geometry: Provide Rect::size()

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/base/geometry.rs b/base/geometry.rs
index 6d424f0649b7f0037e095d4b19c1616db0c87df3..44a31d7ae6b7360eb291f737d17af9e90801f506 100644 (file)
--- a/base/geometry.rs
+++ b/base/geometry.rs
@@ -287,6 +287,13 @@ impl<T> RectC<T> where T: Mean + Debug + Copy {
   }
 }
 
+impl<T> RectC<T> where T: CheckedArith + Debug + Copy {
+  #[throws(CoordinateOverflow)]
+  pub fn size(&self) -> PosC<T> {
+    (self.br() - self.tl())?
+  }
+}
+
 #[test]
 fn empty_area() {
   let empty = Rect::empty();