From 78128762f921e7ea1dcb286a75586fae2e1d21d2 Mon Sep 17 00:00:00 2001
From: Daniel Imms <2193314+Tyriar@users.noreply.github.com>
Date: Thu, 22 Sep 2022 13:06:08 -0700
Subject: [PATCH] Perform texture atlas warm up in an idle callback

Part of #4103
---
 addons/xterm-addon-webgl/src/atlas/WebglCharAtlas.ts | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/addons/xterm-addon-webgl/src/atlas/WebglCharAtlas.ts b/addons/xterm-addon-webgl/src/atlas/WebglCharAtlas.ts
index b4593d909f..9ba83de6df 100644
--- a/addons/xterm-addon-webgl/src/atlas/WebglCharAtlas.ts
+++ b/addons/xterm-addon-webgl/src/atlas/WebglCharAtlas.ts
@@ -121,7 +121,9 @@ export class WebglCharAtlas implements IDisposable {
 
   public warmUp(): void {
     if (!this._didWarmUp) {
-      this._doWarmUp();
+      (typeof requestIdleCallback !== 'function' ? requestIdleCallback : setTimeout)(() => {
+        this._doWarmUp();
+      });
       this._didWarmUp = true;
     }
   }
@@ -129,8 +131,10 @@ export class WebglCharAtlas implements IDisposable {
   private _doWarmUp(): void {
     // Pre-fill with ASCII 33-126
     for (let i = 33; i < 126; i++) {
-      const rasterizedGlyph = this._drawToCache(i, DEFAULT_COLOR, DEFAULT_COLOR, DEFAULT_EXT);
-      this._cacheMap.set(i, DEFAULT_COLOR, DEFAULT_COLOR, DEFAULT_EXT, rasterizedGlyph);
+      if (!this._cacheMap.get(i, DEFAULT_COLOR, DEFAULT_COLOR, DEFAULT_EXT)) {
+        const rasterizedGlyph = this._drawToCache(i, DEFAULT_COLOR, DEFAULT_COLOR, DEFAULT_EXT);
+        this._cacheMap.set(i, DEFAULT_COLOR, DEFAULT_COLOR, DEFAULT_EXT, rasterizedGlyph);
+      }
     }
   }