refactor engine and layout into input and output

engine/src/engine.rs

@@ -1,50 +0,0 @@
-use crate::*;
-
-/// Platform backend.
-pub trait Engine: Send + Sync + Sized {
-    /// Input event type
-    type Input: Input;
-    /// Render target
-    type Output: Output;
-    /// Prepare before run
-    fn setup (&mut self) -> Usually<()> { Ok(()) }
-    /// True if done
-    fn exited (&self) -> bool;
-    /// Clean up after run
-    fn teardown (&mut self) -> Usually<()> { Ok(()) }
-}
-
-/// Event source
-pub trait Input: Send + Sync + Sized {
-    /// Type of input event
-    type Event;
-    /// Result of handling input
-    type Handled;
-    /// Currently handled event
-    fn event (&self) -> &Self::Event;
-    /// Whether component should exit
-    fn is_done (&self) -> bool;
-    /// Mark component as done
-    fn done (&self);
-}
-
-/// Render target
-pub trait Output: Send + Sync + Sized {
-    /// Unit of length
-    type Unit: Coordinate;
-    /// Rectangle without offset
-    type Size: Size<Self::Unit>;
-    /// Rectangle with offset
-    type Area: Area<Self::Unit>;
-    /// Current output area
-    fn area (&self) -> Self::Area;
-    /// Mutable pointer to area
-    fn area_mut (&mut self) -> &mut Self::Area;
-    /// Render widget in area
-    fn place (&mut self, area: Self::Area, content: &impl Render<Self>);
-    #[inline] fn x (&self) -> Self::Unit { self.area().x() }
-    #[inline] fn y (&self) -> Self::Unit { self.area().y() }
-    #[inline] fn w (&self) -> Self::Unit { self.area().w() }
-    #[inline] fn h (&self) -> Self::Unit { self.area().h() }
-    #[inline] fn wh (&self) -> Self::Size { self.area().wh().into() }
-}