From 95bfc43a3b50af966ddd7eed406b731351ca88d2 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Fri, 31 Jul 2020 16:42:49 +0200
Subject: [PATCH] Avoid doing unnecessary work in
 `AnnotationLayerBuilder.render`, such as cloning a `PageViewport`, when no
 annotations exist for a page

---
 web/annotation_layer_builder.js | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/web/annotation_layer_builder.js b/web/annotation_layer_builder.js
index 929010512..fc1707a74 100644
--- a/web/annotation_layer_builder.js
+++ b/web/annotation_layer_builder.js
@@ -66,6 +66,9 @@ class AnnotationLayerBuilder {
       if (this._cancelled) {
         return;
       }
+      if (annotations.length === 0) {
+        return;
+      }
 
       const parameters = {
         viewport: viewport.clone({ dontFlip: true }),
@@ -86,9 +89,6 @@ class AnnotationLayerBuilder {
       } else {
         // Create an annotation layer div and render the annotations
         // if there is at least one annotation.
-        if (annotations.length === 0) {
-          return;
-        }
         this.div = document.createElement("div");
         this.div.className = "annotationLayer";
         this.pageDiv.appendChild(this.div);