Add the math for pane resizing

crates/gpui/src/app/window.rs

@@ -1268,6 +1268,19 @@ impl Vector2FExt for Vector2F {
     }
 }
 
+pub trait RectFExt {
+    fn length_along(self, axis: Axis) -> f32;
+}
+
+impl RectFExt for RectF {
+    fn length_along(self, axis: Axis) -> f32 {
+        match axis {
+            Axis::Horizontal => self.width(),
+            Axis::Vertical => self.height(),
+        }
+    }
+}
+
 #[derive(Copy, Clone, Debug)]
 pub struct SizeConstraint {
     pub min: Vector2F,

crates/gpui/src/gpui.rs

@@ -27,7 +27,7 @@ pub mod json;
 pub mod keymap_matcher;
 pub mod platform;
 pub use gpui_macros::{test, Element};
-pub use window::{Axis, SizeConstraint, Vector2FExt, WindowContext};
+pub use window::{Axis, RectFExt, SizeConstraint, Vector2FExt, WindowContext};
 
 pub use anyhow;
 pub use serde_json;