height.max(widget_size.height);
+        }
+        size
+    }
+
+    async fn render(self: Box<Self>, frame: &mut Frame) {
+        let size = frame.size();
+        let mut widths = self
+            .segments
+            .iter()
+            .map(|s| {
+                let width = s.widget.size(frame, None, Some(size.height)).width;
+                (width, s.expanding)
+            })
+            .collect::<Vec<_>>();
+        expand(&mut widths, size.width);
+
+        let mut x = 0;
+        for (segment, (width, _)) in self.segments.into_iter().zip(widths.into_iter()) {
+            frame.push(Pos::new(x, 0), Size::new(width, size.height));
+            segment.widget.render(frame).await;
+            frame.pop();
+            x += width as i32;
+        }
+    }
+}
+
+/// Place multiple widgets next to each other vertically.
+pub struct VJoin {
+    segments: Vec<Segment>,
+}
+
+impl VJoin {
+    pub fn new(segments: Vec<Segment>) -> Self {
+        Self { segments }
+    }
+}
+
+#[async_trait]
+impl Widget for VJoin {
+    fn size(&self, frame: &mut Frame, max_width: Option<u16>, _max_height: Option<u16>) -> Size {
+        let mut size = Size::ZERO;
+        for segment in &self.segments {
+            let widget_size = segment.widget.size(frame, max_width, None);
+            size.width = size.width.max(widget_size.width);
+            size.height += widget_size.height;
+        }
+        size
+    }
+
+    async fn render(self: Box<Self>, frame: &mut Frame) {
+        let size = frame.size();
+        let mut heights = self
+            .segments
+            .iter()
+            .map(|s| {
+                let height = s.widget.size(frame, Some(size.width), None).height;
+                (height, s.expanding)
+            })
+            .collect::<Vec<_>>();
+        expand(&mut heights, size.height);
+
+        let mut y = 0;
+        for (segment, (height, _)) in self.segments.into_iter().zip(heights.into_iter()) {
+            frame.push(Pos::new(0, y), Size::new(size.width, height));
+            segment.widget.render(frame).await;
+            frame.pop();
+            y += height as i32;
+        }
+    }
+}