make Draw::clip take drawable instead of fn

src/layout/align.rs

@@ -11,10 +11,11 @@ impl<S: Screen, T: Draw<S>> Draw<S> for Align<T> {
         Ok(align::<S>(area, self.1.layout(area)?, self.0))
     }
     fn draw (self, to: &mut S) -> Perhaps<XYWH<S::Unit>> {
-        Ok(self.layout(to.area())?
+        Ok(if let Some(area) = self.layout(to.area())? {
-            .map(|area|to.clip(area, |to|self.1.draw(to)))
+            to.clip(area, self.1)?
-            .transpose()?
+        } else {
-            .flatten())
+            None
+        })
     }
 }
 

src/layout/area.rs

@@ -16,6 +16,7 @@ pub struct Area<S: Screen, T: Draw<S>>(
     pub Option<XYWH<S::Unit>>,
     pub T
 );
+
 impl_draw!(<S: Screen, T: Draw<S>,>|self: Area<S, T>, to: S|{
-    to.clip(self.0, |to|self.1.draw(to))
+    to.clip(self.0, self.1)
 });

src/layout/exact.rs

@@ -22,7 +22,7 @@ impl <S: Screen, I: Draw<S>, X: Into<Option<S::Unit>> + Copy> Draw<S> for Exact<
     fn draw (self, to: &mut S) -> Perhaps<XYWH<S::Unit>> {
         let area = layout_exact(&self, to.area());
         let item = match self { Self::W(i, ..) => i, Self::H(i, ..) => i, Self::WH(i, ..) => i, _ => unreachable!() };
-        to.clip(area, |to|item.draw(to))
+        to.clip(area, item)
     }
 }
 

src/layout/full.rs

@@ -22,17 +22,17 @@ impl_draw!(<T: Screen, I: Draw<T>,>|self: Full<T, I>, to: T|{
     let XYWH(x0, y0, w0, h0) = to.area();
     match self {
         Self::W(item) => if let Some(XYWH(_, y, _, h)) = item.layout(to.area())? {
-            to.clip(XYWH(x0, y, w0, h), |to|item.draw(to))
+            to.clip(XYWH(x0, y, w0, h), item)
         } else {
             Ok(None)
         },
         Self::H(item) => if let Some(XYWH(x, _, w, _)) = item.layout(to.area())? {
-            to.clip(XYWH(x, y0, w, h0), |to|item.draw(to))
+            to.clip(XYWH(x, y0, w, h0), item)
         } else {
             Ok(None)
         },
         Self::WH(item) => if let Some(XYWH(..)) = item.layout(to.area())? {
-            to.clip(XYWH(x0, y0, w0, h0), |to|item.draw(to))
+            to.clip(XYWH(x0, y0, w0, h0), item)
         } else {
             Ok(None)
         },

src/layout/max.rs

@@ -50,6 +50,6 @@ impl<T: Screen, I: Draw<T>, X: Into<Option<T::Unit>> + Copy> Draw<T> for Max<T,
             )),
             _ => return Ok(None)
         };
-        to.clip(area, |to|item.draw(to))
+        to.clip(area, item)
     }
 }

src/layout/min.rs

@@ -24,16 +24,16 @@ impl_draw!(<T: Screen, I: Draw<T>, X: Into<Option<T::Unit>>,>|self: Min<T, I, X>
         Self::__(_) => unreachable!(),
         Self::W(item, w1) if let Some(XYWH(x, y, w, h)) = item.layout(to.area())? => {
             let w = w1.into().map(|w1|w.max(w1)).unwrap_or(w);
-            to.clip(XYWH(x, y, w, h), |to|item.draw(to))
+            to.clip(XYWH(x, y, w, h), item)
         },
         Self::H(item, h1) if let Some(XYWH(x, y, w, h)) = item.layout(to.area())? => {
             let h = h1.into().map(|h1|h.max(h1)).unwrap_or(h);
-            to.clip(XYWH(x, y, w, h), |to|item.draw(to))
+            to.clip(XYWH(x, y, w, h), item)
         },
         Self::WH(item, w1, h1) if let Some(XYWH(x, y, w, h)) = item.layout(to.area())? => {
             let w = w1.into().map(|w1|w.max(w1)).unwrap_or(w);
             let h = h1.into().map(|h1|h.max(h1)).unwrap_or(h);
-            to.clip(XYWH(x, y, w, h), |to|item.draw(to))
+            to.clip(XYWH(x, y, w, h), item)
         },
         _ => Ok(None)
     }

src/layout/push.rs

@@ -25,17 +25,17 @@ impl_draw!(<T: Screen, I: Draw<T>, X: Into<Option<T::Unit>>,>|self: Push<T, I, X
         Self::X(item, x1) if let Some(XYWH(x, y, w, h)) = item.layout(to.area())? => {
             to.clip(XYWH(
                 x + x1.into().unwrap_or_default(), y, w, h
-            ), |to|item.draw(to))
+            ), item)
         },
         Self::Y(item, y1) if let Some(XYWH(x, y, w, h)) = item.layout(to.area())? => {
             to.clip(XYWH(
                 x, y + y1.into().unwrap_or_default(), w, h
-            ), |to|item.draw(to))
+            ), item)
         },
         Self::XY(item, x1, y1) if let Some(XYWH(x, y, w, h)) = item.layout(to.area())? => {
             to.clip(XYWH(
                 x + x1.into().unwrap_or_default(), y + y1.into().unwrap_or_default(), w, h
-            ), |to|item.draw(to))
+            ), item)
         },
         _ => Ok(None)
     }

src/layout/split.rs

@@ -122,14 +122,14 @@ fn draw_stacks <S: Screen> (
     origin_b: impl Into<Option<Azimuth>>,
 ) -> Usually<(Option<XYWH<S::Unit>>, Option<XYWH<S::Unit>>)> {
     let draw_a = |to: &mut S|Ok::<_, Box<dyn Error>>(if let Some(origin_a) = origin_a.into() {
-        to.clip(area_a.into(), |to|a.align(origin_a).draw(to))?
+        to.clip(area_a.into(), a.align(origin_a))?
     } else {
-        to.clip(area_a.into(), |to|a.draw(to))?
+        to.clip(area_a.into(), a)?
     });
     let draw_b = |to: &mut S|Ok::<_, Box<dyn Error>>(if let Some(origin_b) = origin_b.into() {
-        to.clip(area_b.into(), |to|b.align(origin_b).draw(to))?
+        to.clip(area_b.into(), b.align(origin_b))?
     } else {
-        to.clip(area_b.into(), |to|b.draw(to))?
+        to.clip(area_b.into(), b)?
     });
     Ok(if matches!(split, Split::Below) {
         let drawn_b = draw_b(to)?;

src/lib.rs

@@ -1366,12 +1366,12 @@ macro_rules! eval_xy (
     ///     fn area (&self) -> XYWH<Self::Unit> {
     ///         Default::default()
     ///     }
-    ///     fn clip <T> (
+    ///     fn clip (
     ///         &mut self,
     ///         area: impl Into<Option<XYWH<u16>>>,
-    ///         draw: impl FnOnce(&mut Self)->T
+    ///         draw: impl Draw<Self>
-    ///     ) -> T {
+    ///     ) -> Perhaps<XYWH<Self::Unit>> {
-    ///         draw(self)
+    ///         draw.to(self)
     ///     }
     /// }
     ///
@@ -1387,11 +1387,11 @@ macro_rules! eval_xy (
         /// Get current clipping area
         fn area (&self) -> XYWH<Self::Unit>;
         /// Set clipping area
-        fn clip <T> (
+        fn clip (
             &mut self,
             area: impl Into<Option<XYWH<Self::Unit>>>,
-            draw: impl FnOnce(&mut Self)->T
+            draw: impl Draw<Self>
-        ) -> T;
+        ) -> Perhaps<XYWH<Self::Unit>>;
     }
 
     /// Implement the [Draw] trait for a particular drawable and [Screen].
@@ -2645,16 +2645,16 @@ macro_rules! eval_xy (
             }
         }
 
-        fn clip <T> (
+        fn clip (
             &mut self,
             area: impl Into<Option<XYWH<u16>>>,
-            draw: impl FnOnce(&mut Self)->T
+            draw: impl Draw<Self>
-        ) -> T {
+        ) -> Perhaps<XYWH<Self::Unit>> {
             let prev = self.area();
             if let Some(area) = area.into() {
                 *self.area_mut() = area.into();
             }
-            let result = draw(self);
+            let result = draw.draw(self);
             *self.area_mut() = prev;
             result
         }
@@ -2815,10 +2815,10 @@ macro_rules! eval_xy (
             self.1.layout(area)
         }
         fn draw (self, to: &mut Tui) -> Drawn<u16> {
-            self.layout(to.area()).map(|area|to.clip(area, |to|{
+            self.layout(to.area()).map(|area|to.clip(area, draw(|to: &mut Tui|{
                 to.update(&|cell,_,_|{ cell.set_bg(self.0); });
                 self.1.draw(to)
-            }))?
+            })))?
         }
     }