Resize PaneGrid without modifier keys

native/src/widget/pane_grid/axis.rs

@@ -53,6 +53,30 @@ impl Axis {
             }
         }
     }
+
+    pub(super) fn split_line_bounds(
+        &self,
+        rectangle: Rectangle,
+        ratio: f32,
+        spacing: f32,
+    ) -> Rectangle {
+        match self {
+            Axis::Horizontal => Rectangle {
+                x: rectangle.x,
+                y: (rectangle.y + rectangle.height * ratio - spacing / 2.0)
+                    .round(),
+                width: rectangle.width,
+                height: spacing,
+            },
+            Axis::Vertical => Rectangle {
+                x: (rectangle.x + rectangle.width * ratio - spacing / 2.0)
+                    .round(),
+                y: rectangle.y,
+                width: spacing,
+                height: rectangle.height,
+            },
+        }
+    }
 }
 
 #[cfg(test)]

native/src/widget/pane_grid/state.rs

@@ -4,6 +4,7 @@ use crate::{
     Hasher, Point, Rectangle, Size,
 };
 
+use std::cell::RefCell;
 use std::collections::HashMap;
 
 /// The state of a [`PaneGrid`].
@@ -71,6 +72,7 @@ impl<T> State<T> {
             internal: Internal {
                 layout,
                 last_id,
+                split_cache: RefCell::new(None),
                 action: Action::Idle { focus: None },
             },
             modifiers: keyboard::ModifiersState::default(),
@@ -308,6 +310,7 @@ pub struct Internal {
     layout: Node,
     last_id: usize,
     action: Action,
+    split_cache: RefCell<Option<HashMap<Split, (Axis, f32, Rectangle)>>>,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]