src/versioned_canvas.rs

@@ -45,7 +45,7 @@ impl VersionedCanvas {
         }
     }
 
-    pub fn update(&mut self, update_fn: impl FnOnce(&Canvas) -> Canvas) {
+    pub fn update(&mut self, update_fn: impl FnOnce(&mut Canvas)) {
         // This is a linear history,
         // so we first check if there are newer versions, if so
         // this means we are in the past, so a change in the past destroys the future
@@ -53,10 +53,16 @@ impl VersionedCanvas {
         if self.has_newer_versions() {
             self.versions = self.versions.take(self.curr_version + 1);
         }
-        let new_version = update_fn(self.get());
+
+        let mut new_version = self.get().clone();
+        update_fn(&mut new_version);
+
+        // Only push new version if there has been an actual change in the vector
+        if !new_version.elements.ptr_eq(&self.get().elements) {
             self.versions.push_back(new_version);
             self.curr_version = self.curr_version + 1;
         }
+    }
 
     // Do inplace update, which will be irreversible
     pub fn irreversible_update(&mut self, update_fn: impl FnOnce(&mut Canvas)) {