Add Boxed and BoxedAsync widgets

src/widget.rs

@@ -1,7 +1,8 @@
 use async_trait::async_trait;
 
 use crate::widgets::{
-    Background, Border, Either2, Either3, Float, JoinSegment, Layer2, Padding, Resize,
+    Background, Border, Boxed, BoxedAsync, Either2, Either3, Float, JoinSegment, Layer2, Padding,
+    Resize,
 };
 use crate::{Frame, Size, WidthDb};
 
@@ -39,6 +40,20 @@ pub trait WidgetExt: Sized {
         Border::new(self)
     }
 
+    fn boxed<'a, E>(self) -> Boxed<'a, E>
+    where
+        Self: Widget<E> + 'a,
+    {
+        Boxed::new(self)
+    }
+
+    fn boxed_async<'a, E>(self) -> BoxedAsync<'a, E>
+    where
+        Self: AsyncWidget<E> + Send + Sync + 'a,
+    {
+        BoxedAsync::new(self)
+    }
+
     fn first2<W2>(self) -> Either2<Self, W2> {
         Either2::First(self)
     }

src/widgets.rs

@@ -1,5 +1,6 @@
 pub mod background;
 pub mod border;
+pub mod boxed;
 pub mod cursor;
 pub mod editor;
 pub mod either;
@@ -14,6 +15,7 @@ pub mod text;
 
 pub use background::*;
 pub use border::*;
+pub use boxed::*;
 pub use cursor::*;
 pub use editor::*;
 pub use either::*;

src/widgets/boxed.rs

@@ -0,0 +1,116 @@
+use async_trait::async_trait;
+
+use crate::{AsyncWidget, Frame, Size, Widget, WidthDb};
+
+pub struct Boxed<'a, E>(Box<dyn WidgetWrapper<E> + 'a>);
+
+impl<'a, E> Boxed<'a, E> {
+    pub fn new<I>(inner: I) -> Self
+    where
+        I: Widget<E> + 'a,
+    {
+        Self(Box::new(inner))
+    }
+}
+
+trait WidgetWrapper<E> {
+    fn wrap_size(
+        &self,
+        widthdb: &mut WidthDb,
+        max_width: Option<u16>,
+        max_height: Option<u16>,
+    ) -> Result<Size, E>;
+
+    fn wrap_draw(self: Box<Self>, frame: &mut Frame) -> Result<(), E>;
+}
+
+impl<E, W> WidgetWrapper<E> for W
+where
+    W: Widget<E>,
+{
+    fn wrap_size(
+        &self,
+        widthdb: &mut WidthDb,
+        max_width: Option<u16>,
+        max_height: Option<u16>,
+    ) -> Result<Size, E> {
+        self.size(widthdb, max_width, max_height)
+    }
+
+    fn wrap_draw(self: Box<Self>, frame: &mut Frame) -> Result<(), E> {
+        (*self).draw(frame)
+    }
+}
+
+impl<E> Widget<E> for Boxed<'_, E> {
+    fn size(
+        &self,
+        widthdb: &mut WidthDb,
+        max_width: Option<u16>,
+        max_height: Option<u16>,
+    ) -> Result<Size, E> {
+        self.0.wrap_size(widthdb, max_width, max_height)
+    }
+
+    fn draw(self, frame: &mut Frame) -> Result<(), E> {
+        self.0.wrap_draw(frame)
+    }
+}
+
+pub struct BoxedAsync<'a, E>(Box<dyn AsyncWidgetWrapper<E> + Send + Sync + 'a>);
+
+impl<'a, E> BoxedAsync<'a, E> {
+    pub fn new<I>(inner: I) -> Self
+    where
+        I: AsyncWidget<E> + Send + Sync + 'a,
+    {
+        Self(Box::new(inner))
+    }
+}
+
+#[async_trait]
+trait AsyncWidgetWrapper<E> {
+    async fn wrap_size(
+        &self,
+        widthdb: &mut WidthDb,
+        max_width: Option<u16>,
+        max_height: Option<u16>,
+    ) -> Result<Size, E>;
+
+    async fn wrap_draw(self: Box<Self>, frame: &mut Frame) -> Result<(), E>;
+}
+
+#[async_trait]
+impl<E, W> AsyncWidgetWrapper<E> for W
+where
+    W: AsyncWidget<E> + Send + Sync,
+{
+    async fn wrap_size(
+        &self,
+        widthdb: &mut WidthDb,
+        max_width: Option<u16>,
+        max_height: Option<u16>,
+    ) -> Result<Size, E> {
+        self.size(widthdb, max_width, max_height).await
+    }
+
+    async fn wrap_draw(self: Box<Self>, frame: &mut Frame) -> Result<(), E> {
+        (*self).draw(frame).await
+    }
+}
+
+#[async_trait]
+impl<E> AsyncWidget<E> for BoxedAsync<'_, E> {
+    async fn size(
+        &self,
+        widthdb: &mut WidthDb,
+        max_width: Option<u16>,
+        max_height: Option<u16>,
+    ) -> Result<Size, E> {
+        self.0.wrap_size(widthdb, max_width, max_height).await
+    }
+
+    async fn draw(self, frame: &mut Frame) -> Result<(), E> {
+        self.0.wrap_draw(frame).await
+    }
+}