diff --git a/crates/tek_core/src/component/offset.rs b/crates/tek_core/src/component/offset.rs
deleted file mode 100644
index aeaa69a1..00000000
--- a/crates/tek_core/src/component/offset.rs
+++ /dev/null
@@ -1,38 +0,0 @@
-use crate::*;
-use std::ops::Add;
-
-pub struct Offset<N>(pub N, pub N);
-
-impl<N: Copy> From<N> for Offset<N> {
-    fn from (n: N) -> Self {
-        Self(n, n)
-    }
-}
-
-pub struct Inset<N>(pub N, pub N, pub N, pub N);
-
-impl<N: Copy> From<N> for Inset<N> {
-    fn from (n: N) -> Self {
-        Self(n, n, n, n)
-    }
-}
-
-impl<N: Copy> From<(N, N)> for Inset<N> {
-    fn from ((n1, n2): (N, N)) -> Self {
-        Self(n1, n2, n1, n2)
-    }
-}
-
-pub struct Outset<N>(pub N, pub N, pub N, pub N);
-
-impl<N: Copy> From<N> for Outset<N> {
-    fn from (n: N) -> Self {
-        Self(n, n, n, n)
-    }
-}
-
-impl<N: Copy> From<(N, N)> for Outset<N> {
-    fn from ((n1, n2): (N, N)) -> Self {
-        Self(n1, n2, n1, n2)
-    }
-}
diff --git a/crates/tek_core/src/engine.rs b/crates/tek_core/src/engine.rs
index 05fbbae7..da0e008a 100644
--- a/crates/tek_core/src/engine.rs
+++ b/crates/tek_core/src/engine.rs
@@ -1,22 +1,36 @@
 use crate::*;
+use std::ops::{Add, Sub};
+use std::cmp::{Ord, Eq, PartialEq};
 
 /// Entry point for main loop
 pub trait App<T: Engine> {
     fn run (self, context: T) -> Usually<T>;
 }
 
+pub trait Number: Send + Sync + Copy
+    + Add<Self, Output=Self>
+    + Sub<Self, Output=Self>
+    + Ord + PartialEq + Eq {}
+
+impl<T> Number for T where
+    T: Send + Sync + Copy
+        + Add<Self, Output=Self>
+        + Sub<Self, Output=Self>
+        + Ord + PartialEq + Eq
+{}
+
 /// Platform backend.
 pub trait Engine: Sized {
     fn setup (&mut self) -> Usually<()> { Ok(()) }
     fn exited (&self) -> bool;
     fn teardown (&mut self) -> Usually<()> { Ok(()) }
 
-    type HandleInput;
-    fn handle (&self, _: &mut impl Handle<Self>) -> Usually<()> where Self: Sized;
-    type Handled;
+    /// Unit of distance.
+    type Unit: Number;
 
+    type HandleInput;
+    type Handled;
     type RenderInput;
-    fn render (&mut self, _: &impl Render<Self>) -> Usually<()> where Self: Sized;
     type Rendered;
 }
 
@@ -25,9 +39,14 @@ pub trait HandleContext {}
 pub trait RenderContext {}
 
 submod! {
+    collect
+    component
     exit
     focus
     handle
     keymap
+    layered
+    layout
     render
+    split
 }
diff --git a/crates/tek_core/src/component/collect.rs b/crates/tek_core/src/engine/collect.rs
similarity index 100%
rename from crates/tek_core/src/component/collect.rs
rename to crates/tek_core/src/engine/collect.rs
diff --git a/crates/tek_core/src/component.rs b/crates/tek_core/src/engine/component.rs
similarity index 79%
rename from crates/tek_core/src/component.rs
rename to crates/tek_core/src/engine/component.rs
index c9bf9e19..952a4d90 100644
--- a/crates/tek_core/src/component.rs
+++ b/crates/tek_core/src/engine/component.rs
@@ -5,10 +5,3 @@ pub trait Component<E: Engine>: Render<E> + Handle<E> {}
 
 /// Everything that implements [Render] and [Handle] is a [Component].
 impl<E: Engine, C: Render<E> + Handle<E>> Component<E> for C {}
-
-submod! {
-    collect
-    layered
-    offset
-    split
-}
diff --git a/crates/tek_core/src/component/layered.rs b/crates/tek_core/src/engine/layered.rs
similarity index 100%
rename from crates/tek_core/src/component/layered.rs
rename to crates/tek_core/src/engine/layered.rs
diff --git a/crates/tek_core/src/engine/layout.rs b/crates/tek_core/src/engine/layout.rs
new file mode 100644
index 00000000..c8dad2e5
--- /dev/null
+++ b/crates/tek_core/src/engine/layout.rs
@@ -0,0 +1,100 @@
+use crate::*;
+
+/// Compute drawing area before rendering 
+pub trait Layout<E: Engine> {
+    fn layout (&self, area: impl Rectangle<E::Unit>) -> Perhaps<impl Rectangle<E::Unit>>;
+}
+/// Enforce minimum size of drawing area
+pub enum Min<U: Number, L> { W(U, L), H(U, L), WH(U, U, L), }
+/// Enforce maximum size of drawing area
+pub enum Max<U: Number, L> { W(U, L), H(U, L), WH(U, U, L), }
+/// Expand drawing area
+pub enum Outset<U: Number, L> { W(U, L), H(U, L), WH(U, U, L), }
+/// Shrink drawing area
+pub enum Inset<U: Number, L> { W(U, L), H(U, L), WH(U, U, L), }
+/// Move origin point of drawing area
+pub enum Offset<U: Number, L> { X(U, L), Y(U, L), XY(U, U, L), }
+
+impl<E: Engine, L: Layout<E>> Layout<E> for Min<E:: Unit, L> {
+    fn layout (&self, area: impl Rectangle<E::Unit>) -> Perhaps<impl Rectangle<E::Unit>> {
+        match self {
+            Self::W(w, item) => if area.w() < *w { Ok(None) } else {
+                // TODO: axis clamp (subtract from x if width goes out of area
+                item.layout([area.x(), area.y(), area.w().max(*w), area.h()])
+            },
+            Self::H(h, item) => if area.w() < *h { Ok(None) } else {
+                // TODO: axis clamp (subtract from x if width goes out of area
+                item.layout([area.x(), area.y(), area.w(), area.h().max(*h)])
+            },
+            Self::WH(w, h, item) => if area.w() < *w || area.h() < *h { Ok(None) } else {
+                item.layout([area.x(), area.y(), area.w().max(*w), area.h().max(*h)])
+            }
+        }
+    }
+}
+
+impl<E: Engine, L: Layout<E>> Layout<E> for Max<E:: Unit, L> {
+    fn layout (&self, area: impl Rectangle<E::Unit>) -> Perhaps<impl Rectangle<E::Unit>> {
+        match self {
+            Self::W(w, item) => {
+                // TODO: axis clamp (subtract from x if width goes out of area
+                item.layout([area.x(), area.y(), area.w().min(*w), area.h()])
+            },
+            Self::H(h, item) => {
+                // TODO: axis clamp (subtract from x if width goes out of area
+                item.layout([area.x(), area.y(), area.w(), area.h().min(*h)])
+            },
+            Self::WH(w, h, item) => {
+                item.layout([area.x(), area.y(), area.w().min(*w), area.h().min(*h)])
+            }
+        }
+    }
+}
+
+impl<E: Engine, L: Layout<E>> Layout<E> for Outset<E::Unit, L> {
+    fn layout (&self, area: impl Rectangle<E::Unit>) -> Perhaps<impl Rectangle<E::Unit>> {
+        match self {
+            Self::W(w, item) => if area.x() < *w { Ok(None) } else {
+                item.layout([area.x() - *w, area.y(), area.w() + *w, area.h()])
+            },
+            Self::H(h, item) => if area.y() < *h { Ok(None) } else {
+                item.layout([area.x(), area.y() - *h, area.w(), area.h() + *h])
+            },
+            Self::WH(w, h, item) => if area.x() < *w || area.y() < *h { Ok(None) } else {
+                item.layout([area.x()-*w, area.y() - *h, area.w() + *w, area.h() + *h])
+            }
+        }
+    }
+}
+
+impl<E: Engine, L: Layout<E>> Layout<E> for Inset<E::Unit, L> {
+    fn layout (&self, area: impl Rectangle<E::Unit>) -> Perhaps<impl Rectangle<E::Unit>> {
+        match self {
+            Self::W(w, item) => if area.w() < *w { Ok(None) } else {
+                item.layout([area.x() + *w, area.y(), area.w() - *w, area.h()])
+            },
+            Self::H(h, item) => if area.h() < *h { Ok(None) } else {
+                item.layout([area.x(), area.y() + *h, area.w(), area.h() - *h])
+            },
+            Self::WH(w, h, item) => if area.w() < *w || area.h() < *h { Ok(None) } else {
+                item.layout([area.x() - *w, area.y() - *h, area.w() + *w, area.h() + *h])
+            }
+        }
+    }
+}
+
+impl<E: Engine, L: Layout<E>> Layout<E> for Offset<E::Unit, L> {
+    fn layout (&self, area: impl Rectangle<E::Unit>) -> Perhaps<impl Rectangle<E::Unit>> {
+        match self {
+            Self::X(x, item) => if area.w() < *x { Ok(None) } else {
+                item.layout([area.x() + *x, area.y(), area.w() - *x, area.h()])
+            },
+            Self::Y(y, item) => if area.h() < *y { Ok(None) } else {
+                item.layout([area.x(), area.y() + *y, area.w(), area.h() - *y])
+            },
+            Self::XY(x, y, item) => if area.w() < *x || area.h() < *y { Ok(None) } else {
+                item.layout([area.x() + *x, area.y() + *y, area.w() - *x, area.h() - *y])
+            }
+        }
+    }
+}
diff --git a/crates/tek_core/src/component/split.rs b/crates/tek_core/src/engine/split.rs
similarity index 100%
rename from crates/tek_core/src/component/split.rs
rename to crates/tek_core/src/engine/split.rs
diff --git a/crates/tek_core/src/lib.rs b/crates/tek_core/src/lib.rs
index 7ae9fb84..ea624cd7 100644
--- a/crates/tek_core/src/lib.rs
+++ b/crates/tek_core/src/lib.rs
@@ -28,7 +28,6 @@ use better_panic::{Settings, Verbosity};
 
 submod! {
     audio
-    component
     edn
     engine
     space
diff --git a/crates/tek_core/src/space.rs b/crates/tek_core/src/space.rs
index 920749b9..de2c78eb 100644
--- a/crates/tek_core/src/space.rs
+++ b/crates/tek_core/src/space.rs
@@ -1,3 +1,77 @@
+use crate::*;
+
+pub trait Point<N: Number> {
+    fn x (&self) -> N;
+    fn y (&self) -> N;
+    fn w (&self) -> N {
+        self.x()
+    }
+    fn h (&self) -> N {
+        self.y()
+    }
+}
+
+impl<N: Number> Point<N> for (N, N) {
+    fn x (&self) -> N {
+        self.0
+    }
+    fn y (&self) -> N {
+        self.1
+    }
+}
+
+impl<N: Number> Point<N> for [N;2] {
+    fn x (&self) -> N {
+        self[0]
+    }
+    fn y (&self) -> N {
+        self[1]
+    }
+}
+
+pub trait Rectangle<N: Number> {
+    fn x (&self) -> N;
+    fn y (&self) -> N;
+    fn w (&self) -> N;
+    fn h (&self) -> N;
+    fn x2 (&self) -> N {
+        self.x() + self.w()
+    }
+    fn y2 (&self) -> N {
+        self.y() + self.h()
+    }
+}
+
+impl<N: Number> Rectangle<N> for (N, N, N, N) {
+    fn x (&self) -> N {
+        self.0
+    }
+    fn y (&self) -> N {
+        self.1
+    }
+    fn w (&self) -> N {
+        self.2
+    }
+    fn h (&self) -> N {
+        self.3
+    }
+}
+
+impl<N: Number> Rectangle<N> for [N;4] {
+    fn x (&self) -> N {
+        self[0]
+    }
+    fn y (&self) -> N {
+        self[1]
+    }
+    fn w (&self) -> N {
+        self[2]
+    }
+    fn h (&self) -> N {
+        self[3]
+    }
+}
+
 macro_rules! impl_axis_common { ($A:ident $T:ty) => {
     impl $A<$T> {
         pub fn start_inc (&mut self) -> $T {
@@ -19,16 +93,25 @@ macro_rules! impl_axis_common { ($A:ident $T:ty) => {
     }
 } }
 
-pub struct FixedAxis<T> { pub start: T, pub point: Option<T> }
+pub struct FixedAxis<T> {
+    pub start: T,
+    pub point: Option<T>
+}
+
 impl_axis_common!(FixedAxis u16);
 impl_axis_common!(FixedAxis usize);
 
-pub struct ScaledAxis<T> { pub start: T, pub scale: T, pub point: Option<T> }
+pub struct ScaledAxis<T> {
+    pub start: T,
+    pub scale: T,
+    pub point: Option<T>
+}
+
 impl_axis_common!(ScaledAxis u16);
 impl_axis_common!(ScaledAxis usize);
+
 impl<T: Copy> ScaledAxis<T> {
     pub fn scale_mut (&mut self, cb: &impl Fn(T)->T) {
         self.scale = cb(self.scale)
     }
 }
-
diff --git a/crates/tek_core/src/tui.rs b/crates/tek_core/src/tui.rs
index 162d1d2b..1ffba0de 100644
--- a/crates/tek_core/src/tui.rs
+++ b/crates/tek_core/src/tui.rs
@@ -25,10 +25,11 @@ pub struct Tui {
     area:    Rect,
 }
 impl Engine for Tui {
+    type Unit        = u16;
     type HandleInput = Self;
-    type Handled  = bool;
+    type Handled     = bool;
     type RenderInput = Self;
-    type Rendered = Rect;
+    type Rendered    = Rect;
     fn exited (&self) -> bool {
         self.exited.fetch_and(true, Ordering::Relaxed)
     }
@@ -46,12 +47,6 @@ impl Engine for Tui {
         stdout().execute(LeaveAlternateScreen)?;
         disable_raw_mode().map_err(Into::into)
     }
-    fn handle (&self, _: &mut impl Handle<Self>) -> Usually<()> {
-        Ok(())
-    }
-    fn render (&mut self, _: &impl Render<Self>) -> Usually<()> {
-        Ok(())
-    }
 }
 impl Tui {
     /// Run the main loop.
diff --git a/crates/tek_core/src/tui/tui_layout.rs b/crates/tek_core/src/tui/tui_layout.rs
index b952385d..fffcebb3 100644
--- a/crates/tek_core/src/tui/tui_layout.rs
+++ b/crates/tek_core/src/tui/tui_layout.rs
@@ -1,35 +1,69 @@
 use crate::*;
 
-impl<R: Render<Tui>> Render<Tui> for (Offset<u16>, R) {
+impl Rectangle<u16> for Rect {
+    fn x (&self) -> u16 { self.x }
+    fn y (&self) -> u16 { self.y }
+    fn w (&self) -> u16 { self.width }
+    fn h (&self) -> u16 { self.height }
+}
+
+impl<R> Render<Tui> for Min<<Tui as Engine>::Unit, R> where R: Render<Tui> + Layout<Tui> {
     fn render (&self, engine: &mut Tui) -> Perhaps<Rect> {
-        self.1.render(engine.alter_area(|x, y, width, height|(
-            x + self.0.0,
-            y + self.0.1,
-            width.saturating_sub(self.0.0),
-            height.saturating_sub(self.0.1),
-        )))
+        self.layout(engine.area())?
+            .map(|area|engine.with_area(area.x(), area.y(), area.w(), area.h()))
+            .map(|engine|engine.render(match self {
+                Self::W(_, inner) => inner,
+                Self::H(_, inner) => inner,
+                Self::WH(_, _, inner) => inner,
+            }))
     }
 }
 
-impl<R: Render<Tui>> Render<Tui> for (Inset<u16>, R) {
+impl<R> Render<Tui> for Max<<Tui as Engine>::Unit, R> where R: Render<Tui> + Layout<Tui> {
     fn render (&self, engine: &mut Tui) -> Perhaps<Rect> {
-        self.1.render(engine.alter_area(|x, y, width, height|(
-            x + self.0.0,
-            y + self.0.1,
-            width.saturating_sub(self.0.0 + self.0.2),
-            height.saturating_sub(self.0.1 + self.0.3),
-        )))
+        self.layout(engine.area())?
+            .map(|area|engine.with_area(area.x(), area.y(), area.w(), area.h()))
+            .map(|engine|engine.render(match self {
+                Self::W(_, inner) => inner,
+                Self::H(_, inner) => inner,
+                Self::WH(_, _, inner) => inner,
+            }))
     }
 }
 
-impl<R: Render<Tui>> Render<Tui> for (Outset<u16>, R) {
+impl<R> Render<Tui> for Inset<<Tui as Engine>::Unit, R> where R: Render<Tui> + Layout<Tui> {
     fn render (&self, engine: &mut Tui) -> Perhaps<Rect> {
-        self.1.render(engine.alter_area(|x, y, width, height|(
-            x.saturating_sub(self.0.0),
-            y.saturating_sub(self.0.1),
-            width  + self.0.0 + self.0.2,
-            height + self.0.1 + self.0.3,
-        )))
+        self.layout(engine.area())?
+            .map(|area|engine.with_area(area.x(), area.y(), area.w(), area.h()))
+            .map(|engine|engine.render(match self {
+                Self::W(_, inner) => inner,
+                Self::H(_, inner) => inner,
+                Self::WH(_, _, inner) => inner,
+            }))
+    }
+}
+
+impl<R> Render<Tui> for Outset<<Tui as Engine>::Unit, R> where R: Render<Tui> + Layout<Tui> {
+    fn render (&self, engine: &mut Tui) -> Perhaps<Rect> {
+        self.layout(engine.area())?
+            .map(|area|engine.with_area(area.x(), area.y(), area.w(), area.h()))
+            .map(|engine|engine.render(match self {
+                Self::W(_, inner) => inner,
+                Self::H(_, inner) => inner,
+                Self::WH(_, _, inner) => inner,
+            }))
+    }
+}
+
+impl<R> Render<Tui> for Offset<<Tui as Engine>::Unit, R> where R: Render<Tui> + Layout<Tui> {
+    fn render (&self, engine: &mut Tui) -> Perhaps<Rect> {
+        self.layout(engine.area())?
+            .map(|area|engine.with_area(area.x(), area.y(), area.w(), area.h()))
+            .map(|engine|engine.render(match self {
+                Self::X(_, inner) => inner,
+                Self::Y(_, inner) => inner,
+                Self::XY(_, _, inner) => inner,
+            }))
     }
 }