From 435b0b92ee5aaad17c4d81b39c2e44fd97452cd0 Mon Sep 17 00:00:00 2001
From: Beka Westberg <bwestberg@google.com>
Date: Mon, 13 Mar 2023 09:27:21 -0700
Subject: [PATCH] chore: cleanup render management (#6883)

---
 core/insertion_marker_manager.ts | 10 +++++++---
 core/render_management.ts        |  4 ++--
 core/rendered_connection.ts      | 14 ++++++--------
 3 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/core/insertion_marker_manager.ts b/core/insertion_marker_manager.ts
index 20e27d426..8bb130964 100644
--- a/core/insertion_marker_manager.ts
+++ b/core/insertion_marker_manager.ts
@@ -194,9 +194,13 @@ export class InsertionMarkerManager {
       blockAnimations.connectionUiEffect(inferiorConnection.getSourceBlock());
       // Bring the just-edited stack to the front.
       const rootBlock = this.topBlock.getRootBlock();
-      setTimeout(() => {
-        rootBlock.bringToFront();
-      }, 0);
+
+      // bringToFront is incredibly expensive. Delay by at least a frame.
+      requestAnimationFrame(() => {
+        setTimeout(() => {
+          rootBlock.bringToFront();
+        }, 0);
+      });
     }
   }
 
diff --git a/core/render_management.ts b/core/render_management.ts
index a6a79f118..658f0b1d8 100644
--- a/core/render_management.ts
+++ b/core/render_management.ts
@@ -66,8 +66,8 @@ function doRenders() {
 }
 
 /**
- * Recursively renders all of the children of the given block, and then renders
- * the block.
+ * Recursively renders all of the dirty children of the given block, and
+ * then renders the block.
  *
  * @param block The block to rerender.
  */
diff --git a/core/rendered_connection.ts b/core/rendered_connection.ts
index dbe729dd3..42cd94680 100644
--- a/core/rendered_connection.ts
+++ b/core/rendered_connection.ts
@@ -187,27 +187,25 @@ export class RenderedConnection extends Connection {
    *     was updated.
    */
   moveTo(x: number, y: number): boolean {
-    const dx = this.x - x;
-    const dy = this.y - y;
-
-    let moved = false;
+    const moved = this.x !== x || this.y !== y;
+    let updated = false;
 
     if (this.trackedState_ === RenderedConnection.TrackedState.WILL_TRACK) {
       this.db_.addConnection(this, y);
       this.trackedState_ = RenderedConnection.TrackedState.TRACKED;
-      moved = true;
+      updated = true;
     } else if (
         this.trackedState_ === RenderedConnection.TrackedState.TRACKED &&
-        (dx !== 0 || dy !== 0)) {
+        moved) {
       this.db_.removeConnection(this, this.y);
       this.db_.addConnection(this, y);
-      moved = true;
+      updated = true;
     }
 
     this.x = x;
     this.y = y;
 
-    return moved;
+    return updated;
   }
 
   /**