Add Background widget

examples/hello_world_widgets.rs

@@ -18,6 +18,8 @@ fn widget() -> impl Widget<Infallible> {
         .border()
         .look(BorderLook::LINE_DOUBLE)
         .style(ContentStyle::default().dark_red())
+        .background()
+        .style(ContentStyle::default().on_dark_yellow())
         .float()
         .all(0.5)
 }

src/widget.rs

@@ -1,6 +1,6 @@
 use async_trait::async_trait;
 
-use crate::widgets::{Border, Float, Padding};
+use crate::widgets::{Background, Border, Float, Padding};
 use crate::{Frame, Size};
 
 // TODO Feature-gate these traits
@@ -29,6 +29,10 @@ pub trait AsyncWidget<E> {
 }
 
 pub trait WidgetExt: Sized {
+    fn background(self) -> Background<Self> {
+        Background::new(self)
+    }
+
     fn border(self) -> Border<Self> {
         Border::new(self)
     }

src/widgets.rs

@@ -1,9 +1,11 @@
+mod background;
 mod border;
 mod empty;
 mod float;
 mod padding;
 mod text;
 
+pub use background::*;
 pub use border::*;
 pub use empty::*;
 pub use float::*;

src/widgets/background.rs

@@ -0,0 +1,71 @@
+use async_trait::async_trait;
+use crossterm::style::ContentStyle;
+
+use crate::{AsyncWidget, Frame, Pos, Size, Widget};
+
+pub struct Background<I> {
+    inner: I,
+    style: ContentStyle,
+}
+
+impl<I> Background<I> {
+    pub fn new(inner: I) -> Self {
+        Self {
+            inner,
+            style: ContentStyle::default(),
+        }
+    }
+
+    pub fn style(mut self, style: ContentStyle) -> Self {
+        self.style = style;
+        self
+    }
+
+    fn fill(&self, frame: &mut Frame) {
+        let size = frame.size();
+        for dy in 0..size.height {
+            for dx in 0..size.width {
+                frame.write(Pos::new(dx.into(), dy.into()), (" ", self.style));
+            }
+        }
+    }
+}
+
+impl<E, I> Widget<E> for Background<I>
+where
+    I: Widget<E>,
+{
+    fn size(
+        &self,
+        frame: &mut Frame,
+        max_width: Option<u16>,
+        max_height: Option<u16>,
+    ) -> Result<Size, E> {
+        self.inner.size(frame, max_width, max_height)
+    }
+
+    fn draw(self, frame: &mut Frame) -> Result<(), E> {
+        self.fill(frame);
+        self.inner.draw(frame)
+    }
+}
+
+#[async_trait]
+impl<E, I> AsyncWidget<E> for Background<I>
+where
+    I: AsyncWidget<E> + Send + Sync,
+{
+    async fn size(
+        &self,
+        frame: &mut Frame,
+        max_width: Option<u16>,
+        max_height: Option<u16>,
+    ) -> Result<Size, E> {
+        self.inner.size(frame, max_width, max_height).await
+    }
+
+    async fn draw(self, frame: &mut Frame) -> Result<(), E> {
+        self.fill(frame);
+        self.inner.draw(frame).await
+    }
+}