macos: add key binding for equalizing split sizes

src/apprt/embedded.zig

@@ -95,6 +95,9 @@ pub const App = struct {
         /// Resize the current split.
         resize_split: ?*const fn (SurfaceUD, input.SplitResizeDirection, u16) callconv(.C) void = null,
 
+        /// Equalize all splits in the current window
+        equalize_splits: ?*const fn (SurfaceUD) callconv(.C) void = null,
+
         /// Zoom the current split.
         toggle_split_zoom: ?*const fn (SurfaceUD) callconv(.C) void = null,
 
@@ -396,6 +399,15 @@ pub const Surface = struct {
         func(self.opts.userdata, direction, amount);
     }
 
+    pub fn equalizeSplits(self: *const Surface) void {
+        const func = self.app.opts.equalize_splits orelse {
+            log.info("runtime embedder does not support equalize splits", .{});
+            return;
+        };
+
+        func(self.opts.userdata);
+    }
+
     pub fn toggleSplitZoom(self: *const Surface) void {
         const func = self.app.opts.toggle_split_zoom orelse {
             log.info("runtime embedder does not support split zoom", .{});
@@ -1388,6 +1400,11 @@ pub const CAPI = struct {
         ptr.resizeSplit(direction, amount);
     }
 
+    /// Equalize the size of all splits in the current window.
+    export fn ghostty_surface_split_equalize(ptr: *Surface) void {
+        ptr.equalizeSplits();
+    }
+
     /// Invoke an action on the surface.
     export fn ghostty_surface_binding_action(
         ptr: *Surface,