output: more big refactors

output/src/layout.rs

@@ -0,0 +1,98 @@
+use crate::*;
+
+pub trait Layout<O: Out> {
+    fn x (&self, area: O::Area) -> O::Unit {
+        area.x()
+    }
+    fn y (&self, area: O::Area) -> O::Unit {
+        area.y()
+    }
+
+    fn min_w (&self, _area: O::Area) -> O::Unit {
+        0.into()
+    }
+    fn max_w (&self, area: O::Area) -> O::Unit {
+        area.w()
+    }
+
+    fn min_h (&self, _area: O::Area) -> O::Unit {
+        0.into()
+    }
+    fn max_h (&self, area: O::Area) -> O::Unit {
+        area.h()
+    }
+
+    fn layout (&self, area: O::Area) -> O::Area {
+        O::Area::from([
+            self.x(area),
+            self.y(area),
+            area.w().max(self.min_w(area)).min(self.max_w(area)),
+            area.h().max(self.min_h(area)).min(self.max_h(area)),
+        ])
+    }
+}
+
+#[macro_export] macro_rules! layout {
+    // Implement for all [Out] backends.
+    (|$self:ident:$Struct:ident $(<
+        $($L:lifetime),* $($T:ident $(:$Trait:path)?),*
+    >)?, $to:ident|$($method:ident = |$area:ident|$body:expr;)*) => {
+        impl <$($($L),*)? O: Out, $($($T$(:$Trait)?),*)?> Layout<O>
+        for $Struct $(<$($L),* $($T),*>)? {
+            $(fn $method (&$self, $area: O::Area) -> O::Area {
+                $body
+            })*
+        }
+    };
+    // Implement for a specific [Out] backend.
+    ($O:ty:|
+        $self:ident:
+        $Struct:ident $(<$($($L:lifetime)? $($T:ident)? $(:$Trait:path)?),+>)?,
+        $to:ident
+    |$($method:ident = |$area:ident|$body:expr;)*) => {
+        impl $(<$($($L)? $($T)? $(:$Trait)?),+>)? Layout<$O>
+        for $Struct $(<$($($L)? $($T)?),+>)? {
+            $(fn $method (&$self, $area: <$O as Out>::Area) -> <$O as Out>::Area {
+                $body
+            })*
+        }
+    };
+}
+
+impl<O: Out> Layout<O> for () {}
+
+impl<O: Out, L: Layout<O>> Layout<O> for &L { /*FIXME*/ }
+
+impl<O: Out, L: Layout<O>> Layout<O> for RwLock<L> { /*FIXME*/ }
+
+impl<O: Out, L: Layout<O>> Layout<O> for Option<L> { /*FIXME*/ }
+
+//impl<O: Out> Layout<O> for fn(&mut O) {}
+
+impl<O: Out, L: Layout<O>> Layout<O> for Arc<L> {
+    fn layout (&self, to: O::Area) -> O::Area {
+        (**self).layout(to)
+    }
+}
+
+impl<'x, O: Out> Layout<O> for &(dyn Draw<O> + 'x) {
+    fn layout (&self, to: O::Area) -> O::Area {
+        Fill::xy(self).layout(to)
+    }
+}
+
+mod layout_align;     pub use self::layout_align::*;
+mod layout_bsp;       pub use self::layout_bsp::*;
+mod layout_cond;      pub use self::layout_cond::*;
+mod layout_expand;    pub use self::layout_expand::*;
+mod layout_fill;      pub use self::layout_fill::*;
+mod layout_fixed;     pub use self::layout_fixed::*;
+mod layout_map;       pub use self::layout_map::*;
+mod layout_margin;    pub use self::layout_margin::*;
+mod layout_max;       pub use self::layout_max::*;
+mod layout_min;       pub use self::layout_min::*;
+mod layout_padding;   pub use self::layout_padding::*;
+mod layout_pull;      pub use self::layout_pull::*;
+mod layout_push;      pub use self::layout_push::*;
+mod layout_shrink;    pub use self::layout_shrink::*;
+mod layout_stack;     pub use self::layout_stack::*;