separate Input and Output impls

engine/src/engine.rs

@@ -3,17 +3,9 @@ use crate::*;
 /// Platform backend.
 pub trait Engine: Send + Sync + Sized {
     /// Input event type
-    type Input: Input<Self>;
-    /// Result of handling input
-    type Handled;
+    type Input: Input;
     /// Render target
-    type Output: Output<Self>;
-    /// Unit of length
-    type Unit: Coordinate;
-    /// Rectangle without offset
-    type Size: Size<Self::Unit>;
-    /// Rectangle with offset
-    type Area: Area<Self::Unit>;
+    type Output: Output;
     /// Prepare before run
     fn setup (&mut self) -> Usually<()> { Ok(()) }
     /// True if done
@@ -21,3 +13,38 @@ pub trait Engine: Send + Sync + Sized {
     /// 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() }
+}