From 88e66e17ec3da5c37445e5155a483bdc948c2752 Mon Sep 17 00:00:00 2001
From: Joscha <joscha@plugh.de>
Date: Thu, 6 Apr 2023 00:48:53 +0200
Subject: [PATCH] Add Predrawn widget

---
 src/widgets.rs          |  2 +
 src/widgets/predrawn.rs | 86 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+)
 create mode 100644 src/widgets/predrawn.rs

diff --git a/src/widgets.rs b/src/widgets.rs
index dc80eb7..49c65a5 100644
--- a/src/widgets.rs
+++ b/src/widgets.rs
@@ -8,6 +8,7 @@ pub mod float;
 pub mod join;
 pub mod layer;
 pub mod padding;
+pub mod predrawn;
 pub mod resize;
 pub mod text;
 
@@ -21,5 +22,6 @@ pub use float::*;
 pub use join::*;
 pub use layer::*;
 pub use padding::*;
+pub use predrawn::*;
 pub use resize::*;
 pub use text::*;
diff --git a/src/widgets/predrawn.rs b/src/widgets/predrawn.rs
new file mode 100644
index 0000000..e11d9f8
--- /dev/null
+++ b/src/widgets/predrawn.rs
@@ -0,0 +1,86 @@
+use std::mem;
+
+use async_trait::async_trait;
+
+use crate::buffer::Buffer;
+use crate::{AsyncWidget, Frame, Pos, Size, Style, Styled, Widget, WidthDb};
+
+pub struct Predrawn {
+    buffer: Buffer,
+}
+
+impl Predrawn {
+    pub fn new<E, W: Widget<E>>(inner: W, frame: &mut Frame) -> Result<Self, E> {
+        let mut tmp_frame = Frame::default();
+        tmp_frame.buffer.resize(frame.size());
+        mem::swap(&mut frame.widthdb, &mut tmp_frame.widthdb);
+
+        inner.draw(&mut tmp_frame)?;
+
+        mem::swap(&mut frame.widthdb, &mut tmp_frame.widthdb);
+
+        let buffer = tmp_frame.buffer;
+        Ok(Self { buffer })
+    }
+
+    pub async fn new_async<E, W: AsyncWidget<E>>(inner: W, frame: &mut Frame) -> Result<Self, E> {
+        let mut tmp_frame = Frame::default();
+        tmp_frame.buffer.resize(frame.size());
+        mem::swap(&mut frame.widthdb, &mut tmp_frame.widthdb);
+
+        inner.draw(&mut tmp_frame).await?;
+
+        mem::swap(&mut frame.widthdb, &mut tmp_frame.widthdb);
+
+        let buffer = tmp_frame.buffer;
+        Ok(Self { buffer })
+    }
+
+    pub fn size(&self) -> Size {
+        self.buffer.size()
+    }
+
+    fn draw_impl(&self, frame: &mut Frame) {
+        for (x, y, cell) in self.buffer.cells() {
+            let pos = Pos::new(x.into(), y.into());
+            let style = Style {
+                content_style: cell.style,
+                opaque: true,
+            };
+            frame.write(pos, Styled::new(&cell.content, style));
+        }
+    }
+}
+
+impl<E> Widget<E> for Predrawn {
+    fn size(
+        &self,
+        _widthdb: &mut WidthDb,
+        _max_width: Option<u16>,
+        _max_height: Option<u16>,
+    ) -> Result<Size, E> {
+        Ok(self.buffer.size())
+    }
+
+    fn draw(self, frame: &mut Frame) -> Result<(), E> {
+        self.draw_impl(frame);
+        Ok(())
+    }
+}
+
+#[async_trait]
+impl<E> AsyncWidget<E> for Predrawn {
+    async fn size(
+        &self,
+        _widthdb: &mut WidthDb,
+        _max_width: Option<u16>,
+        _max_height: Option<u16>,
+    ) -> Result<Size, E> {
+        Ok(self.buffer.size())
+    }
+
+    async fn draw(self, frame: &mut Frame) -> Result<(), E> {
+        self.draw_impl(frame);
+        Ok(())
+    }
+}