wip: generic render

crates/tek_core/src/focus.rs

@@ -1,17 +1,17 @@
 use crate::*;
 
 /// A component that may contain [Focusable] components.
-pub trait Focus <const N: usize>: Render + Handle {
+pub trait Focus <const N: usize, T, U>: Render<T, U> + Handle {
     fn focus (&self) -> usize;
     fn focus_mut (&mut self) -> &mut usize;
-    fn focusable (&self) -> [&dyn Focusable;N];
-    fn focusable_mut (&mut self) -> [&mut dyn Focusable;N];
+    fn focusable (&self) -> [&dyn Focusable<T, U>;N];
+    fn focusable_mut (&mut self) -> [&mut dyn Focusable<T, U>;N];
 
-    fn focused (&self) -> &dyn Focusable {
+    fn focused (&self) -> &dyn Focusable<T, U> {
         let focus = self.focus();
         self.focusable()[focus]
     }
-    fn focused_mut (&mut self) -> &mut dyn Focusable {
+    fn focused_mut (&mut self) -> &mut dyn Focusable<T, U> {
         let focus = self.focus();
         self.focusable_mut()[focus]
     }
@@ -33,12 +33,14 @@ pub trait Focus <const N: usize>: Render + Handle {
 }
 
 /// A component that may be focused.
-pub trait Focusable: Render + Handle {
+pub trait Focusable<T, U>: Render<T, U> + Handle {
     fn is_focused (&self) -> bool;
     fn set_focused (&mut self, focused: bool);
 }
 
-impl<T: Focusable> Focusable for Option<T> {
+impl<F: Focusable<T, U>, T, U> Focusable<T, U> for Option<F>
+    where Option<F>: Render<T, U>
+{
     fn is_focused (&self) -> bool {
         match self {
             Some(focusable) => focusable.is_focused(),

crates/tek_core/src/jack_core.rs

@@ -1,19 +1,19 @@
 use crate::{*, jack::*};
 
 /// A UI component that may be associated with a JACK client by the `Jack` factory.
-pub trait Device: Render + Handle + Process + Send + Sync {
+pub trait Device<T, U>: Render<T, U> + Handle + Process + Send + Sync {
     /// Perform type erasure for collecting heterogeneous devices.
-    fn boxed (self) -> Box<dyn Device> where Self: Sized + 'static {
+    fn boxed (self) -> Box<dyn Device<T, U>> where Self: Sized + 'static {
         Box::new(self)
     }
 }
 
 /// All things that implement the required traits can be treated as `Device`.
-impl<T: Render + Handle + Process + Send + Sync> Device for T {}
+impl<D, T, U> Device<T, U> for D where D: Render<T, U> + Handle + Process {}
 
-impl Render for Box<dyn Device> {
-    fn render (&self, b: &mut Buffer, a: Rect) -> Usually<Rect> {
-        (**self).render(b, a)
+impl<T, U> Render<T, U> for Box<dyn Device<T, U>> {
+    fn render (&self, to: &mut T) -> Result<Option<U>, Box<dyn std::error::Error>> {
+        (**self).render(to)
     }
 }
 
@@ -143,10 +143,8 @@ impl Jack {
             )?.0,
         })
     }
-    pub fn run <T: Device + Process + Sized + 'static> (
-        self, state: impl FnOnce(JackPorts)->Box<T>
-    )
-        -> Usually<JackDevice>
+    pub fn run <D, T, U> (self, state: impl FnOnce(JackPorts)->Box<D>) -> Usually<JackDevice<T, U>>
+        where D: Device<T, U> + Process + Sized + 'static
     {
         let owned_ports = JackPorts {
             audio_ins:  register_ports(&self.client, self.audio_ins,  AudioIn)?,
@@ -162,7 +160,7 @@ impl Jack {
             .map(|p|Ok(p.name()?)).collect::<Usually<Vec<_>>>()?;
         let audio_ins = owned_ports.audio_ins.values()
             .map(|p|Ok(p.name()?)).collect::<Usually<Vec<_>>>()?;
-        let state = Arc::new(RwLock::new(state(owned_ports) as Box<dyn Device>));
+        let state = Arc::new(RwLock::new(state(owned_ports) as Box<dyn Device<T, U>>));
         let client = self.client.activate_async(
             Notifications(Box::new({
                 let _state = state.clone();

crates/tek_core/src/jack_device.rs

@@ -1,39 +1,51 @@
 use crate::{*, jack::*};
 
 /// A [Device] bound to a JACK client and a set of ports.
-pub struct JackDevice {
+pub struct JackDevice<T, U> {
     /// The active JACK client of this device.
     pub client: DynamicAsyncClient,
     /// The device state, encapsulated for sharing between threads.
-    pub state:  Arc<RwLock<Box<dyn Device>>>,
+    pub state:  Arc<RwLock<Box<dyn Device<T, U>>>>,
     /// Unowned copies of the device's JACK ports, for connecting to the device.
     /// The "real" readable/writable `Port`s are owned by the `state`.
     pub ports:  UnownedJackPorts,
 }
-impl std::fmt::Debug for JackDevice {
+impl<T, U> std::fmt::Debug for JackDevice<T, U> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         f.debug_struct("JackDevice").field("ports", &self.ports).finish()
     }
 }
-render!(JackDevice |self, buf, area| self.state.read().unwrap().render(buf, area));
-handle!(JackDevice |self, event| self.state.write().unwrap().handle(event));
-ports!(JackDevice {
-    audio: {
-        ins:  |s|Ok(s.ports.audio_ins.values().collect()),
-        outs: |s|Ok(s.ports.audio_outs.values().collect()),
+impl<'a, T, U> Render<T, U> for JackDevice<T, U> {
+    fn render (&self, to: &mut T) -> Perhaps<U> {
+        self.state.read().unwrap().render(to)
     }
-    midi: {
-        ins:  |s|Ok(s.ports.midi_ins.values().collect()),
-        outs: |s|Ok(s.ports.midi_outs.values().collect()),
+}
+impl<T, U> Handle for JackDevice<T, U> {
+    fn handle (&mut self, event: &AppEvent) -> Usually<bool> {
+        self.state.write().unwrap().handle(event)
     }
-});
-impl JackDevice {
+}
+impl<T, U> Ports for JackDevice<T, U> {
+    fn audio_ins (&self) -> Usually<Vec<&Port<Unowned>>> {
+        Ok(self.ports.audio_ins.values().collect())
+    }
+    fn audio_outs (&self) -> Usually<Vec<&Port<Unowned>>> {
+        Ok(self.ports.audio_outs.values().collect())
+    }
+    fn midi_ins (&self) -> Usually<Vec<&Port<Unowned>>> {
+        Ok(self.ports.midi_ins.values().collect())
+    }
+    fn midi_outs (&self) -> Usually<Vec<&Port<Unowned>>> {
+        Ok(self.ports.midi_outs.values().collect())
+    }
+}
+impl<T, U> JackDevice<T, U> {
     /// Returns a locked mutex of the state's contents.
-    pub fn state (&self) -> LockResult<RwLockReadGuard<Box<dyn Device>>> {
+    pub fn state (&self) -> LockResult<RwLockReadGuard<Box<dyn Device<T, U>>>> {
         self.state.read()
     }
     /// Returns a locked mutex of the state's contents.
-    pub fn state_mut (&self) -> LockResult<RwLockWriteGuard<Box<dyn Device>>> {
+    pub fn state_mut (&self) -> LockResult<RwLockWriteGuard<Box<dyn Device<T, U>>>> {
         self.state.write()
     }
     pub fn connect_midi_in (&self, index: usize, port: &Port<Unowned>) -> Usually<()> {

crates/tek_core/src/lib.rs

@@ -55,11 +55,13 @@ submod! {
     render
     render_axis
     render_border
+    render_buffer
     render_collect
-    render_fill
     render_layered
     render_split
-    render_theme
+    render_tui
+    render_tui_fill
+    render_tui_theme
     time_base
     time_note
     time_tick
@@ -80,59 +82,39 @@ submod! {
 /// Standard result type.
 pub type Usually<T> = Result<T, Box<dyn Error>>;
 
+/// Standard optional result type.
+pub type Perhaps<T> = Result<Option<T>, Box<dyn Error>>;
+
 /// A UI component.
-pub trait Component: Render + Handle + Sync {
+pub trait Component<T, U>: Render<T, U> + Handle + Sync {
     /// Perform type erasure for collecting heterogeneous components.
-    fn boxed (self) -> Box<dyn Component> where Self: Sized + 'static {
+    fn boxed (self) -> Box<dyn Component<T, U>> where Self: Sized + 'static {
         Box::new(self)
     }
 }
 
-impl<T: Render + Handle + Sync> Component for T {}
+impl<C, T, U> Component<T, U> for C where C: Render<T, U> + Handle + Sync {}
 
 /// Marker trait for [Component]s that can [Exit]
-pub trait ExitableComponent: Exit + Component {
+pub trait ExitableComponent<T, U>: Exit + Component<T, U> {
     /// Perform type erasure for collecting heterogeneous components.
-    fn boxed (self) -> Box<dyn ExitableComponent> where Self: Sized + 'static {
+    fn boxed (self) -> Box<dyn ExitableComponent<T, U>> where Self: Sized + 'static {
         Box::new(self)
     }
 }
 
-impl<T: Exit + Component> ExitableComponent for T {}
+impl<E: Exit + Component<T, U>, T, U> ExitableComponent<T, U> for E {}
 
 /// Run the main loop.
-pub fn run <T> (state: Arc<RwLock<T>>) -> Usually<Arc<RwLock<T>>>
-    where T: Render + Handle + Send + Sync + Sized + 'static
+pub fn run <'a, R> (state: Arc<RwLock<R>>) -> Usually<Arc<RwLock<R>>>
+    where R: Render<TuiOutput<'a>, Rect> + Handle + Sized + 'static
 {
     let exited = Arc::new(AtomicBool::new(false));
     let _input_thread = input_thread(&exited, &state);
     terminal_setup()?;
     panic_hook_setup();
-    let main_thread = render_thread(&exited, &state)?;
+    let main_thread = tui_render_thread(&exited, &state)?;
     main_thread.join().expect("main thread failed");
     terminal_teardown()?;
     Ok(state)
 }
-
-/// Set up panic hook
-pub fn panic_hook_setup () {
-    let better_panic_handler = Settings::auto().verbosity(Verbosity::Full).create_panic_handler();
-    std::panic::set_hook(Box::new(move |info: &std::panic::PanicInfo|{
-        stdout().execute(LeaveAlternateScreen).unwrap();
-        disable_raw_mode().unwrap();
-        better_panic_handler(info);
-    }));
-}
-
-/// Set up terminal
-pub fn terminal_setup () -> Usually<()> {
-    stdout().execute(EnterAlternateScreen)?;
-    enable_raw_mode()?;
-    Ok(())
-}
-/// Cleanup
-pub fn terminal_teardown () -> Usually<()> {
-    stdout().execute(LeaveAlternateScreen)?;
-    disable_raw_mode()?;
-    Ok(())
-}

crates/tek_core/src/render.rs

@@ -2,230 +2,60 @@
 
 use crate::*;
 pub(crate) use ratatui::prelude::CrosstermBackend;
-pub(crate) use ratatui::style::Style;
-pub(crate) use ratatui::layout::Rect;
-pub(crate) use ratatui::buffer::{Buffer, Cell};
 
-/// Main thread render loop
-pub fn render_thread (
-    exited: &Arc<AtomicBool>,
-    device: &Arc<RwLock<impl Render + 'static>>
-) -> Usually<JoinHandle<()>> {
-    let exited = exited.clone();
-    let device = device.clone();
-    let mut terminal = ratatui::Terminal::new(CrosstermBackend::new(stdout()))?;
-    let sleep = Duration::from_millis(20);
-    Ok(spawn(move || loop {
-
-        if let Ok(device) = device.try_read() {
-            terminal.draw(|frame|{
-                let area   = frame.size();
-                let buffer = frame.buffer_mut();
-                device
-                    .render(buffer, area)
-                    .expect("Failed to render content");
-            })
-                .expect("Failed to render frame");
-        }
-
-        if exited.fetch_and(true, Ordering::Relaxed) {
-            break
-        }
-        std::thread::sleep(sleep);
-    }))
+/// Trait for things that are displayed to the user.
+pub trait Render<T, U>: Send + Sync {
+    fn render (&self, to: &mut T) -> Perhaps<U>;
 }
 
-/// Trait for things that render to the display.
-pub trait Render: Send + Sync {
-    // Render something to an area of the buffer.
-    // Returns area used by component.
-    // This is insufficient but for the most basic dynamic layout algorithms.
-    fn render (&self, _b: &mut Buffer, _a: Rect) -> Usually<Rect> {
-        Ok(Rect { x: 0, y: 0, width: 0, height: 0 })
-    }
-    fn into_collected <'a> (self) -> Collected<'a> where Self: Sized + 'a {
-        Collected::Box(Box::new(self))
-    }
-}
-
-/// Implement the `Render` trait.
-#[macro_export] macro_rules! render {
-    ($T:ty) => {
-        impl Render for $T {}
-    };
-    ($T:ty |$self:ident, $buf:ident, $area:ident|$block:expr) => {
-        impl Render for $T {
-            fn render (&$self, $buf: &mut Buffer, $area: Rect) -> Usually<Rect> {
-                $block
-            }
-        }
-    };
-    ($T:ty = $render:path) => {
-        impl Render for $T {
-            fn render (&self, buf: &mut Buffer, area: Rect) -> Usually<Rect> {
-                $render(self, buf, area)
-            }
-        }
-    }
-}
-
-impl Render for () {
-    fn render (&self, _: &mut Buffer, a: Rect) -> Usually<Rect> {
-        Ok(Rect { x: a.x, y: a.y, width: 0, height: 0 })
-    }
-}
-
-impl<T: Render> Render for &T {
-    fn render (&self, buf: &mut Buffer, area: Rect) -> Usually<Rect> {
-        (*self).render(buf, area)
-    }
-    fn into_collected <'a> (self) -> Collected<'a> where Self: Sized + 'a {
-        Collected::Ref(self)
-    }
-}
-
-impl<T: Render> Render for &mut T {
-    fn render (&self, buf: &mut Buffer, area: Rect) -> Usually<Rect> {
-        (**self).render(buf, area)
-    }
-    fn into_collected <'a> (self) -> Collected<'a> where Self: Sized + 'a {
-        Collected::Ref(self)
-    }
-}
-
-impl<T: Render> Render for Option<T> {
-    fn render (&self, b: &mut Buffer, a: Rect) -> Usually<Rect> {
+/// Options can be rendered optionally.
+impl<R, T, U> Render<T, U> for Option<R> where R: Render<T, U> {
+    fn render (&self, to: &mut T) -> Perhaps<U> {
         match self {
-            Some(widget) => widget.render(b, a),
-            None => ().render(b, a),
+            Some(component) => component.render(to),
+            None => Ok(None)
         }
     }
 }
 
-impl<'a> Render for Box<dyn Render + 'a> {
-    fn render (&self, buf: &mut Buffer, area: Rect) -> Usually<Rect> {
-        (**self).render(buf, area)
-    }
-    fn into_collected <'b> (self) -> Collected<'b> where Self: Sized + 'b {
-        Collected::Box(self)
+/// Boxed references can be rendered.
+impl<'a, T, U> Render<T, U> for Box<dyn Render<T, U> + 'a> {
+    fn render (&self, to: &mut T) -> Perhaps<U> {
+        (**self).render(to)
     }
 }
 
-impl<T: Render> Render for Arc<T> {
-    fn render (&self, b: &mut Buffer, a: Rect) -> Usually<Rect> {
-        self.as_ref().render(b, a)
+/// Immutable references can be rendered.
+impl<R, T, U> Render<T, U> for &R where R: Render<T, U> {
+    fn render (&self, to: &mut T) -> Perhaps<U> {
+        (*self).render(to)
     }
 }
 
-impl<T: Render> Render for Mutex<T> {
-    fn render (&self, b: &mut Buffer, a: Rect) -> Usually<Rect> {
-        self.lock().unwrap().render(b, a)
+/// Mutable references can be rendered.
+impl<R, T, U> Render<T, U> for &mut R where R: Render<T, U> {
+    fn render (&self, to: &mut T) -> Perhaps<U> {
+        (**self).render(to)
     }
 }
 
-impl<T: Render + Sync> Render for RwLock<T> {
-    fn render (&self, b: &mut Buffer, a: Rect) -> Usually<Rect> {
-        self.read().unwrap().render(b, a)
+/// Counted references can be rendered.
+impl<R, T, U> Render<T, U> for Arc<R> where R: Render<T, U> {
+    fn render (&self, to: &mut T) -> Perhaps<U> {
+        self.as_ref().render(to)
     }
 }
 
-//impl<'a, T: Fn(&mut Buffer, Rect) -> Usually<Rect> + Send + Sync + 'a> Render for T {
-    //fn render (&self, b: &mut Buffer, a: Rect) -> Usually<Rect> {
-        //(*self)(b, a)
-    //}
-//}
-
-impl<'a> Render for Box<dyn Fn(&mut Buffer, Rect) -> Usually<Rect> + Send + Sync + 'a> {
-    fn render (&self, b: &mut Buffer, a: Rect) -> Usually<Rect> {
-        (*self)(b, a)
+/// References behind a [Mutex] can be rendered.
+impl<R, T, U> Render<T, U> for Mutex<R> where R: Render<T, U> {
+    fn render (&self, to: &mut T) -> Perhaps<U> {
+        self.lock().unwrap().render(to)
     }
 }
 
-pub fn center_box (area: Rect, w: u16, h: u16) -> Rect {
-    let width  = w.min(area.width * 3 / 5);
-    let height = h.min(area.width * 3 / 5);
-    let x = area.x + (area.width  - width)  / 2;
-    let y = area.y + (area.height - height) / 2;
-    Rect { x, y, width, height }
-}
-
-pub fn half_block (lower: bool, upper: bool) -> Option<char> {
-    match (lower, upper) {
-        (true, true)  => Some('█'),
-        (true, false) => Some('▄'),
-        (false, true) => Some('▀'),
-        _ => None
-    }
-}
-
-pub trait Blit {
-    // Render something to X, Y coordinates in a buffer, ignoring width/height.
-    fn blit (&self, buf: &mut Buffer, x: u16, y: u16, style: Option<Style>) -> Usually<Rect>;
-}
-
-impl<T: AsRef<str>> Blit for T {
-    fn blit (&self, buf: &mut Buffer, x: u16, y: u16, style: Option<Style>) -> Usually<Rect> {
-        if x < buf.area.width && y < buf.area.height {
-            buf.set_string(x, y, self.as_ref(), style.unwrap_or(Style::default()));
-        }
-        Ok(Rect { x, y, width: self.as_ref().len() as u16, height: 1 })
-    }
-}
-
-//impl WidgetRef for &dyn Render {
-    //fn render_ref (&self, area: Rect, buf: &mut Buffer) {
-        //Render::render(*self, buf, area).expect("Failed to render device.");
-    //}
-//}
-
-//impl WidgetRef for dyn Render {
-    //fn render_ref (&self, area: Rect, buf: &mut Buffer) {
-        //Render::render(self, buf, area).expect("Failed to render device.");
-    //}
-//}
-
-#[derive(Default)]
-pub struct BigBuffer {
-    pub width:   usize,
-    pub height:  usize,
-    pub content: Vec<Cell>
-}
-
-impl BigBuffer {
-    pub fn new (width: usize, height: usize) -> Self {
-        Self { width, height, content: vec![Cell::default(); width*height] }
-    }
-    pub fn get (&self, x: usize, y: usize) -> Option<&Cell> {
-        let i = self.index_of(x, y);
-        self.content.get(i)
-    }
-    pub fn get_mut (&mut self, x: usize, y: usize) -> Option<&mut Cell> {
-        let i = self.index_of(x, y);
-        self.content.get_mut(i)
-    }
-    pub fn index_of (&self, x: usize, y: usize) -> usize {
-        y * self.width + x
-    }
-}
-
-pub struct If<'a>(pub bool, pub &'a (dyn Render + Sync));
-
-impl<'a> Render for If<'a> {
-    fn render (&self, buf: &mut Buffer, area: Rect) -> Usually<Rect> {
-        match self.0 {
-            true  => self.1 as &dyn Render,
-            false => &() as &dyn Render
-        }.render(buf, area)
-    }
-}
-
-pub struct IfElse<'a>(pub bool, pub &'a (dyn Render + Sync), pub &'a (dyn Render + Sync));
-
-impl<'a> Render for IfElse<'a> {
-    fn render (&self, buf: &mut Buffer, area: Rect) -> Usually<Rect> {
-        match self.0 {
-            true  => self.1 as &dyn Render,
-            false => &() as &dyn Render
-        }.render(buf, area)
+/// References behind a [RwLock] can be rendered.
+impl<R, T, U> Render<T, U> for RwLock<R> where R: Render<T, U> {
+    fn render (&self, to: &mut T) -> Perhaps<U> {
+        self.read().unwrap().render(to)
     }
 }

crates/tek_core/src/render_buffer.rs

@@ -0,0 +1,25 @@
+use crate::*;
+
+#[derive(Default)]
+pub struct BigBuffer {
+    pub width:   usize,
+    pub height:  usize,
+    pub content: Vec<Cell>
+}
+
+impl BigBuffer {
+    pub fn new (width: usize, height: usize) -> Self {
+        Self { width, height, content: vec![Cell::default(); width*height] }
+    }
+    pub fn get (&self, x: usize, y: usize) -> Option<&Cell> {
+        let i = self.index_of(x, y);
+        self.content.get(i)
+    }
+    pub fn get_mut (&mut self, x: usize, y: usize) -> Option<&mut Cell> {
+        let i = self.index_of(x, y);
+        self.content.get_mut(i)
+    }
+    pub fn index_of (&self, x: usize, y: usize) -> usize {
+        y * self.width + x
+    }
+}

crates/tek_core/src/render_collect.rs

@@ -1,45 +1,40 @@
 use crate::*;
 
-pub enum Collected<'a> {
-    Box(Box<dyn Render + 'a>),
-    Ref(&'a (dyn Render + 'a)),
-    None
+pub enum Collected<'a, T, U> {
+    Box(Box<dyn Render<T, U> + 'a>),
+    Ref(&'a (dyn Render<T, U> + 'a)),
 }
-
-impl<'a> Render for Collected<'a> {
-    fn render (&self, buf: &mut Buffer, area: Rect) -> Usually<Rect> {
-        Ok(match self {
-            Self::Box(item) => (*item).render(buf, area)?,
-            Self::Ref(item) => (*item).render(buf, area)?,
-            Self::None => ().render(buf, area)?
-        })
+impl<'a, T, U> Render<T, U> for Collected<'a, T, U> {
+    fn render (&self, to: &mut T) -> Perhaps<U> {
+        match self {
+            Self::Box(item) => (*item).render(to),
+            Self::Ref(item) => (*item).render(to),
+        }
     }
 }
-
-pub struct Collection<'a>(pub Vec<Collected<'a>>);
-
-impl<'a> Collection<'a> {
+pub struct Collection<'a, T, U>(
+    pub Vec<Collected<'a, T, U>>
+);
+impl<'a, T, U> Collection<'a, T, U> {
     pub fn new () -> Self {
         Self(vec![])
     }
 }
-
-pub trait Collect<'a> {
-    fn add_box (self, item: Box<dyn Render + 'a>) -> Self;
-    fn add_ref (self, item: &'a dyn Render) -> Self;
-    fn add <T: Render + Sized + 'a> (self, item: T) -> Self
+pub trait Collect<'a, T, U> {
+    fn add_box (self, item: Box<dyn Render<T, U> + 'a>) -> Self;
+    fn add_ref (self, item: &'a dyn Render<T, U>) -> Self;
+    fn add <R: Render<T, U> + Sized + 'a> (self, item: R) -> Self
         where Self: Sized
     {
         self.add_box(Box::new(item))
     }
 }
-
-impl<'a> Collect<'a> for Collection<'a> {
-    fn add_box (mut self, item: Box<dyn Render + 'a>) -> Self {
+impl<'a, T, U> Collect<'a, T, U> for Collection<'a, T, U> {
+    fn add_box (mut self, item: Box<dyn Render<T, U> + 'a>) -> Self {
         self.0.push(Collected::Box(item));
         self
     }
-    fn add_ref (mut self, item: &'a dyn Render) -> Self {
+    fn add_ref (mut self, item: &'a dyn Render<T, U>) -> Self {
         self.0.push(Collected::Ref(item));
         self
     }

crates/tek_core/src/render_layered.rs

@@ -1,29 +1,30 @@
 use crate::*;
 
-pub struct Layered<'a>(Collection<'a>);
+pub struct Layered<'a, T, U>(Collection<'a, T, U>);
 
-impl<'a> Layered<'a> {
+impl<'a, T, U> Layered<'a, T, U> {
     pub fn new () -> Self {
         Self(Collection::new())
     }
 }
 
-impl<'a> Render for Layered<'a> {
-    fn render (&self, buf: &mut Buffer, area: Rect) -> Usually<Rect> {
-        for layer in self.0.0.iter() {
-            layer.render(buf, area)?;
-        }
-        Ok(area)
-    }
-}
-
-impl<'a> Collect<'a> for Layered<'a> {
-    fn add_box (mut self, item: Box<dyn Render + 'a>) -> Self {
+impl<'a, T, U> Collect<'a, T, U> for Layered<'a, T, U> {
+    fn add_box (mut self, item: Box<dyn Render<T, U> + 'a>) -> Self {
         self.0 = self.0.add_box(item);
         self
     }
-    fn add_ref (mut self, item: &'a dyn Render) -> Self {
+    fn add_ref (mut self, item: &'a dyn Render<T, U>) -> Self {
         self.0 = self.0.add_ref(item);
         self
     }
 }
+
+impl<'a, 'b> Render<TuiOutput<'b>, Rect> for Layered<'a, TuiOutput<'b>, Rect> {
+    fn render (&self, to: &mut TuiOutput<'b>) -> Perhaps<Rect> {
+        let area = to.area;
+        for layer in self.0.0.iter() {
+            layer.render(to)?;
+        }
+        Ok(Some(area))
+    }
+}

crates/tek_core/src/render_split.rs

@@ -17,13 +17,13 @@ impl Direction {
     }
 }
 
-pub struct Split<'a> {
-    items:     Collection<'a>,
+pub struct Split<'a, T, U> {
+    items:     Collection<'a, T, U>,
     direction: Direction,
     focus:     Option<usize>
 }
 
-impl<'a> Split<'a> {
+impl<'a, T, U> Split<'a, T, U> {
     pub fn new (direction: Direction) -> Self {
         Self {
             items: Collection::new(),
@@ -41,47 +41,53 @@ impl<'a> Split<'a> {
         self.focus = focus;
         self
     }
-    pub fn render_areas (&self, buf: &mut Buffer, area: Rect) -> Usually<(Rect, Vec<Rect>)> {
-        let Rect { mut x, mut y, mut width, mut height } = area;
-        let mut areas = vec![];
-        for (index, item) in self.items.0.iter().enumerate() {
-            if width == 0 || height == 0 {
-                break
-            }
-            let result = item.render(buf, Rect { x, y, width, height })?;
-            match self.direction {
-                Direction::Down => {
-                    y += result.height;
-                    height = height.saturating_sub(result.height);
-                },
-                Direction::Right => {
-                    x += result.width;
-                    width = width.saturating_sub(result.width);
-                },
-                _ => unimplemented!()
-            };
-            areas.push(result);
-            if self.focus == Some(index) {
-                Corners(Style::default().green().not_dim()).draw(buf, result)?;
-            }
-        }
-        Ok((area, areas))
-    }
 }
 
-impl<'a> Render for Split<'a> {
-    fn render (&self, buf: &mut Buffer, area: Rect) -> Usually<Rect> {
-        Ok(self.render_areas(buf, area)?.0)
-    }
-}
-
-impl<'a> Collect<'a> for Split<'a> {
-    fn add_box (mut self, item: Box<dyn Render + 'a>) -> Self {
+impl<'a, T, U> Collect<'a, T, U> for Split<'a, T, U> {
+    fn add_box (mut self, item: Box<dyn Render<T, U> + 'a>) -> Self {
         self.items = self.items.add_box(item);
         self
     }
-    fn add_ref (mut self, item: &'a dyn Render) -> Self {
+    fn add_ref (mut self, item: &'a dyn Render<T, U>) -> Self {
         self.items = self.items.add_ref(item);
         self
     }
 }
+
+impl<'a> Render<TuiOutput<'a>, Rect> for Split<'a, TuiOutput<'a>, Rect> {
+    fn render (&self, to: &mut TuiOutput<'a>) -> Perhaps<Rect> {
+        Ok(Some(self.render_areas(to)?.0))
+    }
+}
+
+impl<'a> Split<'a, TuiOutput<'a>, Rect> {
+    pub fn render_areas (&self, to: &mut TuiOutput<'a>) -> Usually<(Rect, Vec<Rect>)> {
+        let Rect { mut x, mut y, mut width, mut height } = to.area;
+        let mut areas = vec![];
+        let buffer = &mut to.buffer;
+        for (index, item) in self.items.0.iter().enumerate() {
+            if width == 0 || height == 0 {
+                break
+            }
+            let target = TuiOutput { buffer, area: Rect { x, y, width, height } };
+            if let Some(result) = item.render(&mut target)? {
+                match self.direction {
+                    Direction::Down => {
+                        y += result.height;
+                        height = height.saturating_sub(result.height);
+                    },
+                    Direction::Right => {
+                        x += result.width;
+                        width = width.saturating_sub(result.width);
+                    },
+                    _ => unimplemented!()
+                };
+                areas.push(result);
+                if self.focus == Some(index) {
+                    Corners(Style::default().green().not_dim()).draw(buffer, result)?;
+                }
+            }
+        }
+        Ok((to.area, areas))
+    }
+}

crates/tek_core/src/render_tui.rs

@@ -0,0 +1,110 @@
+use crate::*;
+
+pub(crate) use ratatui::buffer::Cell;
+
+pub struct TuiOutput<'a> {
+    pub buffer: &'a mut Buffer,
+    pub area:   Rect
+}
+
+/// Main thread render loop
+pub fn tui_render_thread <'a, T: Render<TuiOutput<'a>, Rect> + 'static> (
+    exited: &Arc<AtomicBool>, device: &Arc<RwLock<T>>,
+) -> Usually<JoinHandle<()>> {
+    let exited = exited.clone();
+    let device = device.clone();
+    let mut terminal = ratatui::Terminal::new(CrosstermBackend::new(stdout()))?;
+    let sleep = Duration::from_millis(20);
+    Ok(spawn(move || loop {
+
+        if let Ok(device) = device.try_read() {
+            terminal.draw(|frame|{
+                let area = frame.size();
+                let buffer = frame.buffer_mut();
+                let mut output = TuiOutput { buffer, area };
+                device.render(&mut output).expect("Failed to render content");
+            })
+                .expect("Failed to render frame");
+        }
+
+        if exited.fetch_and(true, Ordering::Relaxed) {
+            break
+        }
+        std::thread::sleep(sleep);
+    }))
+}
+
+/// Set up panic hook
+pub fn panic_hook_setup () {
+    let better_panic_handler = Settings::auto().verbosity(Verbosity::Full).create_panic_handler();
+    std::panic::set_hook(Box::new(move |info: &std::panic::PanicInfo|{
+        stdout().execute(LeaveAlternateScreen).unwrap();
+        disable_raw_mode().unwrap();
+        better_panic_handler(info);
+    }));
+}
+
+/// Set up terminal
+pub fn terminal_setup () -> Usually<()> {
+    stdout().execute(EnterAlternateScreen)?;
+    enable_raw_mode()?;
+    Ok(())
+}
+
+/// Cleanup
+pub fn terminal_teardown () -> Usually<()> {
+    stdout().execute(LeaveAlternateScreen)?;
+    disable_raw_mode()?;
+    Ok(())
+}
+
+/// A simpler analog to [Render].
+pub trait Blit {
+    // Render something to X, Y coordinates in a buffer, ignoring width/height.
+    fn blit (&self, buf: &mut Buffer, x: u16, y: u16, style: Option<Style>) -> Perhaps<Rect>;
+}
+
+/// Text can be rendered.
+impl<T: AsRef<str>> Blit for T {
+    fn blit (&self, buf: &mut Buffer, x: u16, y: u16, style: Option<Style>) -> Perhaps<Rect> {
+        if x < buf.area.width && y < buf.area.height {
+            buf.set_string(x, y, self.as_ref(), style.unwrap_or(Style::default()));
+        }
+        Ok(Some(Rect { x, y, width: self.as_ref().len() as u16, height: 1 }))
+    }
+}
+
+/// Rendering unit struct to Ratatui returns zero-sized [Rect] at render coordinates.
+impl<'a> Render<TuiOutput<'a>, Rect> for () {
+    fn render (&self, (_, area): (&mut Buffer, Rect)) -> Perhaps<Rect> {
+        Ok(Some(Rect { x: area.x, y: area.y, width: 0, height: 0 }))
+    }
+}
+
+/// Boxed closures can be rendered.
+/// 
+/// Rendering unboxed closures should also be possible;
+/// but in practice implementing the trait for an unboxed
+/// `Fn` closure causes an impl conflict.
+impl<'a, T, U> Render<T, U> for Box<dyn Fn(T) -> Usually<U> + Send + Sync + 'a> {
+    fn render (&self, to: T) -> Usually<U> {
+        (*self)(to)
+    }
+}
+
+pub fn center_box (area: Rect, w: u16, h: u16) -> Rect {
+    let width  = w.min(area.width * 3 / 5);
+    let height = h.min(area.width * 3 / 5);
+    let x = area.x + (area.width  - width)  / 2;
+    let y = area.y + (area.height - height) / 2;
+    Rect { x, y, width, height }
+}
+
+pub fn half_block (lower: bool, upper: bool) -> Option<char> {
+    match (lower, upper) {
+        (true, true)  => Some('█'),
+        (true, false) => Some('▄'),
+        (false, true) => Some('▀'),
+        _ => None
+    }
+}

crates/tek_core/src/render_tui_fill.rs

@@ -2,10 +2,12 @@ use crate::*;
 
 pub struct FillBg(pub Color);
 
-render!(FillBg |self, buf, area| {
-    fill_bg(buf, area, self.0);
-    Ok(area)
-});
+impl<'a> Render<TuiOutput<'a>, Rect> for FillBg {
+    fn render (&self, to: &mut TuiOutput<'a>) -> Perhaps<Rect> {
+        fill_bg(to.buffer, to.area, self.0);
+        Ok(Some(to.area))
+    }
+}
 
 pub fn make_dim (buf: &mut Buffer) {
     for cell in buf.content.iter_mut() {