support multipass layout, barely

src/layout.rs

@@ -0,0 +1,103 @@
+use crate::*;
+
+impl<S: Screen, T: Draw<S>> Layout<S> for T {}
+
+pub trait Layout<S: Screen>: Draw<S> + Sized {
+    fn full_w (self) -> impl Draw<S> {
+        Full::W(self)
+    }
+    fn full_h (self) -> impl Draw<S> {
+        Full::H(self)
+    }
+    fn full_wh (self) -> impl Draw<S> {
+        Full::WH(self)
+    }
+
+    fn origin (self, azimuth: impl Into<Option<Azimuth>>) -> impl Draw<S> {
+        Origin(azimuth.into(), self)
+    }
+    fn origin_c (self) -> impl Draw<S> {
+        Origin(Some(Azimuth::C), self)
+    }
+    fn origin_x (self) -> impl Draw<S> {
+        Origin(Some(Azimuth::X), self)
+    }
+    fn origin_y (self) -> impl Draw<S> {
+        Origin(Some(Azimuth::Y), self)
+    }
+
+    fn origin_n (self) -> impl Draw<S> {
+        Origin(Some(Azimuth::N), self)
+    }
+    fn origin_s (self) -> impl Draw<S> {
+        Origin(Some(Azimuth::S), self)
+    }
+    fn origin_e (self) -> impl Draw<S> {
+        Origin(Some(Azimuth::E), self)
+    }
+    fn origin_w (self) -> impl Draw<S> {
+        Origin(Some(Azimuth::W), self)
+    }
+
+    fn origin_ne (self) -> impl Draw<S> {
+        Origin(Some(Azimuth::NE), self)
+    }
+    fn origin_se (self) -> impl Draw<S> {
+        Origin(Some(Azimuth::SE), self)
+    }
+    fn origin_nw (self) -> impl Draw<S> {
+        Origin(Some(Azimuth::NW), self)
+    }
+    fn origin_sw (self) -> impl Draw<S> {
+        Origin(Some(Azimuth::SW), self)
+    }
+}
+
+/// Uses [AtomicUsize] to measure size during\
+/// rendering (which is normally read-only).
+#[derive(Default, Debug, Clone)]
+pub struct Sizer(
+    /// Width
+    pub Arc<AtomicUsize>,
+    /// Height
+    pub Arc<AtomicUsize>,
+);
+
+impl Xy<u16> for Sizer {
+    fn x (&self) -> u16 {
+        self.0.load(Relaxed) as u16
+    }
+    fn y (&self) -> u16 {
+        self.1.load(Relaxed) as u16
+    }
+}
+impl Wide<u16> for Sizer {
+    fn w (&self) -> u16 {
+        self.0.load(Relaxed) as u16
+    }
+}
+impl Tall<u16> for Sizer {
+    fn h (&self) -> u16 {
+        self.1.load(Relaxed) as u16
+    }
+}
+impl PartialEq for Sizer {
+    fn eq (&self, _: &Self) -> bool { todo!() }
+}
+
+impl Sizer {
+    pub const fn of <T: Screen> (&self, of: impl Draw<T>) -> impl Draw<T> {
+        draw(move|to: &mut T|{
+            let area = of.draw(to)?;
+            self.0.store(area.map(|a|a.w()).unwrap_or(T::Unit::zero()).into(), Relaxed);
+            self.1.store(area.map(|a|a.h()).unwrap_or(T::Unit::zero()).into(), Relaxed);
+            Ok(area)
+        })
+    }
+}
+
+mod area;    pub use self::area::*;
+mod axis;    pub use self::axis::*;
+mod azimuth; pub use self::azimuth::*;
+mod cond;    pub use self::cond::*;
+mod iter;    pub use self::iter::*;