From 5bf90b39cb097b967f6e51d7000fa505d0d377d9 Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 25 Jan 2024 13:17:52 +0100
Subject: [PATCH 1/2] Refactor to prepare for follow-on change

---
 crates/fj-core/src/operations/split/face.rs | 36 ++++++++++++---------
 1 file changed, 20 insertions(+), 16 deletions(-)

diff --git a/crates/fj-core/src/operations/split/face.rs b/crates/fj-core/src/operations/split/face.rs
index 07683674c..ebbc50851 100644
--- a/crates/fj-core/src/operations/split/face.rs
+++ b/crates/fj-core/src/operations/split/face.rs
@@ -132,18 +132,20 @@ impl SplitFace for Shell {
             services,
         )
         .update_region(|region| {
-            let mut region = region.update_exterior(|cycle| {
-                cycle
-                    .add_half_edges(half_edges_b_to_c_inclusive)
-                    .add_half_edges([dividing_half_edge_c_to_b])
-                    .insert(services)
-            });
+            let mut region = region
+                .update_exterior(|cycle| {
+                    cycle
+                        .add_half_edges(half_edges_b_to_c_inclusive)
+                        .add_half_edges([dividing_half_edge_c_to_b])
+                        .insert(services)
+                })
+                .insert(services);
 
             if let Some(color) = face.region().color() {
-                region = region.set_color(color);
+                region = region.set_color(color).insert(services);
             }
 
-            region.insert(services)
+            region
         })
         .insert(services);
 
@@ -157,18 +159,20 @@ impl SplitFace for Shell {
             services,
         )
         .update_region(|region| {
-            let mut region = region.update_exterior(|cycle| {
-                cycle
-                    .add_half_edges(half_edges_d_to_a_inclusive)
-                    .add_half_edges([dividing_half_edge_a_to_d])
-                    .insert(services)
-            });
+            let mut region = region
+                .update_exterior(|cycle| {
+                    cycle
+                        .add_half_edges(half_edges_d_to_a_inclusive)
+                        .add_half_edges([dividing_half_edge_a_to_d])
+                        .insert(services)
+                })
+                .insert(services);
 
             if let Some(color) = face.region().color() {
-                region = region.set_color(color);
+                region = region.set_color(color).insert(services);
             }
 
-            region.insert(services)
+            region
         })
         .insert(services);
 

From 2bfb010dba6b619276ad9020a26645476863d25b Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 25 Jan 2024 13:20:58 +0100
Subject: [PATCH 2/2] Implement `SetColor` for `Handle<Region>` instead

This is required to extract appearance into a separate layer, as
associating attributes to objects can only work, if we have a unique
`Handle` to that object.
---
 crates/fj-core/src/operations/presentation.rs | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/crates/fj-core/src/operations/presentation.rs b/crates/fj-core/src/operations/presentation.rs
index b2e9c9211..e58323531 100644
--- a/crates/fj-core/src/operations/presentation.rs
+++ b/crates/fj-core/src/operations/presentation.rs
@@ -2,16 +2,19 @@
 
 use fj_interop::Color;
 
-use crate::objects::Region;
+use crate::{
+    objects::{IsObject, Region},
+    storage::Handle,
+};
 
 /// Set the color of an object
-pub trait SetColor {
+pub trait SetColor: IsObject {
     /// Set the color of the object
-    fn set_color(&self, color: impl Into<Color>) -> Self;
+    fn set_color(&self, color: impl Into<Color>) -> Self::BareObject;
 }
 
-impl SetColor for Region {
-    fn set_color(&self, color: impl Into<Color>) -> Self {
+impl SetColor for Handle<Region> {
+    fn set_color(&self, color: impl Into<Color>) -> Self::BareObject {
         Region::new(
             self.exterior().clone(),
             self.interiors().into_iter().cloned(),