Add Border widget

src/ui/widgets.rs

@@ -1,4 +1,5 @@
 pub mod background;
+pub mod border;
 pub mod empty;
 pub mod join;
 pub mod list;

src/ui/widgets/border.rs

@@ -0,0 +1,49 @@
+use async_trait::async_trait;
+use toss::frame::{Frame, Pos, Size};
+
+use super::{BoxedWidget, Widget};
+
+pub struct Border(BoxedWidget);
+
+impl Border {
+    pub fn new<W: Into<BoxedWidget>>(inner: W) -> Self {
+        Self(inner.into())
+    }
+}
+
+#[async_trait]
+impl Widget for Border {
+    fn size(&self, frame: &mut Frame, max_width: Option<u16>, max_height: Option<u16>) -> Size {
+        let max_width = max_width.map(|w| w.saturating_sub(2));
+        let max_height = max_height.map(|h| h.saturating_sub(2));
+        let size = self.0.size(frame, max_width, max_height);
+        size + Size::new(2, 2)
+    }
+
+    async fn render(self: Box<Self>, frame: &mut Frame) {
+        let mut size = frame.size();
+        size.width = size.width.max(2);
+        size.height = size.height.max(2);
+
+        let right = size.width as i32 - 1;
+        let bottom = size.height as i32 - 1;
+        frame.write(Pos::new(0, 0), "┌");
+        frame.write(Pos::new(right, 0), "┐");
+        frame.write(Pos::new(0, bottom), "└");
+        frame.write(Pos::new(right, bottom), "┘");
+
+        for y in 1..bottom {
+            frame.write(Pos::new(0, y), "│");
+            frame.write(Pos::new(right, y), "│");
+        }
+
+        for x in 1..right {
+            frame.write(Pos::new(x, 0), "─");
+            frame.write(Pos::new(x, bottom), "─");
+        }
+
+        frame.push(Pos::new(1, 1), size - Size::new(2, 2));
+        self.0.render(frame).await;
+        frame.pop();
+    }
+}